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 important 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 > or = to 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.
Conclusion: 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.