The study group consisted of 68 cardiac allograft recipients (63 men and 5 women, 43 +/- 12 years old). We performed a re-evaluation of 1071 endomyocardial biopsy specimens to search for microvascular diseases and lipofuscin in cardiocytes. Endomyocardial biopsy specimens with an International Society for Heart and Lung Transplantation rejection grade of 2 or more and those without arterioles were excluded. Abnormalities found in the remaining 517 specimens were correlated with the grade of rejection