Determinants of left ventricular structure after kidney transplantation

Assessment of hypertension in kidney transplantation by ambulatory blood pressure monitoring: a systematic review and meta-analysis

Background

Hypertension (HTN) is common following renal transplantation and it is associated with adverse effects on cardiovascular (CV) and graft health. Ambulatory blood pressure monitoring (ABPM) is the preferred method to characterize blood pressure (BP) status, since HTN misclassification by office BP (OBP) is quite common in this population. We performed a systematic review and meta-analysis aimed at determining the clinical utility of 24-h ABPM and its potential implications for the management of HTN in this population.

Methods

Ovid-MEDLINE and PubMed databases were searched for interventional or observational studies enrolling adult kidney transplant recipients (KTRs) undergoing 24-h ABP readings compared with OBP or home BP. The main outcome was the proportion of KTRs diagnosed with HTN by ABPM, home or OBP recordings. Additionally, day-night BP variability and dipper/non-dipper status were assessed.

Results

Forty-two eligible studies (4115 participants) were reviewed. A cumulative analysis including 27 studies (3481 participants) revealed a prevalence of uncontrolled HTN detected by ABPM of 56% [95% confidence interval (CI) 46-65%]. The pooled prevalence of uncontrolled HTN according to OBP was 47% (95% CI 36-58%) in 25 studies (3261 participants). Very few studies reported on home BP recordings. The average concordance rate between OBP and ABPM measurements in classifying patients as controlled or uncontrolled hypertensive was 66% (95% CI 59-73%). ABPM revealed HTN phenotypes among KTRs. Two pooled analyses of 11 and 10 studies, respectively, revealed an average prevalence of 26% (95% CI 19-33%) for masked HTN (MHT) and 10% (95% CI 6-17%) for white-coat HTN (WCH). The proportion of non-dippers was variable across the 28 studies that analysed dipping status, with an average prevalence of 54% (95% CI 45-63%).

Conclusions

In our systematic review, comparison of OBP versus ABP measurements disclosed a high proportion of MHT, uncontrolled HTN and, to a lesser extent, WCH in KTRs. These results suggest that HTN is not adequately diagnosed and controlled by OBP recordings in this population. Furthermore, the high prevalence of non-dippers confirmed that circadian rhythm is commonly disturbed in KTRs.

Blood pressure monitoring in kidney transplantation: a systematic review on hypertension and target organ damage

BACKGROUND

Sparse studies show that ambulatory blood pressure monitoring (ABPM) is superior to office BP (oBP) measurements to predict target organ damage and cardiovascular (CV) events in kidney transplant recipients (KTRs). We performed a systematic review aimed at determining the potential associations between BP recordings by different methods and renal and CV outcomes in this population.

METHODS

Major medical databases were searched for studies enrolling adult KTRs undergoing 24h ABPM compared to office or home BP measurements. Main outcomes were: associations between different BP recordings and renal and CV outcomes. Additionally, any association between the circadian BP pattern (dipping/non-dipping status) and outcomes was assessed.

RESULTS

Twenty-two studies (2078 participants) were reviewed. Amongst 12 studies collecting data on renal endpoints, ten studies found that BP assessed by ABPM was a stronger predictor of renal function decline, assessed by serum creatinine (SCr) and/or creatinine clearance (CrCl) or estimated glomerular filtration rate (eGFR), than traditional office measurements. Twelve studies analyzed the relation between different BP recordings and CV target organ damages and reported robust correlations between echocardiographic abnormalities [i.e. left ventricular mass index (LVM/LVMI)] and 24h ABPM, but not with office BPs. Furthermore, 24h ABPM correlated better than oBP with markers of vascular damage, such as carotid intima-media thickness (IMT), diffuse thickening, and endothelial dysfunction. Additionally, abnormal circadian BP pattern (non-dippers and reverse dippers) identified a group of kidney recipients at risk for kidney function loss and CV abnormalities.

CONCLUSIONS

In our systematic review, ABPM reflected target organ damage more closely than oBP in KTRs. Furthermore, altered circadian BP profile associated with renal and CV target organ damages.

