Heart 1996;75:451-454

Spontaneous coronary artery dissection: a

neglected cause of acute myocardial ischaemiaand sudden death

Cristina Basso, Gian Luigi Morgagni, Gaetano Thiene

AbstractSpontaneous coronary artery dissectionis a rare cause of acute myocardialischaemia. Eight consecutive fatal caseswhich occurred in women aged 34-54 years(mean 43) are described. The dissectioninvolved the left anterior descending coro-

nary artery in four, the left main trunk intwo, the right coronary artery in one, andboth left anterior descending and circum-flex arteries in one. The clinical presenta-tion was sudden death in six cases, andacute myocardial infarction in two.Diagnosis was made at necropsy in everycase but one, in which coronary dissectionwas diagnosed during life by selectivecoronary angiography. The only ascer-tained risk factor was hypertension in one

patient; none of the women was in thepuerperium, and Marfan syndrome was

excluded in all. Histology showed a

haematoma between the coronary tunicamedia and adventitia, that flattened andoccluded the lumen; a coronary intimaltear was detected in only two cases.

Unusual histological findings were cysticmedial necrosis in one case, eosinophilicinflammatory infiltrates in four, andangiomatosis of the tunica adventitia inone. Patients dying of spontaneous coro-

nary dissection are usually middle agedwomen, with no coronary atherosclerosisand apparently no risk factors. Spon-taneous coronary artery dissection isunpredictable, and sudden death is theusual mode of clinical presentation.Prompt diagnosis and life saving treat-ment is far from being achieved.

ischaemia, was first described in 1931 in a 42year old white woman who died suddenly afterexperiencing chest pain.' Since then more than100 cases have been reported in English lan-guage journals,2-5 mostly in young, otherwisehealthy women, particularly in the puerperium.

In this report we describe the clinical andmorphological features of isolated spontaneouscoronary artery dissection in eight necropsycases, all females, none of whom was in thepuerpernum.

Methods and definitionsSpontaneous coronary artery dissection hasbeen defined as an intramural haematoma ofthe media of the vessel wall (false lumen) whichflattens the true lumen, leading to blood flowobstruction and acute myocardial ischaemia, inthe absence of trauma or iatrogenic causes.

A review of our anatomical collection ofheart specimens since 1985 showed eightnecropsy cases that fulfilled these criteria. Theclinical records in these subjects were reviewed.After excluding cardiac and extracardiac causes

of death, the heart specimens were firstinspected macroscopically. Subsequently, thefour major epicardial trunks (left main, leftanterior descending, left circumflex, and rightcoronary artery) were examined by cuttingthem into serial cross sections at 3 mm inter-vals. These coronary specimens were thendehydrated, embedded in paraffin, and stainedwith haematoxylin-eosin, Weigert-Van Gieson,Azan Mallory, and Alcian PAS. The myo-

cardium was also examined macroscopicallyand microscopically for myocardial ischaemicdamage.

(Heart 1996;75:451-454)

Keywords: coronary artery dissection; ischaemic heartdisease; sudden death

Department ofPathology, UniversityofPadua MedicalSchool, Padua, ItalyC BassoG ThieneDivision of Cardiology,Civil Hospital, Forli,ItalyG L MorgagniCorrespondence to:Dr G Thiene, Istituto diAnatomica Patologica,Via A Gabelli 61, 35121Padova, Italy.Accepted for publication17 October 1995

Spontaneous coronary artery dissection, a rare

condition responsible for acute myocardial

Coronary artery dissections: main clinical and pathologicalfinc

Results

The eight cases of spontaneous coronary arterydissection were all women, ranging in age from34 to 54 years (mean 43). The most importantclinical and pathological findings are sum-

marised in the table.

dings

Case Sex Clinical Circumstances Risk CoronaryNo age presentation ofdeath factors site Histology

1 F, 34 Sudden death At rest - LDA2 F, 54 Sudden death At rest - RCA Cystic medial necrosis3 F, 43 Sudden death At rest Hypertension LDA Eosinophilic infiltrate4 F, 50 Sudden death At rest - LDA Eosinophilic infiltrate5 F, 45 Myocardial At rest - LMC Intimal teat

infarction6 F, 48 Myocardial At rest - LDA, CX Intimal tear, angiomatosis,

infarction eosinophilic infiltrate7 F, 35 Sudden death At rest - LDA8 F, 37 Sudden death After strenuous effort - LMC Eosinophilic infiltrate

