Repeated intravascular ultrasound imaging in cardiac transplant recipients does not accelerate transplant coronary artery disease

OBJECTIVES: This study was designed to examine the impact of repeated intravascular ultrasound (IVUS) examinations on transplant coronary artery disease (CAD). BACKGROUND: Serial IVUS is the most accurate method for early detection and surveillance of transplant CAD. However, the long-term safety of serial IVUS exams is not well described. Accordingly, we examined the impact of repeated IVUS examinations on transplant CAD. METHODS: We examined 226 transplant recipients who underwent one or more IVUS examinations and coronary angiography at least one year after the last IVUS exam. The coronary angiograms were analyzed using quantitative coronary angiography. Vessel diameters, frequency, and severity of stenoses in IVUS-imaged and nonimaged coronary arteries were compared. In a subgroup analysis of 31 patients, angiographic lumen diameters were measured at baseline (within eight weeks of transplantation) and during follow-up (after two, three, or four IVUS studies). RESULTS: In the 226 patients, 548 coronary arteries were previously imaged by IVUS and 130 arteries were not imaged by IVUS. On subsequent angiograms, stenoses were observed in 16.2% (21/130) of nonimaged arteries and 19.5% (107/548) of imaged arteries (p = 0.38). The arterial diameters of nonimaged and imaged arteries were not significantly different (p = 0.07), regardless of the number of IVUS exams and duration of follow-up. Subgroup analysis revealed a significant decrease in vessel lumen diameter over time in nonimaged as well as imaged arteries. The magnitude of the diameter decrease was not significantly different between the two groups. CONCLUSIONS: Repeated IVUS examinations following heart transplantation do not result in angiographically evident acceleration of transplant CAD. Therefore, serial IVUS imaging is a safe method for the detection and surveillance of transplant CAD.