C H A P T E R 2 5

HEART SURGERYJOHN C. BALDWIN, M.D., JOHN A. ELEFTERIADES, M.D.,

and GARY S. KOPF, M.D.

INTRODUCTION

Mankind has long recognized the heart as vital tosustaining life-often romanticizing it as the reposi-tory of the soul and the seat of the emotions—but wedid not have the ability to repair it surgically until arelatively short time ago. Open-heart surgery seemsso commonplace now that it is sometimes difficult toremember that it was not widely available until themid-1970s. Curiosity and experimentation, however,have existed for centuries.

Although the first successful operation on the liv-ing heart was not until the middle of this century, therecorded history of open-heart surgery goes back asfar as about 400 B.c., when Greek physicians providedan account of the workings of the aortic and pul-monary valves. A second-century-A.D. Greek physi-cian, Galen of Pergamon, who was an active dissectorof human cadavers, described the heart in detail, butwith some notable inaccuracies that were not clearedup until the writings of Andreas Vesalius in 1534.

It was not until the pioneering work of WilliamHarvey, the 17th-century English physician, thatblood circulation and the role of veins and arterieswere understood. Prior to Harvey's famous disser-tation, De Mortu Cordis, it was generally thought thatthe blood ebbed and flowed like whimsical tides, con-trolled by the consumption of food.

The first recorded successful heart surgery per-formed on a living human being was in 1896, whena Frankfurt physician sutured a wound in the heart

of a young German soldier. Great strides have beenmade in this field of surgery since the removal of shellfragments from the hearts of American soldiers inWorld War II and the first repairs of inborn (con-genital) abnormalities in 1945.

Surgical technique in the early 1900s was far moreadvanced than the ability to keep patients alive. Abil-ity to operate, however, was limited by the inabilityto operate on a heart that was still beating.

The difficulty of operating on a beating heart wasnot resolved until the mid-1950s and early 1960s. Inearly experiments, scientists found they could stopand restart the heart, but this left less than three min-utes in which to operate before irreparable braindamage occurred. Philadelphia’s John Gibbon wasone of the doctors working on a solution: a machinethat would take over the circulation of the blood. Hisfirst model was tested in animal experiments in 1931,but it was not until 1953 that Gibbon was able toperform a successful operation on a human patientusing total cardiopulmonary bypass.

Taking over the blood circulation involves farmore than simply pumping blood. The machine hasto resupply the oxygen that the body’s cells have re-moved from the red blood cells and pump the bloodat sufficient pressure to supply all the organs in thebody, without damaging the white or red blood cellsor the platelets carried by the circulating blood.

It was not until the mid-1970s that the machinesbecame sufficiently sophisticated to achieve safe,widespread use. Today’s bypass machines can main-tain the patient’s circulation for many hours withoutserious side effects. Nevertheless, cardiothoracic sur-

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Oxygenator

Figure 25.1

The heart-lung machine takes blood from the patient’s heart to a res-ervoir from which it travels through a series of thin-walled mem-branes. these membranes allow oxygen to enter the red blood cells.After impurities are filtered from the blood, it is pumped to the aortafor distribution to the body.

geons seek to keep operating time to a minimum inorder to reduce even the small chance of ill effects.

The cardiopulmonary bypass machine (popularlyknown as the “heart-lung machine”) works as follows(see Figure 25.1). Blood is passed along a tube fromthe patients heart (usually from the right atrium) toa pump that pushes blood through a series of thin-walled membranes that duplicate the lung’s methodof allowing oxygen to enter red blood cells. The ox-ygenated blood is passed through a series of fine-meshed filters to trap any impurities. The blood isthen redirected to the aorta, the body’s largest artery,where it is distributed to the arteries around the body.

The other technical innovation that allowed doc-tors to operate on the heart for an extended periodof time was the introduction of safe preservationtechniques, using extremely cold temperatures (hy-pothermia), for a heart that has been stopped. In thelate 1950s, Dr. Norman Shumway showed that theheart’s demand for oxygen could be considerably re-duced and the heart muscle cells preserved if theheart was immersed in a cold salt (saline) solution.

During today’s heart operations, three methods ofhypothermia are combined: cooling of the entirebody by cooling the blood in the heart-lung machine,

immersing the heart in cold saline, and injecting acold solution of potassium directly into the heart. Thehigh concentration of potassium instantly stops theheart’s electrical activity. By slowing down the heartmuscle’s demand for oxygen, the surgeon is able topreserve heart muscle (myocardial) cells for as longas six hours. The enhanced techniques of cell pres-ervation have also made it possible to preserve adonor heart for cardiac transplantation during long-distance transport.

OPEN-HEART SURGERY

A description of a coronary artery bypass operationis somewhat representative of other types of heartsurgery that follow similar patterns, although thereis obviously some variation, depending on the par-ticular surgery. A primary difference between cor-onary artery bypass and most of the other surgeriesis that the heart chambers are not opened in bypasssurgery-as they would be for valve replacement, forexample. Surgery in which the heart’s chambers areentered always carries some additional risk; this isprimarily due to the increased possibility of air en-tering the heart, and surgeons take extra care to avoidthis.

Once a physician has determined that surgery isnecessary, the preparation begins. (See box, “Beforeand After Open Heart Surgery What to Expect forAdults.”) On the morning of surgery, the patient isgiven a mild tranquilizer to reduce any anxiety relatedto the operation. Electrodes connected to an ECGmonitor are then attached to the patient’s back toallow constant monitoring of the heart’s electrical ac-tivity during the operation. Following the adminis-tration of a local anesthetic, intravenous (IV) lines areinserted into the veins of the arm or wrist. These IVlines allow the anesthesia team to administer anes-thetics directly into the bloodstream and to replenishbody fluid with salt solution. One of these lines isthreaded up the vein all the way to the vena cava (alarge vein near the heart) to allow administration ofmedication directly to the heart. Another IV line al-lows measurement of the pressure and oxygen levelin the arteries.

A special balloon-tipped catheter, known as theSwan-Ganz catheter, is inserted into a neck vein andthreaded down into the cavity of the right heart andthrough the right ventricle; blood flow carries it

HEART SURGERY4

Before and After Open Heart Surgery: What to Expect for AdultsBefore having open heart surgery, the patient will

meet with the cardiothoracic surgeon, who willalready have reviewed the tests (such as films fromthe angiography) and will explain the results ofthese tests, what the surgery entails, the benefitsthe patient can expect from surgery, and,especially, the risks of surgery. This meetingprovides the patient a chance to voice fears, askquestions, and perhaps look over the angiogramfilm to develop a better understanding of why theoperation is necessary. The hospital where thesurgery is to take place will most likely provideeasy-to-follow literature on the particular surgeryand informative meetings for the whole family todiscuss pre- and postoperative care.

