Autoimmune Disease and Spontaneous Coronary Artery Dissection

Spontaneous coronary artery dissection in a young patient with antiphospholipid syndrome

A 28-year-old man diagnosed with triple positive antiphospholipid syndrome (APS) and undergoing warfarin experienced three separate admissions to the cardiac ward within a one-month period due to escalating chest pain. While the initial two admissions revealed normal results in cardiological investigations, such as blood tests, electrocardiogram, and echocardiography, the third admission unveiled signs of ST-elevation myocardial infarction (STEMI), despite the patient maintaining an INR (International Normalized Ratio) of 4. Subsequent percutaneous coronary intervention (PCI) exposed spontaneous coronary artery dissection (SCAD) of type 3. Faced with hemodynamic instability and worsening symptoms, the patient underwent stenting and was prescribed dual antiplatelet therapy in addition to warfarin. A follow-up evaluation one month later indicated a normalization of his condition.

Vascular histopathology and connective tissue ultrastructure in spontaneous coronary artery dissection: pathophysiological and clinical implications

Aims 

Spontaneous coronary artery dissection (SCAD) is a cause of acute coronary syndromes and in rare cases sudden cardiac death (SCD). Connective tissue abnormalities, coronary inflammation, increased coronary vasa vasorum (VV) density, and coronary fibromuscular dysplasia have all been implicated in the pathophysiology of SCAD but have not previously been systematically assessed. We designed a study to investigate the coronary histological and dermal collagen ultrastructural findings in SCAD.

Methods and results

Thirty-six autopsy SCAD cases were compared with 359 SCAD survivors. Coronary and myocardial histology and immunohistochemistry were undertaken. Transmission electron microscopy (TEM) of dermal extracellular matrix (ECM) components of n = 31 SCAD survivors and n = 16 healthy volunteers were compared. Autopsy cases were more likely male (19% vs. 5%; P = 0.0004) with greater proximal left coronary involvement (56% vs. 18%; P < 0.0001) compared to SCAD survivors. N = 24 (66%) of cases showed no myocardial infarction on macro- or microscopic examination consistent with arrhythmogenic death. There was significantly (P < 0.001) higher inflammation in cases with delayed-onset death vs. sudden death and significantly more inflammation surrounding the dissected vs. non-dissected vessel segments. N = 17 (47%) cases showed limited intimal fibro-elastic thickening but no features of fibromuscular dysplasia and no endothelial or internal elastic lamina abnormalities. There were no differences in VV density between SCAD and control cases. TEM revealed no general ultrastructural differences in ECM components or markers of fibroblast metabolic activity.

Conclusions 

Assessment of SCD requires careful exclusion of SCAD, particularly in cases without myocardial necrosis. Peri-coronary inflammation in SCAD is distinct from vasculitides and likely a reaction to, rather than a cause for SCAD. Coronary fibromuscular dysplasia or increased VV density does not appear pathophysiologically important. Dermal connective tissue changes are not common in SCAD survivors.