The AVOID-HF Trial: Points to Consider.

The large-scale AVOID-HF (Aquapheresis Versus Intravenous Diuretics and Hospitalization for Heart Failure) trial compared ultrafiltration and medical treatment in acute heart failure (HF) (1). A major advantage of this study was the use of adjustable, rather than fixed, treatment regimens in both arms. The study was terminated early but still could demonstrate a nonsignificant trend for longer time to first HF event in the ultrafiltration group. We think there are a number of points that, if addressed in future studies, could help further elucidate the role of ultrafiltration in this setting. First, more patients in the ultrafiltration group experienced adverse events, some of which appear to be related to venous access complications (e.g., bleeding, infection, venous thrombosis). The portable ultrafiltration devices are marketed as having the possibility of using peripheral venous access, and the investigators of AVOID-HF also mention that the ultrafiltration could be performed through the use of a variety of peripheral, midline, and central catheters (2). However, the number and types of venous access that were used for these patients are not reported in the article. This could have been helpful in characterization of the potential link between the type of venous access and the pertinent complications. Second, diuretics are widely used for management of patients with HF and the previous ultrafiltration studies have reported between 90% and 100% of patients receiving diuretics at the time of admission (3,4). Although the inclusion criteria, the baseline characteristics (e.g., patients’ weight), and the outcomes imply that the study population in AVOID-HF has been comparable to other trials, it is not clear why only 55% of the patients were receiving diuretics. A key indication for the use of ultrafiltration in HF is diuretic-refractory volume overload; therefore, this point merits clarification by the investigators. Third, in acute HF, there exists substantial discrepancy between the amount of fluid removed and weight loss. In AVOID-HF, too, the patients in the ultrafiltration group had significantly greater net and total fluid removal, whereas weight loss was found to be comparable in both arms. This lends support to the previously proposed notion that ultrafiltration has a higher efficacy for decongestion, but it also raises the question of whether “equivalent” fluid removal would portend similar beneficial effects for ultrafiltration.