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FDA panel recommends HeartMate II for approval
The wearable left ventricular assist system demonstrated reasonable safety and efficacy.
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The FDA Circulatory System Devices Advisory Panel voted to recommend, with conditions, approval of the HeartMate II left ventricular assist system.
The HeartMate II (Thoratec) is an LV pump designed to bridge the gap of time between the failure of the left ventricle and a heart transplant.
Unanimous vote
“I voted affirmatively for the device,” Norman S. Kato, MD, cardiothoracic surgeon with the Cardiac Care Medical Group, Encino, Calif., said at the meeting held in Gaithersburg, Md. “This is an exciting device because of its small size and its ability to be implanted in many more patients. I look forward to the sponsor and the FDA to try to tighten up the indications so we can reduce the variability of the successes.”
Although the vote to recommend was unanimous, the approval recommendation came with conditions. The panel determined that a postapproval study complete with a concurrent comparator group, data on women and data on patients with smaller body surface area would be required for their continued recommendation. The postapproval study is also required to capture bleeding and anticoagulation data and also to carry a warning label prohibiting use of the device in patients who are unable to receive anticoagulation medication.
“I voted in favor, but I must say that the safety and efficacy were very difficult to discern,” John C. Somberg, MD, professor of medicine and pharmacology at Rush University, Chicago, said at the meeting. “There is a lot of science to be investigated here, especially as it relates to bleeding and to the use of anticoagulation as a surrogate for rheology. So I think there are many questions that are left unanswered today that could make a major difference in the use of this device.”
The bleeding rate was too high and this may be due to the use of anticoagulation to change blood viscosity that “lubricates” the pump rotor — the single moving part of the device, according to the panel. There may be more effective ways to change blood viscosity that do not increase bleeding and thus are safer. This needs to be studied in an organized fashion with a coherent protocol developed by the sponsor, the panel said.
Improved survival
The device consists of a continuous axial flow pump connected to an external system controller and battery power system by a percutaneous lead. By anastomosing the inflow cannula to the left ventricle and the outflow cannula to the ascending aorta, the pump assembly essentially replaces the left ventricle. The patient is able to control the pump pressure and other functions from the external controller worn on a belt.
Researchers of the pivotal clinical study of the HeartMate II established their performance goal as survival to 180 days, regardless of transplant status at 180 days. Of the 126 patients enrolled in the pivotal study cohort, 89 (70.6%) met the primary endpoint, and 37 (29.4%) did not meet the endpoint. Of the 37 patients who failed to meet the study endpoint, 25 (19.8%) died before transplantation or before 180 days, primarily due to sepsis. Three of these patients died due to device-related complications, such as malfunction and power loss. Although the rate of bleeding was notable, the panel decided that these adverse events, taken in totality with the rest of the data, did not constitute a serious safety signal. - by Eric Raible
This is a good device with a number of advantages over the standard XVE. It is smaller and can fit in smaller patients. It is very reliable, and that’s probably the most important thing I would single out. The device has very few moving parts. There is not a lot of mechanical failure, whereas the XVE, the device previously approved for bridge-to-transplant, had a decent amount of mechanical failures after 16 to 18 months. The downside to the HeartMate II device is that it requires anticoagulation, but it is no worse than an aortic or mitral valve that is a prosthetic valve. It seems to be fairly easy to use. Again, I’ve been fairly impressed with the device itself, the engineering of it and its reliability.
– Frank Smart, MD