Approximately two weeks before the surgery, thepatient may be instructed to stop taking anymedications that might affect the ability of theblood to clot, including aspirin, dipyridamole(Persantine), and warfarin (Coumadin). The patientshould continue taking beta blockers and calciumantagonists if he or she is on them and cancontinue use of nitrates to relieve chest pain. Theday before the operation, the patient will beexpected to check into the hospital and againundergo a battery of tests—chest X-ray, ECGs,blood tests, urinalysis—even though he or she mayrecently have had all these tests. This is animportant step to make sure that there has been nochange in the status of the patient’s health and toensure that no small but important detail has beenomitted. The patient will be asked aboutmedications and alcohol, cigarette, andrecreational drug use. It is vital that the answersbe forthright and complete, as any of thesesubstances can adversely affect the healingprocess.

The night before the surgery, the patient will be askedto shower in order to reduce the bacteria on theskin. No food will be allowed after midnight,because anesthesia is safer on an empty stomach.The anesthesiologist will usually visit the patientthe night before in order to explain what the

anesthesia does and how the anesthesia teamtakes care of the patient’s breathing with therespirator. The chest area will be scrubbed cleanand washed with an antiseptic solution, and bodyhair will be shaved where necessary.

On the morning of the surgery, the person will begiven a mild tranquilizer to reduce anxiety aboutthe operation. Monitoring electrodes will beattached, and local anesthetic will be administeredbefore placement of intravenous lines. Catheters(thin tubes) that perform such duties as collectingurine and monitoring blood pressure are inserted.The first few seconds of the administration of thegeneral anesthetic should be the last part of theoperation the patient remembers.

After the surgery, the patient is taken to the intensivecare unit (ICU), where specialized nursing care isavailable around the clock and sophisticatedinstruments monitor the heart’s electrical activity,blood pressure, temperature, and other vital signs.The patient’s family will generally be allowed tovisit at this time, although the patient will begroggy from the anesthetic and unable to speakbecause of a tube in the windpipe (endotracheal)that helps the person breathe with a respirator. TheICU experience can be disorienting, as there islittle to differentiate day and night, and the patientwill drift in and out of consciousness. The nursesare specially trained in communicating by touchand signboard, and they will do everything possibleto make the patient comfortable.

Each person recovers at his or her own speed, andmuch depends on the nature of the surgery, Inmost cases, the patient will be taken off therespirator the morning after surgery, and thecatheters and intravenous lines will II be removedwithin two days. The patient can then hasten his orher recovery by following the guide lines forinflating the lungs (by sucking on a special lung-exercising device) and by making an effort tobecome mobile, especially by walking. (SeeChapter 28 for more information on cardiacrehabilitation. )

through the pulmonic valve into the lung or pulmo-nary artery. The Swan-Ganz catheter provides an ac-curate reading of the pulmonary arterial bloodpressure (based on the pressure at the tip of the bal-loon) and indicates how well the heart is functioning.A sensitive temperature probe at the tip of this cath-eter can also tell the surgical team how well blood iscirculating.

A Foley catheter is inserted into the patient’s blad-der before the operation. The amount of urine col-

lected by this catheter is a sign of how well thepatient’s kidneys are functioning and whether thekidneys are receiving sufficient oxygenated blood.

Anesthetic agents are then administered directlyinto the veins. These agents have three functions: toblock pain and induce drowsiness, to relax the mus-cles and prevent the person from moving and jerkingduring the operation, and to cause temporary am-nesia so the person is not disturbed by a detailedrecollection of the operation. The anesthesiologist

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carefully monitors the patient’s vital signs throughoutthe operation, adjusting the dosage of medicationsand anesthetics appropriately.

Once the patient has been anesthetized, a tube (en-dotracheal) is inserted into the patient’s windpipe.The tube connects to the respirator—a bellows-likeinstrument that performs the work of breathing forthe patient. Another tube (nasogastric, or NG) is alsoinserted to collect stomach fluids that might other-wise nauseate the anesthetized patient.

An anticoagulant, heparin, is also administered atthe start of the operation. This “blood-thinner” pre-vents clots, or emboli, from forming and helps to pro-tect the patient from a stroke. The effects of theheparin will be reversed at the end of the operationby the administration of another drug, protamine,that encourages coagulation.

Once the patient has been prepared, the surgeonsbegin. For open-heart surgery, the chest is cut openat the midline of the breastbone (sternum) and thebreastbone is separated. The chest is then graduallypried open with special retractors to reveal the lungsand, between them, the tough sac of tissue (the peri-cardium) that protects the heart.

If the internal mammary artery (an artery that sup-plies blood to the chest wail) is to be used for bypassgrafting, at this time it will be gently separated fromthe chest wall. During the opening of the chest, an-other surgeon wiIl have been working on the patient’slegs to remove several usable lengths of a vein (ap-proximately 20 centimeters, or 8 inches, for each by-pass). These lengths of vein are about the diameterof a drinking straw. Later in the operation, the sur-geon will take each in turn and sew one end into atiny hole punched into the aorta and attach the otherend to a coronary artery, thereby providing the by-pass pathway around each narrowing in the coronaryarteries. (See Figure 25.2.)

Once the sac covering the heart has been opened,the surgical team sets up the heart-lung machine.Several plastic tubes are hooked up to the machine.When it is clear that the heart-lung machine is pro-viding adequate circulation, the aorta is clamped, andthe heart is stopped with an injection of cold potas-sium solution directly into the aorta. The outside ofthe heart is also bathed in a cold salt solution to fur-ther induce hypothermia. The patient is now on totalbypass; his or her blood circulation has been com-pletely taken over by machine. The surgeons now canattach the bypassing vessels. (Or, if this is an oper-ation other than a coronary bypass, the chambers ofthe heart can be opened and the appropriate surgeryperformed.)

Figure 25.2This illustrates the two main types of coronary bypass grafts:saphenous vein and internal mammary artery. On the left, a sectionof saphenous vein from the leg is sutured between the aorta and acoronary artery, bypassing the blockage. The left internal mammaryartery, normally found in the chest, is redirected to bypass anotherblockage.

Once the direct surgery on the heart has been per-formed, the aortic clamp is removed, and the bloodis gradually warmed. The heart may begin beatingby itself, or the surgeon uses a brief shock to restoreelectric activity. Pacemaking wires are placed to allowelectrical control of the heart rate. When the heartsupports its own blood circulation again, the patientcan be taken off the heart-lung machine, any bleedingcan be stopped, and incisions can be closed. Afterthe patient is taken off the bypass machine, protamineis injected to reverse the effects of the heparin byrestoring the normal clotting ability of blood, and thepatient is transferred to an intensive care unit.

