Changes in Blood Pressure and Arterial Hemodynamics following Living Kidney Donation

Kidney transplantation and kidney donation do not affect short-term blood pressure variability

PURPOSE

Blood pressure variability (BPV) is an independent cardiovascular risk factor in CKD. Kidney transplantation (KTx) is associated with improved BP levels for kidney transplant recipient (KTRs), without evoking significant changes in donors. The aim of this study was to assess the short- and mid-time effects of KTx and donation on short-term BPV in KTRs and their respective living kidney donors.

MATERIALS AND METHODS

Forty KTRs and their respective donors were evaluated with 24-h ABPM (Mobil-O-Graph-NG) at baseline (1 month before), 3-months and 12-months after KTx. Standard-deviation (SD), weighted-SD (wSD), coefficient-of-variation (CV), average-real-variability (ARV) and variability independent of mean (VIM) for SBP/DBP were calculated with validated formulas.

RESULTS

All 24-h systolic and diastolic BPV indexes studied did not change significantly from baseline to 3-month (SBP-wSD: 12.8 ± 3.0 vs 13.2 ± 3.4 mmHg, p = 0.608; SBP-ARV: 10.3 ± 2.4 vs 10.8 ± 2.6 mmHg, p = 0.463) and 12-month evaluation (SBP-wSD 12.8 ± 3.0 vs 12.1 ± 2.8; p = 0.424 and SBP-ARV: 10.3 ± 2.4 vs 10.2 ± 2.5; p = 0.615) after kidney transplantation in the KTRs.In kidney donors, all 24-h systolic BPV indices displayed a trend towards higher values at 3 months compared to baseline, but without reaching statistical significance (SBP-wSD: 12.2 ± 2.8 vs 13.6 ± 4.2 mmHg, p = 0.107 and SBP-ARV: 10.1 ± 2.1 vs 11.2 ± 3.1 mmHg, p = 0.099), the levels of 24-h systolic SBP indices at 12-months were almost identical to baseline values. 24-h diastolic BPV indices at 3-month and 12-month evaluation were similar to baseline.

CONCLUSION

Short-term BPV did not change significantly 3 and 12 months after kidney transplantation/donation neither in KTRs nor in living kidney donors. Longitudinal studies examining associations of BPV with adverse outcomes in these individuals are needed.

Chronic Kidney Disease Risk in Living Kidney Transplant Donors: A Long-Term Follow-Up Study

BACKGROUND

Living kidney donors (LKD) may experience some untoward consequences following donation such as development of chronic kidney disease (CKD). In this study, we aimed to investigate the rate of development of CKD and factors affecting the development of CKD in LKDs during long-term follow-up from a center in Turkey.

METHODS

This study was a retrospective analysis of LKDs followed between January 2000 and December 2017. Pre-transplant and post-transplant clinical data of the 338 LKDs were recorded and compared. Factors affecting the development of stage 3 and later stages of CKD were analyzed.

RESULTS

Majority of the donors were females (64.2%), and the median age of all donors was 47 (39-54) years. Stage 3 CKD developed in 50 donors during the median follow-up of 71 months. Older age at the time of transplantation and a low pre-transplant estimated glomerular filtration rate (eGFR) were determined as the factors affecting the development of stage 3 CKD (p < 0.001, p < 0.001). The receiver operating characteristic analysis showed that the cut-off age for the development of stage 3 CKD was 50.5 years. Newly diagnosed hypertension was detected in 57 patients (16.8%) after the transplantation. While hypertension was seen at a rate of 42% in those with an eGFR <60 mL/min/1.73 m2, it was detected at 19.4% in the group with an eGFR >60 mL/min/1.73 m2 (p < 0.001).

CONCLUSION

These results reveal that being a LKD is associated with the development of CKD and hypertension. Age and eGFR values at the time of transplantation were the determinants for the development of CKD.

Effect of Congenital or Acquired Renal Mass Reduction on Arterial Stiffness

BACKGROUND

The changes in kidney functions, adversely affect the cardiovascular system. The aim of this study was to investigate whether arterial stiffness (AS), an indicator of subclinical atherosclerosis, was affected in patients with congenital or acquired reduced renal mass.

METHODS

In this prospective study, a total 135 patients (mean age 43.4±8.5 years and 71.9% female) with congenital unilateral small/non-functioning kidney or unilateral agenesis or with unilateral nephrectomy were included. As control group, 44 healthy individuals with similar age and gender (mean age, 42.5±7.1 year and 61.4% female) were included. Estimated glomerular filtration rate (eGFR) was calculated by Modification of Diet in Renal Disease formula. Official blood pressures (BP) and 24-h ambulatory non-invasive BP of both groups were measured. AS was assessed with pulse wave velocity (PWV) by using Mobile-O-Graph NG arteriograph device using oscillometrical method.

RESULTS

There was no difference in terms of BP parameters and body mass index between groups. eGFR values of control group and study group were 93±19ml/min/1.73m² and 89±28ml/min/1.73m², respectively (p=0.379). Compared with control group, the study group had higher PWV values (6.72±1.11m/sec vs 6.29±0.75m/sec, p=0.018). In linear regression analysis, PWV was found to be correlated with age (β=0.752, p<0.001), and daytime ambulatory systolic BP (β=0.345, p<0.001).

