Impact of continuous-flow left ventricular assist device support on right ventricular function.

BACKGROUND

Continuous-flow (CF) pumps have yielded improvements in short- and long-term survival and quality of life, and have reduced the number of left ventricular assist device (LVAD)-related complications. However, their ability to unload the right ventricle (RV) and improve RV function has not been as clearly defined. We evaluated the short- and mid-term effects of CF-LVADs on central venous pressure (CVP), pulmonary artery pressures (PAP), pulmonary capillary wedge pressure (PCWP), cardiac index (CI), RV ejection fraction (RVEF), RV end-diastolic dimension (RVEDD), RV stroke work index (RVSWI), tricuspid annular plane systolic excursion (TAPSE) and severity of tricuspid regurgitation (TR).

METHODS

From March 2006 through June 2012, 130 patients with chronic heart failure underwent implantation of a CF-LVAD (122 HeartMate II and 8 HeartWare devices) as a bridge to transplant (n = 76) or as destination therapy (n = 54). Patients with pre-operative long-term LVADs (n = 4) and patients who underwent concomitant tricuspid valve repairs during their LVAD implant (n = 21) were excluded from the analysis. Echocardiograms and right heart catheterizations of the remaining 105 patients were reviewed pre-operatively and at 1 and 6 months post-LVAD implantation.

RESULTS

At 1 month post-LVAD implantation, CVP decreased from 12.4 ± 5.9 mm Hg to 8.7 ± 4.5 mm Hg (p < 0.001), systolic PAP decreased from 52.3 ± 14.1 mm Hg to 36.8 ± 11.3 mm Hg (p < 0.001), PCWP decreased from 23.0 ± 9.4 mm Hg to 12.9 ± 8.0 mm Hg (p < 0.001), CI index increased from 1.8 ± 0.5 liters/min m2 to 2.4 ± 0.5 liters/min m2 (p < 0.001), RVEF increased from 33.1 ± 4.9% to 40.4 ± 6.2% (p < 0.001), RVEDD decreased from 36 mm to 31 mm (p = 0.020), RVSWI improved from 408.6 ± 144.6 mm Hg ml m2 to 614.4 ± 196.2 mm Hg ml m2 (p < 0.001), and mean TAPSE increased from 1.1 ± 0.4 cm to 1.9 ± 0.4 cm (p = 0.004). Similarly, qualitative RV function on echocardiography improved from 57.1% moderately or severely reduced pre-operatively to 38.1% at 1 month (p = 0.008). Severity of TR decreased from 11.4% moderate or severe pre-operatively to 4.8% at 1 month (p < 0.001). These improvements were maintained at 6 months post-LVAD.

CONCLUSIONS

CF-LVAD support significantly decreased CVP and RVEDD, with concomitant improvement in RV function, as measured by increases in RVEF, RVSWI and TAPSE, as well as improvements in the qualitative echocardiographic appearance of RV contractility and a reduction in TR.