CORONARY ARTERY BYPASSS U R G E R Y

In the last few years, coronary artery bypass graftinghas become not only the most common heart oper-ation, but also one of the most frequently performedsurgical procedures. In 1988, 320,000 bypass opera-tions took place in the United States. The procedurehas become so entrenched that it is easy to forget thefirst such operation was performed as recently as

HEART SURGERY

1967, at the Cleveland Clinic, when Dr. Rene Favaloroused a vein from a leg to bypass a blocked coronaryartery. The basic operation has remained much thesame, but improvements in surgical technique, inheart preservation during heart-lung machine use,and in the understanding of when and how to alsouse an artery from the chest wall as a graft have ledto longer-lasting grafts, reduced death rates, and in-creased ability to provide relief for older and sickerpatients.

This surgery is usually elective (except for theemergencies that may occur during a threatenedheart attack), and the patient often plays a large rolein deciding both when and whether to have the op-eration. By the time most patients are consideringthe operation, they will have experienced symptomsof heart disease and already have made life-stylechanges and been treated with medication.

It is useful to distinguish between surgery that isrequired based on the location of blockage in an ar-tery (anatomic indications) and surgery that is doneto improve the heart’s function and relieve symptoms(functional or symptomatic indications). Anatomic in-dications are determined by cardiac catheterizationand other tests. Currently, coronary angioplasty mayprovide an effective alternative to surgery in certaininstances. (See Chapter 24.)

Several types of artery narrowing call for surgery.The left main branch of the coronary arteries is ashort section leading from the aorta (like the maintrunk of a tree) that divides into the circumflex andleft anterior descending arteries. If the left mainbranch is narrowed or constricted (stenotic), it is ofparticular concern, because the blood supply to muchof the heart could be suddenly reduced. People withuntreated left main artery disease have an approxi-mate death rate of 50 percent over a five-year period.

The other major artery, which also divides intosmaller branches, is the right coronary artery. It sup-plies blood mainly to the right side of the heart andthe underside of the left ventricle. When this arterybecomes narrowed or blocked, it is usually not asserious as when the left arteries are affected; surgeryis usually not necessary if right artery blockage is theonly major problem.

Triple-vessel disease refers to significant (greaterthan 70 percent) narrowing of the interior of all threecoronary arteries. Without coronary bypass, patientswith triple-vessel disease have a relatively poor prog-nosis, particularly if heart function is reduced.

Patients who have suffered damage to the muscleof the main pumping chamber from a heart attackmay also be considered candidates for coronary ar-

tery bypass surgery. This chamber, the left ventricle, plays a crucial role in pumping arterial blood to the rest of the body (including the coronary arteriesthemselves), so its efficiency must be maintained. Left ventricle efficiency is usually determined by the amount of blood squeezed out with each beat (the ejection fraction). Coronary artery bypass surgery is advisable when this becomes reduced to a less than adequate level.

Choosing surgery to improve function or relieve symptoms is a more subjective decision; the person’s own feelings about life-style restriction may be an important criterion. When chest pain (angina) occurs with unusual frequency or at rest, despite continuinguse of medication, surgery may be strongly urged:These symptoms are often warning signs of an im-pending heart attack. However, some patients withless serious angina that may not actually be gettingworse may also opt for surgery, as they may be in-tolerant of the medications or of the restrictions im-posed upon their work and leisure activities.

The principle of coronary artery bypass surgery isto provide a new blood supply for sections of theheart muscle whose own supply of arterial blood isrestricted by a blocked artery. The conduit that sup-plies the new route for blood can be a section of avein that has been removed from the leg (saphenousvein) and attached to the aorta and the coronary ar-tery to bypass the narrowed section. Another pos-sible conduit source is an artery called the internalmammary artery, a blood vessel that usually suppliesblood to the chest wall. There is strong evidence thata bypass using a section of this artery is less suscep-tible to becoming blocked in the future. Only 60 per-cent of grafts using a vein are still open after ten yearsas opposed to more than 90 percent of grafts usingan artery.

Surgery using internal mammary artery graftstakes slightly longer because the detaching and reat-taching process is more complicated, so there wassome early resistance to their use. Nearly all bypasssurgery patients who have multiple grafts now haveat least one using the internal mammary artery. Thereare, however, some reasons to avoid using it; thesewill be considered by the surgeon.

It should be noted that internal mammary arterygrafts are often performed in conjunction with sa-phenous vein grafts. Surgeons believe that providingmore new conduits to replenish the blood supply in-creases the chances of a successful long-term out-come. This is the reason for triple, quadruple, andeven quintuple bypasses (referring to the number ofnew conduits created). The number of bypass grafts

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does not necessarily indicate the severity of the dis-ease. Too often, patients are led to believe that a quad-ruple or triple bypass implies that they may have aterrible condition. This is not true. Several of theblockages bypassed may have been relatively “mi-nor” ones.

The patient who has received a coronary arterybypass graft can expect considerable relief fromsymptoms, and, in many cases, increased lifespan. Itshould be remembered, however, that the graft ves-sels are subject to fatty blockage at an increased rate,so care must still be taken to reduce the risk factorsthat caused the original blockage. (See Chapter 3.)The surgery sets the disease back to an earlier stage;it does not “cure” atherosclerosis. A certain numberof patients—especially those whose original bypasssurgery occurred more than ten years ago—will findthat they are candidates for a second bypass (or“re-op”). This second bypass operation carries onlyslightly more risk than the first and is an importantoption for people whose grafts have become con-stricted and whose symptoms have recurred.

Newer and better surgical techniques now allowsurgeons to operate safely and effectively on somepeople who only a few years ago might have beenconsidered too old or too sick for surgery.

VALVE REPLACEMENT

The heart’s valves perform the vital function of main-taining blood flow in the correct direction. The mitralvalve directs the flow of blood from the left atriuminto the left ventricle, and the aortic valve allowsblood to pass from the left ventricle into the aorta.The tricuspid and pulmonary valves perform theequivalent tasks on the right side, but are under con-siderably less pressure than the valves on the left sideand—although they may suffer from similar dis-orders—are less likely to be so severely impaired asto require surgery. (See Chapter 13.)

Problems with the heart valves and their function-ing can be of two kinds: narrowing (stenosis), whenthe valve opening is constricted and blood flow re-duced, and regurgitation, when some of the bloodleaks back into sections of the heart from which ithas just been expelled because the valve leaflets donot close properly. A poorly functioning valve inwhich the leaflets neither open nor close properlymay cause both problems.

