Does Severe Tricuspid Valve Insufficiency Impact the Performance of the left Ventricular Assist Devices? Acute Animal Studies

Objectives: Up to 50% of the left ventricular assist device (LVAD) candidates present with moderate–severe tricuspid valve insufficiency (TVI) at the time of LVAD implantation. The exact strategy whether to perform a TV repair (TVR) or not in these patients is not well investigated. We aimed to evaluate the impact of severe iatrogenic TVI at the time of LVAD implantation on the hemodynamic and LVAD parameters in an acute ovine model.

Methods: Chronic stabile heart failure (HF) was induced in 10 ovines (mean weight 61 ± 7 kg) through the application of several coronary ligations. Once stabile HF was obtained (after 15 ± 5 days), animals were brought back to the operating room and supported with HeartWare LVAD (HeartWare Inc., Framingham, Massachusetts, United States). Hemodynamic data (mean arterial pressure (MAP), pulmonary artery pressure, central venous pressure (CVP), cardiac output (CO) and heart rate), as well as pump flow, speed, and power consumption were obtained in two settings; first with LVAD in place after weaning from cardiopulmonary bypass (CPB) machine (no TVI setting) and second following reinitiating the CPB and induction of severe TRI through resection of the tricuspid valve (TVI setting). Hemodynamic and pump parameters were compared between these two settings without changing the pump speed.

Results: The total CPB time was 101 ± 22 minutes and the total LVAD support time was 41 ± 20 minutes. There were no statistical significant differences in the hemodynamic and pump parameters between TVI setting and no TVI conditions except for expected higher CVP in the TVI setting (27 ± 6 vs. 18 ± 8 mm Hg, p = 0.013) and higher CO in the TVI setting (2.4 ± 1.5 L/min vs. 3.2 ± 1.0 L/min, p = 0.011). At average pump speed of 2,300 ± 87 rpm in the TVI and 2,322 ± 130 rpm in the no TVI setting, the mean pump flow in the TVI and no TVI setting were 3.3 ± 2.1 and 3.3 ± 1.0 L/min, respectively (p = 0.895). Meanwhile, a MAP of 70 ± 9 and 69 ± 14 mmHg in the TVI and no TVI setting was measured, respectively (p = 0.779).

Conclusion: This study of severe iatrogenic TVI in chronic HF animals with preserved right ventricular function (RVF) showed no significant differences in the pump performance between TVI setting and no TVI condition. This finding may questions the necessity of TVR by preserved RVF at the time of LVAD implantation.