Retrospective single center cohort study: effect of intensive home hemodialysis on right ventricular systolic pressure and clinical outcomes

BACKGROUND

Increased right ventricular systolic pressure (RVSP), a surrogate marker for pulmonary hypertension, is common in patients with end-stage kidney disease. Limited data suggest improvement of RVSP with intensive dialysis, but it is unknown whether these improvements translate to better clinical outcomes.

METHODS

We conducted a retrospective single center cohort study at the Toronto General Hospital. All patients who performed intensive home hemodialysis (IHHD) for at least a year between 1999 and 2017, and who had a baseline as well as a follow-up echocardiogram more than a year after IHHD, were included. Patients were categorized into two groups based on the RVSP at follow-up: elevated (≥ 35 mmHg) and normal RVSP. Multivariate and cox regression analyses were done to identify risk factors for elevated RVSP at follow-up and reaching the composite endpoint (death, cardiovascular hospitalization, treatment failure), respectively.

RESULTS

One hundred eight patients were included in the study. At baseline, 63% (68/108) of patients had normal RVSP and 37% (40/108) having elevated RVSP. After a follow-up of 4 years, 70% (76/108) patient had normal RVSP while 30% (32/108) had elevated RVSP. 8 (10%) out of the 76 patients with normal RVSP and 15 (47%) out of the 32 patients with elevated RVSP reached the composite endpoint of death, cardiovascular hospitalization or technique failure. In a multivariate analysis, age, diabetes and smoking were not associated with elevated RVSP at follow-up. Elevated RVSP at baseline was not associated with a higher likelihood in reaching the composite endpoint or mortality.

CONCLUSION

Mean RVSP did not increase in patients on IHHD over time, and maintenance of normal RVSP was associated with better clinical outcomes.

Association between conversion to in-center nocturnal hemodialysis and right ventricular remodeling

Background

In-center nocturnal hemodialysis (INHD) is associated with favorable left ventricular (LV) remodeling. Although right ventricular (RV) structure and function carry prognostic significance, the impact of dialysis intensification on RV is unknown. Our objectives were to evaluate changes in RV mass index (MI), end-diastolic volume index (EDVI), end-systolic volume index (ESVI) and ejection fraction (EF) after conversion to INHD and their relationship with LV remodeling.

Methods

Of 67 conventional hemodialysis (CHD, 4 h/session, three times/week) patients, 30 continued on CHD and 37 converted to INHD (7-8 h/session, three times/week). Cardiac magnetic resonance imaging was performed at baseline and 1 year using a standardized protocol; an experienced and blinded reader performed RV measurements.

Results

At 1 year there were significant reductions in RVMI {-2.1 g/m2 [95% confidence interval (CI) -3.8 to - 0.4], P = 0.017}, RVEDVI [-9.5 mL/m2 (95% CI - 16.3 to - 2.6), P = 0.008] and RVESVI [-6.2 mL/m2 (95% CI - 10.9 to - 1.6), P = 0.011] in the INHD group; no significant changes were observed in the CHD group. Between-group comparisons showed significantly greater reduction of RVESVI [-7.9 mL/m2 (95% CI - 14.9 to - 0.9), P = 0.03] in the INHD group, a nonsignificant trend toward greater reduction in RVEDVI and no significant difference in RVMI and RVEF changes. There was significant correlation between LV and RV in terms of changes in mass index (MI) (r = 0.46), EDVI (r = 0.73), ESVI (r = 0.7) and EF (r = 0.38) over 1 year (all P < 0.01).

Conclusions

Conversion to INHD was associated with a significant reduction of RVESVI. Temporal changes in RV mass, volume and function paralleled those of LV. Our findings support the need for larger, longer-term studies to confirm favorable RV remodeling and determine its impact on clinical outcomes.

Comparative Effectiveness of Phosphate Binders in Patients with Chronic Kidney Disease: A Systematic Review and Network Meta-Analysis

BACKGROUND

Chronic kidney disease-mineral and bone disorder (CKD-MBD) has been linked to poor health outcomes, including diminished quality and length of life. This condition is characterized by high phosphate levels and requires phosphate-lowering agents-phosphate binders. The objective of this systematic review is to compare the effects of available phosphate binders on patient-important outcomes in patients with CKD-MBD.

METHODS

Data sources included MEDLINE and EMBASE Trials from 1996 to February 2016. We also searched the Cochrane Register of Controlled Trials up to April 2016. Teams of two reviewers, independently and in duplicate, screened titles and abstracts and potentially eligible full text reports to determine eligibility, and subsequently abstracted data and assessed risk of bias in eligible randomized controlled trials (RCTs). Eligible trials enrolled patients with CKD-MBD, randomized them to receive calcium (delivered as calcium acetate, calcium citrate or calcium carbonate), non-calcium-based phosphate binders (NCBPB) (sevelamer hydrochloride, sevelamer carbonate, lanthanum carbonate, sucroferric oxyhydroxide and ferric citrate), phosphorus restricted diet, placebo or no treatment, and reported effects on all-cause mortality, cardiovascular mortality or hospitalization at ≥4 weeks follow-up. We performed network meta-analyses (NMA) for all cause-mortality for individual agents (seven-node analysis) and conventional meta-analysis of calcium vs. NCBPBs for all-cause mortality, cardiovascular mortality and hospitalization. In the NMAs, we calculated the effect estimates for direct, indirect and network meta-analysis estimates; for both NMA and conventional meta-analysis, we pooled treatment effects as risk ratios (RR) and calculated 95% confidence intervals (CIs) using random effect models. We used the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach to rate the quality of evidence for each paired comparison.