While poorly functioning valves most often can be

detected by listening with a stethoscope, a definitivediagnosis of valve disease usually requires such testsas X-rays and an echocardiogram. The decision tooperate and correct a valve abnormality will dependon whether the condition is life-threatening and towhat extent it has affected the person’s life-style.Most problems with valve disease are not of an ur-gent nature, and the decision does not have to berushed.

The exception is when the valve opening betweenthe aorta and the left ventricle is blocked (aortic ste-nosis), which surgeons consider an urgent problemif symptoms occur (such as chest pain, faintness, andshortness of breath) and if the narrowing is severe.About 50 percent of such patients die within fouryears without surgery. When the aortic valve doesnot close properly (aortic insufficiency), the decisionto operate depends on the degree of damage thatshows upon various tests and on whether the personhas symptoms. (Less active people may be willing tocurb their activity-thus reducing demand on theheart-in order to keep their symptoms to a mini-mum and avoid surgery.) Poorly functioning aorticvalves can result in enlargement of the left ventricle,a condition that must be monitored carefully.

When the valve opening between the upper andlower chambers of the left side of the heart (mitralvalve) becomes severely blocked (mitral stenosis), itusually requires surgery. Because the narrowing ofthe valve opening may cause blood to back up intothe lungs, careful monitoring of symptoms such asshortness of breath is required, and surgery maybecalled for to prevent serious heart failure. When themitral valve closes improperly (mitral insufficiency),the desirability of surgery is usually determined byhow severely the symptoms affect the patients life-style and how well they can be controlled by medicaltreatment.

Heart valve disease can be surgically treated inthree ways: Constricted openings can be enlargedwith a balloon catheter; the injured valve can be sur-gically reconstructed; or the valve can be replaced,either with an artificial valve or with a healthy valvefrom a pig’s heart.

A balloon catheter can be used to alleviate mitralstenosis in some cases. (See Chapter 24.) Mitral valveproblems associated with rheumatic fever usually oc-cur because the leaflets stick together. Sometimessimply opening the leaflets enough to separate themfrom each other is all that is required to solve theproblem. To accomplish this, the balloon catheter isthreaded through the valve. When it is in place, theballoon at the tip of the catheter is inflated gently until

HEART SURGERY<

it enlarges the opening. This procedure is rarely anoption for aortic stenosis, except in people whose lifeexpectancy is limited because of other diseases. Bal-loon dilation is not effective, and there is a risk thatthe calcified leaflets will break off and enter the blood-stream, causing a stroke.

Surgical repair can be performed on the mitralvalve, particularly to relieve mitral insufficiency. Theprocedure followed is the same as for other forms ofopen-heart surgery. The heart is stilled and the leftatrial chamber opened, then the leaflets are recon-structed to allow the valve to close properly. If theleaflets of the mitral valve have become stuck togetheras the result of rheumatic fever, the surgeon can sep-arate them and suture any damaged edges to ensurethat they close efficiently. The advantage of this sur-gery is that there is no new valve to wear out, nordoes the patient ordinarily have to follow a regimenof blood thinners as he or she would with a mechan-ical heart valve replacement.

Artificial valves have been in use since 1952, whenCharles Hufnagel successfully replaced a patient’saortic valve with a caged-ball artificial valve. Somemechanical valves are of the “tilting disk” variety,while others are of the “ball-and-cage” variety. (Fig-ures 25.3A–C show some commonly used artificialvalves.) The latter consist of a metal ring covered inDacron and a thin metal cage. Inside the cage is aball, which exactly fits the dimension of the ring.Blood flowing in the correct direction moves the ballaway from the ring towards the cage and flows byuninterrupted. When the blood begins to flow in theopposite direction, it pushes the ball back into thering, creating a tight seal that prevents leaking. Thetilting disk valves work somewhat along the principleof a hinged door that is opened due to pressure fromone side and shut tightly due to pressure from theopposite side. Mechanical valves make a clickingnoise with each heartbeat, but the patient usually cannot hear this.

Valve replacement is performed during open-heart surgery. Artificial valves are carefully suturedor sewn into the ring surrounding the valve opening,completely replacing the natural valve. (See Figure25.3D.) Approximately 80 percent of patients whosurvive the first postoperative year are able to returnto normal activity, even though they may previouslyhave been severely restricted by breathlessness fromheart failure or by fainting spells and angina. Thedownside of the operation is that it carries with it a5 percent mortality risk (somewhat higher than forcoronary artery bypass surgery), partly because ofthe possibility of a stroke caused by loosened calcium

METHODS OF TREATMENT

Figure 25.3DA Carpentier-Edwards model replacing the mitral valve in theheart. The arrows indicate the direction of blood flow.

deposits or air bubbles entering the bloodstream (thelatter being a risk in any open-heart surgery). Con-valescence may also be prolonged, especially forolder people.

An alternative to mechanical valves is the use ofvalves from pigs. There is currently some debate asto which replacement valves are most suitable, thesynthetic ones or those obtained from pig hearts. Thepatient should carefully weigh the advantages anddisadvantages of each, recognizing that technical cir-cumstances may occasionally require the surgeon touse one or the other.

The synthetic valves have the advantage of dura-bility they may often last a lifetime. On the rare oc-casions that a mechanical valve does fail, it may doso suddenly and cause the heart to fail. A disadvan-tage is that the patient will have to follow a lifetimeregimen of anticoagulants such as warfarin (Cou-madin) to prevent blood clots from forming aroundthe mechanical parts. Taking anticoagulants alsoplaces some restrictions on the patient’s activity; con-tact sports or other activities that could result inbruising or internal bleeding usually have to beavoided. Patients also have to be more careful toavoid infections that might form on the new valvesurface. Antibiotics have to be taken before the pa-tient undergoes procedures such as dental work.

Valves taken from pig hearts do not ordinarily re-quire the patient to take anticoagulant medication formore than six to eight weeks following surgery. Thedisadvantage of these replacement valves is that theydo wear out and may have to be replaced after aboutten years. They wear out gradually, so there is littlerisk of a sudden episode of heart failure. It should benoted that valve tissue does not cause rejection prob-lems as seen with heart transplantation. Recent stud-ies have shown that the natural valve comparesfavorably with the artificial valve over a ten-year pe-riod; patient longevity may even be enhanced. Whencomparing the statistics, people should bear in mindnot just the length of time a valve will last, but alsothe problems of infection and anticoagulant drugtherapy.