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None of the patients had a previchistory, and the only ascertainedwas hypertension in one (case Nosyndrome was excluded in all. Norwomen was in the puerperium or v

to have been taking oral contraceptiwas a smoker; none had a history ofuse; and toxicological examinationtive in every case. One patient hadintense physical exercise (swimminprior training two hours before the.(case No 8). In six subjects, the clsentation was sudden death. Twi(cases Nos 5 and 6) had complaineddial chest pain, and died of antemyocardial infarction six hours andlater, respectively. Diagnosis was a

life only in case No 6, in whom selenary angiography was performedafter an acute myocardial infarction

At necropsy, heart weights rangecto 340 g (mean 310). The dissectiothe left anterior descending coronar

four cases, the left main trunk in tw(coronary artery in one, and both th(rior descending and circumflex arterCoronary atherosclerosis was absMorphological evidence of anteimyocardial infarction was presercases. Histological examination of tkcoronary segments showed a more c

centric haematoma, located betweernary tunica media and adventitflattened and occluded the lumeAlthough serial histological sectiexamined, intimal tears connectin,lumen with the intramural hematobserved in only two cases. Unu!logical findings were cystic mediain one case, angiomatosis of the tuntitia in one and adventitial-peri

eosinophilic infiltrates in four (fig 2b). Signs ofhyperacute ischaemic damage in the tributarymyocardium of the involved coronary artery,consisting of contraction band necrosis, werealways observed in the cases of sudden death.Myocardial infarctions showed the classicalpicture of coagulation necrosis at various stageof healing.

DiscussionSpontaneous coronary artery dissection, alsoknown as dissecting aneurysm, intramuralhaemorrhage or haematoma, is an uncommon

a morbid entity.1-5 The dissection usually occursin the outer media and determines luminalocclusion by pushing the inner media againstthe opposing wall. Clot filling the false lumenmay simulate coronary thrombosis at thenaked eye, masking the dissection. Thus thereal incidence of this entity may be underesti-mated at necropsy, unless a careful histologicalexamination of the coronary segment is con-ducted.A review of published reports showed that

69% of the cases were diagnosed at necropsy.5About 80% of the cases occurred in women,and more than 25% of these were in the peri-

b partum period.20 Dissection of the right coro-nary artery seems to be more frequent in men,

)us cardiac whereas dissection of the left anterior descend-risk factor ing coronary artery appears more common in3); Marfan women. Coronary artery dissection affectsie of these young adults; in a series of cases that werevas known diagnosed before death, De Maio et aP4 foundives. None a mean age of 46 years in males and 38 yearsillicit drug in females. The clinical presentation of thiswas nega- entity includes the entire spectrum of coronaryperformed syndromes, and is primarily related to theg) without extent of the dissection and the vesselfatal event involved. Nonetheless, sudden death withoutlinical pre- evidence of myocardial infarction is mucho patients more frequent.2' Survival is possible if obstruc-of precor- tion of the lumen is not complete, or if anrior acute myocardial infarction develops without fataleight days complications.22-25 Spontaneous healing of achieved in coronary dissection has also been shown toctive coro- occur, on both clinical and histological evi-eight days dence."'24(fig 1). When secondary causes, such as aortici from 280 dissection, trauma, coronary angiography,n involved angioplasty, or surgical manipulations arery artery in excluded,9 13 22 26-34 the aetiology of spontaneouso, the right coronary artery dissection remains uncertain.e left ante- Most of the patients do not have risk factorsries in one. for coronary artery disease, and hypertensionent in all. has rarely been reported.9rior acute Arterial wall changes during pregnancy orit in two the use of oral contraceptives have been wellie involved documented35; hormonal and haemodynamic)r less con- factors may result in a weakening of the tunicaa the coro- media, thereby explaining the higher incidencetia, which of female patients with spontaneous coronaryn (fig 2 e the 6-143637

ions were in our experience, none of the women was ing the true the peripartum period, or taking oral contra-toma were ceptives.sual histo- A true pattern of cystic medial necrosis hasal necrosis rarely been described in the involved coronaryLica adven- artery as the cause of spontaneous coronaryiadventitial artery dissection.3640

Figure 1 A 48 year oldwoman with acute anteriormyocardial infarction (caseNo 6). (a) Selective leftcoronary angiography atbaseline (frontal view):detection of two luminaseparated by a radiolucentflap in the proximal as wellas in the mid-third of theleft anterior descendingcoronary artery. (b)Selective left coronaryangiography (frontal view)at onset of acute ischaemiaduring catheterisation:stoppage of bloodflow tothe entire left anteriordescending coronarysystem.

