Background: Despite improvements in the care of patients who have received cardiac transplants, coronary allograft vasculopathy (CAV) remains the most prevalent cause of late allograft failure and cardiac mortality. Few proven therapies are available for this important disease. The presence of coronary collaterals imparts a favorable prognosis in patients with native ischemic heart disease; however, the impact of collaterals in CAV is unknown.
Methods and results: To determine whether the development of coronary collaterals is associated with improved outcomes in patients with CAV, we performed a retrospective analysis of patients followed in the heart transplant program at Barnes Jewish Hospital from 1994 to 2008. The primary end points included all cause mortality and the composite of all cause mortality, retransplantation, and inotrope dependence. We screened 485 patients and identified 59 (12%) subjects with moderate-to-severe CAV. Angiographically visible coronary collaterals were present in 34 (57%) subjects. Kaplan-Meier and Cox multivariable analyses revealed that patients with collaterals had reduced incidence of all cause mortality (hazard ratio, 0.20; P<0.001) and the composite end point (hazard ratio, 0.17; P<0.001). In addition, patients with collaterals had less severe heart failure symptoms as measured by New York Heart Association class. Immunostaining of biopsy specimens revealed that among patients with CAV, the presence of coronary collaterals correlated with increased microvascular density, reduced fibrosis, and decreased left ventricular end-diastolic pressure.
Conclusions: Together, these data demonstrate that the presence of coronary collaterals predicts a favorable prognosis in patients with CAV and suggests that interventions aimed at promoting collateral and microvascular growth may serve as effective therapies for this disease.
Keywords: collateral circulation; coronary circulation; heart transplantation.