Subclinical impairment of coronary flow velocity reserve assessed by transthoracic echocardiography in young renal transplant recipients

Background: In renal transplant recipients (RTR) an increased risk to develop cardiovascular injury is present. Transthoracic Doppler echocardiographic assessment of coronary flow velocity reserve (CFVR), a sensitive and minimally invasive technique, was recently employed to detect both macrovascular and microvascular coronary artery disease (CAD) in different clinical settings. The prevalence of coronary involvement in young adult RTR is still unknown. The aim of the study was to investigate the presence of early cardiovascular damage in asymptomatic young adult RTR. Methods: Transthoracic Doppler echocardiographic-derived CFVR and common carotid intima-media thickness (IMT) were assessed in 25 asymptomatic young adult RTR (mean age 25.7 ± 7.0 years; range 17.3–43.9) without CAD and 25 healthy controls. Results: CFVR was lower in young adult RTR compared to controls (2.8 ± 0.6 vs. 3.5 ± 0.8; P < 0.001), meanwhile left ventricular wall motion and common carotid IMT were comparable in both groups. We found a negative correlation between CFVR and age (r = −0.50; P = 0.018) and months on dialysis (r = −0.54; P < 0.01). Conclusions: Young adult RTR showed a reduced CFVR reflecting an impaired coronary microcirculation, which is significantly related to the age and duration of dialysis; coronary microvascular damage is detectable in the absence of changes in common carotid IMT. Non-invasive evaluation of CFVR by transthoracic stress echocardiography could be a reliable method for identification of early coronary microvascular involvement in young adult RTR.