[Prevalence of posttransplant hypertension in pediatric kidney transplant recipients: effect on long term allograft survival].

Background: Arterial hypertension after renal transplantation has been identified as an adverse factor over the long term allograft function, thus identification and treatment of this entity has an impact on graft survival, as in patient survival. Studies about pediatric receptor populations have reported a prevalence of hypertension after renal transplantation ranging from 58 to 90%. In Mexico, the pre-valence of arterial hypertension after renal transplantation has been reported as 71% for an adult population attending a main hospital center in Mexico. No pediatric receptor studies in Mexico have reported the prevalence of hypertension after renal transplantation so far. The purpose of our study was to document the prevalence of arterial hypertension after renal transplantation in pediatric receptors, as well as its impact on allograft survival on a long term basis.

Material And Methods: We performed a retrospective analysis among pediatric patients who underwent renal transplantation at our center, Centenario Hospital Miguel Hidalgo, between years 2000 to 2006.

Results: A total of 111 pediatric renal transplantation receptors were included, among whom 56 patients were classified as hypertensive (HT) and 54 patients were classified as nomotensive (NT) (one patient had to be excluded due to early allograft dysfunction). The mean age at the time of transplantation for the population under study was 14 +/- 3 years, with a predominance of male gender over females (1.5:1). In 89% of the transplantations, the source of the allograft was a living donor. The prevalence of arterial hypertension after renal transplantation in our population was 50.5%. Among patients in the HT group at least an episode of acute rejection presented in 8.9% (n=5) of the cases, compared to only 3.7% (n=2) of patients in the NT group with an episode of acute rejection. Likewise, the prevalence of chronic allograft nephropathy detected in the HT group was 11% (n=6) vs. 7% (n=4) in the NT group. The mean serum creatinine levels were 1.0 +/- 0.4 mg/dL for the HT group and 0.9 +/- 0.3 mg/dL for the NT group at the first month followup, however mean serum creatinine levels addressed at the last consult were different among groups: 1.7 +/- 1.8 mg/dL for the HT group versus 1.1 +/- 0.5 mg/dL for the NT group. Patient survival was similar for both groups (98%) and the follow-up period was also similar, being 39 +/- 12 months for the HT group and 39 +/- 17 months for the NT group. The multivariate Cox proportional hazard analysis demonstrated that the number of antihypertensive drugs needed to achieve the control of blood pressure, and the presence of chronic allograft nephropathy, were the independent risk factors associated to a graft loss at long term.

Conclusion: The prevalence of hypertension after renal transplantation in our pediatric population was 50.5%, which is clearly towards the inferior limit of the reported prevalence in other studies (50-90%). The tight control of blood pressure is an intervention that may have a significant impact on graft survival at long term. In our study, the severity of arterial hypertension after renal transplantation represented as the number of antihypertensive drugs needed to achieve control of blood pressure, as well as the presence of chronic allograft nephropathy, were the factors associated to long term graft loss.