Ultrafiltration for acute heart failure

Ultrafiltration in Heart Failure: A Review

Ultrafiltration is an effective method to get rid of fluid retention and congestion in patients with acute decompensated heart failure (HF) without affecting the circulating volume. Although its efficacy in comparison to diuretics is debatable, the evaluation of our analysis is based on various studies that comprise published clinical trials on ultrafiltration and studies comparing the efficacy of diuretics and ultrafiltration. Apart from this, we also look at literature that provides shortcomings of the said procedure and its scope for future advancements. Heart failure ultimately leads to volume overload, which is a highly concerning complication. Diuretics have been used as a first-line treatment for fluid overload but are becoming inefficacious due to the development of resistance and renal dysfunction. Ultrafiltration, on the other hand, is an attractive alternative to counter volume overload and congestion, which are unresponsive to medical therapy. There is also evidence that it significantly decreases the probability of future episodes of decompensation. There are, however, disagreements about whether ultrafiltration is an effective method to improve mortality in these patients. There is a lack of conclusive studies demonstrating the superiority of one fluid removal method over another. Hence, it is imperative to continue searching for the most effective method to treat congestion. Priority should be given to more mechanistic studies regarding ultrafiltration.

Ultrafiltration for acute heart failure

BACKGROUND

Pharmacotherapies such as loop diuretics are the cornerstone treatment for acute heart failure (AHF), but resistance and poor response can occur. Ultrafiltration (UF) is an alternative therapy to reduce congestion, however its benefits, efficacy and safety are unclear.

OBJECTIVES

To assess the effects of UF compared to diuretic therapy on clinical outcomes such as mortality and rehospitalisation rates.

SEARCH METHODS

We undertook a systematic search in June 2021 of the following databases: CENTRAL, MEDLINE, Embase, Web of Science CPCI-S and ClinicalTrials.gov. We also searched the WHO ICTRP platform in October 2020.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared UF to diuretics in adults with AHF.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. We contacted study authors for any further information, and language interpreters to translate texts. We assessed risk of bias in included studies using Risk of Bias 2 (RoB2) tool and assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We included 14 trials involving 1190 people. We included people who had clinical signs of acute hypervolaemia. We excluded critically unwell people such as those with ischaemia or haemodynamic instability. Mean age ranged from 57.5 to 75 years, and the setting was a mix of single and multi-centre. Two trials researched UF as a complimentary therapy to diuretics, while the remaining trials withheld diuretic use during UF. There was high risk of bias in some studies, particularly with deviations from the intended protocols from high cross-overs as well as missing outcome data for long-term follow-up.  We are uncertain about the effect of UF on all-cause mortality at 30 days or less (risk ratio (RR) 0.61, 95% confidence interval (CI) 0.13 to 2.85; 3 studies, 286 participants; very low-certainty evidence). UF may have little to no effect on all-cause mortality at the longest available follow-up (RR 1.00, 95% CI 0.73 to 1.36; 9 studies, 987 participants; low-certainty evidence). UF may reduce all-cause rehospitalisation at 30 days or less (RR 0.76, 95% CI 0.53 to 1.09; 3 studies, 337 participants; low-certainty evidence). UF may slightly reduce all-cause rehospitalisation at longest available follow-up (RR 0.91, 95% CI 0.79 to 1.05; 6 studies, 612 participants; low-certainty evidence). UF may reduce heart failure-related rehospitalisation at 30 days or less (RR 0.62, 95% CI 0.37 to 1.04; 2 studies, 395 participants; low-certainty evidence). UF probably reduces heart failure-related rehospitalisation at longest available follow-up, with a number needed to treat for an additional beneficial effect (NNTB) of 10 (RR 0.69, 95% CI 0.53 to 0.90; 4 studies, 636 participants; moderate-certainty evidence).  No studies measured need for mechanical ventilation.  UF may have little or no effect on serum creatinine change at 30 days since discharge (mean difference (MD) 14%, 95% CI -12% to 40%; 1 study, 221 participants; low-certainty evidence). UF may increase the risk of new initiation of renal replacement therapy at longest available follow-up (RR 1.42, 95% CI 0.42 to 4.75; 4 studies, 332 participants; low-certainty evidence).  There is an uncertain effect of UF on the risk of complications from central line insertion in hospital (RR 4.16, 95% CI 1.30 to 13.30; 6 studies, 779 participants; very low-certainty evidence).  AUTHORS' CONCLUSIONS: This review summarises the latest evidence on UF in AHF. Moderate-certainty evidence shows UF probably reduces heart failure-related rehospitalisation in the long term, with an NNTB of 10. UF may reduce all-cause rehospitalisation at 30 days or less and at longest available follow-up. The effect of UF on all-cause mortality at 30 days or less is unclear, and it may have little effect on all-cause mortality in the long-term.  While UF may have little or no effect on serum creatinine change at 30 days, it may increase the risk of new initiation of renal replacement therapy in the long term. The effect on complications from central line insertion is unclear.  There is insufficient evidence to determine the true impact of UF on AHF. Future research should evaluate UF as an adjunct therapy, focusing on outcomes such as heart failure-related rehospitalisation, cardiac mortality and renal outcomes at medium- to long-term follow-up.