SURGERY FOR HEART RHYTHMDISORDERS (ARRHYTHMIAS)

Arrhythmias are disturbances in the heart's electricalconduction system, which controls both the sequenceand the frequency of heartbeats. These can take theform of harmless “palpitations” or become presentas a sign of injury or disease. Irregular or rapidrhythms generally originate in two areas: the ventri-cles (the lower part of the heart) or the supraventri-cular areas (the upper part of the heart). Ventriculararrhythmias commonly occur as extra beats and aregenerally of no importance. In people who have hadheart attacks with tissue damage, however, a sus-tained run of extra beats can be serious. Between thedead muscle and the normal muscle is an unstable“border zone” from which extra beats may arise. Ifthey occur in sequence and at a rapid rate (ventriculartachycardia) or as rapid, irregular, and uncoordi-nated beats (ventricular fibrillation), urgent treatmentis required.

Many people with a history of ventricular tachy-cardia or fibrillation come to the surgeon after havingexperienced near “sudden death” and resuscitation.If these arrhythmias have been recurrent and are notcontrolled by medical therapy (see Chapter 16), fur-ther studies may be necessary. Cardiac catheteriza-tion and the use of an electric probe may help to locatea problem in the heart muscle. The surgeon then cutsout unstable areas that are causing the arrhythmia.The operation has a mortality rate of around 12 per-cent, but it is effective in preventing these serious

HEART SURGERY

arrhythmias from recurring. This type of procedureis necessary only in a very small number of patientswith severe arrhythmias. In certain patients with ar-rhythmias and additional problems such as angina,the surgeon may also place an implantable defibril-lator (AICD) at the time of bypass surgery. (See Chap-ter 26.)

Arrhythmias can also occur in people who areborn with extra conducting pathways. The impulsefrom the atria short-circuits the normal pathway andactivates the ventricle sooner than normal. The short-circuiting is detectable on an electrocardiogram. Themost common type of abnormal pathway result isWolff-Parkinson-White (WPW) syndrome, in whichan additional conducting pathway bypasses theatrioventricular (AV) node, which separates the atriafrom the ventricles. The AV node normally acts as aregulating block for electrical impulses passing fromthe atrium to the ventricle, and the additional path-”way can allow abnormally frequent electrical signalsfrom the atria to setup arrhythmias in the ventricles.

Patients with Wolff-Parkinson-White syndromeare, for the most part, young and have otherwisenormal hearts. Most of them have few symptoms, butmay experience episodes of rapid heartbeats, someof which maybe severe. The syndrome was formerlytreated with medication, which was not completelyeffective in preventing recurring arrhythmias. Today,if symptoms are recurrent and severe, the extra con-ducting pathway can be removed during open-heartsurgery. This operation provides a cure, and the mor-tality rate during surgery is low.

REPAIR OF ANEURYSMS

An aneurysm is a severe weakening in the wall of anartery or organ. The weakened area balloons out. Inaddition, the bulging area may either press on anddisrupt the function of other vital organs or burst andhemorrhage.

There are two kinds of aneurysms that may di-rectly affect the heart: left ventricular aneurysm andaortic aneurysm. Left ventricular aneurysms may ap-pear following a heart attack (myocardial infarction,or MI). This is a relatively uncommon occurrence. Itis a bad sign, because it indicates that a lack of oxygenhas caused extensive damage to the muscular wall ofthe left ventricle. Surgeons operate on left ventricularaneurysms if they are accompanied by arrhythmias,congestive heart failure, or blood clots. The operation

is performed through the area of the heart attack, and the surgeon seeks to remove or repair the weak- ened area of the ventricle wall. This operation allows the ventricle to function more effectively (although heart muscle that has been destroyed cannot be re- stored) and can usually give the person a reasonable life expectancy.

An aneurysm in the aorta may be surgically re- paired by replacing that section with a prosthetic graft, usually made of Dacron. This surgery can also have decent results, but it carries a mortality risk of approximately 10 percent.

HEART TRANSPLANTS

The idea of replacing a diseased heart with a healthyone has long fascinated surgeons. The earliest hearttransplant was carried out in 1903 at the Universityof Chicago. Doctors successfully implanted a heartinto a dog’s neck; a beat was sustained for severalhours. The first demonstration of the possibility thata transplanted heart could completely take over thecirculation was made by a Russian physician in the1950s.

Transplants in which the transplanted heart isplaced in the normal anatomical position and the dis-eased heart removed were soon recognized as beingdesirable. The first such transplants were done in theearly 1960s using animals. In 1964, a dying 67-year-old man’s defective heart was replaced with that ofa chimpanzee; a beat was sustained for a few hours.Three years later, Christian Barnard became aworldwide celebrity as the first surgeon to success-fully transplant a heart from one human being to an-other.

These initial attempts were dampened by poor sur-vival rates for the patients. Several more advanceswere required before heart transplantation becamea truly viable method of treatment in the early 1970s.

PATIENT SELECTION

Careful selection of transplant recipients has led toan improvement in the success of these operationsand in the more effective use of the limited pool ofavailable donor organs. A recipient of a heart trans-plant should be someone who is less than 60 yearsold (there is no lower age limit), who is suffering fromend-stage congestive heart failure (see Chapter 14)with severe symptoms, and for whom survival with-

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out the transplant is extremely limited. The maincauses of this type of severe heart failure are coronaryartery disease (see Chapter 11) and heart muscle dis-ease (see Chapter 15), although some transplants arenow being done for congenital heart disease (seeChapter 20).

A transplant is usually not advised when anothermajor systemic disease exists, such as a malignancy,lung disease, collagen vascular disease (such as lu-pus), or insulin-requiring diabetes mellitus.

Rigorous criteria for donor selection have alsogreatly increased the success of heart transplanta-tion. The suitable donor has to be less than 35 yearsof age and to have sustained brain death (usually fromcerebral trauma, for example a head injury or stroke)with no evidence of chest injury. Signs of infection,a history of cardiac illness, or prolonged use of car-diopulmonary resuscitation would rule out the do-nor’s organ.

When a donor heart that meets these criteria be-comes available, the next step is to match it promptlywith an appropriate recipient. Matching is now donethrough regional organ banks, and the donor organis flown to the hospital where the recipient is con-currently being prepared to receive it. Matching isdone on the basis of blood type, and there is a generalrequirement that the donor be approximately thesame size or larger than the recipient. The reason forthe latter requirement is to avoid exposing the do-nated heart to the increased blood pressure require-ment that is present in a larger person.

THE OPERATION

When an appropriate donor/recipient match hasbeen made, based on careful screening techniques,the donor’s chest is opened. The heart is carefullyexamined for previously unrecognized injury, iscooled, and then is removed from the chest. It is par-ticularly important that the correct protocol for thedonor operation be followed carefully.

