Sudden Cardiac Death Due to Triple Vessel Coronary Dissection
A 55-year–old white woman with no previous medical history collapsed when driving home in her car after a leisurely swimming session. She had sufficient time to communicate to a bystander a recent history (1 week prior) of chest pain for which she had not consulted a physician. She took no medication and had no cardiovascular risk factors. Cardiorespiratory reanimation was performed for 40 minutes by bystanders without success, and the woman was pronounced dead by the time professional help arrived on the scene. No ECG or other noninvasive examinations of her heart are thus available. At autopsy, no Marfan or Ehlers-Danlos syndrome was noted. The heart weighted 310 g (body weight 55 kg, height 165 cm, and body-mass index 20.2). No vascular or myocardial abnormalities were noted and no cardiac hypertrophy (left ventricle 1.3 cm and right ventricle 0.5 cm). Examination of the coronary tree revealed no atherosclerotic changes but complete occlusion of all 3 main coronary arteries: the right coronary artery from 0.5 cm of the ostium down to 12.5 cm, the left coronary artery from 0.7 cm to 1.9 cm, and then into the left anterior descending coronary artery for 6.5 cm and the common coronary artery for 5.5 cm (Figure 1A through 1C). The ascending aorta, the coronary artery orifices, and the proximal coronary trunks were macroscopically normal (Figure 1D through 1F). Besides acute pulmonary edema (pulmonary weight 1350 g), no abnormalities were noted. Histologically, all 3 coronary arteries showed dissection through the outer third of the media (Figure 2A and 2B), with no apparent intimal tear on serial sectioning and a dense eosinophilic infiltrate restricted to the adventitial side of the dissection plane (Figure 2B and 2C). Sections through the affected as well as the unaffected part of the coronary wall, as well as various portions of the ascending aorta, were devoid of medial cystic disease, inflammation, or any other pathology (Figure 2D). No myocardial infarct was noted in the extensively sampled myocardium.
Spontaneous coronary artery dissection (SCAD) is a rare cause of sudden death. Most reported cases have affected a single coronary artery, usually the left anterior descending coronary artery, but in about one fifth of cases >1 vessel is affected. To date, 6 cases of triple SCAD have been reported. All patients survived thanks to adequate interventions, usually by stenting the affected vessels or by bypass grafting.1,2,3 Predisposing conditions to SCAD include atherosclerosis, hormonal dysbalance during the postpartum period, and Marfan and Ehlers-Danlos syndromes. In contrast, potential triggers of the actual dissecting event remain anecdotal but include physical exercise (aerobics, baseball, rugby) or prolonged sneezing, all having in common an acute elevation of momentary peak coronary perfusion pressure.4 The question remains, why and how can 2 or even 3 coronary arteries simultaneously experience dissection? Because all previously described triple SCAD patients have survived, the possibility of a common dissecting origin at the level of the aortic root has to date not been excluded. To the best of our knowledge, this is the first published case of an acutely fatal triple SCAD, which has allowed us to examine by macroscopic and histological techniques not only the dissected part of the coronary arteries but also the proximal coronary arteries as well as the aortic root. The absence of even the minutest morphological abnormalities of the latter arterial segments strongly argues against a common dissection origin into the coronary artery tree. The restriction of the eosinophilic infiltrate to the abluminal aspect of the dissecting plane underscores the reactive nature of the inflammatory infiltrate,5 and the freedom from inflammation in the other parts of the coronary artery tree also argues against an inflammatory origin. In the absence of other potentially causative artery wall lesions, in particular lytic medial necrosis (Figure 2D) and atherosclerosis, a strong mechanical trigger event remains the most likely cause of this rare disease.
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