Patients hospitalized with vascular congestion caused by an acute exacerbation of heart failure universally receive loop diuretics, but most patients continue to have persistent congestion and poor outcomes following treatment. In one recent trial, fewer than 20% of patients left the hospital with adequate decongestion regardless of whether they received high- or low-dose furosemide and whether they received it as a bolus or as a continuous infusion (N Engl J Med. 2011 Mar 3;364[9]:797-805). We need an alternative to decongestion by loop-diuretic treatment.
Ultrafiltration offers a number of potential advantages for treating acute congestion, especially for patients unresponsive to diuretic treatment. It provides a way to quickly and predictably remove isotonic fluid with no effect on electrolytes, no neurohormonal stimulation, and in several trials, no significant effect on renal function. It also can restore diuretic responsiveness,
Critics of ultrafiltration often cite the results of the CARRESS-HF [Cardiorenal Rescue Study in Acute Decompensated Heart Failure] trial, which I led (N Engl J Med 2012 Dec 13;367[24]:2296-304). I’m not convinced that the CARRESS-HF results apply to the large majority of patients with acute heart failure. All of the patients enrolled in this trial had acute kidney injury. Also, in CARRESS-HF, we used a control arm that received diuretic treatment in a stepped pharmacologic way, which is not the dosing strategy we usually see in community practice. In addition, CARRESS-HF did not use variable dosing in the ultrafiltration arm. A better comparison of diuretic treatment and ultrafiltration would use variable dosing in both arms.
That’s the design used in AVOID-HF. In this trial, clinicians adjusted both diuretic and ultrafiltration dosages based on the renal function and hemodynamics of each enrolled patient. Unfortunately, AVOID-HF ended too soon, after enrolling just a quarter of the patients calculated as necessary to produce a statistically significant difference in outcomes between the two treatment arms. This appeared to result in a nonsignificant trend in favor of ultrafiltration for the study’s primary endpoint. Despite being extremely underpowered, the results showed significant benefits for ultrafiltration for several secondary endpoints. The results also showed no deleterious effects on renal function with ultrafiltration.
If AVOID-HF had shown no signal of benefit from ultrafiltration then I think that would have meant to end of ultrafiltration, but that is not what happened. The strong trends in favor of ultrafiltration make the case to keep studying it for patients who have become unresponsive to diuretics. In these patients ultrafiltration is a good alternative. Several questions remain unanswered about the use of ultrafiltration, such as exactly when a patient has become too unresponsive to diuretic treatment to warrant using ultrafiltration, and how to optimally dose ultrafiltration. Despite this lingering uncertainty ultrafiltration remains a viable option that deserves more study.
Dr. Bradley A. Bart is professor of medicine at the University of Minnesota and chief of cardiology at Hennepin County Medical Center, both in Minneapolis. He had no financial disclosures. Dr. Bart was lead investigator for the CARRESS-HF trial and a coinvestigator on the AVOID-HF trial. He made these comments in a talk at the meeting and during an interview.
