the pathological4-:anatomy of …thorax.bmj.com/content/thoraxjnl/12/2/125.full.pdfthorax(1957), 12,...

Thorax (1957), 12, 125.

THE PATHOLOGICAL4-:ANATOMY OF DEFICIENCIESBETWEEN THE AORTIC ROOT AND THE HEART,

INCLUDING AORTIC SINUS ANEURYSMSBY

JESSE E. EDWARDS AND HOWARD B. BURCHELLFrom the Sections of Pathologic Anatomy and of Medicine, Mayo Clinic and Mayo Foundation, Rochester,

Minnesota, U.S.A.

(RECEIVED FOR PUBLICATION MARCH 7, 1957)

A ruptured aneurysm of an aortic sinus (Valsalva)represents a serious threat to the patient's life,chiefly in its tendency to cause cardiac failure. Whenthis lesion occurs alone the clinical diagnosis isrelatively simple to make. Particularly is this trueshould cardiac catheterization and- perhaps aorto-graphic studies be included in the investigation ofthe patient. When a ruptured aneurysm of an aorticsinus occurs in association with a second lesion,particularly ventricular septal defect, the presenceof the latter lesion may not be readily establishedeven with the aid of the special studies named.

Surgical therapy for an aneurysm of an aorticsinus has only recently been introduced. In view ofthis, it is essential that the anatomical relations ofthe aortic sinuses and of aneurysms occurring inthese regions be understood. At the same time, it isimportant to appreciate the nature of lesions thatmay be associated with aortic sinus aneurysm.

In study of the nature of aortic sinus aneurysmswe observed that the essential lesion is a separationbetween the aortic media and the heart (Edwards,Burchell, and Christensen, 1956). This separationor lack of fusion, occurs at the annulus fibrosus ofthe aortic valve and consequently is located abovethe valve. It is also apparent that there are cases inwhich the separation between the aortic media andthe heart is below the aortic valve. These lesions,which may occur independently of aortic sinusaneurysm, produce different gross anatomicallesions from those defects that occur above theaortic valve. They have in common with defectsabove the aortic valve the feature that the nature ofthe resulting lesion depends only in part on whetherit lies above or below the valve, but also to whichof the three of the aortic sinuses or valve cusps it isrelated.The purpose of this communication is to review

the anatomy of the aortic sinuses and the patho-

logical anatomy of those lesions which lie at theaortic root and represent a deficiency between theaortic media and the heart. Deficiencies both aboveand below the aortic valve will be covered.The anatomy of the aortic root has already

been reviewed. Gross and Kugel (1931) emphasizedthe structure of the aortic valve leaflets and presentedsome details regarding the relations of the aorticsinuses to surrounding structures.

Ostrum, Robinson, Nichols, and Widmann (1938)emphasized the anatomical features as they pertainto radiological interpretation. In describing theanatomy of the aortic sinuses, it is our purpose toemphasize those relations which are of importancefor the orientation of the surgeon.

It is not uncommon that as a result of infection,chiefly bacterial endocarditis and less commonlysyphilis, deficiencies in the areas of the aortic sinusesmay develop. We are not chiefly concerned in thispaper with lesions of a primarily inflammatorynature, although the anatomical relations ofdeficiencies so developing have similarities to thosewhich occur spontaneously and with which we arehere concerned.Emphasis in this paper will be on pathological

material which we ourselves have examined.Comprehensive reviews on the subject of aorticsinus aneurysm have been presented by Raman andMenon (1919), by Jones and Langley (1949), andby Oram and East (1955).

ANATOMY OF THE AORTIC SINUSESNormally, there are three sinuses at the aortic

valve, each related to one of the three cusps of thevalve. The sinus is a specialized part of the aorticlumen, being walled by its respective valve cuspmedially and by the origin of the aorta laterally. Thecoronary arterial ostia are related to the aorticsinuses, but since these normally arise at a level just

on 7 June 2018 by guest. Protected by copyright.

http://thorax.bmj.com

/T

horax: first published as 10.1136/thx.12.2.125 on 1 June 1957. Dow

nloaded from

http://thorax.bmj.com/

JESSE E. EDWARDS and HOWARD B. BURCHELL

distal to the level of the upper edge of the valvecusps, they do not, in the strict sense, arise from theaortic sinuses but rather from the aortic wall justabove the sinuses.The names given to the aortic sinuses are the same

as those for the valve cusps to which each is related.In this paper we shall speak of left, right, andposterior aortic cusps and sinuses. The left and rightsinuses are the ones above which the left and rightcoronary arteries respectively arise. The posteriorsinus (sometimes called the non-coronary) is theone not directly related to a coronary arterial ostium.

