Coronary atherosclerosis in unheralded sudden coronary death under age 50:histo-pathologic comparison with 'healthy' subjects dying out of hospital

Aim: sudden coronary death (SCD) in older individuals is generally associat ed with extensive coronary atherosclerosis, although it may be the first ma nifestation of ischaemic heart disease. in younger age-groups, SCD may occu r in the presence of less severe disease. We sought to (1) examine the exte nt of coronary atherosclerosis in young victims of SCD compared with age- a nd sex-matched controls, (2) analyse the composition of atherosclerotic pla ques in these patients, (3) identify the predominant mechanism of SCD, and (4) evaluate the possibility of detecting this mechanism on the basis of mo rphologic plaque features, in particular presence and amount of lipid accum ulation and calcific deposits, Methods cmd results: coronary arteries were obtained at autopsy from 28 victims of SCD under age 50 with no prior clini cal manifestation of ischaemic heart disease (THD) and no myocardial scar f ormation and from 16 age- and sex-matched subjects dying of noncardiac caus es out of hospital. Sections of all available major coronary arteries were cut in 5-mm intervals to yield a total of 1357 histologic sections, which w ere analysed using digitised planimetry. Victims of SCD had significantly m ore major coronary arteries per subject with luminal area narrowing greater than or equal to 75% than controls ton average, 2.1 vs. 0.2). Plaque area per histologic section was 5.1 +/- 2.1 mm(2) in SCD cases and 2.0 +/- 0.9 m m(2) in controls (P < 0.001). The major constituent of all plaques was fibr ous tissue. Lipid core area per section was 0.49 <plus/minus> 0.59 mm(2) in SCD cases and 0.004 +/- 0.01 mm in controls (P(0.001), and calcified plaqu e area was 0.18 +/- 0.19 mm(2) in SCD cases and 0.02 +/- 0.05 mm(2) in cont rols (P < 0.001), both defining significant differences between SCD cases a nd controls. Arterial thrombosis, most often with underlying plaque rupture was the mechanism of SCD in > 80% of the cases. Considering histologic sec tions with greater than or equal to 50 and with greater than or equal to 75 % area stenosis, plaque rupture was independently predicted by lipid core a rea. Calcific deposits were a frequent feature of plaque rupture but were o nly associated with it in univariate analysis. Conclusions: the extent and severity of coronary atherosclerosis in young victims of SCD as the first m anifestation of IHD was substantially greater than in age-and sex-matched c ontrols and comparable with that previously reported in SCD cases with a br oader age range. Lipid core and calcified plaque areas provided for excelle nt separation between the two groups, which may have implications for ident ifying persons at increased risk for SCD by non invasive visualisation and assessment of the coronary arteries. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.