The recipient is also carefully prepared for sur-gery; the surgeons try to time the use of the heart-lung machine with the arrival of the donor organ.The recipient’s heart is not removed in its entirety—some portions of the atria, or thin upper chambers,are preserved. (See Figure 25.4A.)

Transplanting only part of the heart greatly sim-plifies the operation. The main sections that need re-placing are the ventricles (whose muscular walls domost of the heart’s work), the valves, and only partof the atria. (See Figure 25.4B.)

HEART SURGERY.

Care is taken throughout the operation to keep thedonor heart cool and to keep air from being trappedin the heart chambers. (See Figure 25.4C.) When theconnections are complete (see Figures 25.4D–F), thepatient’s new heart is gradually warmed and resus-citated, then taken off the bypass machine. As in mostother forms of heart surgery, atrial and ventricularpacing wires are attached to the outside of the heartto allow for rapid treatment of any rhythm disturb-ances after the chest has been closed.

Two major issues are of concern after surgerypreventing and diagnosing the possible rejection ofthe donor heart by the recipient’s body, and avoidinginfections, The high mortality and failure rate of hearttransplants in the late 1960s arose largely from a lackof knowledge in properly managing these potentialdifficulties.

Graft rejection results when the body's immunesystem recognizes the donated organ as an alien sub-stance and begins attacking and trying to destroy the“intruder.” Because perfect matching of donated tis-sue with the recipient’s tissue is simply not feasiblefor these kinds of operations, the immune systemneeds to be suppressed, The discovery of cyclospor-ine (Sandimmune), a drug that originated in a soil

METHODS OF TREATMENT

mold from Norway (dug up by a vacationing re-searcher), has increased the ability to suppress cer-tain aspects of the immune system that may causegraft rejection, while still allowing the body to main-tain its defenses against infection. Cyclosporine, evenin small doses, mainly suppresses one kind of immunecell (T-eel lymphocyte), whereas earlier immunosup-pressant medications unnecessarily suppressed abroader range. T-cell lymphocytes are importantcomponents of the system that tends to surround andget rid of foreign substances. Cyclosporine is gen-erally taken in combination with other immunosup-pressant drugs—such as a steroid medication calledprednisone (Deltasone) and azathioprine (Imuran)—so smaller doses of each medication can be used.

Improved methods of diagnosing rejection havealso led to better long-term management of thebody's immune response. Effective testing is essen-tial, because the clinical signs of rejection are gen-erally unreliable: The patient may complain of malaiseor have a low-grade fever, but often there are nodiscernible symptoms. Rejection of the new heartcannot be reliably diagnosed using an electrocardi-ogram. Cardiac biopsy, performed under local anes-thesia by passing a biopsy instrument through a veinand into the heart, is required to allow microscopicstudy of the tissue. If rejection appears to be takingplace, the dosage of cyclosporine can be increasedand then lowered again to normal levels once thepatient has improved.

Heart transplantation has come to bean effectiveand beneficial option for some patients who, withoutthe surgery, would have lived for only a few monthsat best. Approximately 85 percent of patients are stillalive after the first year and 65 percent after five years,and complete rehabilitation occurs in about 87 per-cent of the patients. Patients must be followed veryclosely after transplantation: Routine clinic visits arenecessary with regular biopsies scheduled in orderto detect rejection. In addition, cardiac catheteriza-tion and coronary angioplasty maybe performed an-nually to assess the condition of the heart andcoronary arteries.

HEART AND LUNG TRANSPLANTS

Transplanting both the heart and one or both lungsis becoming more common for seriously ill patients.Recipients for the double transplant may have suffi-ciently high blood pressure in their own lungs to

cause the failure of a donor heart, or they may bepatients suffering from end-stage lung disease withassociated heart failure. Distant procurement oflungs has only recently become possible, because thelungs have an extreme sensitivity to oxygen depri-vation (ischemia). Lungs can now be maintained forup to six hours outside the body by a new techniqueof preservation.

The combined heart-lung transplant has a highermortality than the heart transplant alone, but betterpreservation of donated organs and improvementsin postoperative care have made this an option forselected patients. While technically feasible in manypatients, transplantation of a heart or heart and lungsis a major, serious operation with a long period ofconvalescence. It is a clearly desirable option for onlya small number of younger people with advanced,nontreatable heart and lung disease.

PEDIATRIC HEART SURGERY

Approximately 10 percent of the cardiac surgery inthis country is performed on infants and children.Problems requiring this surgery are almost exclu-sively congenital in nature-the children are bornwith heart defects. (See Table 25.1.) This is in contrastto cardiac surgery performed on adults, which is pre-dominantly for problems acquired during their life-time, such as coronary artery disease.

Congenital defects vary from straightforwardproblems, such as a “hole” in the heart, producingmild symptoms or none at all, to complicated mal-formations that result when a good portion of theheart has failed to develop. Normally, these lead tolife-threatening situations. Depending on the heartdefect, there are two common conditions that mayarise. Children who have more than the normalamount of blood flow to the lungs as a result of adefect may suffer from congestive heart failure. Thisoften causes difficulties in eating, lack of weight gain,rapid breathing, and sweating. A large hole betweenthe left and right main chambers of the heart (ven-tricles) can produce this.

On the other hand, children with blockage result-ing in less blood flow to the lungs may suffer fromblueness of the skin (cyanosis). Although they maygain weight and grow well, they are cyanotic becauseof the low level of oxygen in their blood. These chil-dren are often physically limited, and they can sufferfrom complications such as infections and blackouts.

There are many different congenital heart defects,some of which are quite rare. More common defectsaccount for the majority of clinical problems. It mustbe remembered that each individual case is uniqueand may have mitigating factors that require specialconsideration or treatment.

When there are one or more holes in the wall thatseparates the right atrium from the left atrium, thechild has an atrial septal defect. This results in someshunting of blood from the left side (high-pressureside) of the heart to the right side (low-pressure side)through the hole. This is called a “left-to-right shunt.”There is increased blood flow to the lungs, but pres-sure in the lungs generally remains low, and the childusually shows no symptoms. The problem is mostoften diagnosed when a heart murmur is discoveredor when there has been an increase in heart size(noted on an electrocardiogram or chest X-ray).While the defect may not produce symptoms in thechild, if the hole is large enough it may cause heartenlargement, heart failure, or heart rhythm disordersover the years, significantly decreasing the normallife span.