In the body the aortic valve is so orientated thatthe stream of blood flowing through it is directedto the right and upward. The valve does not lie inthe same transverse plane of the body. The portion

of the left aortic cusp nearest the right is mostsuperior and anterior, while the posterior cuspand the adjacent part of the left cusp lie at the mostinferior and posterior levels. The most antero-superior portion of the left aortic cusp lies at thesame level as the nearby left cusp of the pulmonaryvalve. Otherwise, the aortic valve lies inferior tothe pulmonary valve. The inferior position of theposterior part of the aortic valve may be appreciatedfrom the fact that, at this level, the aortic valve liesinferior to the transverse sinus of the pericardiumand anterior to the adjacent portions of the twoatria and atrial septum.

Fig. 1 illustrates a gross section through thenormal heart, aorta, and pulmonary trunk at alevel above the two semilunar valves. The plane

FIG. I.-Gross section through base of normal heart. The plane of section is more superior anteriorly (lower portion of illustration) thanposteriorly (upper portion of illustration). In the inset is a simplified diagram of the photograph to assist in understanding the planesof sections used in subsequent illustrations. R.P., L.P., and A.P. =right, left, and anterior pulmonary cusps and sinuses, respectively.R.A., P.A., and L.A.=right, posterior, and left aortic cusps and sinuses, respectively. R.C. and L.C.=right and left coronary arteries,respectively. Tr.S.=transverse sinus of pericardium. In right atrium, A.T., P.T., and S.T.=anterior, posterior, and septal leaflets,respectively, of tricuspid valve. In left atrium, A.M.= anterior mitral leaflet. The posterior leaflet of the mitral valve is shown oppositethe anterior leaflet and below the word " atrium."

126



/T


nloaded from


PATHOLOGICAL ANATOMY

of the section is such that at the front of the specimenit corresponds to a more superior level in the bodythan at the posterior part of the specimen. In theillustration an inset appears which in a simplifiedway shows the essentials of the photograph appear-ing in the same figure. The simplified diagram willappear in subsequent illustrations with planes of thesection indicated of normal aortic sinuses that areshown in low-power photomicrographs.

THE RIGHT AORTIC SINus.-Not only does eachaortic sinus have relations that are quite differentfrom those of the other two sinuses but, significantly,differences in relationships exist at different partsof each sinus. Ostrum and his associates (1938)divided each sinus into two parts. The differencesare perhaps best understood if each aortic sinusis considered as having three more or less equalparts as follows: (a) a central or intermediate thirdand (b and c) two other thirds, each adjacent to oneof the other two valve cusps and sinuses. Thus theright aortic sinus and cusp may be said to have anintermediate part, a posterior part which lies nextto the posterior aortic cusp and sinus, and a leftpart lying next to the left aortic cusp and sinus.The right aortic sinus is entirely related to a

cardiac chamber, mainly, the right ventricularoutflow tract. The central part of the sinus liesagainst the crista supraventricularis, the prominentridge seen in the outflow tract of the right ventriclein the upward prolongation of the muscular part ofthe ventricular septum (Fig. 2). The left part of theright aortic sinus is the most anteriorly locatedof the three parts of this sinus. It abuts againstthe outflow tract of the right ventricle in the anglebetween the upper aspect of the crista supraventricu-laris and the pulmonary valve. In cases in which thecrista is particularly large, a portion of it may berelated to part of the left portion of the right aorticsinus.The posterior third of the right aortic sinus, that

third that lies next to the posterior aortic sinus, liesmainly against the right ventricle just postero-inferior to the crista supraventricularis. The mostposterior aspect of this third of the sinus may lieagainst the right atrium at the base of the septalleaflet of the tricuspid valve.Below all parts of the right aortic sinus lies the

ventricular septum. Beneath the central and leftparts the muscular portion is constant. Beneath theposterior part of the right aortic sinus lies either themuscular or the membranous portion of the ventri-cular septum, depending on the size of the latter.When the membranous portion is large, it lies inrelation to the posterior part of the right sinus.

Otherwise, and more commonly, the muscularportion is in this position.THE POSTERIOR AoRTIc SINUS.-The posterior

aortic sinus, like the right, is also related entirelyto intracardial structures, which are the right andleft atria and the atrial septum. The posterior aorticcusp and sinus may also be divided into three parts,which are the central, the right, and the left.

Adjacent to the right and intermediate parts of theposterior aortic sinus is the atrial septum (Fig. 3).Lesions of this region are directed into the right orleft atrial cavities or directly into the atrial septum,depending on the extent and direction of the process.The inferior relations of the right part of the

posterior aortic sinus are similar to those of theadjacent part of the right aortic sinus. Here theventricular septum lies, either the muscular or themembranous portion, again depending on the sizeof the membranous septum. Beneath the central orintermediate portion of the posterior aortic sinusthe membranous portion of the ventricular septumis a constant structure.The left part of the posterior aortic cusp shares

with the adjacent third of the left aortic leaflet thepeculiarity of being continuous with tissue of theanterior mitral leaflet inferiorly (Figs. 3a and 4a).Here is the only part of the aortic wall which is notconnected with the ventricular portion of the heart;rather, the aorta is connected with the base of theanterior mitral leaflet. Adjacent to the left part ofthe posterior aortic sinus lies the left atrial wall.

