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.