CONCLUSION

Our study showed that AS was increased in patients with reduced renal mass and this increase in AS was related to age and systolic BP. No relation was determined between AS and eGFR. This article is protected by copyright. All rights reserved.

A parallel evaluation of short- and mid-term changes of ambulatory blood pressure in kidney transplant recipients and kidney donors

Introduction

Kidney transplantation (KTx) is associated with improved blood pressure (BP) levels for kidney transplant recipients (KTRs) without evoking significant changes in donors. However, there is a paucity of studies offering simultaneous detailed evaluation of BP profiles over time in transplant donor-recipient pairs. The aim of the present study was the parallel evaluation of ambulatory BP levels and trajectories in KTRs and their respective living kidney donors in the short and mid-term following KTx.

Methods

The study enrolled 40 prospective adult KTRs and their 40 respective donors. All participants were evaluated with 24-h ambulatory BP monitoring (Mobil-O-Graph NG device) at three time points: baseline (1 month before KTx), 3 months and 12 months after KTx.

Results

In KTRs, 3-month 24-h systolic BP (SBP) was marginally reduced and 12-month 24-h SBP significantly reduced compared with baseline [131.9 ± 13.3 versus 126.4 ± 11.9 mmHg (P = .075) and 123.9 ± 10.3 mmHg (P = .009),  respectively]. At both the 3- and 12-month time points, 24-h diastolic BP (DBP) was significantly reduced [86.7 ± 11.5 versus 82.2 ± 8.1 mmHg (P = .043) and 80.3 ± 8.5 mmHg (P = .009)]. Similar observations were made for day- and night time SBP and DBP. Repeated-measures analysis of variance (ANOVA) showed a significant gradual decrease over time in mean 24-h SBP [F(1.463, 39.505) = 3.616; P = .049, partial η ² = 0.118] and DBP [F(1.374, 37.089) = 11.34; P = .055, partial η ² = 0.116]. In contrast, in kidney donors, 24-h SBP [118.5 ± 11.6 versus 118.2 ± 12.8 mmHg (P = .626) and 119.2 ± 11.4 mmHg (P = .748)] and DBP did not change at 3 or 12 months compared with baseline; repeated measures ANOVA showed no differences in the mean 24-h SBP and DBP levels over time. The number of antihypertensive agents decreas in KTRs and remained stable in donors.

Conclusions

KTx reduces ambulatory BP levels and trajectories in KTRs at 3 months and further so at 12 months post-surgery. Kidney donation does not affect the ambulatory BP levels and trajectories of donors at the same intervals.

Risk for subsequent hypertension and cardiovascular disease after living kidney donation: is it clinically relevant?

The first successful live donor kidney transplant was performed in 1954. Receiving a kidney transplant from a live kidney donor remains the best option for increasing both life expectancy and quality of life in patients with end-stage kidney disease. However, ever since 1954, there have been multiple questions raised on the ethics of live kidney donation in terms of negative impacts on donor life expectancy. Given the close relationship between reduced kidney function in patients with chronic kidney disease (CKD) and hypertension, cardiovascular disease and cardiovascular mortality, information on the impact of kidney donation on these is particularly relevant. In this article, we review the existing evidence, focusing on the more recent studies on the impact of kidney donation on all-cause mortality, cardiovascular mortality, cardiovascular disease and hypertension, as well as markers of cardiovascular damage including arterial stiffness and uraemic cardiomyopathy. We also discuss the similarities and differences between the pathological reduction in renal function that occurs in CKD, and the reduction in renal function that occurs because of a donor nephrectomy. Kidney donors perform an altruistic act that benefits individual patients as well as the wider society. They deserve to have high-quality evidence on which to make informed decisions.

Uraemic solutes as therapeutic targets in CKD-associated cardiovascular disease

Chronic kidney disease (CKD) is characterized by the retention of a myriad of solutes termed uraemic (or uremic) toxins, which inflict damage to several organs, including the cardiovascular system. Uraemic toxins can induce hallmarks of cardiovascular disease (CVD), such as atherothrombosis, heart failure, dysrhythmias, vessel calcification and dysregulated angiogenesis. CVD is an important driver of mortality in patients with CKD; however, reliance on conventional approaches to managing CVD risk is insufficient in these patients, underscoring a need to target risk factors that are specific to CKD. Mounting evidence suggests that targeting uraemic toxins and/or pathways induced by uraemic toxins, including tryptophan metabolites and trimethylamine N-oxide (TMAO), can lower the risk of CVD in patients with CKD. Although tangible therapies resulting from our growing knowledge of uraemic toxicity are yet to materialize, a number of pharmacological and non-pharmacological approaches have the potential to abrogate the effects of uraemic toxins, for example, by decreasing the production of uraemic toxins, by modifying metabolic pathways induced by uraemic toxins such as those controlled by aryl hydrocarbon receptor signalling and by augmenting the clearance of uraemic toxins.