A Spontaneous Coronary Artery Dissection Autopsy in a 64-Year-Old Male
Article information
Abstract
Spontaneous coronary artery dissection (SCAD) is a condition in which an intramural hematoma within the coronary artery leads to acute coronary syndrome without atherosclerosis, trauma, or iatrogenic causes. It predominantly affects middle-aged women and is associated with several predisposing conditions, including fibromuscular dysplasia, systemic inflammatory disorders, connective tissue diseases, and coronary artery spasms. We report the case of a 64-year-old male with a history of hypertension who died of SCAD. His death occurred suddenly and without preceding trauma while the decedent was working overtime at a construction site. On gross examination, a thrombus-like material was identified in a branch of the left anterior descending artery and was initially presumed to be a postmortem clot. However, microscopic examination revealed an intramural hemorrhage, medial dissection, and formation of a false lumen within the coronary artery. This case report highlights the importance of a thorough histopathological examination of the coronary arteries during autopsy, even in the absence of atherosclerosis.
Case Report and Discussion
Spontaneous coronary artery dissection (SCAD) is a rare cause of acute coronary syndrome (ACS) that is characterized by the spontaneous formation of an intramural hematoma in a coronary artery without trauma, iatrogenic intervention, or underlying atherosclerosis [1-3]. SCAD predominantly affects middle-aged women, who account for approximately 87%-95% of reported patients, whereas it is rarely observed in men. Here, we report the autopsy case of a 64-year-old male who died from ACS secondary to SCAD.
The deceased was a tiler who worked at an apartment construction site. He had worked overtime the night prior and was found dead the following morning at his workplace. He had been taking antihypertensive medications for approximately four years and had no other known medical history aside from recent complaints of back pain. An autopsy was performed 48 hours postmortem. He measured 167 cm in height and weighed 66 kg, and the results of his external examination were unremarkable. Cardiomegaly was observed in the heart, which weighed 530 g, while his major coronary arteries, including the left anterior descending artery (LAD), were grossly unremarkable (Fig. 1). However, on the epicardial cut surface, a thrombuslike material of approximately 3 cm in length was identified within the lumen of a branch of the LAD (Fig. 2). No other abnormalities were observed in the cardiac structures, including the myocardium, endocardium, or valves, and the other organs showed no significant gross findings. Initially, the thrombus-like material was presumed to be a postmortem clot. Given the absence of atherosclerosis, the preliminary cause of death was sudden cardiac death due to hypertensive heart disease. However, the presence of an apparent thrombus in the coronary artery branch was considered unusual and prompted further histological examination. Microscopic examination revealed an intramural hemorrhage and medial dissection with the formation of a false lumen, which nearly collapsed the true lumen (Fig. 3A). The intimal layer remained relatively intact with no evidence of an intimal tear. The tunica intima showed diffuse fibromuscular hyperplasia. Periadventitial infiltration of lymphocytes, macrophages, and eosinophils was noted. Elastic Van Gieson staining revealed focal fragmentation of the external elastic lamina with erythrocyte extravasation, while internal elastic lamina remained relatively preserved (Fig. 3B, C). These findings are consistent with those of coronary artery dissections and suggest the possibility of underlying fibromuscular dysplasia (FMD). No definitive ischemic changes were observed in the myocardium, and the toxicological examinations revealed no abnormalities. Consequently, the cause of death was determined to be ACS caused by SCAD.
The left anterior descending artery is grossly unremarkable without atherosclerotic plaque.
Thrombus-like material of approximately 3 cm in length was identified within the lumen of a branch of the left anterior descending artery (A, B).
Microscopic findings. (A) A branch of the left anterior descending artery had intramural hemorrhage and medial dissection with formation of the false lumen (FL), which had nearly collapsed the true lumen (TL) (H&E, ×40). (B, C) The external elastic lamina was focally fragmented with erythrocyte extravasation (arrows), whereas the internal elastic lamina was relatively intact (arrowheads) with intimal fibromuscular hyperplasia (asterisk) (Elastic Van Gieson stain, ×40 and ×200).
