Myocardial infarctions, subtypes and coronary atherosclerosis in SLE: a case–control study

OBJECTIVE: Patients with SLE have increased risk of myocardial infarction (MI). Few studies have investigated the characteristics of SLE-related MIs. We compared characteristics of and risk factors for MI between SLE patients with MI (MI-SLE), MI patients without SLE (MI-non-SLE) and SLE patients without MI (non-MI-SLE) to understand underlying mechanisms. METHODS: We identified patients with a first-time MI in the Karolinska SLE cohort. These patients were individually matched for age and gender with MI-non-SLE and non-MI-SLE controls in a ratio of 1:1:1. Retrospective medical file review was performed. Paired statistics were used as appropriate. RESULTS: Thirty-four MI-SLE patients (88% females) with a median age of 61 years were included. These patients had increased number of coronary arteries involved (p=0.04), and ≥50% coronary atherosclerosis/occlusion was numerically more common compared with MI-non-SLE controls (88% vs 66%; p=0.07). The left anterior descending artery was most commonly involved (73% vs 59%; p=0.11) and decreased (<50%) left ventricular ejection fraction occurred with similar frequency in MI-SLE and MI-non-SLE patients (45% vs 36%; p=0.79). Cardiovascular disease (44%, 5.9%, 12%; p<0.001) and coronary artery disease (32%, 2.9%, 0%; p<0.001), excluding MI, preceded MI/inclusion more commonly in MI-SLE than in MI-non-SLE and non-MI-SLE patients, respectively. MI-SLE patients had lower plasma albumin levels than non-MI-SLE patients (35 (29-37) vs 40 (37-42) g/L; p=0.002). CONCLUSION: In the great majority of cases, MIs in SLE are associated with coronary atherosclerosis. Furthermore, MIs in SLE are commonly preceded by symptomatic vascular disease, calling for attentive surveillance of cardiovascular disease and its risk factors and early atheroprotective treatment.