One hundred patients with the HeartMate left ventricular assist device: evolving concepts and technology

Implantable left ventricular assist devices are common as a bridge to transplantation but are just reaching their goal as an alternative to transplantation.

From December 1991 until December 1996, 97 left ventricular assist devices were implanted as a bridge to transplantation, one as an alternative to transplantation, and two as a bridge to recovery. Included were 64 pneumatic devices and 36 electric devices. Most patients (69%) had ischemic cardiomyopathy and most (53%) had had previous cardiac surgery. Preoperative circulatory support (extracorporeal membrane oxygenation) was used in 25.

Perioperative insertion of a right ventricular assist device was unusual (11%). The mean duration of support with a left ventricular assist device (bridge to transplantation) was 70 +/- 41 days (up to 206 days). Survival to transplantation was 76%. Cause of death included multiple organ failure (n = 13), perioperative stroke (n = 5), device failure (n = 5), and controller disconnect (n = 1). Significant risk factors for death included (1) preoperative need for ventilator or extracorporeal membrane oxygenation, (2) elevated blood urea nitrogen, creatinine, or bilirubin, and (3) low pulmonary artery pressures. Risks after insertion of the left ventricular assist device were reoperation for bleeding, support with a right ventricular assist device, dialysis, or device failure. Catastrophic failure of the device occurred 14 times in 12 patients and was treated by emergency pump exchange in six instances. Only two device-related thromboembolic episodes were detected. Positive blood cultures were found in 59% of patients, driveline infection in 28%, and pump infection in 11%.

The HeartMate device provided excellent hemodynamic support with low device-related thromboembolic events. Infection and reliability of the device contributed to the high cost of therapy. These areas need to be improved for the left ventricular assist device to attain its goal as a viable alternative to transplantation.