However, the pathophysiology of ACS caused by SCAD remains poorly understood. Traditional cardiovascular risk factors for atherosclerosis are generally not significant in SCAD, although hypertension has been reported in approximately one-third of patients [1,2]. Furthermore, SCAD has been associated with emotional stress or intense physical exertion, with one study identifying potential precipitating stressors in 62% of patients [3]. Several underlying conditions that compromise the arterial wall structure have been implicated, including FMD, systemic inflammatory diseases such as systemic lupus erythematosus or Crohn’s disease, connective tissue disorders such as Marfan syndrome, Ehlers-Danlos syndrome, and coronary artery spasms [1,3,4]. The high incidence of SCAD among young women during pregnancy, the postpartum period, or after exogenous hormone therapy also suggests a possible role for sex hormones in its pathogenesis [5]. SCAD is also reportedly associated with coronavirus disease 2019 [6], and a genome-wide association study identified the PHACTR1 (phosphatase and actin regulator 1)/EDN1 (endothelin 1) locus as a genetic risk factor for SCAD [7].
Two hypotheses have been proposed to explain the pathophysiological mechanisms of SCAD [2,8]. The first is the “inside-out” hypothesis, which suggests that an intimal tear allows blood to enter the subintimal space from the true lumen. The second is the “outsidein” hypothesis, wherein an intramural hematoma forms within the tunica media, possibly due to rupture of the vasa vasorum, without the presence of an intimal tear. The hematoma separates the tunica intima from the outer arterial wall to create a false lumen that compresses the true lumen and ultimately leads to impaired coronary blood flow and ACS [2,5]. SCAD accounts for approximately 3%-4% of ACS cases [4]. In the present case, microscopic examination revealed fragmentation of the external elastic lamina with erythrocyte extravasation, thus supporting the “outside-in” hypothesis.
With advancements in coronary angiography, the number of early SCAD diagnoses has increased in recent years. Based on angiographic findings, SCAD can be classified into three types [4]. Type 1 is characterized by multiple radiolucent lumens or contrast staining of the arterial wall. Type 2 presents as a long, diffuse arterial narrowing (typically >2 cm) of varying severity. Type 3 manifests as focal or tubular stenosis and often mimics atherosclerosis. In the present patient, if post- or antemortem coronary angiography had been performed, the SCAD in the branch of the LAD would likely have been classified as type 2.
Although SCAD can affect any coronary artery, approximately 50% of cases involve the LAD and its branches [1]. Multivessel involvement may also occur, and the distal vessels are more frequently affected than the proximal vessels. The clinical presentation of SCAD resembles that of atherosclerotic ACS and includes chest pain, elevated cardiac biomarker levels, and electrocardiographic changes indicative of acute myocardial infarction (AMI). With early diagnosis and appropriate management, the overall prognosis is generally favorable; however, SCAD-related AMI during pregnancy is associated with poor prognosis [5]. According to the literature, the recurrence rate ranges from 13.1% to 17% [4].
In reality, SCAD may be more common than currently recognized, because limitations in coronary angiography can lead to misdiagnosis or underdiagnosis [4,9]. Although SCAD has been predominantly reported in white populations, similar findings have also been observed in Hispanic and Black populations [1]. Moreover, in a Korean study of 148 female patients with AMI, SCAD was diagnosed in 13 (8.78%) individuals [10]. Some patients with SCAD are idiopathic and lack identifiable predisposing conditions [4,9]. These findings highlight the importance of recognizing that SCAD may be underdiagnosed, and that its prevalence in Korean patients may be comparable to that observed in other populations.
This case report highlights the following three important aspects. First, SCAD should not be regarded as a condition exclusive to women, as approximately 10%-15% of incidences occur in men [6]. Second, careful examination of the small branches of the coronary arteries is essential in the absence of other identifiable causes of death, such as coronary artery atherosclerosis. Finally, when an unusual thrombus is incidentally found in a coronary artery or its branches, histopathological evaluation is warranted to rule out underlying pathologies, such as SCAD.
Notes
Conflicts of Interest
Jinhyuk Choi, a contributing editor of the Korean Journal of Legal Medicine, was not involved in the editorial evaluation or decision to publish this article. All remaining authors have declared no conflicts of interest related to this study and its publication.