Status of the coronary arteries at necropsy in diabetes mellitus with onset after age 30 years. Analysis of 229 diabetic patients with and without clinical evidence of coronary heart disease and comparison to 183 control subjects.

Clinical and morphologic observations were made in 229 necropsy patients with diabetes mellitus (DM) with onset of diabetes mellitus after 30 years of age--65 without (DM-CHD) and 164 with (DM + CHD) clinical evidence of coronary heart disease (CHD). These observations were compared to those in 183 age-sex-matched nondiabetic control subjects who died from a fatal coronary event (CHD-DM). The average number of three major (right, left anterior descending, left circumflex) coronary arteries per patient narrowed > 75 percent in cross-sectional area by atherosclerotic plaques was identical in the 229 diabetic patients (DM-CHD and DM + CHD) and in the control subjects (CHD-DM), namely, 2.5/3.0. This similarity in the amount of coronary arterial narrowing was present irrespective of the age at onset (after 30 years) or duration of diabetes mellitus. The DM + CHD patients had more severe narrowing of the three major coronary arteries than did the DM-CHD patients (p < 0.01). The amount of severe narrowing in the proximal halves of each of these three arteries was similar to that in the distal halves. The amount of severe (> 75 percent in cross-sectional area) narrowing of the left main coronary artery was greater in the patients with diabetes mellitus than in the nondiabetic controls: 13 percent versus 6 percent (p < 0.01). The type of treatment received by the patients with diabetes mellitus or their adherence to the therapeutic program as measured by the level of random fasting blood sugar did not alter the amount of severe coronary narrowing observed at necropsy.