Pretransplant Stable Systolic Cardiac Functions Play an Important Role in Short-term Systolic Cardiac Functions After Kidney Transplant in Children

OBJECTIVES

In this study, our aim was to evaluate the systolic cardiac parameters and related risk factors in children within 6 months after kidney transplant.

MATERIALS AND METHODS

We retrospectively evaluated 24 children who received kidney transplants. Clinical and laboratory parameters before and after transplant were recorded. Results were evaluated statistically, with a P value less than .05 considered significant.

RESULTS

Before transplant, systolic cardiac functions were within normal limits. After transplant, ejection fraction (63.35% ± 5.38% vs 66.95% ± 4.62%; P = .01) was significantly increased and left ventricular mass index (32.63 ± 17.21 g/m2.7 vs 31.29 ± 15.65 g/m2.7; P = .78) was not significantly decreased, whereas fractional shortening (52.16% ± 15.32% vs 59.8% ± 12.94%; P = .54) did not change. Systolic blood pressure, systolic blood pressure index, diastolic blood pressure, and diastolic blood pressure index values were not statistically different before and after transplant (P > .05). The number of antihypertensive agents was significantly decreased (P = .001). Before and after transplant, cardiac geometry was normal in 15 patients (62.5%) and 17 patients (70.8%).

CONCLUSIONS

Our patients, who had stable systolic cardiac function before transplant, showed further improvements in systolic cardiac function even within 6 months after transplant. Therefore, strictly monitored and controlled blood pressure, volume, anemia, and nutrition in children before transplant may play important roles in achieving better cardiac systolic function after kidney transplant.

The association of long-functioning hemodialysis vascular access with prevalence of left ventricular hypertrophy in kidney transplant recipients

Left ventricular hypertrophy (LVH) is frequently observed in chronic dialysis patients and is also highly prevalent in kidney transplant recipients. This study evaluates the impact of long-functioning hemodialysis vascular access on LVH in single center cohort of kidney transplant recipients. 162 patients at 8.7 ± 1.8 years after kidney transplantation were enrolled. Echocardiography, carotid ultrasound, and assessment of pulse wave velocity were performed. LVH was defined based on left ventricular mass (LVM) indexed for body surface area (BSA) and height(2.7). There were 67 patients with and 95 without patent vascular access. Both study groups were comparable with respect to gender, age, duration of dialysis therapy, and time after transplantation, kidney graft function, and cardiovascular comorbidities. Patients with patent vascular access were characterized by significantly elevated LVM and significantly greater percentage of LVH, based on LVMI/BSA (66.7 versus 48.4%, P = 0.02). OR for LVH in patients with patent vascular access was 2.39 (1.19-4.76), P = 0.01. Regression analyses confirmed an independent contribution of patent vascular access to higher LVM and increased prevalence of LVH. We concluded that long-lasting patent hemodialysis vascular access after kidney transplantation is associated with the increased prevalence of LVH in kidney transplant recipients.

Ambulatory blood pressure monitoring in chronic renal disease: technical aspects and clinical relevance

PURPOSE OF REVIEW

To evaluate the current value of ambulatory blood pressure monitoring in patients with chronic renal disease and end-stage renal disease.

RECENT FINDINGS

Ambulatory blood pressure monitoring has become an important tool in hypertension research and clinical practice. Its use in essential hypertension shows a strong predictive ability in the assessment of cardiovascular outcomes. In chronic renal failure and end-stage renal disease, the role of ambulatory blood pressure monitoring is still being actively evaluated, and available evidence shows that it is better than office blood pressure in predicting left ventricular hypertrophy and progression of renal dysfunction in patients with chronic renal failure. In end-stage renal disease, preliminary data suggest better prediction of mortality in hemodialysis patients in comparison with clinic blood pressures. The most conspicuous problems with the literature on this subject are small sample sizes and the paucity of longitudinal observational studies and intervention trials.

SUMMARY

Preliminary data and extrapolations from essential hypertension have justified a growing excitement about the use of ambulatory blood pressure monitoring in renal disease. However, further research will have to address the limitations of the available literature before generalization of its use is implemented.