Dichotomous pattern of coronary atherosclerosis 1 to 9 years after transplantation: Insights from systematic intravascular ultrasound imaging

Objective. The aim of this study was to evaluate the extent and distribution of coronary atherosclerosis after transplantation. Background. Transplant coronary artery disease is an impor tant cause of death after cardiac transplantation. Unlike coronary angiography, intravascular ultrasound is a sensitive tool for detection and quantitation of this disease. Methods. We performed intravascular ultrasound imaging in 132 (106 men, 50 ± 10 years) patients, 1 to 9 years after transplantation using a 30 MHz ultrasound catheter. Results. All three coronary arteries were visualized in 49, two in 62 and one in 21 patients. Of the 1,188 coronary artery segments, 706 were imaged (74% proximal, 64% mid and 40% distal). At least one site with atherosclerosis (intimal thickness ≥ 0.5 mm) was found in 83% of patients. Atherosclerosis was noted in 64% of proximal, 43% of mid- and 26% of distal segments. Disease was diffuse in 48% and focal in 52%, circumferential in 66% and noncircumferential in 34%. Focal atherosclerosis was more common in proximal (59%) than mid (48%) and distal segments (27%) (p = 0.001). Noncircumferential plaques were more common in the proximal (42%) than mid- (28%) and distal segments (12%) (p = 0.001). This pattern of focal and noncircumferential disease proximally, diffuse and circumferential disease distally, was observed irrespective of the time from transplantation. Conclusions. Atherosclerosis was detected in more than 80% of patients, with proximal segments most frequently involved. Diffuse and circumferential atherosclerosis was more common in mid- and distal segments. However, focal and noncircumferential involvement was more frequent proximally, a similar pattern to native atherosclerosis. These findings suggest that transplant coronary artery disease has a dual etiology based on the dichotomous pattern of atherosclerosis seen by intravascular ultrasound.