Objective: Assess the clinical implication of microvasculopathy detected by endomyocardial biopsy samples in patients post heart transplantation.
Methods: Light microscopic evaluations were performed in 278 endomyocardial biopsies harvested from 64 patients post heart transplantation for more than one year, microvasculopathy was defined as stenotic endothelial and/or medial disease.
Results: The patients with stenotic microvasculopathy were younger than those without microvasculopathy (40.7 ± 15.9 vs. 49.4 ± 8.7, P < 0.05). The mean score of acute cellular rejection (0.83 ± 0.39 vs. 0.37 ± 0.32, P < 0.01) and the numbers of ≥ grade II acute rejection (0.84 ± 0.16 vs. 0.23 ± 0.10, P < 0.01) were significantly greater in stenotic microvasculopathy group compared to those of non-stenotic group. Multivariate regression analysis confirmed that stenotic microvasculopathy is the independent risk factor for the mean acute rejection score (OR = 3.40, 95%CI, 4.62 - 193.07, P < 0.01), but not for the Quilty lesion, coronary heart disease of donor, diabetes mellitus. Angiographically confirmed coronary vasculopathy and cardiac dysfunction (χ(2) = 0.94, P > 0.05 and χ(2) = 2.90, P > 0.05) were similar between microvasculopathy group and non-microvasculopathy group.
Conclusion: Post heart transplantation microvasculopathy is an immune-mediated phenomenon and associated with higher mean score of acute cellular rejection and higher numbers of ≥ grade II acute rejection but was not the prognostic risk factor for coronary vasculopathy and function reduction after heart transplantation.