Diuretics beat ultrafiltration at treating congestive heart failure with acute renal failure (RCT)

Ultrafiltration No Better Than Diuresis for CHF Exacerbations

by Blair Westerly, MD

Cardiorenal syndrome -- simultaneous heart failure and renal failure -- is a frequently encountered problem in people with acute decompensated heart failure.  Treatment with diuretics for congestive heart failure exacerbations is standard care, but diuretics may at times worsen renal function. Venovenous ultrafiltration (UF) is an alternative therapy to remove fluid and provides the advantages of greater control over the rate of removal, less neurohormonal activation and greater net loss of sodium (Bart et al). When diuretics fail to remove adequate volume from patients with acute decompensated heart failure, many physicians believe ultrafiltration or renal replacement therapies are the next step up in care. However, a new randomized trial in the New England Journal of Medicine challenges that notion.

What They Did

The CARRESS-HF study was an unblinded trial of 188 patients with acute decompensated heart failure and cardiorenal syndrome who were randomized to a therapeutic strategy of pharmacotherapy versus ultrafiltration for fluid and sodium removal. All patients included had clinical or radiographic evidence of volume overload and a primary diagnosis of acute decompensated heart failure. Patients were excluded if they had serum creatinine greater than 3.5 mg/dL or were receiving intravenous vasodilator or inotropic agents. Patients in the ultrafiltration group could not receive loop diuretics during the duration of UF. Ultrafiltration was performed at a fluid removal rate of 200 mL per hour, which had previously been shown to be safe.  An algorithmic approach was used for the pharmacotherapy group with a target urine output of 3 to 5 L per day. The primary bivariate endpoint was change from baseline in serum creatinine level and bodyweight at 96 hours and patients were followed for 60 days.

What They Found

Enrollment was discontinued early because of lack of clear benefit and an excess of adverse events in the patients receiving ultrafiltration, mainly due to more renal failure, bleeding, and complications related to intravenous catheters. Here are the primary endpoints:

• Creatinine was significantly different at 96 hours, mostly due to the increased creatinine in patients receiving UF; however, creatinine was better than baseline in both groups at 30 and 60 days

• No difference in mean weight-loss at 96 hours.

• The combined bivariate endpoint of significant weight loss and renal improvement was not statistically different between the two groups at 96 hours or seven days.

• While underpowered to detect this endpoint, there was no difference in 60 day mortality or composite rate of death or re-hospitalization for heart failure.

Clinical Takeaway: In CARRESS-HF, the increased cost and complications associated with ultrafiltration do not provide any substantial benefit to justify its use over pharmacologic therapy for acute decompensated heart failure and cardiorenal syndrome. While the mechanisms of worsening renal function in the ultrafiltration group at 96 hours are not entirely clear, it is reassuring that renal function improved to better than baseline at 30 and 60 days in both treatment groups. At this time, physician-directed diuretic therapy appears to be the most cost-effective and safest manner in which to remove fluid for patients with acute decompensated heart failure and cardiorenal syndrome. Bart BA et al. Ultrafiltration in decompensated heart failure with cardiorenal syndrome. NEJM 2012;367:2296-304.