Blood Pressure In Renal Transplant Recipients Research Articles

The role of dietary cations in the blood pressure of renal transplant recipients

The role of dietary cations in hypertension has been evaluated in the general population and selected subgroups, but its contribution to blood pressure (BP) elevations in patients with functional renal allografts has not been critically examined. After counseling based on Dietary Approaches to Stop Hypertension (DASH) guidelines, we measured timed 24-h urine excretion rates of sodium, potassium, calcium, and magnesium as a surrogate for their dietary intake, in 244 stable adult single-organ renal transplant recipients, correlating these with averaged blinded clinic-measured BP values. Multiple linear regression analysis adjusting for factors affecting BP in transplant recipients was performed. There was no correlation between systolic (SBP) or diastolic pressure (DBP) and 24-h urine excretion rates of each cation. There was no BP difference between patients receiving cyclosporine and tacrolimus (127/77 vs. 129/78 mmHg, p = 0.38), or in cation excretion except for calcium (2.85 +/- 2.0 vs. 2.90 +/- 2.8, p = 0.002). Protein excretion (p < 0.0001), age (p = 0.002), and weight (p = 0.04) were positively associated with SBP, while only weight (p = 0.01) was associated with DBP by multivariate analysis. Dietary cation intake is not significantly associated with BP in renal transplant recipients. These data do not support recommendations to alter dietary cation intake as part of the management of post-transplantation hypertension.

Insights from ambulatory blood pressure monitoring: diagnosis of hypertension and diurnal blood pressure in renal transplant recipients.

Accurate diagnosis of hypertension is essential in chronic kidney disease patients, as it is linked to increased left ventricular mass, stroke, cardiovascular mortality and morbidity, and progression to end-stage renal disease. Elevated blood pressure (BP) detected by ambulatory BP monitoring (ABPM) has been shown to be predictive of worse outcome in chronic kidney disease patients. Another predictor of worse outcome is diurnal BP variation, measured also by ABPM. In this study, the authors examined the relationship (concordance or discordance) between blood pressure measured by ABPM compared with daytime office BP, and also explored the predictors of diurnal variation in renal transplant recipients. All the patients who underwent renal transplantation and follow-up at the authors' institution from January 1998 to January 2003 were involved in this study (n=177) in addition to another randomly selected 64 patients that underwent transplantation before 1998. All patients had their ABPM performed according to previously described protocols at least 2 weeks after discharge from the hospital, dialysis-independent and with a functioning renal allograft. The authors found a positive correlation between systolic BP (SBP) diurnal variation and age (r =0.263, P <0.0001), glomerular filtration rate (GFR) (r =-0.229, P <0.0001), cyclosporine trough (r =0.171, P =0.047), and ABPM-to-transplant interval (r =-0.133, P =0.039). After fitting a regression model, the authors found that only GFR (P <0.0001) and age (P =0.001) were independent predictors of SBP diurnal variation (r =0.357). Concordance rate between casual BP and ABPM was 80%, and by using casual BP, only 15% of hypertensive renal transplant patients would be erroneously diagnosed as normotensive. The authors found that SBP diurnal variation is predicted independently by age and GFR, although it does correlate with cyclosporine trough and ABPM-to-transplant interval. In addition, the authors showed that ABPM is a more sensitive method for diagnosing hypertension than is sole reliance on office BP in renal transplant recipients.

A prospective study of the physician effect on blood pressure in renal-transplant recipients.

Physician presence results in elevated blood pressure (BP) in the general population. The determinants of this phenomenon in renal-transplant recipients are not known. We prospectively evaluated BP changes with physician presence in 231 stable adults with graft survival > or =1 year. A nurse measured timed sitting BP by Korotkoff phase I and V sounds before physician entry, during physician presence and upon exit. The haemoglobin, creatinine, weight, immunosuppressive drug dosage and/or level, and anti-hypertensive medication profile were recorded. Paired Student's t-test with Bonferroni correction and multiple linear regression analysis were used to examine BP changes. Characteristics of patients with change in mean arterial BP > or =+10 mmHg (n=55, "high") were compared with those with change < or =+5 mmHg (n=132, "low") by chi-square or Wilcoxon rank sum test as appropriate. A group of 100 recipients served as controls in whom BP was measured thrice without physician presence on any occasion. A multivariate analysis was performed for the combined groups controlling for physician entry as a predictor variable. In the study group, systolic BP (mean+/-SE) rose by 4.2+/-0.8, diastolic BP by 3.5+/-0.5 and mean arterial BP by 3.5+/-0.5 mmHg in physician presence. The BP returned to baseline with exit (P<0.001 for each). Higher haemoglobin and creatinine demonstrated a trend towards influencing the physician-induced rise in diastolic BP. The "high" sub-group demonstrated a shorter time to the second BP measurement in physician presence (P=0.03) and a trend towards morning measurements (P=0.08). In the control group, systolic BP declined by 3.2+/-0.9 mmHg from the first to the second measurement, with a further decline of 2.4+/-0.6 mmHg from the second to third measurements. Diastolic BP did not change. In the combined multivariate analysis, physician entry was an independent predictor of BP change (P=0.0001). Renal-transplant recipients demonstrate a significant physician effect on BP despite adequate experience with post-transplant clinic visits and BP-altering medication. This population deserves further evaluation through ambulatory BP monitoring.

Effect of Dietary Fish Oil on Renal Function and Rejection in Cyclosporine-Treated Recipients of Renal Transplants

Dietary fish oil exerts effects on renal hemodynamics and the immune response that may benefit renal-transplant recipients treated with cyclosporine. To evaluate this possibility, we studied the effect of fish oil on renal function, blood pressure, and the incidence of acute rejection episodes in cyclosporine-treated recipients of renal transplants. In a randomized, double-blind trial, 33 recipients of first cadaveric kidney transplants who were treated with cyclosporine and prednisolone ingested 6 g of fish oil daily during the first postoperative year (the fish-oil group), whereas another 33 renal-graft recipients treated with cyclosporine and prednisolone ingested 6 g of coconut oil daily for three months after which time it was stopped (the control group). One year after transplantation, the fish-oil group had higher median values than the controls for glomerular filtration rate (53 vs. 40 ml per minute per 1.73 m2, P = 0.038) and effective renal plasma flow (214 vs. 178 ml per minute per 1.73 m2, P = 0.023) and lower mean arterial pressure (103 vs. 118 mm Hg, P = 0.0011). The cyclosporine doses in the two groups were similar. The cumulative number of rejection episodes was 20 in the controls, as compared with 8 in the fish-oil group (P = 0.029). One-year graft survival also tended to be better in the fish-oil group, (97 vs. 84 percent, P = 0.097). The daily administration of 6 g of fish oil during the first postoperative year has a beneficial effect on renal hemodynamics and blood pressure in renal-transplant recipients treated with cyclosporine. Although the fish-oil group had significantly fewer rejection episodes than the control group, graft survival at one year was not significantly better in the fish-oil group.