International Society of Rotatry Blood Pumps edition:20 location:Istanbul date:20-20 September 2012
Mechanical support of the failing right ventricle (RV) can be a life-saving option in patients with pulmonary hypertension. However, the RV is very afterload dependent and the pulmonary resistance is lower than the systemic resistance. Supporting a failing RV with a VAD can have unpredictable effects and is more likely to lead to RV dilatation. Therefore we wanted to assess the acute hemodynamic effects of right ventricular support in different conditions of RV-failure.
A CirculiteTM SynergyTM micro-pump was inserted in adult sheep via a left thoracotomy. Blood was withdrawn from the right atrium to the pulmonary artery (PA). Arterial blood pressure (ABP), pulmonary arterial pressure (PAP), central venous pressure (CVP), heart rate (HR), pulmonary and pump flow were registered at baseline and at 22000 RPM. To mimic different types of RV failure, this procedure was performed in each animal 1) in control conditions (STANDARD), 2) after induction of pressure overload by banding the PA distal to the pump outflow tract (BANDING) and 3) after ligating the right coronary artery in these banded PA sheep (BANDING + LIGATION).
Changes in hemodynamics (from 0 to 22000 RPM) in the 3 different experimental conditions are depicted in table 1. The CVP remained constant (both 12 1 mmHg in STANDARD, 13.3 3.1 vs 12.7 2.5 mmHg in BANDING and 14 3.5 vs 14.3 2.3 mmHg in BANDING+LIGATION).
Right ventricular support in different types of RV-failure improves both systemic and pulmonary hemodynamics. The gain of systemic and pulmonary pressures is the highest in the pressure overloaded RV. An increased total cardiac output with stable CVP over the three hemodynamic conditions reflects the successful unloading of the RV and the good tolerance of this support.
Table 1. Acute hemodynamic changes versus the unsupported condition