Clinical and Functional Correlates of Early Microvascular Dysfunction After Heart Transplantation

1 Stanford University, Stanford, CA
Circulation Heart Failure (Impact Factor: 5.95). 08/2012; 5(6). DOI: 10.1161/CIRCHEARTFAILURE.111.962787
Source: PubMed

ABSTRACT BACKGROUND: -Microvascular dysfunction is emerging as a strong predictor of outcome in heart transplant recipients. At this time, the determinants and consequences of early microvascular dysfunction are not well established. The objective of the study was to determine risk factors and functional correlates associated with early microvascular dysfunction in heart transplant recipients. METHODS AND RESULTS: -Sixty-three heart transplant recipients who had coronary physiology assessment, right heart catheterization and echocardiography performed at the time of their first annual evaluation were included in the study. Microvascular dysfunction was assessed using the recently described index of microcirculatory resistance (IMR). The presence of microvascular dysfunction, pre-defined by an IMR > 20, was observed in 46% of patients at 1 year. A history of acute rejection and undersized donor hearts were associated with microvascular dysfunction at 1 year with an OR=4.0 (1.3-12.8) and OR=3.6 (1.2-11.1), respectively. Patients with microvascular dysfunction had lower cardiac index (3.1 ± 0.7 vs. 3.5 ± 0.7 L/min/m(2), p=0.02), and mild graft dysfunction measured by echocardiography-derived left and right myocardial performance indices [(0.54 ± 0.09 vs. 0.43 ± 0.09, p< 0.01) and (0.47 ± 0.14 vs. 0.32 ± 0.05, p< 0.01), respectively]. Microvascular dysfunction was also associated with a higher likelihood of death, graft failure or allograft vasculopathy at 5 years post transplant (hazard ratio of 2.52, 95% confidence interval between 1.04 and 5.91). CONCLUSIONS: -A history of acute rejection during the first year and smaller donor hearts were identified as risk factors for early microvascular dysfunction. Microvascular dysfunction assessed using IMR at 1 year was also associated with worse graft function and possibly worse clinical outcomes.

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