Conclusion and results

An autopsy was performed, and in the heart the left ventricular wall was hypertrophic. The myocardium in the antero-lateral part of the left ventricle and the anterior 2/3 of septum was characterized by severe transmural reperfusion injury (Figure 2A). In the same region, fibrotic tissue was identified, indicating previous infarction. In the left main coronary artery and LAD, the SCAD changes were located and confirmed (Figure 2B). In all coronary arteries, only mild atherosclerotic changes in the form of fatty streaks were identified. The patient had previously at age 39 been admitted to emergency care with a Non-ST-elevation myocardial infarction, where a coronary angiography showed SCAD in a branch of LAD resulting in 50% stenosis. At age 48, she was again acutely hospitalized with severe chest pain, and was diagnosed with an ST-elevation myocardial infarction. Coronary angiography showed SCAD from the middle part of LAD involving the distal half of the artery. The patient was treated conservatively at both occasions, due to spontaneous symptom remission. Following the event, the patient was genetically tested for potential pathogenic gene variants related to aortic vascular disease. This was performed due to possible familiar disposition given a twin-sister also diagnosed with SCAD, and her father and paternal aunt both having aortic aneurisms. However, no pathogenic genetic variants were identified. Post-mortem, supplementary more extensive genetic testing of 106 genes involved in hereditary cardiomyopathies and familial hypercholesterolemia was performed; The testing among others, included the genes ACTC1, MYBPC3, MYH7, MYL2, MYL3, TNNI3 and TNNT2 involved in hypertrophic cardiomyopathy [6], DSP, LDB3, LMNA, PLN, RBM20, SCN5A and TTN involved in dilated cardiomyopathy [7], as well as APOB, LDLR and PCSK9 involved in familiar hypercholesterolemia [8]. No pathogenic or likely pathogenic variants were identified.

Discussion

While SCAD is a relatively rare cause of myocardial infarction among the general population, it is estimated to be the cause of up to 35% of infarctions in females younger than 50 years [2]. Further, SCAD is the most common cause of myocardial infarction among pregnant women and in the post-partum period, and should be excluded in case of acute chest pain in this specific patient group [9]. SCAD recurs in approximately 10% of patients, and the recurrence risk increases with untreated or insufficiently treated hypertension [10]. Given the relatively low recurrence risk, a presentation as reported in this case, with multiple recurrences leading to several myocardial infarctions, and ultimately death, is unusual and a reminder of the potential severity of SCAD, which is usually treated conservatively [11]. The reported prevalence of SCAD-patients with simultaneous vascular- and/or connective tissue disease varies significantly, ranging from 30.1-80.7% [2]. When SCAD is diagnosed, genetic testing for potential underlying predisposing diseases should therefore be considered. In patients with underlying vascular- and/or connective tissue disease experiencing symptoms of myocardial infarction, SCAD should be considered as a differential diagnosis. In this case, supplementary comprehensive genetic testing was performed without positive findings, thereby excluding the most well annotated genetic causes of aortic disease, cardiomyopathy and familial hypercholesterolemia. Taken together, SCAD is a relatively rare cause of myocardial infarction among the general population, however, in younger and predisposed females <50 years old, SCAD is an important differential diagnosis as the cause of myocardial infarction.