Heterogeneity of coronary flow reserve in the examination of multiple individual allograft coronary arteries

Background-Epicardial and resistance vessel function in the transplanted he art has been evaluated primarily in regions supplied by a single vessel. He terogeneity of flow among multiple perfusion fields as a marker of early en dothelial dysfunction in the microcirculation has not been evaluated previo usly. This study tested the hypothesis that increased variability of corona ry flow reserve (CFR) among multiple vascular regions would be associated w ith allograft coronary vasculopathy. Methods and Results-One hundred six posttransplant patients undergoing card iac catheterization had measurement of CFR in at least 3 major epicardial v essels. Patients were divided into those with minimal angiographic abnormal ities (n=37) and those with no angiographic abnormalities (n=69). The range s, coefficients of variation, and univariate and multivariate regression an alyses of CFR were computed to determine the major clinical factors influen cing the degree of variability. The abnormal angiographic group was older ( 54+/-11 versus 47+/-13 years; P<0.003), had older hearts (35+/-11 versus 27 +/-10 years; P<0.005), and were further posttransplant (1626+/-1022 versus 931+/-984 days; P<0.0009), There was no difference in global CFR between gr oups (normal, 3.4+/-0.8 versus abnormal, 3.4+/-0.7; P=NS), The coefficient of variation of CFR was higher for the abnormal group (16.3+/-8.6% versus 1 1.0+/-5.5%; P<0.0006). Univariate and multivariate predictors of increased variability in CFR included angiographic abnormalities, patient age, and bo dy mass index. Both angiographic abnormalities and an elevated CV of CFR we re predictive of a combined end point of death, congestive heart failure, o r subsequent development of greater than or equal to 50% coronary stenosis. Conclusions-These data demonstrate that increased variability of CFR is ass ociated with discernible allograft coronary arteriopathy and is predictive of outcome in patients after heart transplantation.