Less-invasive ultrafiltration device may be practical alternative to diuretics

11/29/05

Device removes fluid from patients with heart failure, without drawbacks of earlier machines

A device that performs ultrafiltration of blood, without requiring specialized nursing care or invasive central intravenous access, can reduce fluid overload in patients with congestive heart failure, according to a new study in the Dec. 6, 2005, issue of the Journal of the American College of Cardiology.

"We found that this form of ultrafiltration therapy was safe, effective and successfully applied to patients in a variety of hospital settings. Compared to patients receiving standard treatment with intravenous diuretics, patients undergoing ultrafiltration had more fluid removed in the first 24 and 48 hours and improved symptoms of heart failure and shortness of breath at 48 hours," said Bradley A. Bart, M.D., F.A.C.C., from the Minnesota Heart Failure Consortium in Minneapolis, Minnesota.

Patients admitted to the hospital with acute decompensated heart failure are suffering from symptoms primarily related to fluid build-up and congestion, including swelling around the feet and ankles, bloated abdomens, cough and shortness of breath.

The RAPID-CHF trial is the first randomized controlled trial of ultrafiltration for acute decompensated heart failure. As blood passes through the device, ultrafiltration removes water and some small molecules through a membrane, before the blood is returned to the patient.

Researchers randomly assigned 40 hospitalized patients to receive either usual care, including diuretic medicine in most cases, or a single eight-hour ultrafiltration treatment, in addition to usual care. The ultrafiltration was performed with a device that has been approved by the federal Food and Drug Administration for use outside of intensive care units and without specialized nursing or central intravenous access. The manufacturer of the device, CHF Solutions Inc., funded this study.

Ultrafiltration was successful in 18 of the 20 patients in the group. After 24 hours, an average of 4,650 milliliters of fluid had been removed from patients in the ultrafiltration group, compared to 2,838 ml among patients usual care group. Patients in the ultrafiltration group also lost more weight on average, 2.5 kilograms compared to 1.86 kg average for the usual care group. However, the difference was not statistically significant. Intravenous access was unsuccessful in one patient, and one patient could not be treated due to inability to withdraw blood from the catheter.

Diuretics have been used to treat fluid overload for over 50 years; but the drugs drain electrolytes from patients, including potassium and magnesium, and it can be difficult to determine the proper dose for each patient. A practical, safe and effective ultrafiltration device could be an attractive alternative to diuretics.

"Ultrafiltration has been available for many years. In the past, it has been reserved for heart failure patients who fail all traditional therapies, as a form of rescue therapy. Traditional ultrafiltration requires invasive central intravenous access, monitoring in an intensive care unit and specialized nursing care. The ultrafiltration device used in this study can be operated by standard hospital nurses outside the setting of the intensive care unit, does not require invasive central IV access and, in the RAPID-CHF trial, was used as an early treatment strategy rather than for rescue therapy," Dr. Bart said.

Dr. Bart noted that this was a feasibility study that enrolled only a small number of patients. A larger trial to compare the effectiveness of this ultrafiltration device with standard care, including diuretics, is underway, with results expected in the spring, Dr. Bart said.

The journal also includes another preliminary ultrafiltration trial involving 20 heart failure patients who were resistant to diuretics. Maria Rosa Costanzo, M.D., F.A.C.C., and her co-authors reported that ultrafiltration before intravenous diuretics effectively and safely decreased the length of hospital stays and readmissions. This study also was funded by CHF Solutions.

Robert C. Bourge, M.D. F.A.C.C., from the University of Alabama in Birmingham, Alabama, who co-authored an editorial in the journal with José A. Tallaj, M.D., said ultrafiltration for fluid removal offers potential advantages over diuretics, including more precise control over the amount of fluid removed, and possibly fewer side effects.

"From the results of these two studies, ultrafiltration is probably safe and results in a fast and effective method of fluid removal and decreasing ventricular filling pressures in patients with decompensated heart failure," Dr. Bourge said.

However, he noted concerns as well, including the small number of patients included in these preliminary studies, the risk of infection in the intravenous lines, the duration of any benefits, and, importantly, the potential cost of the therapy compared to the inexpensive use of intravenous diuretics.

"As exciting as these results are, we think we should wait for the results of a large randomized trial, to assure that the safety profile, beneficial effects, and cost/benefit analysis justify its use." Dr. Bourge said.

Mandeep R. Mehra, M.D., F.A.C.C., from the University of Maryland School of Medicine in Baltimore, who was not connected with these studies, noted that current therapy with diuretics is not as effective as physicians would like.

"Ultrafiltration might be an important new technique to treat diuretic resistance in heart failure, but it is invasive. The current studies are clearly steps in the right direction, but they are not definitive, since they examined few patients. Definitive studies are in progress," Dr. Mehra said.

Source: Eurekalert & others

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