Described herein are necropsy findings in the 4 major (left main, left anterior descending, left circumflex, and right) epicardial coronary arteries in 86 patients aged 10-70 years who never had symptoms of myocardial ischemia, and at autopsy had otherwise anatomically normal hearts. All 86 died of a non-cardiovascular condition. In each of these patients all 4 major epicardial coronary arteries were excised intact from the heart, divided into 5-mm segments, and each segment prepared for histologic examination. The degrees of cross-sectional area (CSA) narrowing were determined from histologic examination of each 5-mm segment. The degree of narrowing in each 5 mm segment was divided into 4 categories: 0% to 25%, 26% to 50%, 51% to 75%, and 76% to 100%. Twelve patients (14%) had ≥1 artery narrowed >75% in CSA, a single artery in 9 patients, and 2 arteries in each of 3 patients. In contrast to the relative infrequency of narrowing >75%, narrowing 51-75% was common, and was present in 36 (42%) of the 86 patients. Of the 258 major coronary arteries (excludes the left main) studied in the 86 patients, 15 (6%) were narrowed >75%, and 70 (24%) were narrowed 51% to 75% in CSA. Even mild narrowing (26% to 50%) of the left main coronary artery (66 patients) was generally accompanied by 51% to 75% or greater narrowing of at least one of the other major coronary arteries. In conclusion, even hearts which have functioned normally and are otherwise anatomically normal, usually have some degree of atherosclerotic plaque in the major epicardial coronary arteries.
Although there is considerable information on the status of the epicardial coronary arteries in patients with fatal myocardial ischemia, there is much less morphologic information about the status of the major epicardial coronary arteries in persons without symptoms of myocardial ischemia. Earlier studies of the prevalence of coronary disease in the general population have not focused exclusively on asymptomatic persons with otherwise morphologically and functionally normal hearts. Such is the purpose of this report.
Method
The 86 asymptomatic (from a cardiac standpoint) patients, aged 10 to 70 years, 43 male and 45 female, were studied in the Pathology Branch of the National Heart, Lung, and Blood Institute of the National Institutes of Health in the years 1975 and 1976. Of the 86 patients, 77 (90%) had died from neoplastic diseases (carcinoma 37, lymphoma 19, leukemia 15, sarcoma 6) and 9, from nonneoplastic diseases (systemic lupus erythematosus 2, and one each from 7 different conditions). Among the 86 patients, 10 (12%) had had systemic hypertension; 6 (7%), diabetes mellitus; 25 (29%) had received corticosteroids for >1 month, and 15 (17%) had received therapeutic irradiation to the mediastinum, possibly also to the heart ( Table 1 ). None had ever reported symptoms or had signs compatible with heart disease. In each the electrocardiogram was either normal, or if abnormal only because of nonspecific ST-T abnormalities. The serum total cholesterol values (71 patients) ranged from 66 to 400 mg/dl (mean 169): in 17 patients (24%) the level was >200 mg/dl, and in 26 (37%) the level was ≤150 mg/dl. In each patient, the heart weighed ≤400 g, the left and right ventricular wall thicknesses and cavity sizes were normal, and each was free of foci of myocardial fibrous and necrosis ( Table 2 ). The mean heart weights in the patients >20 years of age were as follows: 240g in the group aged 10 to 30 (13 patients were >20 years of age); 272 g in those aged 31 to 50, and 303 g for the group aged 51 to 70 years. In the patients >20 years of age, the body weight ranged from 26 to 123 Kg (mean 61) (57 to 218 lbs [mean 134]).
| Variable | Age group (Years) | |||
|---|---|---|---|---|
| 10 – 30 (n = 22) | 31 – 50 (n = 27) | 51 – 70 (n = 37) | Totals (n = 86) | |
| Males | 15 (71%) | 11 (41%) | 16 (42%) | 42 (49%) |
| Females | 7 (29%) | 16 (59%) | 21 (58%) | 44 (51%) |
| Systemic Hypertension | 1 (4%) | 2 (7%) | 7 (18%) | 10 (12%) |
| Diabetes Mellitus | 0 | 1 (4%) | 5 (14%) | 6 (7%) |
| Corticosteroids Rx >1 month | 9 (40%) | 9 (33%) | 12 (32%) | 25 (29%) |
| Mediastinal Irradiation | 3 (13%) | 8 (30%) | 4 (11%) | 15 (17%) |
| Total cholesterol (mg/dL) | 84-226 (m 136) | 106 – 248 (m 168) | 66 – 400 (m 179) | 66 – 400 (m 169) |
| Body weight (Kg) | 29 – 83 (m 52) | 44 – 99 (m 64) | 26 – 96 (m 64) | 26 – 99 (m 61) |
| Heart Weight (g) | Age group (Years) | ||
|---|---|---|---|
| 10 – 30 (n=22) * | 31 – 50 (n=27) | 51 – 70 (n -37) | |
| Males | 180 – 400 (263) | 210 – 380 (287) | 280 – 400 (340) |
| Females | 180 – 260 (217) | 150 – 350 (263) | 130 – 370 (275) |
| Totals | 180 – 400 (247) * | 150 – 380 (272) | 130 – 400 (303) |
⁎ Of the 22 patients, 13 were >20 years (10 male and 3 female). Their heart weights ranged from 210 – 400g, (average 296 g).