THEm LEFT AORTIC SINus.-The left aortic sinusand cusp may also be divided into three parts fordescriptive purposes. These are the central orintermediate, the posterior and the right.The posterior part of the left aortic cusp and

sinus is adjacent to the posterior cusp and sinus.Its relations are identical to those of the adjacentthird of the posterior sinus and cusp (Figs. 3a and4a).The other extreme of the left aortic cusp -and

sinus is termed the right part and lies in an anteriorposition and adjacent to the right aortic cusp andsinus. Since this third of the left cusp is the only onerelated to the ventricular septum, it may also becalled " the septal part of the left aortic cusp."

This part of the left aortic cusp and the corre-sponding wall of the aorta are connected inferiorlywith the most anterosuperior aspect of the muscularpart of the ventricular septum (Fig. 4b). This isthe portion of the aortic valve that lies mostsuperiorly in the body. Adjacent to the right partof the left aortic sinus is the wall of the pulmonarytrunk at the level of the left pulmonary sinus.

127



/T


nloaded from


Pulmoncxtttrunk

Rightpulmonary

Cu .3p

Inft±ndibu-Ilar7waLll

*.9A;t.. ANAV1/

L At

RAt

,///, A

Fig. La

Fi(J. Lu.-Loss-powser pihotomicrograph of Iongitudinal sectionlthrough normiial central third of riglt aortic cusp and sinus anditrough right pulmonary cusp. Plane of section indicated bxheavy linie in inset. Besidle Ithis portion of the aortic valve liesthe upper prolonigation of the ventricular septum (infundibularwall). which forms a part of the wall of thC outflows tract of theright ventricle and wshich includes the crista supraventricularis.Below this portion of thle right cusp and sinus lies thle muscularportion of the ventricular septuimi. Note the norn,lal distancebetween right pulmonary cusp and central part of righit aorticcusp. Note also intinmate connexion between aortic media andorigin of aortic cusp (annulus fibrosus). b.-Low-pTow&erphotomicrograplh through entire normal heart sectioned througlhcentral portions of the right andi left aortic cusps and sinuses.The pulmlionary trunk ies anterior to this plane of section and isnot shown in the illustration. The relations of the right aorticsinus (R.S.) are essentiall] the same as illustrated in ui. Therelations of the eft aortic s inus at i ts central portion (L. S.) ar c ofespecial interest in that this is the only part of the aortic originthat does not lie against a cardiac chamber or pulmonary trunk.but instead lies against the epicardium.

R.C.A-

Fig. Lb



/T


nloaded from


Posterioraortic cttsp

_l.. M,,,

USCtStt''''e

Fig. 3b

F t(. i. -CGross specimet ()o' a niormiial heart sectioned tlhroughcenitral portion ot posterior aortic cusp anrd s inus andposterior portion ot left aortic cusp anid SinluS. The anterior

portion o(f thle hcart ha,1s been remosved. and the reaider ltooksi1tt11 tthe losterior portion of the right (RN. iand left (L.\.ventricles. the right Ittriutm,. and ascending aorta. Note theclose retltionship betmseen the aortic s\all and(l tuhe mem-branious portion of tte sentricular septumn (\letm. Sept.) at

the level of the central part of ttse posterior (P.) aortic leaflet.The adjacent Parts of thc posterior and lett (L.) aortic leafletsare conitinuous swith the aniterior nmitral leaflet (A.M.). Itis this portion of thie heart ini shicth the aorta aittacties to a

salte. thie anterior nmitral leaflet. rather th;an to the leftsentricle. f.-Loss-poser photomicrograph of sectiontlhrough inornial cenitrat part of posterior aortic leaflet. Thetissue niarked righlt atriatwattIwl hich lies against theaorticoriin.i.s tihesepta lpart ot therightatrial ssatt. Notethein tinmate connexion between tthe aortic media and thle ori(inof thesvals e cusp. Jn ttle 1osermIost part of the niemiibranousseptunm and inferior to the basal attachmenit of the septaltricuspid leaflet ties thc bundle of His.

N

Fi. ia



/T


nloaded from


f'..

t:*

i r

..:v

'3~~~~~~~~~~~~~~~~~~~~~s'

/~~~~~~~~~

i~~~ ~ ~~~~~4

So~~~~~~it4!J. ^*; @t~~~̂V....;4.F.