If surgery is considered necessary, it is usually per-formed electively when the child is between the agesof 2 and 4. (See box, “Before and After Open HeartSurgery: What to Expect for Children.”) The holesmost often can be closed with a suture, but if theyare particularly large, a small patch made from thepatient’s own pericardial (outside wrapping of theheart) tissue or a Dacron patch can be used. The op-

eration provides a complete cure, and it is extremelyrare for the holes to open up again. Antibiotic treat-ment to prevent infection need not be required formore than a few months after the operation, and thepatient should be able to lead a full and active life. Arecently developed catheterization procedure that isstill considered investigational by the Food and DrugAdministration shows promise in treating atrial sep-tal defects. See Chapter 20 for more information.

When there is a hole in the septum, or dividingmuscle, between the right and left ventricles, the de-fect is called ventricular septal defect. As with theatrial septal defect, a considerable amount of bloodis pumped back into the low-pressure right ventricle(left-to-right shunting), This condition may exist with-out symptoms for many years. When they do occur,symptoms can include breathing difficulties and con-gestive heart failure as a result of the large amountsof blood filling and congesting the lungs.

If the opening is large and the infant is very smalland ill, a band maybe placed around the pulmonaryartery to restrict blood flow into the lungs and pre-

Before and After Open HeartSurgery: What to Expect forChildrenMost children who require open-heart surgery are

admitted to the hospitaI the day before surgery.They undergo the usual preoperative tests, suchas an electrocardiogram (ECG), chest X-ray, andblood work. The children are familiarized withthe hospital setting, and the parents areintroduced to the staff and setting of theintensive care unit (ICU). Surgery usually lastsseveral hours, depending on the complexity ofthe operation. After surgery, the child will betaken either to a cardiothoracic intensive careunit or a special pediatric intensive care unit.

For simple procedures, children may be dischargedfrom the hospital four to five days after theoperation. More complex procedures entail alonger stay of ten days or more. Once home, thechildren can be treated much as always—although care should be taken not to put stresson the surgical incisions until full healing hastaken place. In children, it takes a month forthe breastbone (sternum) to heal fully.Obviously it is difficult to restrict the activitiesof infants or young children, and all that isusually required is that parents themselves limittheir contact with the incision area. Parentsshould also ensure that the children understandthe need to take prescribed medicationsregularly, and, if the child is being treated withblood thinners such as warfarin (Coumadin), toavoid activities that might result in bruising.Continued follow-up after discharge and closecommunication with physicians are essential forgood results.

vent heart failure. Complete repair is then carried outwithin the first year or two of life, when the band isremoved. This course of action is becoming less com-mon; even in very young infants, repair as a first stepis considered optimal.

The holes are closed, usually with a small patch ofDacron or Gore-Tex rather than the sutures that areused to close atrial septal defects. The long-term re-sults are very good once the hole is closed, and cureis essentially complete. Postoperative complicationsare uncommon, but they can include heart rhythmirregularities or the presence of a small residual hole.

The most common form of cyanotic congenitalheart disease is tetralogy of Falot. Even so, it is rel-atively rare. The syndrome includes four abnormal-ities: a large ventricular septal defect; a displacementof the aorta to the right side so that blood withoutadequate oxygen enters it from the right ventricle; a

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Table 25.1Corrective Surgery for Congenital Heart Defects

Defect Description Surgery Prognosis

Atrial septal defect

Ventricular septaldefect

Tetralogy of Fallot

Transposition of thegreat arteries

Congenital valvedisorder

Completeatrioventricular canal

One or more holes inthe wall that separatesthe right and left atria

A hole in the septumbetween the right andleft ventricles

A large ventricularseptal defect, adisplacement of theaorta so blood with lowoxygen enters it fromthe right ventricle, athickened rightventricular wall fromincreased pressure, andpartial blockage of thepathway from the heartto the lungs

Transposition of aortaand pulmonary artery

A deformity of any ofthe heart’s four valves,most commonly aorticvalve constriction ornarrowing (stenosis)

A central defectconnecting all fourchambers in the centralpart of the heart withonly one large commonatrioventricular valve

Hole(s) closed with asuture or a small patchmade from the patientsown tissue or fromDacron.

Hole(s) closed with asmall patch of Dacron orGore-Tex.

Ventricular septal defectclosed and blockage ofblood flow removedfrom between the rightventricle and the lungs.

Most common operationfor past few years isarterial switch operation(ASO), in which theaorta and pulmonaryartery are reconnectedat the proper locations,and the coronaryarteries are switched aswell.

Valve is opened andrepaired and/or replacedwith a mechanical valvewhen child is largeenough to accommodatevalve of available size.

Atrial and ventricularseptal defect is closed,and two valves arecreated from the onevalve,

Operation providesa complete cure;extremely rare for holesto open up again.

Cure is essentiallycomplete; rarecomplications are heartrhythm problems orsmall residual septaldefect.

Good long-term results;minority experienceright-heart failure orheart rhythm disordersrequiring additionalsurgery or continuedmedication.

Short-term results aregood; it is too soon toknow long-term results.

Results with mechanicalvalves are good,but anticoagulantmedication must betaken indefinitely.

Results are generallygood; significantnumber of patientsneed valve repair orreplacement later.

HEART SURGERY

Defect Description Surgery Prognosis

Tricuspid atresia A severelyunderdeveloped rightside of the heart(usually with only oneadequately sizedventricular chamber)

Hypoplastic left heart A severelysyndrome underdeveloped left side

of the heart, includingthe ventricle andascending aorta

Patent ductusarteriosis

A blood vessel that failsto close after birth andcontinues to connect theaorta and pulmonaryartery

Coarctation of the Narrowing of the aortaaorta

Fontan procedurediverts all the venousblood return from thebody directly into thelungs, bypassing thepumping chambers andreturning to the lungs tothe one good ventricleto be pumped out,

Norwood procedurecreates new outflow forheart and shunt toprovide blood to lungsuntil child is old enoughto undergo Fontan-typeprocedure; other optionis cardiac transplant.

Abnormal connection isclosed with small, metalclip; does not requireopen-heart surgery.

Constriction removedthrough reconstructionof aorta.

Does not provide curebut seems to offerlong-term relief fromcyanosis and heartfailure; children requirecareful lifelong follow-up; long-termconsequences remainto be seen.

Results are encouragingin both cases; however,long-term effects ofimmunosuppressivedrugs on growth anddevelopment notunderstood.

Provides a completecure.

