Aquapheresis: A New Treatment for Heart Failure

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Aquapheresis: A New Treatment for Heart Failure (Part 1)
Joshua Schwimmer, MD, FACP, FASN

Congestive heart failure (CHF) is a condition where the heart's pumping of blood is inadequate and consequently, fluid builds up in the lungs. (As a nod to my readers who are cardiologists -- CHF has many causes and is much more complicated that this simple explanation.) Symptoms of heart failure can include shortness of breath, low blood pressure, and a lack of blood flow to other organs of the body, like the kidneys.

Ninety percent of hospitalizations for congestive heart failure are due to shortness of breath from fluid overload. In patients with CHF, the major treatment for fluid overload has classically been diuretics injected intravenously. There are many types of diuretics, but Lasix (furosemide), is the one most commonly used.

The use of diuretics, while often quite effective, has many potential problems. First, an inadequate dose may be given, which may require a longer course of hospitalization until titration to the proper dose is achieved. Second, the patient may respond too well to the diuretic (a condition called \"overdiuresis\"), which can lead to low blood pressure and decreased kidney function. Third, even if the proper dose is given, diuretics may occasionally still lead to decreased kidney function and other complications, like low potassium.

For patients with congestive failure who already have significantly decreased kidney function, an alternative to diuretics is a process called \"ultrafiltration.\" During dialysis -- a way of cleaning and filtering the blood using a dialysis machine -- fluid may be removed from the blood directly. In patients with CHF, ultrafiltration of extra fluid, which is performed during dialysis, can relieve symptoms of shortness of breath the same way diuretics can. The downside is that ultrafiltration requires a dialysis machine and is usually only used in patients with decreased kidney function.

In an attempt to overcome the problems with diuretics and the requirement of a dialysis machine for ultrafiltration, a company called CHF solutions has designed a device for ultrafiltration -- which they call \"aquapheresis\" -- called the AquaDex FlexFlow Fluid Removal System. A recently published study called the UNLOAD trial has shown impressive results in using the machine to treat patients with heart failure.


Aquapheresis: A New Treatment for Heart Failure (Part 2)
Joshua Schwimmer, MD, FACP, FASN

In Part 1, I introduced the problem of heart failure and the use of intravenous diuretics, the standard therapy to treat fluid overload in hospitalized patients.

Recently, the UNLOAD trial was published in the Journal of the American College of Cardiology. This study compared intravenous diuretics with aquapheresis, a new treatment for heart failure.

Aquapheresis -- also called ultrafiltration -- is a technique for removing excess fluid from the body. It involves the placement of an catheter in the bloodstream that continuously runs the patient's blood through a filter. Excess fluid is remove from the blood through this filter, and the blood is then returned to the patient. Up to half a liter an hour of extra fluid can be precisely removed from the body in this way. (This technique is different than dialysis, which also involves the removal of excess toxins from the body -- using the process of diffusion -- when the kidneys have failed.)

In the UNLOAD trial, two hundred patients with heart failure were randomized to receive either intravenous diuretics or aquapheresis/ultrafiltration. After 48 hours, patients receiving aquapheresis had the following results:

* 38 % greater weight loss over standard care
* 28 % greater net fluid loss over standard care
* Equal improvement in dyspnea score (breathing)

Ninety days after hospital discharge, patients receiving aquapheresis showed

* 43% reduction in patients requiring re-hospitalizations for heart failure over standard care
* 50% reduction in the total number of re-hospitalizations for heart failure over standard care
* 52% reduction in emergency department or clinic visits over standard care
* 63% total reduction in days re-hospitalized for heart failure over standard care

This study suggests that aquafiltration is an alternative therapy for hospitalized patients with heart failure that may be more effective than standard therapy.