Continuous ultrafiltration in acute decompensated heart failure: current issues and future directions

Utilization of aquapheresis among hospitalized patients with end-stage liver disease: A case series and literature review

Third-spacing of fluid is a common complication in hospitalized patients with decompensated cirrhosis. In addition to ascites, patients with advanced cirrhosis may develop significant peripheral edema, which may limit mobility and exacerbate debility and muscle wasting. Concomitant kidney failure and cardiac dysfunction may lead to worsening hypervolemia, which may ultimately result in pulmonary edema and respiratory compromise. Diuretic use in such patients may be limited by kidney dysfunction and electrolyte abnormalities, including hyponatremia and hypokalemia. A slow, continuous form of ultrafiltration known as aquapheresis is a method of extracorporeal fluid removal whereby a pump generates a transmembrane pressure that forces an isotonic ultrafiltrate across a semipermeable membrane. This leads to removal of an ultrafiltrate that is isotonic to blood without the need for dialysate or replacement fluid as is necessary in other forms of continuous kidney replacement therapy. This technique has been utilized in other conditions including acute decompensated heart failure, with trials showing mixed, but generally favorable results. Herein, we present a series of our own experience using aquapheresis among patients with cirrhosis, review the literature regarding its use in other hypervolemic states, and discuss how we may apply lessons learned from use of aquapheresis in heart failure to patients with end-stage liver disease.

A novel pump-free ultrafiltration rate modulation system for continuous renal replacement therapy applications

Purpose

Extracorporeal ultrafiltration is an attractive alternative to diuretics for removing excess plasma water in critically ill patients suffering from fluid overload. In continuous renal replacement therapy (CRRT), ultrafiltration occurs in isolated form (SCUF) or supplemented by replacement fluid infusion (CVVH) and the net fluid removal rate is controlled by peristaltic pumps. In this work, a pump-free solution for regulating the ultrafiltration rate in CRRT applications is presented.

Methods

The system consists of a motorized clamp on the ultrafiltration line, whose intermittent opening is modulated with a closed-loop control system based on monitoring of ultrafiltrate collected and any replacement fluid infused. The system was tested on two platforms for SCUF and CVVH, with “low-flux” and “high-flux” hemofilter, with various ultrafiltration setpoints and patient net weight loss targets.

Results

In all configurations the set ultrafiltration rate was achieved with a maximum error of 5% and the values recorded were kept within ± 100 ml/h with respect to the setpoint, as recommended by international standard IEC 60601-2-16. The net fluid removal trend was highly correlated with that expected (95%<R2<99%) and the weight loss target was reached in the expected time. For low ultrafiltration rates (60-150 ml/h) the system accuracy was better with the “low-flux” hemofilter.

Conclusion

The developed clamp system represents a valid alternative to state-of-the-art solutions with peristaltic pumps in terms of performance, with potential usability advantages. The compliance with safety requirements given by international standard IEC 60601-2-16 is a prerequisite for clinical use.

Ultrafiltration for patients with acute decompensated heart failure: A systematic review and meta-analysis

BACKGROUND

Ultrafiltration plays an indispensable role in relieving congestion and fluid retention in patients with acute decompensated heart failure (ADHF) in recent years. So far, there is no consistent agreement about whether early ultrafiltration (UF) is a first-line treatment for patients with ADHF. We, therefore, conducted a meta-analysis to assess the efficacy and safety of UF.

METHODS

PubMed, Embase, and Cochrane Library databases were searched for randomized controlled trials (RCTs) that compared UF with diuretics in patients with ADHF and included our interested outcomes. The primary outcomes are heart failure rehospitalization, all-cause rehospitalization, and mortality. The second outcomes are fluid loss, weight loss, and adverse events. RevMan Version 5.4.1 was used to analyze the data of included studies.

