A Medical Device Daily

Women and men of small size who suffer heart failure for the first time now have an option to receive mechanical support, with yesterday's report by Thoratec (Pleasanton, California) that it has received FDA approval of its HeartMate II Left Ventricular Assist System (LVAS).

"The HeartMate II is an important advance in mechanical heart technology," said Daniel Schultz, MD, director of FDA's Center for Devices and Radiological Health, in an agency statement. "Until now, some heart transplant candidates have been under-served due to the large size of previously approved heart-assist devices."

Heart-assist devices help the ventricle pump blood to the rest of the body. Previous models were too large to be placed in the upper abdomen of some women and small-sized men. The HeartMate II features a first-of-a-kind design for a reduced size.

An advanced generation of the company's original Heartmate device, the HeartMate II has been seen as an important product for driving company profits.

Rather than the standard pulsatile pump that simulates the action of the heart, HeartMate II uses a continuous-flow pump that constantly moves blood with a single moving part, a spinning rotor. This allows the device to be slimmed down to 3 inches in length and a weight of about one pound.

Approval of the HeartMate II didn't come easily.

Following FDA approval of a pivotal study in February 2005, Thoratec completed enrollment of the agreed-upon total of 133 patients in May 2006. In April 2007, the FDA sent a major deficiency letter to Thoratec regarding the trial, and that Thoratec had implanted the device in another 280 patients in a continuous-access program.

Thoratec presented all the data both to FDA and to the panel in support of its application, but the panel was more focused on the pivotal trial data, with the device missing the prescribed objective performance criteria by one percentage point (Medical Device Daily, Dec. 4, 2007).

During that panel meeting, bleeding events were the focus of discussions, with 59 of the adverse events reported consisting of hemorrhage (the FDA data did not indicate whether these 59 events represented exactly 59 patients), a level that some panelists saw as higher than expected.

The HeartMate II includes an electrical cable to power the blood pump which passes through the patient's skin to an external controller that the patient wears on his or her waist. The controller is powered either by batteries or connected to an electrical power outlet. Blood flow is set through the pump based on the patient's need, and the controller monitors pump performance, sounding alarms if it detects dangerous conditions or a possible malfunction.

The system can operate on two external batteries, allowing the patient to move freely for up to three hours.

In a clinical study of 126 patients at 26 transplant centers, 57% of patients with the HeartMate II survived to heart transplant, which is comparable to the survival of patients treated with currently approved heart-assist devices.

The FDA reported that Thoratec is required to conduct a post-approval study to further evaluate the HeartMate II's performance.

The HeartMate II LVAS received the CE mark in November 2005, an okay for commercial sale of the device in Europe.