Some patients haverecurrence ofcoarctation, but it canbe repaired by a balloondilation procedure in acardiac cath lab.

thickened right ventricular wall resulting from theincreased pressure inside the right ventricular cavity;and partial blockage of the pathway from the heartto the lungs (pulmonary artery),

The symptoms of tetralogy of Fallot are differentfrom those of a simple ventricular septal defect be-cause of the effects of the other complications; bloodflow does not increase in the lungs and cause heartfailure. Instead, there is a right-to-left shunt of blood—blood without adequate oxygen travels from theright ventricle out the aorta, Not enough blood passesthrough the pulmonary artery to receive oxygen fromthe lungs, so children with this defect are often in-tensely cyanotic; they appear blue from lack of oxy-gen. Under certain conditions, such as stress, this

oxygen deficiency may suddenly become muchworse, This results in “cyanotic spells,” which can beserious. Urgent surgery of some kind is necessary.

If an infant has severe symptoms at an early age,placement of a temporary shunt maybe required toprovide more blood flow to the lungs. The long-termcorrective procedure involves open-heart surgery,including two steps: closing the hole between the twoventricles and opening up the artery from the rightventricle to the lungs. The long-term results of theoperation are good; most patients grow normally andhave normal lives. A minority of patients have diffi-culties later in life with heart failure or heart rhythmdisorders and may require additional surgery or con-tinued medication.

METHODS OF TREATMENT

A very rare congenital defect in which the aortaand pulmonary artery are switched is called trans-position of the great arteries. The aorta is connectedto the right ventricle instead of the left ventricle, andthe pulmonary artery is connected to the left ventricleinstead of the right ventricle. So blood that containsa great deal of oxygen that normally should go intothe arteries of the body via the aorta is insteadpumped back into the lungs. Blood with less oxygenends up in the liver, brain, kidneys, and so on. Theseinfants are often severely cyanotic.

This transposition can be corrected, but that re-quires a complicated surgical procedure that some-times has less than satisfying results. However, newersurgical approaches to correcting this rare abnor-mality appear promising.

An infant can be born with a deformity of any ofthe heat's four valves, but the most common con-genital valve disorder is aortic constriction or nar-rowing (stenosis). In this defect, the aortic valve maybe small or poorly developed (hypoplastic), or theleaflets may be thickened. The decision on how earlyto operate depends on the extent of the narrowingand the symptoms. During the operation, the valvewill be opened and repaired, if possible; otherwise,it will have to be replaced. There currently are noartificial valves small enough for very young infants,so valve reconstruction has to be done in these cases,with possible replacement at a later stage. Childrenfrequently require placement of mechanical valves,because valves from pig hearts tend to harden rapidlywith calcium deposits when placed in someone soyoung. Mechanical valves require that children takeanticoagulant medication indefinitely to keep bloodclots from forming in the valves.

A defect seen in children with Down syndrome isa complete atrioventnricular canal. In this disorder, in-stead of two separate atrial-ventricular valves—themitral on the left and the tricuspid on the right—thereis only one large common atrioventricular valve.These children may require several complicated op-erations to correct this major defect.

In extremely rare cases, infants are born with aseverely underdeveloped right side of the heart (usu-ally with only one ventricular chamber instead oftwo). The defect is referred to as tricuspid atresia. Avariety of problems can result, and the infant maybeeither cyanotic or experiencing heart failure, de-pending on the amount of blood flow to the lungs.One or more procedures will be required to relievesymptoms during infancy; the nature of these willdepend on the physiology of the individual defect.

Usually at about age 2, the patient can undergo aFontan procedure, an operation first performed inthe early 1970s, which involves diverting all the ven-ous blood return from the body directly into thelungs, thus bypassing the pumping chambers. Bloodthen returns from the lungs to the one good ventricle,where it is pumped out to the body. Consequently,the one ventricle does the work of two: pumping theblood through the arterial system and then throughthe lungs in series. Although this operation does notreally cure the defect, it appears to offer the best long-term relief available to children with only one heartpumping chamber. The operation does relieve cy-anosis and heart failure. These children, however, dorequire careful lifelong follow-up, and the long-term consequences of the operation remain to bedetermined.

The vast majority of children with hypoplastic leftheart syndrome-another rare abnormality that con-sists of a severely underdeveloped left heart, includ-ing the ventricle and ascending aorta-die within thefirst week after birth. Two recent surgical approacheshave had encouraging results, however. One is theNorwood procedure, which does not provide a curebut does allow children to grow enough to undergoa Fontan-type operation. The Norwood procedurecreates a new outflow for the heart, using the pul-monary artery, and creates a shunt to provide bloodflow to the lungs.

The other approach to these babies is heart trans-plant shortly after birth. Early results are encourag-ing, but the long-term effects of the necessary drugs(which repress the immune system and fight rejec-tion) on growth and development in children are notwell understood. However, with these two ap-proaches, there is some hope for these infants whootherwise cannot survive.

Two other more common congenital problems,easily treated surgically, are patent ductus arteriosisand coarctation of the aorta. A patent ductus arter-iosis can be treated with a simple surgical procedurethat does not require open-heart surgery. The ductusarteriosis is a blood vessel that connects the aortaand the pulmonary artery while the child is still in thewomb. Its purpose is to allow blood to bypass thelungs, because they are not functioning before birth.Blood flows from the right side of the heart to thepulmonary artery directly to the aorta and out to thebody. In a few cases, this vessel fails to close normallywithin a few days after birth and remains open or“patent.” Blood then flows into the lungs and maycause heart failure. The defect usually can be treated

HEART SURGERY

successfully in the newborn period with medicine ora simple surgical procedure in which the abnormalconnection is closed with a small metal clip, appliedthrough an incision in the left side of the chest.

Coarctation of the aorta refers to a congenital nar-rowing of the aorta after it leaves the heart. This ob-structs and reduces blood flow to the rest of the aorta,the arms, legs, kidneys, and other vital organs. Thiscondition also causes arise in the blood pressure nearthe blockage (in the arms). The constriction is re-moved by surgical reconstruction of the aorta. Nor-mal circulation is restored. High blood pressure,which may become permanent, is common in patientswho have not been treated early enough, but whenit is adequately treated in childhood, the hypertensionis most often relieved eventually. Some patients mayhave a “recurrence” of coarctation later in life. Thiscan often be repaired by a balloon dilation proceduredone in the cardiac catheterization laboratory. (SeeChapter 24.)

Children with coarctation usually have no symp-toms early in life. An elevated blood pressure, heartmurmur, diminished pulses in the legs, or poor de-velopment of the lower extremities may suggest thediagnosis.

SPECIAL CONSIDERATIONS IN PEDIATRICHEART SURGERY

Like all heart surgery, this area is highly specializedand should be performed only in medical centers bysurgeons who devote a large part of their profes-sional careers to the treatment of congenital heartdisease. Availability of experts in pediatric cardiol-ogy, pediatric anesthesia, and pediatric intensive careis essential to the successful outcome of these oper-ations. Technological advances in all these areas haveled to lower mortality and better long-term successrates.

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