The major epicardial coronary arteries were dissected intact from the heart, and each was placed in a separate container and fixed in 10% buffered formalin. After fixation, each artery was decalcified (if needed) and cut transversely at 5-mm intervals. The 5-mm segments were placed in individual plastic containers. The tissues were then dehydrated (alcohols), cleared (xylene), imbedded in paraffin, and cut into 6-um thick sections. Two histologic sections, one stained with hematoxylin and eosin, and the other by the Movat method, were prepared from each 5-mm section. In each of the 86 patients, the left anterior descending, right, and left circumflex coronary arteries were so prepared. In addition, in 66 of the 86 patients the left main coronary was of sufficient length to prepare a good right angle section, and it also was so prepared. Each histologic section was examined microscopically and the degree of cross-sectional area (CSA) luminal narrowing scored as 0 to 25%, 26% to 50%, 51% to 75%, and 76% to 100%. The most narrowed 5-mm section in each of the major coronary arteries was the one reported in this study. In addition to determining the degree of CSA luminal narrowing, the various components of the luminal plaques were determined, and the presence or absence of intramural hemorrhage and luminal thrombus was recorded. A total of 3501 histologic sections representing 1,750 cm of coronary artery were examined.
Results
The maximal degree of CSA luminal narrowing of any of the 3 major epicardial coronary arteries (left anterior descending, left circumflex, and right) is shown in Table 3 . Of the 22 patients aged 10 to 30 years, 2 (9%) (single artery in both) had a coronary artery narrowed >75%; of the 27 patients aged 31 to 50 years, 3 (11%) had a coronary artery narrowed >75%, and among the 37 patients aged 51 to 70 years, 7 (19%) had at least one artery narrowed >75%. A total of 258 coronary arteries (3 per patient) were examined in the 86 patients, and 12 (14%) had a major coronary artery narrowed >75%: a single artery in 9 patients, and 2 arteries in each of 3 patients ( Table 4 ). Of the latter 3 patients, 2 were men aged 65 and 66 years, respectively, and the third was a woman aged 68 years. In contrast to the relative infrequency of CSA narrowing >75%, 51% to 75% CSA narrowing was common, and was present in 36 ([42%] of the 86 patients), and was often present in >1 coronary artery. Of the 258 major coronary arteries 70 (24%) were 51% to 75% narrowed. The left anterior descending coronary artery was the one most often narrowed >75% (9 patients), and the right was the next most commonly narrowed to this degree (6 patients). In none of the patients was the left circumflex coronary artery narrowed >75 % ( Table 5 ).
a* One coronary artery in 3 patients and 2 coronary arteries in 1 patient
b† One coronary artery in 6 patients, 2 coronary arteries in 3 patients, all 3 coronary arteries in 2 patients
c‡ One coronary artery in 5 patients, 2 coronary arteries in 6 patients, all 3 coronary arteries in 10 patients
d§ One coronary artery in 2 patients
e¶ One other coronary artery 51 – 75% in 2 patients, 2 other coronary arteries 51 – 75% in 1 patient
f ⁎⁎ Three patients with 2 coronary arteries > 75%, 1 of whom had 51 – 75% of the third coronary artery, and 2 patients who had < 50% of the third coronary artery Four patients with 1 coronary artery >75%, 1 of whom had 51 – 75% of the other 2 coronary arteries, 2 patients with 51 – 75% of 1 coronary artery and < 50% narrowing of the third coronary artery, 1 patient with <50% narrowing of the other 2 coronary arteries
| Number of coronary arteries maximally narrowed | Age group (Years) | Totals | |||
|---|---|---|---|---|---|
| 10 – 30 (n=22) | 31 – 50 (n=27) | 51 – 70 (n=37) | |||
| Categories of Narrowing | Patients | ||||
| 26 – 50% 0 1 2 3 | 11 (50%) 4 (18%) 1 (5%) 0 | 8 (30%) 4 (15%) 0 1 (4%) | 4 (11%) 3 (8%) 1 (3%) 1 (3%) 333 | 23 (27%) 11 (13%) 2 (2%) 2 (2%) | |
| 51 – 75% 1 2 3 | 3 (14%) 1 (5%) 0 | 6 (22%) 3 (11%) 2 (7%) | 5 (14%) 6 (16%) 10 (27%) | 14 (16%) 10 (12%) 12 (14%) | |
| ≥ 75% 1 2 3 | 2 (9%) 0 0 | 3 (11%) 0 0 | 4 (11%) 3 (8%) 0 | 9 (10%) 3 (3%) 0 | |
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