VenttriXctlar zettmn 'A



/T


nloaded from



DEFECTS BETWEEN THE AORTiC ROOT AND THEHEART OCCURRING SINGLY

DEFECTS ABovE THE RIGHT AORTIC Cusp.-In ourcollection, there are three cases which portray adefect between the aortic root above the level of theright cusp and the heart, each occurring in menwhose ages ranged from 63 to 75 years. In each casethe lesion was found incidentally at necropsy. Intwo of the instances, the defect was not associatedwith aneurysm formation. The base of the defectwas walled by the crista supraventricularis of theright ventricle, which could be seen from the aorticlumen (Figs. Sa and b).

In the third case, at the site of the deficiency,there was an aneurysm of the right aortic sinus,beyond which the crista supraventricularis bulgedinto the right ventricle (Fig. 6). In none of the threecases cited had a rupture occurred, although itis recognized that such complications occur inaneurysms of the right aortic sinus. When thishappens, the rupture of the aorta is almost alwaysinto the outflow tract of the right ventricle.

In an additional case, we observed a rupturedaneurysm of the right aortic sinus, but in thisinstance there was in addition a ventricular septaldefect. The case will be discussed in the latersection dealing with combinations of defectsbetween the aortic root and the heart.

In an unusual instance an aneurysm may involvethe most posterior portion of the right aortic cuspand so may rupture into the right atrium, into theright ventricle, or into both (Oram and East, 1955).

Warthen's (1949) case of ruptured aneurysm ofthe right aortic sinus was unusual in that theaneurysm burrowed downward in the ventricularseptum and then communicated with the leftventricJe. A clinical picture resembling that ofaortic valvular insufficiency resulted.

In the case of Raman and Menon (1949) theaneurysm originating in the right aortic sinuspresented into both the right and left ventricles buthad not ruptured into either.DEFECTS BELOW THE RIGHT AORTIC CuSP.

Defects of continuity between the aorta and theheart that occur below the right aortic cusp appearas ventricular septal defects. Usually the deficiencyis not restricted to the area beneath the right cuspbut also includes varying amounts of deficiencybeneath an adjacent aortic cusp. When there is adefect beneath the right aortic cusp and an adjacentcusp, the posterior cusp is usually related to thedefect, less commonly the left cusp. In thecommonest situation the defect lies beneath theintermediate and right parts of the posterior cuspand beneath the posterior part of the right cusp.

FIG. 5.-From a man, 68 years old, with separation of the aorticmedia from the heart at the right aortic sinus, but withoutaneurysm formation. a.-Gross photograph of aortic valve. Theaortic wall has separated from the heart, centred at the centralportion of the right aortic sinus (R.), allowing the crista supra-ventricularis of the right ventricle to be seen from this view.L. = left and P. =posterior aortic cusps. b.-Low-powerphotomicrograph through central portion of right aortic sinus.The aortic media has separated from the heart, but no aneurysmhas yet formed. The crista supraventricularis (C.S.) forms thewall of the right aortic sinus.

I:ig. 5a

/

Fg.̀ I,

These defects represent the commonest type ofventricular septal defect. From the right ventricularaspect they lie in the right ventricular outflow tractbetween the crista supraventricularis above and thearea where the membranous septum lies, or shouldlie, below. Often the membranous septum isabsent, in which case the postero-inferior wall ofthe defect is formed by the anterior surface of the

131

..: ... '.

:-, '-AortcL



/T


nloaded from



-:.Y

.

/e;us~-

ntric.u.Iar-

?.: .,oj.:,

FIG. 6.-From a 75-year-old man with an unruptured aneurysm of the right aortic sinus. a.-At the right aortic sinus there is an aneurysm,

the' floor of which is formed by the crista supraventricularis of the right ventricle. b.-The outflow tract of the right ventricle and thepulmonary valve. Within the circle is an unruptured aneurysm at the crista supraventricularis. c.-Low-power photomicrograph of thecentral portion of the right aortic sinus, showing separation of the aortic media from the heart. The aneurysm of the aortic sinus is walledby atrophic muscular tissue, which is the crista supraventricularis of the right ventricle.

A....:'s. ..s;:*

U.

>e

...,

"....,1 :.;;-c..

I

'I:

At

*gJ

5'

132



/T


nloaded from



anterior mitral leaflet where it joins the septalleaflet of the tricuspid valve. The anatomicaldetails of this and of the other types of ventricularseptal defect have been described in another paperfrom this institution (Becu, Fontana, DuShane,Kirklin, Burchell, and Edwards, 1956).When a defect lies inferior to the left third of the

right aortic cusp it usually also includes the tissuebeneath the adjacent (right) third of the left aorticcusp. These defects form the less common varietyof ventricular septal defects in the outflow portionof the ventricular septum. From the right side theyall are seen to lie just inferior to the right and leftpulmonary cusps and above the crista supraventri-cularis.DEFECTS ABOVE THE POSTERIOR AORTIC CuSP.-

