Sudden coronary death caused by pathologic intimal thickening without atheromatous plaque formation

Atherosclerotic plaques progress from early lesions with little free cholesterol and lipid to late fibroatheromas with necrotic cores that may rupture. The frequency of severe coronary atherosclerosis without core formation in any artery in sudden coronary death is not known.

We studied 314 hearts from 253 men and 61 women who died suddenly from severe coronary stenosis (≥ 1 epicardial artery with ≥ 75% luminal area narrowing) and with no other cause of death. If no section demonstrated any necrotic core, the designation was nonatheromatous atherosclerosis; if there was ≥ 1 necrotic core, the designation was atheromatous atherosclerosis. Plaques were scored for the presence of calcification, intimal inflammation, and neovasculature on a 5-point scale. Plaque burden was estimated semiquantitatively.

In 22 men (9%) and 14 women (23%), there were no necrotic cores in any plaque (nonatheromatous atherosclerosis). Fourteen of these 36 nonatheromatous atherosclerosis cases had focal acute thrombus due to erosion (39%). Of the remaining 278 cases (atheromatous atherosclerosis), acute erosions were present in 25 (9%; P<.0001). Sudden death due to nonatheromatous atherosclerosis occurred more frequently in women (P<.001), in Blacks (20%; P=.003), and at a younger age (44± 12 years) than atheromatous atherosclerosis (52 ± 12 years; P=.0003). On multivariate analysis, nonatheromatous atherosclerosis was associated with younger age (P=.001), female gender (P=.004), and Black race (P=.006).

Nonatheromatous atherosclerosis constitutes slightly >10% of sudden coronary deaths and is more frequent in young Black women. Nonatheromatous atherosclerosis is a relatively infrequent pathway for coronary plaque progression, leading to severe disease and sudden death that may involve plaque erosion.