Advanced heart failure patients treated via a continuous-flow left ventricular assist device (LVAD) showed increased survival rates and a decrease in adverse events and device replacements compared to those treated with pulsatile-flow LVADs, a trial published Nov. 17 in the New England Journal of Medicine found.
According to the authors, “[M]edical and electrical therapies for systolic heart failure have improved outcomes and altered the natural history of the disease. However, heart failure commonly progresses and becomes refractory to current treatments.”
Mark S. Slaughter, MD, chief of thoracic and cardiovascular surgery at the University of Louisville in Kentucky, and colleagues conducted a randomized trial of 200 advanced heart failure patients. Eligible participants consisted of patients who were ineligible for a heart transplant and whose heart failure was refractory to optimal medical management.
At a 2 to 1 ratio, study participants were selected to have either a continuous-flow (133 patients) or a pulsatile-flow LVAD (59 patients) implanted.
According to the authors, mechanical circulatory-support devices have been used as therapy because of the small number of suitable heart donors and because continuous IV isotropic support has been reported to have an insignificant survival rate (10 to 30 percent).
The more modern mechanical devices are not only smaller and quieter, according to the authors, but have been shown to improve hemodynamics, end-organ function and patient quality of life.
The devices used in the study were Pleasanton, Calif.-based Thoractec’s pulsatile-flow HeartMate XVE and the continuous-flow HeartMate II, both with flow rates up to 10 liters per minute with an average pressure of 100 mm Hg.
During the study period, data including patient demographics, use of medications and health history were recorded before implantation, while data regarding device performance, lab results and medications were recorded in daily, weekly and monthly intervals after surgery.
Of the total study participants, 114 of the 133 who received continuous-flow LVAD implantations were discharged with the device in place, compared to 45 of the 59 patients implanted with the pulsatile-flow LVADs.
Results showed that after a one-year follow up, survival rates in patients who were transplanted with a continuous-flow LVAD were significantly higher than those with a pulsatile-flow LVAD, 58 to 24 percent, respectively.
There was a 38 percent relative reduction in the rate of rehospitalization among patients with a continuous-flow left ventricular assist device compared to those with a pulsatile-flow device. However, the rates of stroke were similar in all patients (17 vs. 14 percent, continuous- vs. pulsatile-flow, respectively).
Patients who received the pulsatile-flow LVAD required 21 replacement pumps, one patient required an urgent transplant and three required a device explantation. In 18 patients, the pulsatile-flow LVADs were replaced with a continuous-flow device and of the 133 patients implanted with a continuous-flow LVAD, 12 required pump replacements.
In addition, the authors noted that the rates of infection in patients with a continuous-flow device decreased by 50 percent due to the smaller incision needed compared to that needed to implant the pulsatile-flow LVAD.
Slaughter and colleagues found limitations in device durability for long-term therapy, most notably the fact that there were only two patients at the end of the study with the pulsatile-flow LVAD. However, no patients with continuous-flow devices experienced pump failures.
Slaughter received grant support from Thoratec.