When lack of continuity exists between the aorticmedia and the heart above the posterior aortic cusp,the defect is usually in relation to the intermediatepart of the sinus. The lesion represents the classicaneurysm of the posterior aortic sinus, which is lesscommon than aneurysm of the right aortic sinus.The basic lesion is the same in either location. Theusual aneurysm of the posterior aortic sinus presentsin the septal wall of the right atrium, and ruptureinto thls chamber may occur. In the septal wall ofthe right atrium, the aneurysm lies just superior tothe annulus fibrosus of the septal leaflet of thetricuspid valve and in this position is closely relatedto the membranous portion of the ventricularseptum and to the conduction bundle of His.While aneurysms of the right aortic sinus arefrequently associated with ventricular septal defect,aneurysms of the posterior aortic sinus are usuallynot associated with such a defect. An exceptionalcase in which the two were associated will bedescribed in a subsequent section of this paper.The one example of an aneurysm of the posterior

aortic sinus occurring as a single lesion involved awoman who was 42 years of age at the time of herdeath from cardiac failure. The essential patho-logical features of this case have been described inan earlier report (Edwards and others, 1956).While it is theoretically possible on the basis of

anatomical relationships for aneurysms arising fromthe intermediate part of the posterior aortic sinusto rupture into the left atrium or simply to enterthe atrial septum, we do not know of such anoccurrence in examples of uninfected aneurysm.In a case of bacterial endocarditis described byOrbison and Mostofi (1956), a mycotic aneurysmdeveloping in this position ruptured into the atrialseptum. This caused a haematoma of the atrialseptum to form, but there was no communicationwith either atrial cavity. We are not aware of

L

aneurysms restricted to either the right or the leftparts of the posterior aortic sinus, though, theoreti-cally, such lesions could occur. Should this happen,those originating from the right part would presentinto the right atrium and those from the left partinto the left atrium.DEFECTS ABOVE THE LEFT AORTIC Cusp.-

Aneurysms restricted to the left aortic sinus are rare.Oram and East (1955) have credited Higgins (1934)with reporting the occurrence of an aneurysm ofthe left aortic sinus which ruptured into the rightatrium. Herson and Symons (1946) interpretedMacleod's (1944) case similarly. Review of thesetwo reports makes it doubtful that they werecorrectly interpreted. The use of different termin-ology for the aortic sinus from that which weemploy makes an exact interpretation impossible.Nevertheless, it is probable that both in Higgins'and in Macleod's respective cases the aneurysmsoriginated in the posterior (non-coronary) aorticsinus.

Dilatation of all three aortic sinuses has beenreported pathologically by Micks (1940).

In the case of Raman and Menon (1949) a 29-year-old man showed aneurysms of the right and theleft aortic sinuses. Neither aneurysm had ruptured.The aneurysm of the left sinus presented in theepicardium medial to the left auricular appendage.Death of the patient seemed related to completeheart block.No specimen with an aneurysm of the left aortic

sinus is in our pathological collection. A specimenwhich appears to be an example of this was shownto one of us (Edwards) by Dr. John Coe, ofMinneapolis. In this case there was an aneurysmcentred at the intermediate part of the left aorticsinus, the mouth of the aneurysm lying at thelowermost part of the sinus and therefore relativelydistant from the origin of the left coronary artery.The aneurysm presented into the epicardium abovethe left auricular appendage and behind the aorta.The body of the aneurysm communicated with theright atrial chamber through the anterior wall ofthe latter. Such a case brings up for consideration thequestion whether the lesion represents communica-tion of an accessory left coronary artery with theright atrium and aneurysmal dilatation of theaccessory artery. The facts that the mouth of theaneurysm lay in the depths of the sinus and that thewall of the aneurysm was shown on histologicalexamination to be composed of non-specificconnective tissue rather than arterial wall deterone- from accepting such an explanation of thepathogenesis. The same facts suggest that the basiclesion is a separation of the aortic wall from the

133



/T


nloaded from



left ventricle at the level of the intermediate partof the left aortic sinus. The aneurysm is thenexplained as a false aneurysm resulting from anepicardial haematoma which ruptured secondarilyinto the right atrium.

DEFECTS BELOW THE LEFT AoRTIc Cusp.-Weare not aware of any examples of separation betweenthe aorta on the one hand and the heart on the otherbeneath the posterior part of the left aortic cusp.However, examples of separation beneath theintermediate part and beneath the right (septal)part exist.

