Filter more effective than diuretics for heart failure

Mar 13 2006

Researchers in the U.S. say that filtering the blood works better than diuretic drugs to remove excess fluid in patients admitted to hospital for heart failure.

As many as a million Americans each year are admitted to hospital for heart failure, which is the inability of the heart to pump enough blood to support vital organs and often leads to a buildup of fluid, causing swollen legs and arms, fatigue and eventually excess fluid in the lungs and severe life-threatening shortness of breath.

Dr. Maria Rosa Costanzo, medical director of the advanced heart failure center at the Midwest Heart Foundation in Lombard, Illinois, says heart failure is the most common cause of hospitalization in the United States.

Standard treatment for such patients includes intravenous diuretics.

Dr. Costanzo, the lead investigator of a 200-patient trial comparing the two therapies says they found that patients hospitalized with heart failure undergoing filtration lost more weight and experienced greater net fluid loss than patients treated primarily with diuretics.

Apparently after 90 days, the filtration group had significantly fewer days in hospital, and there were 50 percent fewer rehospitalizations for heart failure.

There was also a 52 percent reduction in unscheduled heart failure doctor's office and emergency room visits.

Costanzo says the findings are immediately applicable to a large number of patients with heart failure.

The filtration process involves withdrawing the patient's blood through tubing in a small vein, circulating it through a filtering system that removes excess fluid, then returning the blood through a tube in another vein.

New technology apparently means the process now allows blood to be taken from a peripheral vein and only a small amount is outside of the body at any one time.

Dr. Costanzo says that previous machines required central venous access and she believes the new technique may be better for patients, because, unlike diuretics, it does not activate some of the harmful hormonal changes that worsen heart failure.

The filtering machine can remove up to a pound per hour of excess salt and water from the blood stream without clinical effects on kidney function, heart rate, blood pressure or electrolyte balance.

The filter used in the process costs about $800, but Dr. Costanzo says as rehospitalization rates are lower, savings would be made in the longterm.