Endothelial dysfunction and cytomegalovirus replication in pediatric heart transplantation

Background-Cardiac allograft vasculopathy is the major limiting factor to the long-term success of pediatric heart transplantation. Cytomegalovirus (CMV) has been shown to be a significant risk factor for the development of cardiac allograft vasculopathy. Recent work has demonstrated CMV DNA in leukocytes in the absence of direct allograft infection, suggesting that vascular changes may not be limited to the allograft. Method and Results-Systemic arterial endothelial function was assessed with high- resolution ultrasound to determine brachial artery flow-mediated dilation in 50 pediatric heart transplant recipients (8 to 17 years of age; 27 male). Patients were separated into 2 groups according to CMV status: those without evidence of CMV replication after transplantation (n=38; 19 male) and patients with evidence of viremia after transplantation (n=12; 8 male). No patient had detectable viremia at the time of study. Flow-mediated dilation was significantly impaired in patients with evidence of CMV replication after transplantation (6.64 +/- 1.12%, mean +/- SE) compared with those without (9.48 +/- 0.56%; P=0.02). This difference remained after adjustment for age, time since transplantation, and medication. Pretransplantation recipient and donor CMV status and traditional CMV risk were not associated with flow-mediated dilation. Conclusions-CMV replication after cardiac transplantation is associated with chronic endothelial dysfunction in the systemic circulation in children. The implication for both systemic and coronary vascular health requires prospective evaluation.