In another case which was observed at necropsyby Dr. Coe and the specimen kindly sent to us,there was a separation between the aorta and theheart beneath the intermediate part of the leftaortic cusp (Fig. 7). This is the area, it will berecalled, in which the aortic valve is not related to acardiac chamber or to the pulmonary trunk. Thelesion in this particular case had the nature of ananeurysm of the base of the left ventricle. Weconsider that, following separation between theaorta and the heart, there had been a haemorrhage,which was not fatal, into the epicardium. Thisbecame organized to create the fibrous and partlycalcified wall of the aneurysm. In the strict sensethis is a false rather than a true aneurysm of theleft ventricle. Two cases which bear some similarityto this one have recently been reported by Barnardand Brink (1956).The right or septal part of the left aortic cusp is

related to the ventricular septum and the rightventricle. In this position lack of continuity betweenthe aorta and the heart is represented by therelatively uncommon type of ventricular septaldefect which on the right side lies above the cristasupraventricularis and just below the pulmonaryvalve. As has been indicated in the section regardingdefects below the right aortic cusp, when a defectexists beneath the adjacent parts of either the rightor the left aortic cusp, it is usually beneath both.

COMBiNED DEFECTS BETWEEN THE AORTIC ROOTAND THE HEART

At times certain lesions which occur singly andwhich have been de3cribed in the previous sectionmay appear in combination with one another in thesame heart. It is important to emphasize this, since,when such lesions occur in combination, it may bedifficult or impossible by functional studies todetermine that two lesions exist rather than one.When two defects occur together, it is usual but notinvariable that the loss of continuity between theheart and the aorta is related to the same aorticcusp. Specifically, the combination of lesions

usually means that an aneurysm of an aortic sinusis associated with a ventricular septal defect beneaththe corresponding aortic cusp, but there are rareexceptions wherein a combination of lesions isrepresented by other gross alterations, includinganeurysms of two or three aortic sinuses (Ramanand Menon, 1949).DEFECTS ABOVE AND BELOW THE RIGHT AORTIC

Cusp.-In one case in our collection there was acombination of defects above and below the rightaortic cusp that was represented grossly by a com-bination of aneurysm of the right aortic sinus and aventricular septal defect. This case has previouslybeen reported (Morgan and Burchell, 1950; Burchelland Edwards, 1951). It seems representative of anumber of reported instances wherein these twolesions were combined. Basically, the abnormalityin this case was represented by a wide gap betweenthe lower end of the aorta and the ventricularseptum (Fig. 8a). Though, in essence, there was onedeficiency, there appeared to be two by the presenceof the right cusp of the aortic valve. At the involvedregion, the mid-portion of the right aortic cusp hadattachment neither to the aorta nor to the heart.The cusp was maintained in its relatively normalposition by the fixation imparted by its lateralattachments.From the right ventricular aspect in this case, the

aneurysm lay centred at the expected location of thecrista supraventricularis. Because of its large sizethe upper aspect of the aneurysm was adjacent tothe pulmonary valve. Several perforations werepresent in the aneurysm which allowed a communica-tion above the aortic valve between the aorta and theright ventricular outflow tract. Below the aorticvalve the defect between the aorta and the heartwas represented by a ventricular septal defect.

In yet another case, which involved a 21-year-oldwoman, there was a peculiar combination of defectswhich resulted in an abnormal communicationbetween the aorta and the left ventricle in thepresence of a basically normal aortic valve (Fig. 8b).In this case there was a separation between theaorta and the heart, centred at the commissurebetween the left and the right aortic cusps. Thisdeficiency was not associated with an interventricularcommunication. Instead, the deficiency led intoan aneurysm, which lay against the outflow tractof the right ventricle and the origin of the pulmonarytrunk.The aneurysm also communicated with the right

aortic sinus. In the usual circumstance, when adeficiency exists in an aortic sinus it is at thejunction of the aorta and the heart. Here, thedeficiency was somewhat higher in that some aortic

134



/T


nloaded from


Fig. 7b

rig. ia

FIG. 7.-From a 39-year-old woman with an aneurysm at the baseof the left ventricle (case of Dr. J. I. Coe). a.-The left ventricleand aortic origin. The mouth of the aneurysm lies between theaortic and the mitral valve and is centred at the level of the centralportion of tht left aortic leaflet. The aneurysm protrudes into theepicardium. b.-Close-up view of area involved by aneurysm.The mouth of the aneurysm lies between the central portion of theleft aortic leaflet above, and the left ventricle just in front of themitral valve below. This lesion is assumed to be a separationbetween the aorta and the heart inferior to the aortic valve andat the leval of the central portion of the left aortic leaflet.

tissue remained in the depths of the involved rightsinus. Pathogenetically, we consider that thefollowing events had transpired to create the lesions.It is assumed that the first process was a rupturebetween the aorta and the heart, centred at thecommissure between the right and the left cusps.It is further assumed that the rupture between theaorta and the heart was continued into the aortaitself at the right aortic sinus. The two defects thencommunicated with a haematoma, which becameorganized to form the (false) aneurysm.

Regurgitation of aortic blood into the leftventricle was accomplished by aortic blood flowinginto the aneurysm and from the latter into the leftventricle through the deficiency beneath the aorticvalve.

