Left ventricular assist devices (LVADs) – heart pumps – worked better than medical therapy in keeping seriously ill congestive heart failure patients alive, despite an increased risk of neurological complications, researchers report in today’s rapid access issue of Circulation: Journal of the American Heart Association.
Congestive heart failure occurs when the heart can no longer pump enough blood to the body’s other organs. As blood flow slows, blood returning to the heart through the veins backs up, causing congestion or swelling in the legs, ankles and other tissues. Treatment includes medications that strengthen the heart’s pumping ability, make the heart’s work easier, and help the body eliminate excess fluid. If symptoms are life-threatening, despite optimal drug treatment, heart transplantation is considered.
The newest treatment option, the LVAD, is a pump implanted in the abdomen and attached to the left ventricle and the main blood vessel carrying blood from the heart to the body. A tube connects the pump to controls and a power supply worn outside the body.
Previously, the landmark Randomized Evaluation of Mechanical Assistance of the Treatment of Congestive Heart Failure (REMATCH) trial found that patients too ill to undergo heart transplant fared better if they received a pumping device rather than optimal treatment with medications. The LVAD was already used as temporary “bridge” therapy for patients anticipating transplant within a few months. REMATCH was the first test of their value for permanent treatment.
But the survival success was tempered by a significant number of adverse neurological events, such as stroke, transient ischemic attack (“mini-stroke”) or toxic metabolic encephalopathy.
In this study – a sub-analysis of REMATCH – researchers investigated if stroke risk lessens the survival benefits of LVAD by comparing the rates of stroke-free survival between the two treatment groups.
“With an LVAD the patients’ survival more than doubled, and cardiac functioning unequivocally improved, but there were concerns about neurological complications. In this analysis, we took the view that outcome should be considered in terms of both survival and significant disability,” said principal investigator Ronald M. Lazar, Ph.D., professor of clinical neuropsychology in neurology and neurological surgery at the Columbia University College of Physicians and Surgeons in New York.
“We found a 44 percent decreased risk of stroke or death in the LVAD group versus the optimal medical group. So even when we handicapped the LVAD group by adding stroke to the analysis, they still survived longer,” Lazar said.
Between 1998 and 2001, 61 terminally ill heart failure patients, average age 68, were randomly assigned to receive drug therapy and close medical monitoring, while 68 others, average age 66, received an LVAD. To enter the study, patients had to have persistent, severe heart failure while on appropriate drug therapy, and to be ineligible for heart transplantation because of age or illness. Patients were followed for two years.
Even with the improved survival, there was a greater risk of neurological complications in patients who received an LVAD. A total of 42 complications occurred in 30 of the patients who received the LVAD, compared with four complications in four patients on medical treatment. Two-thirds of the complications were temporary, including transient ischemic attacks (“mini-strokes” with symptoms lasting less than 24 hours) and temporary changes in mental status.
Sixteen percent of all LVAD patients had strokes during the trial – 11 LVAD patients suffered a total of 12 strokes. Ten strokes resulted from blood clots and two from bleeding. Four were fatal.
In contrast, two patients in the medical therapy group experienced non-fatal strokes.
The strokes tended to occur in two time periods: either in the month immediately following surgery (either initial implantation or needed revisions), or after more than a year on the device.
“This means there may be more than one stroke mechanism, with the early flurry of strokes related to the risk of clotting following surgery, and the later strokes related to the disease process itself,” Lazar said. Heart failure is a leading risk factor for stroke.
He said a combination of drugs to reduce the risk of clotting may be needed, even though there are risks for bleeding. In REMATCH, each physician determined whether to administer clot-preventing medications, and many of the participants did not receive them.
“Design modifications and better medical management should result in fewer complications, but people considering this device should realize that there are risks that go along with the considerable benefits,” Lazar said.
Co-authors are Peter A. Shapiro, M.D.; Brian E. Jaski, M.D.;, Michael K. Parides, Ph.D.; Robert C. Bourge, M.D.; John T. Watson, Ph.D.; Laura Damme, R.N., M.P.H.; Walter Dembitsky, M.D.; Jeffrey D. Hosenpud, M.D.; Lopa Gupta, R.D., M.P.H.; Anita Tierney, M.P.H.; Tonya Kraus, R.N., M.S.N.; and Yoshifumi Naka, M.D.
The National Heart, Lung, and Blood Institute funded the study.