Impact of Severe Tricuspid Valve Insufficiency on the Performance of Left Ventricular Device

Objectives: Up to 50% of the left ventricular device (LVAD) candidates present with moderate -severe tricuspid valve insufficiency (TVI) at the time of LVAD implantation. The exact strategy weather to perform a TV repair (TVR) or not in these patients is not well investigated. We aimed to evaluate the impact of severe 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 6 ovines (mean weight: 62 ± 2 kg) through the application of several coronary ligations. Once stabile HF was obtained (after 15 ± 4 days), the animals were brought back to the operating room and supported with HeartWare LVAD (HeartWare Inc., Framingham, MA). 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. The severity of TVI was assessed using intraoperative echocardiographic examinations.

Results: The total CPB time was 104 ± 22 minute and the total LVAD support time was 35 ± 9 minute. Except for expected higher CVP in the TVI setting (27 ± 7 mm Hg vs. 19 ± 9 mm Hg, p = 0.108) there were no statistical significant differences in the hemodynamic and pump parameters between TVI setting and no TVI condition. At average pump speed of 2267 ± 82 rpm, the mean CO and pump flow in the TVI and no TVI setting were 1.8 ±0.7 L/min versus 2.4 ± 1.2 L/min and 3.4 ±1.2 L/min versus 3.1 ± 0.6 L/min respectively (p = 0.224 and 0.562 respectively). Meanwhile, a MAP of 70 ± 11 mm Hg and 72 ± 16 mm Hg in the TVI and no TVI setting was measured respectively (p = 0.268).

Conclusion: This study of severe TVI in chronic HF animals with preserved right ventricular function (RVF) showed no significant differences in the hemodynamic and pump parameters between TVI setting and no TVI condition. This finding may questions the necessity of TVR by preserved RVF at the time of LVAD support. We plan chronic animal studies in the same settings to investigate long term impact of the severe TVI on the outcome and LVAD performance.