In this case the right coronary ostium was narrowand the lumen was completely obstructed as thevessel passed through the aortic wall. It is con-sidered probable that, at the time of the presumedtear in the aorta, the ostium of the right coronaryartery had been torn away and that secondarychanges (haematoma or thrombosis) led to theocclusion of the right coronary artery as it passedthrough the aortic wall.



/T


nloaded from



FIG. 8a.-From a 36-year-old man. Sagittal section through theoutflow tracts of both ventricles and the aortic and pulmonaryvalves in a case with aneurysm of the right aortic sinus and aventricular septal defect immediately subjacent to the aneurysm.

:>-t....- The two lesions are considered to be a separation of the aortafrom the heart of extensive nature, and lying both above andbelow the levels of the right aortic leaflet. P.A. posterioraortic cusp. b.-From a 21-year-old woman. The aorticvalve and origin of the aorta. There is a separation betweenthe aorta and the heart at the commissure between the left andthe right aortic leaflet. This separation has extended into thesortic wall at the level of the right aortic sinus. Each of theseopenings communicates with an aneurysm, through which bloodabove the aortic valve was regurgitated into the left ventricle.Edges of the tear have been indicated by bold lines.

DEFECTS ABOVE POSTERIOR A ORTIC CUSP ANDBELOW COMMISSURE BETWEEN RIGHT AND POSTERIORAORTIC Cusps.-In the case of a 28-year-old manwe found a large aneurysm of the posterior aorticsinus (Fig. 9a) and a ventricular septal defect belowthe commissure between the right and the posterioraortic cusps.The aneurysm of the aortic sinus resembled the

aneurysm of the posterior aortic sinus whichoccurred singly and to which we referred in a fore-going section. In the case now considered, the defectwas larger and occupied most of the sinus but was

centred at the intermediate part of it. The aneurysm,Fig. 8a which presented into the right atrium through the

septal wall of the latter, showed several perforations(Figs. 9b and c).

In this case the centre of the ventricular septaldefect, which lay below the aortic valve (Fig. 9d),was not in line with the centre of the aortic sinus

_s' _ :.~~~~~~~~~~~~~0

44~~~~~~~~~~~~~~~~~~~~~~~

J!~~~~~~~~~~~~~~~-~~~~~~~k A!wiF

.t.-zs._INcra............ ............

Fig. 8b

136



/T


nloaded from


aneurysm, the subvalvular defect being inl6" i _amore anterior position. From the right

ventricular aspect the subvalvular defectopened into the right ventricle postero-:-iwS t -T& °!; 8 _; o >_inferior to the crista supraventricularis and

* <tb Si_g &> _ just in front of the membranous portion ofthe ventricular geptum.

rffi-*. -";. ,.,x, X , In this case there was also an accessoryorifice of the tricuspid valve throughwhich the stream constituting the shuntfrom the left ventricle could enter the rightatrium when the main tricuspid orificewas closed (Fig. 9b).The findings of this case are duplicated

in that of Herson and Symons (1946). Thecase of the latter authors had in addition a

4 g_ second aortic sinus aneurysm whichinvolved the right aortic sinus and wasnot ruptured.

COMMENTThis communication does not primarily

concern itself with those deficienciesbetween the aortic media and the heartthat develop as a result of infection. Atthe same time it is recognized that

Fig. 9a , p:f9 .

FIG. 9.-From a 28-year-old man with an aneurysmof the posterior aortic sinus and a ventricularseptal defect associated with a double orifice of A.i_the tricuspid valve. a.-Sagittal section of heartthrough central portion of posterior aortic sinus(plane of section indicated in inset). There is a p-nlarge aneurysm of the posterior aortic sinus,which protrudes into the right atrium through itsseptai walL. (Area in rectangle shown as photo-micrograph in c.) b.-Close-up view of rightatrial aspect of aneurysm of posterior aorticsinus. Two openings are present in theaneurysm, which lies just above the septalleaflet of the tricuspid valve. Probe is in theaccessory orifice of the tricuspid valve, throughwhich blood that shunted through the coexistingventricular septal defect could enter the rightatrium. X

Fig. 9b



/T


nloaded from



FIG. 9c.-Low-power photomicrograph throughupper edge of aneurysm and right atrium.There is an abrupt interruption of the aorta,at which level the aneurysm originates.

K k M d.-Left ventricle and aortic valve. A smallventricular septal defect (point of arrow)lies just beneath the aortic valve at the levelof the commissure between the right (R.)and the posterior (P.) aortic leaflet. Theaneurysm of the posterior aortic sinus ishidden from view by the posterior aorticcusp.

