Cellular rejection and rate of progression of transplant vasculopathy: a 3-year serial intravascular ultrasound study.

Intravascular ultrasound (IVUS) is established as the optimal method for early detection of transplant vasculopathy. The association between cellular rejection and development of transplant vasculopathy remains controversial. This study attempts to determine the rate of progression of transplant vasculopathy lesions and its relationship with cellular rejection in a long-term (> 1 year) IVUS serial follow-up.A study cohort of 47 patients undergoing heart transplantation from 1993 to 1995 was evaluated. Intravascular ultrasound was performed at baseline (within 8 weeks) and annually for a period of 3 years to determine maximum intimal thickness and maximum plaque area in each coronary segment. Significant allograft vasculopathy was defined as a site with intimal thickness > 0.5 mm not present at baseline. Biopsy results were scored by assigning a numerical weight to each ISHLT grade during the first year. Donor lesions ranged from 0.86 to 1.1 mm, showing no evidence of progression at serial follow-up. De novo lesions were identified in 30 patients. These lesions appeared yearly but progressed slowly. The average biopsy score in the entire cohort was 1.1 +/- 0.8. Average biopsy score was > 1.0 in 35 patients with significant linear correlation between the rate of intimal progression and biopsy score (r = 0.42, p = 0.01). Multivariate analysis demonstrated that only the biopsy score correlated with the rate of progression. Lesions of donor atherosclerosis do not change significantly after transplantation. However, de novo lesions continue to develop every year. In patients with evidence of rejection, the rate of progression of transplant vasculopathy correlates with the severity of rejection.