Investigation of the frequency of hypertension and cardiovascular complications in pediatric kidney transplant recipients

Hypertension is one of the common comorbid conditions in pediatric kidney transplant recipients; associated with cardiovascular morbidity and mortality. Cardiovascular changes secondary to hypertension can be evaluated with left ventricular mass index (LVMI), carotid intima-media thickness (cIMT), pulse wave velocity (PWV), aortic stiffness index (ASI) and biochemical indicators. In our prospective case-control study, the frequency and risk factors of hypertension in pediatric kidney transplant recipient were examined; left ventricular hypertrophy, arterial stiffness (pulse wave velocity, aortic strain, aortic distensibility, aortic stiffness index), carotid intima-media thickness, serum hs-Troponin T and NT-proBNP values were compared in patients with and without hypertension and healthy volunteers. Seventy-seven kidney transplant recipients with a height of at least 120 cm, aged 5-18 years, who were followed up in the Pediatric Nephrology Department at least one year after the kidney transplant and 10 patients receiving dialysis and 10 healthy volunteers were included in the study. Demographic data, primary kidney disease and transplant characteristics, presence of hypertension in the post-transplant follow-up and treatments used were recorded. Office blood pressure, ambulatory 24-hour blood pressure, echocardiographic examination, analysis of cardiac biochemical indicators and carotid intima-media thickness measurements were performed. The prevalence of hypertension in kidney transplant recipients was 52% pre-transplant and 63.6% post-transplant, of whom 12.9% had resolution of hypertension during follow-up. 24.7% of post-transplant HT patients had uncontrolled hypertension, 24.7% had controlled hypertension and 2.6% had untreated hypertension. Masked hypertension was detected in 21 patients and white coat hypertension was detected in 6 patients. Hypertension was lower in patients who underwent bilateral nephrectomy. On the other hands, the frequency of humoral rejection were more frequent in the group with post-transplant HT. In addition, patient age and presence of HT before transplantation were found to be risk factors for post-transplant HT. LVMI, PWV and aortic stiffness index were higher in kidney transplant recipients compared to healthy volunteers. In addition, patients with uncontrolled HT had higher LVMI than the group with controlled HT. After kidney transplantation, more than half of the patients were confronted with HT. Patient age and the presence of HT before transplantation increased the risk. Cardiovascular parameters were more affected in the group of patients with uncontrolled HT. Therefore, regular blood pressure monitoring after transplantation is important and the high-risk group should be closely monitored. Cardiovascular organ scans should be performed regularly in patients with HT. Key Words: Kidney transplantation, Hypertension, Left ventricular mass index, Arterial stiffness, Pulse wave velocity