RESULTS

A total of 12 studies with 1197 patients were included. Our results showed a reduction in heart failure rehospitalization (risk ratio [RR] 0.67, 95% confidence interval [CI]: 0.52-0.87, P = .003) and all-cause rehospitalization (RR 0.62, 95% CI: 0.42-0.92; P = .02), an increase in fluid loss (1.47 L, 95% CI: 0.95-1.99 L, P < .001) and weight loss (1.65 kg, 95% CI: 0.90-2.41 kg; P < .001). There was no difference in mortality (RR 1.09, 95% CI: 0.78-1.51; P = .62). There were inconsistent agreements about which group have more total adverse events. Subgroup analysis showed that UF with larger mean fluid-remove rate (≥200 mL/h) could significantly remove more fluid, lose more weight, and decrease heart failure rehospitalization. Less weight loss for patients with ADHF may correlated to higher percent of ischemic etiology (ischemic etiology ≥50%).

CONCLUSION

Although UF is more effective in removing fluid than diuretics and decrease rehospitalization of heart failure and all causes, there is not enough evidence to prove that UF is superior because of adverse events and mortality in the UF group. The mean fluid-removal rates should be set to ≥200 mL/h. Patient with different etiology may have different effects when treated with UF and it is a weak conclusion.Trial registration: The systematic review was registered with the International Prospective Registry of Systematic Reviews. (https://www.crd.york.ac.uk/prospero/, registration number CRD42021245049).

Efficacy and Renal Tolerability of Ultrafiltration in Acute Decompensated Heart Failure: A Meta-analysis and Systematic Review of 19 Randomized Controlled Trials

Background: Acute decompensated heart failure (ADHF) is a life-threatening and costly disease. Controversy remains regarding the efficacy and renal tolerability of ultrafiltration for treating ADHF. We therefore performed this meta-analysis to evaluate this clinical issue.Methods: A search of PubMed, EMBASE, and the Cochrane database of controlled trials was performed from inception to March 2021 for relevant randomized controlled trials. The quality of the included trials and outcomes was evaluated with the use of the risk of bias assessment tool and the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach, respectively. The risk ratio and the standardized mean difference (SMD) or weighted mean difference (WMD) were computed and pooled with fixed-effects or random-effects models.Results: This meta-analysis included 19 studies involving 1281 patients. Ultrafiltration was superior to the control treatments for weight loss (WMD 1.24 kg, 95% confidence interval [CI] 0.38‐2.09 kg, P=0.004) and fluid removal (WMD 1.55 L, 95% CI 0.51‐2.59 l, P=0.003) and was associated with a significant increase in serum creatinine level compared with the control treatments (SMD 0.15 mg/dL, 95% CI 0.00‐0.30 mg/dL, P=0.04). However, no significant effects were found for serum N-terminal prohormone of brain natriuretic peptide level, length of hospital stay, all-cause mortality, or all-cause rehospitalization in the ultrafiltration group.Conclusions: The use of ultrafiltration in patients with ADHF is superior to the use of the control treatments for weight loss and fluid removal, but has adverse renal effects and lacks significant effects on long-term prognosis, indicating that this approach to decongestion in ADHF patients is efficient for fluid management but less safe renally.

Extracorporeal ultrafiltration for acute heart failure: patient selection and perspectives

Most patients presenting with acute heart failure (AHF) show signs and symptoms of fluid overload, which are closely associated with short-term and long-term outcomes. Ultrafiltration is an extremely appealing strategy for patients with AHF and concomitant overt fluid overload not fully responsive to diuretic therapy. However, although there are several theoretical beneficial effects associated with ultrafiltration, published reports have shown controversial findings. Differences in selection of the study population and in ultrafiltration indications and protocols, and high variability in the pharmacologic therapy used for the control group could explain some of these conflicting results. Here, we aimed to provide an overview on the current medical evidence supporting the use of ultrafiltration in AHF, with a special focus on the identification of potential candidates who may benefit the most from this therapeutic option.