RESULTS

Our search yielded 1190 citations, of which 71 RCTs were retrieved for full review and 15 proved eligible. With 13 eligible studies from a prior review, we included 28 studies with 8335 participants; 25 trials provided data for our quantitative synthesis. Results suggest higher mortality with calcium than either sevelamer (NMA RR, 1.89 [95% CI, 1.02 to 3.50], moderate quality evidence) or NCBPBs (conventional meta-analysis RR, 1.76 [95% CI, 1.21 to 2.56, moderate quality evidence). Conventional meta-analysis suggested no difference in cardiovascular mortality between calcium and NCBPBs (RR, 2.54 [95% CI, 0.67 to 9.62 low quality evidence). Our results suggest higher hospitalization, although non-significant, with calcium than NCBPBs (RR, 1.293 [95% CI, 0.94 to 1.74, moderate quality evidence).

DISCUSSION/CONCLUSIONS

Use of calcium results in higher mortality than either sevelamer in particular and NCBPBs in general (moderate quality evidence). Our results raise questions about whether administration of calcium as an intervention for CKD- MBD remains ethical. Further research is needed to explore the effects of different types of phosphate binders, including novel agents such as iron, on quality and quantity of life.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD-42016032945.

Extraosseous calcification in end-stage renal disease: from visceral organs to vasculature

In earlier days, periarticular accumulations of calcium phosphate causing tumor-like depositions were considered the result of passive precipitation and referred to as metastatic calcifications. From sophisticated computer tomographic studies and growing insight, we have learned that calcifications in the cardiovascular system are far more threatening and in fact one of the most important sequela of end-stage renal disease. The histologic characteristic of uremia-related calcification is arteriosclerosis of the media. In addition, there is atherosclerosis of the intima, due to the high prevalence of classic cardiovascular risk factors in renal disease. The two vascular features can frequently exist at different sites in the vasculature. Novel diagnostic techniques are helping to elucidate the pathogenetic mechanisms of active conversion of vascular smooth muscle cells to osteochondritic cells. Through this process, extensive calcification of the central and peripheral vasculature ensues, influenced by different promotors and inhibitors. Calciphylaxis is a special form of extraosseous calcification leading to skin necrosis. The factors that trigger the development of calciphylaxis are not completely understood, but this syndrome shares part of the pathophysiologic basis of extraosseous calcification in general. However, the therapeutic approach must be prompt and aggressive, because of the poor prognosis. Frequently, a fatal outcome cannot be avoided in calciphylaxis.

Mechanistic insights into vascular calcification in CKD

Cardiovascular disease begins early in the course of renal decline and is a life-limiting problem in patients with CKD. The increased burden of cardiovascular disease is due, at least in part, to calcification of the vessel wall. The uremic milieu provides a perfect storm of risk factors for accelerated calcification, but elevated calcium and phosphate levels remain key to the initiation and progression of vascular smooth muscle cell calcification in CKD. Vascular calcification is a highly regulated process that involves a complex interplay between promoters and inhibitors of calcification and has many similarities to bone ossification. Here, we discuss current understanding of the process of vascular calcification, focusing specifically on the discrete and synergistic effects of calcium and phosphate in mediating vascular smooth muscle cell apoptosis, osteochondrocytic differentiation, vesicle release, calcification inhibitor expression, senescence, and death. Using our model of intact human vessels, factors initiating vascular calcification in vivo and the role of calcium and phosphate in driving accelerated calcification ex vivo are described. This work allows us to link clinical and basic research into a working theoretical model to explain the pathway of development of vascular calcification in CKD.

Patient perceptions of remote monitoring for nocturnal home hemodialysis

Adoption of nocturnal home hemodialysis (NHHD) has been slow, due in part to patient-perceived barriers, such as anxiety and lack of self-efficacy. This study investigates patient perception of remote monitoring in addressing these barriers. Perceptions of remote patient monitoring (RPM) were studied through a quantitative survey and qualitative interviews. The NHHD and conventional hemodialysis (CHD) were included in the survey (209 in total). Twenty semistructured interviews were conducted as well as a focus group that included NHHD patients and family caregivers. The CHD patients had greater interest in adopting NHHD with RPM than without (1.90±1.37 vs. 1.71±1.28, P<0.002), with the negative intensity ratio declining from 10.50 to 5.56. Interest in RPM was correlated with interest in NHHD (r=0.768, P<0.001). Other significant factors correlated with interest in NHHD include the belief that remote monitoring will ease the performing of NHHD (r=0.452, P=0.001) and the belief that RPM should be mandatory (r=0.541, P=0.000). Qualitative findings supported three themes: (1) There is an expectation for the use of RPM, (2) RPM should be used at a minimum transitionally, and (3) RPM acts as a surrogate support of family-caregivers. The RPM may lower perceived barriers to the adoption of NHHD, in part through its surrogate support of family caregivers. However, RPM alone is likely insufficient to alter patients' attitudes to undergo NHHD. RPM is a common expectation of CHD patients considering the therapy, at a minimum during the transitional phase.