Quantification of amounts of coronary arterial narrowing in patients with types II and IV hyperlipoproteinemia and in those with known normal lipoprotein patterns.

The amount of cross-sectional area narrowing by atherosclerotic plaques in each 5 mm long sement of the left main, left anterior descending, left circumflex, and right coronary arteries was analyzed at necropsy in 15 patients with type II hyperlipoproteinemia (HLP), in 13 with type IV HLP, and in 10 with known normal lipoprotein patterns. All 38 study patients had clinical evidence of coronary heart disease. Of the 2593 five mm segments examined histologically, narrowing of 76% to 100% in cross-sectional area by aterosclerotic plaques was as follows: type II = 39%, type IV = 67%, and normal lipoprotein pattern = 35% (controls = 4%). Utilizing a scoring system of 1 to 4 for the four categories of narrowing (0% to 25%, 26% to 50%, 51% to 75%, 76% to 100%), the mean score per 5 mm segment for the patients with type IV HLP was significantly higher (3.5) than that for the patients with type II HLP (3.0), normal lipoprotein patterns (3.0), and the controls (2.3). Thus, our patients with type II HLP and those with normal lipoprotein patterns had similar amounts of severe coronary narrowing and significantly less severe coronary narrowing than the patients with type IV HLP.