Minimal extra-cardiac atherosclerosis in people <50 years with sudden cardiac death due to coronary disease

Abstract Background The association between severe coronary artery disease and widespread atherosclerosis in younger individuals remains uncertain. Purpose To characterise the association between severe (fatal) coronary disease and extra-cardiac atherosclerosis in a population of young and middle-aged individuals. Methods Individuals aged 1-50 years with sudden cardiac death (SCD) from 2019-23, autopsy-proven to be due to coronary artery disease, were identified using the state-wide EndUCD registry. The presence of extra-coronary atherosclerosis greater than modified American Heart Association class III was documented in five arterial beds (intra-cerebral vessels, carotid arteries, aorta, renal and femoral arteries). Results Of 3,044 individuals who experienced SCD, 372 were due to coronary artery disease and 71 of these (19.1%) had extra-coronary plaque. Plaque was identified in aorta (68/372 patients, 18.3%), carotid arteries (11/372, 3.0%), iliofemoral arteries (11/372, 3.0%), intracerebral arteries (4/157 patients who underwent examination of the brain, 2.6%) and renal arteries (7/372 patients, 1.9%). 51 patients (13.7%) had plaque in ≥2 arterial beds in addition to their coronary disease. Predictors of extra-coronary plaque were older age (median 47.7 vs 44.4 years, p<0.0001), hypertension (32.3% vs 18.9%, p=0.013), and previous percutaneous coronary intervention (9.9% vs 3.0%, p=0.01). Patients with extra-coronary plaque had higher rates of cardiomegaly (68.8% vs 51.1%, p=0.01), cardiac fibrosis indicative of previous myocardial infarction (49.3% vs 31.9%, p=0.006) and multi-vessel coronary disease (73.5% vs 55.6%, p=0.007). Conclusion Only 1 in 5 people aged 1-50 years experiencing SCD from a coronary cause exhibit extra-coronary plaque. This limits the utility of screening for carotid or aortic plaque to predict coronary atherosclerosis. Individuals with extra-coronary plaque had a higher burden of cardiovascular risk factors and more established coronary disease.