Minimal extra-cardiac atherosclerosis present in young people with sudden cardiac death due to coronary artery disease

Abstract Aim To define the association between severe coronary artery disease and widespread atherosclerosis in younger 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. Presence of extra-coronary atherosclerosis greater than modified American Heart Association class III was assessed in 5 arterial beds (intra-cerebral vessels, aorta, carotid, renal and femoral arteries). Results 3,044 individuals experienced SCD; 356 were due to coronary artery disease and 64 (18.0%) had extra-coronary plaque. Plaque was identified in aorta (61/356 patients, 17.1%), carotid arteries (9/356, 2.5%), iliofemoral arteries (11/356, 3.1%), intracerebral arteries (4/153, 2.6%) and renal arteries (6/356 patients, 1.7%). The only feature associated with extra-coronary plaque was older age (median 47.8 vs 44.4 years, p=0.0002). Patients with extra-coronary plaque had higher rates of cardiomegaly (67.2% vs 50.7%, p=0.022), cardiac fibrosis indicative of previous myocardial infarction (45.3% vs 31.2%, p=0.030) and multi-vessel coronary disease (72.6% vs 55.6%, p=0.014). Conclusion Fewer than 1 in 5 people aged 1-50 years experiencing SCD from a coronary cause exhibit extra-coronary plaque, suggesting that in young people severe atherosclerosis is not necessarily a systemic disease. This limits the utility of screening for carotid or aortic plaque to predict coronary atherosclerosis on an individual level. Individuals with extra-coronary plaque were older with more established coronary disease.