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Spontaneous coronary artery dissection: a neglected cause of acute myocardial ischaemia and sudden death

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Figure 2 A 43 year old woman who died suddenly at rest (case No 3). (a) Left anterdescending coronary artery occluded by dissecting haematoma. Azan-Mallory stain,magnification x 17-5. (b) Eosinophilic infiltrates in the adventitia. HE stain,magnification x 132.

The vasa vasorum have been implicatedpossible initiating site for coronary dissectithey may be abnormal in this grouppatients, as in our case of angiomatosis, anc

some way fragile and susceptible to haemrhage,4' thus constituting the initial sourcebleeding.As in aortic dissection, the source of

blood could be the true lumen through an i:mal tear, which has been detected in acases.42-45 However, we observed an intiitear in only two cases on serial histological s

tions, and we do not know whether it wassite of intramural ingress or egress of bloOne of these cases displayed both angiomat4and eosinophilic infiltrates in the turadventitia, highly suggestive of a primary in'mural haematoma.

In many published cases, as well as in ffrom our own series, a fairly diffuse adventiand periadventitial inflammatory reacticonsisting mainly of eosinophils, i

observed.278 448 Because of the presencethese "periarteritis-like" adventitial change,was proposed that the dissection is a resulilytic action of protease released fr

eosinophils.'8 However, it is likely that theperiadventitial inflammation seen in somecases is reactive in nature, rather thancausative.48

Intense physical exercise as a precipitatingfactor of coronary artery dissection has alreadybeen described.4950 Noteworthy is a recentreport of cocaine induced coronary artery dis-section, which adds this entity to the long listof cardiovascular complications of cocaineabuse.5"The in vivo diagnosis of spontaneous coro-

nary artery dissection by selective angiographydepends on the visualisation of two luminaseparated by a radiolucent intimal flap.552-54This procedure entails the risk of cardiacarrest by injection of hypertonic medium intothe false lumen, thus aggravating the dissec-tion. Some cases may not be recognised if anintimal tear does not occur or if the true lumenis severely narrowed or if the false lumen isoccluded by a clot.The prognosis for these patients is poor. In a

survey of 123 cases, Benham and Tillinghastt found that 67% of the patients died and 33%survived, treated either surgically or med-

4* ically.55 Since sudden death is the most fre-8> quent clinical presentation, the clinician is left,. without the time of any potential therapeutic

option in the majority of cases. Medical treat-ment may play a palliative role. Ramamurti et al

> first reported the use of intravenous streptoki-nase in a case with left anterior descendingcoronary artery dissection.56 Several workers

: think that this treatment may be effective inlysing the clot in the false lumen and in re-

4 establishing patency of the true lumen55;nonetheless, we wonder whether thrombolysis

> might aggravate the bleeding, thus worseningthe coronary dissection.

nor Although the outcome for patients withspontaneous coronary dissection is consideredgrim, with a high mortality rate, aggressivesurgical treatment in a recent series of 10 con-

as a secutive patients resulted in 100% survival.5ion; Forker et al carried out the first operationof for a spontaneous dissection of the right coro-

d in nary artery in 1969 by performing an aorto-ior- coronary bypass.57 Thayer et al 3 recommended- of coronary artery bypass grafting for all patients

with spontaneous dissection, whereas Dethe Maio et a14 advocated this intervention only innti- cases of left main disease, three vessel disease,few or recurrent ischaemia. Indeed, this technicalmal approach may be considerably difficult in thesec- setting of vessel wall dissection, with the falsethe lumen underlying the site of graft anastomo-ood. sis.58 Successful surgical repair by extrusion ofosis the intramural haematoma was reported iniica 1986 by Vicari et al.59 In cases of severe hearttra- failure following myocardial infarction caused

by coronary artery dissection, cardiac trans-our plantation has been performed and total artifi-itial cial heart implantation attempted as aion, temporary measure.606' Nowadays, new inter-was ventional techniques, such as stents and bal-of lons, are being considered for the management

s, it of coronary dissection.6263t of In conclusion, the possibility of a sponta-.om neous coronary artery dissection should be

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Basso, Morgagni, Thiene

considered in any young adult woman whopresents with an unexpected circulatory col-lapse, myocardial ischaemia, or infarction,without a previous history or risk factors, andnot necessarily in puerperium. Suspicion ofthe diagnosis may then lead to emergencyinvestigation of the coronary arteries, and sur-gical or interventional treatment. However,the high incidence of sudden death withoutpremonitory symptoms casts doubt on the realpossibility of prompt diagnosis and life savingtreatment in the majority of cases.

This work is supported by Target Project AGING, NationalCouncil for Research, Rome, and by Target Project "JuvenileSudden Death", Veneto Region, Venice, Italy.

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