Fig. 9c

lesions in the same anatomico-patho-logical sphere mightcomplicate bacterialendocarditis. Here, too, the peculiari-ties of the lesion would depend on theparticular areas related to the aorticvalve that were involved.We stress that, in cases with ruptured

aneurysms of an aortic sinus and incases of ventricular septal defect, bac- pterial endocarditis may occur as a ,.complication (Jones and Langley, 1949; A:Abbott, 1919). At the same time, it isrealized that in a heart without aspontaneous defect the destructivefeatures of bacterial endocarditis may ilead to a defect of continuity betweenthe aorta and the heart. These factsmake it obvious that, in a case with a ldefect in this area and with bacterialendocarditis also existing, it may bedifEcult or impossible to decide whichwas the primary lesion and which thecomplicating one.

In the cases that were discussed, thedefects that lay inferior to the aorticvalve and that appeared as interventri-cular communications are all consideredcongenital defects and are generallyclassified as ventricular septal defects.

Fig. 9d

gal.

138



/T


nloaded from



We have indicated that such defects represent adeficiency of the normal continuity between theaorta and the heart. This deficiency may representeither failure of union or secondary separation.

It is not known whether those deficiencies thatoccur between the aorta above the valve and theheart develop before or after birth. It is possiblethat a congenital weakness in these areas is respon-sible for post-natal separation. Venning (1951)credited Dr. C. V. Harrison with the suggestion thatthe fundamental defect in aortic sinus aneurysmshould be regarded as a defect of development ofelastic tissue at the base of the aorta. This viewsupports the concept of " late "-either before orafter birth-separation in this region.Absence of inflammatory reaction in relation to

aneurysms of the aortic sinus, as observed byKawasaki and Benenson (1946), by Maynard andThompson (1948), and by ourselves, supports acongenital basis for the genesis of these aneurysms.

Whatever the time of appearance of the aorticsinus aneurysm, when it ruptures it does so almostinvariably in post-natal, usually adult, life.The observations cited suggest that proper repair

of deficiencies of the types described requires thatthe aortic wall be reunited, either directly or in-directly by a prosthesis, with the heart.

Mere closure of an aortic aneurysm, withoutreuniting the aortic media with the heart, fails toovercome the basic lesion.

SUMMARYA series of lesions representing separation

between the aortic wall and the heart are described.The gross pathological nature of the lesion dependson which of the three aortic cusps it is related to.It also depends on whether the deficiency occursabove or below the aortic valve.Those deficiencies that occur above the valve are

aortic sinus aneurysms, while most of those that liebelow the valve usually represent ventricular septaldefect. Rarely, the picture of aneurysm of the leftventricular base results.Two or more lesions may coexist.The anatomical relations of the normal three

aortic cusps and sinuses are reviewed.REFERENCES

Abbott, M. E. (1919). In Contributions to Medical and BiologicalResearch, dedicated to Sir William Osler, vol. 2, p. 899. Hoeber,New York.

Barnard, P. J., and Brink, A. J. (1956). Brit. Heart J., 18, 309.Becu, L. M., Fontana, R. S., DuShane, J. W., Kirklin, J. W., Burchell,

H. B., and Edwards, J. E. (1956). Circulation, 14, 349.Burchell, H. B., and Edwards, J. E. (1951). Proc. Mayo Clin., 26, 336.Edwards, J. E., Burchell, H. B., and Christensen, N. A. (1956). Ibid.,

31, 407, 464.Gross, L, and Kugel, M. A. (1931). Amer. J. Path., 7, 445.Herson, R. N.. and Symons, M. (1946). Brit. Heart J., 8, 125.Higgins, A. R. (1934). Nav. med. Bull. (Wash.), 32, 47.Jones, A. M., and Langley, F. A. (1949). Brit. Heart J., 11, 325.Kawasaki, I. A., and Benenson, A. S. (1946). Ann. intern. Med., 25,

150.Macleod, A. (1944). Brit. Heart J., 6, 194.Maynard, R. M., and Thompson, C. W. (1948). Arch. Path. (Chicago),

45, 65.Micks, R. H. (1940). Brit. Heart J., 2, 63.Morgan, E. H., and Burchell, H. B. (1950). Proc. Mayo Clin., 25, 69.Oram, S., and East, T. (1955). Brit. Heart J., 17, 541.Orbison, J. L., and Mostofi, F. K. (1956). Amer. Heart J., 51, 636.Ostrum, H. W., Robinson, B. D., Nichols, C. F., and Widmann, B. P.

(1938). Amer. J. Roentgenol., 40, 828.Raman, T. K., and Menon, T. B. (1949). Indian Heart J., 1, 1.Venning, G. R. (1951). Amer. Heart J., 42, 57.Warthen, R. 0. (1949). Ibid., 37, 975.

139



/T


nloaded from


the pathological4-:anatomy of …thorax.bmj.com/content/thoraxjnl/12/2/125.full.pdfthorax(1957), 12,...

Documents