Left ventricular function during support with an asynchronous pulsatile left ventricular assist device.

BACKGROUND: Left ventricular assist devices (LVADs) are frequently used to maintain patients with severe heart failure until heart transplantation becomes possible. Some patients may experience recovery of LV function during such support. Therefore, it is essential to be able to monitor changes in LV function in this setting. METHODS: We studied LV function in 10 patients (median age 34 years, 9 male) who had LVADs implanted because of severe heart failure due to dilated cardiomyopathy a median of 4 months previously. Median pre-implant ejection fraction was 27% and all patients had been on maximal medical therapy, including intravenous inotropic support, prior to insertion of the LVAD. RESULTS: During LVAD support there were cyclical variations in LV dimensions, fractional shortening (FS) and transmitral flow, related to changes in the phase relationship of the LV and the LVAD. The "best" FS occurred when LV systole coincided with device filling and the "worst" FS when LV systole coincided with device ejection. Median FS with the pump switched off was 18% (10% to 32%). Pump-off FS was significantly greater than the "worst" FS with the pump on (5%, p = 0.002), and similar to the "best" pump-on FS (19%, p = NS). CONCLUSIONS: LV function could be studied echocardiographically during LV support and brief periods of interruption in support. Function varied according to the phase relationship of the LV and LVAD. The "best" FS measured during LVAD support was more closely related to the FS with the device switched off than the "worst" pump on FS. The "best" pump-on LV function is therefore most representative of intrinsic LV performance and can be used as a guide to recovery and the potential need for pump-off studies.     

Successful intraventricular thrombolysis during ventricular assist device support

Different types of mechanical ventricular assist devices are available for treating end stage congestive heart failure. Despite technical improvements, however, various complications are still reported for patients during mechanical support. We report our experience with intraventricular thrombolysis as a treatment for possible thrombosis of a continuous flow device that had been implanted as a bridge to heart transplantation. This approach has been demonstrated to be both effective and safe.     

Left ventricular decompression during peripheral extracorporeal membrane oxygenation support with the use of the novel iVAC pulsatile paracorporeal assist device

Extracorporeal membrane oxygenation (ECMO) has become a widely accepted short-term mechanical circulatory support device in patients with refractory cardiogenic shock. A major drawback of the peripheral venoarterial extracorporeal membrane oxygenation is that in patients with profoundly reduced left ventricular contractility associated with high left-heart filling pressure, there is always concern for venting the failing ventricle. We describe a minimally invasive technique for decompressing the left ventricle in this setting using a novel pulsatile paracorporeal assist device, the iVAC 3L (PulseCath, Groningen, The Netherlands). It is implanted through the right axillary artery and provides hemodynamic support while directly off-loading the left ventricle.     

Left ventricular assist device performance with long-term circulatory support: lessons from the REMATCH trial

Background

Left ventricular assist device (LVAD) failure and malfunction rates are critical gauges for establishing LVADs as a long-term therapy for end-stage heart failure patients. These device performance measures, however, have been inadequately characterized in the bridge-to-transplantation literature.

Methods

REMATCH is a randomized trial that compares optimal medical management with LVAD implantation for patients with end-stage heart failure. An independent committee adjudicated patient outcomes. The primary endpoint—survival—was analyzed by intention to treat using the log-rank statistic. Frequency of event occurrence was analyzed by Poisson regression. The time to first event was analyzed by the product limit method. Device performance was disaggregated into confirmed malfunctions and system failures. The latter were events in which patients could not be rescued with backup circulatory support measures.

Results

The 1-year survival rate was 52% (95% confidence limit [CL]; 40%-63%) for LVAD patients versus 28% (95% CL; 17%-39%) for medical patients and the 2-year survival rate was 29% (95% CL; 19%-40%) for LVAD patients versus 13% (95% CL; 5%-22%) for medical patients. System failure was 0.13 per patient per year and the confirmed LVAD malfunction rate was 0.90. Freedom from device replacement was 87% at 1 year and 37% at 2 years.

Conclusions

Despite the observed rates of device malfunction and replacement, LVAD implantation confers clinically significant improvement with regard to survival as compared with medical management. Device modifications and innovations for infection management exhibit great promise of improving device performance in the near future.     

Percutaneous ventricular assist device support during off-pump surgical coronary revascularization

Intraaortic balloon pump counterpulsation has been used for mechanical circulatory support in cardiogenic shock patients, but percutaneous left ventricular assist devices can provide superior circulatory support in the same group of patients. We describe the case of a patient in cardiogenic shock after a myocardial infarction. A percutaneous ventricular assist device was used to provide immediate active hemodynamic support, and, because the patient's condition necessitated surgical revascularization, percutaneous left ventricular assist device support was continued during off-pump coronary artery bypass.