A relationship of intradialytic blood pressure variability with vascular access outcomes in patients on hemodialysis

Elevated plasma leptin levels are associated with vascular access dysfunction in patients on maintenance hemodialysis

BACKGROUND

Inflammation has been associated with vascular access (VA) dysfunction. The adipocytokine leptin can directly induce pro-inflammatory T helper 1 immune responses and the pathogenesis of chronic inflammation. We explored the association between plasma leptin and VA dysfunction in patients on maintenance hemodialysis (HEMO).

METHODS

A total of 344 consecutive patients who received anastomosis for VA at a single HEMO center between June 1, 2010 and December 31, 2021 were screened. Of these patients, 267 met the inclusion criteria and were included. ELISA was used to measure circulating levels of leptin.

RESULTS

The VA dysfunction group had a higher leptin level than the patent VA group. A higher concentration of leptin was independently and significantly associated with an elevated risk of VA dysfunction. Multiple logistic regression analysis showed that leptin, female sex, and hypertension were independently associated with VA dysfunction, even after adjusting for known biomarkers. We then evaluated the ability of leptin, female sex, and hypertension to predict the risk of VA dysfunction, and the area under the curve (AUC) for leptin was 0.626 (p = 0.0001). When leptin, female sex, and hypertension were added to this multivariate model, the AUC increased to 0.679 (p = 0.001) for leptin and hypertension, and 0.690 for leptin, hypertension, and female sex (p = 0.004). In addition, plasma leptin levels were associated with sex, body mass index, and hemoglobin.

CONCLUSIONS

In addition to the association between leptin and VA dysfunction, hypertension and female sex independently predicted VA dysfunction in patients with HEMO.

The association of long-term blood pressure variability with hemodialysis access thrombosis

Background

Blood pressure variability (BPV) is an important risk factor for cardiovascular events in hemodialysis patients. We sought to determine the impact of BPV on hemodialysis access thrombosis.

Methods

We enrolled 1,011 prevalent hemodialysis patients from 12 hemodialysis centers since January 2018 and followed them until December 2020. Predialysis blood pressure (BP) was assessed at 12-week intervals. The coefficient of variation derived from 36 consecutive BP measurements was used as the metric for variability. The primary outcome was incident hemodialysis access thrombosis. Linear regression models were used to assess factors associated with BPV at baseline. Kaplan-Meier curves of the time until vascular access events were drawn and log-rank tests were calculated. Cox proportional hazards models were performed to assess the association of BPV with incident vascular access events.

Results

The average coefficient of variance for systolic BPV was 10.9%. BPV was associated with age, body mass index, mean BP, diabetes, coronary and peripheral artery disease, history of access dysfunction, graft access, intradialytic hypotension, and use of antihypertensive medications. There were 194 access thrombosis events and 451 access stenosis events during a median follow-up period of 30 months. After adjustment of potential confounding factors, BPV was associated with increased risk of access thrombosis [hazard ratio = 1.27, 95% confidence interval (CI), 1.18–1.44, per 1 standard deviation increase in BPV]. The patients in the highest BPV quartile had 2.45 times the risk of thrombosis (CI, 1.62–3.70). The association was independent of average BP, intradialytic hypotension, and comorbidities. Similar trends of association were found in the subgroups analyzed. Comparative analysis using a time-varying variable model and different metrics of BPV showed consistent results.

Conclusion

Our findings underscored the impact of BP fluctuation on vascular access thrombosis.

Intradialytic BP variability is associated with cardiovascular mortality and hospitalization in HD patients

INTRODUCTION

Studies showed that pre-dialysis BP variability (BPV) was an independent risk factor of cardiovascular disease (CVD) among HD patients, but which is limited on how intradialytic BPV affects prognosis.

METHODS

In this study, we designed a retrospective cohort study to examine the association between intradialytic BPV and CVD outcomes in HD patients. A total of 202 patients who underwent HD in our center were included, and all intradialytic BP measurements of November 2017 were obtained from the database. Patients were divided into four groups according to variability independent of the mean (VIM) interquartile.

RESULTS

The mean age was 62.1 ± 14.3 years, 60.9% were male, and median VIM was 14.75 (12.60-18.59). Multiple-regression analyses showed patients age, dialysis vintage, serum albumin, and the percentage of intradialytic weight gain as significant predictors of VIM (all p values were <0.05). Kaplan-Meier survival curves showed that CVD mortality was greater in patients with higher VIM (p = 0.05), whereas all-cause mortality had no significant difference between the four groups overall (p = 0.149). Furthermore, multivariate regression analyses demonstrated that VIM (HR = 1.091, p < 0.004) and age (HR = 1.059, p = 0.003) were significant independent predictors for CVD death. Logistic-regression models revealed that higher VIM groups were more likely to have CVD-related hospitalization (OR = 1.085, p = 0.030), whereas the association between VIM and all-cause hospitalization was not statistically significant (OR = 1.015, p = 0.669).

CONCLUSIONS

This retrospective study suggested that higher intradialytic BPV was associated with increasing age, longer dialysis vintage, lower albumin, and greater ultrafiltration; intradialytic BPV could be an effective predictor for CVD mortality and hospitalization in the HD population.

Influence of intradialytic systolic blood pressure changes on arteriovenous access thrombosis in maintenance hemodialysis patients

BACKGROUND

Arteriovenous access (AV) thrombosis is an important and preventable problem amongst chronic hemodialysis (HD) patients. Systolic blood pressure (SBP) fluctuation relates to higher cardiovascular mortality amongst these patients. We proposed there is a close relation between SBP changes and arteriovenous (AV) access thrombosis. We also determined other risk factors and biochemical parameters related to AV access failure.

METHODS

50 HD patients with thrombosis and 50 HD patients without thrombosis were included in the study. Odds ratios and 95% confidence intervals were estimated with multivariate-adjusted logistic regression models to determine the association between potential thrombosis-related risk factors and thrombosis risk.

RESULTS

Elder adults, women, and patients with AV grafts, lower intradialytic SBP and higher SBP variations during HD sessions had higher incidence of AV access thrombosis. AV access infection and decreased blood flow (BF) velocity were associated with an increased incidence of thrombotic events, whereas the use of anti-thrombotic agents was associated with a decreased incidence of thrombotic events. Further, anaemia, hypoalbuminemia, hyperlipidemia, and impaired mineral metabolism parameters were also found to be associated with AV access thrombosis.

CONCLUSIONS

Close monitoring and management of intradialytic hypotension and SBP fluctuation in every HD session are important. Some important and novel modifiable risk factors related to AV access thrombosis were identified in this study (eg, AV access infection, decreased BF and abnormal biochemical parameters, etc). Earlier surveillance and modification of these risk factors is crucial to prevent AV access failure in HD patients.