Invasive versus Echocardiographic Hemodynamics in the First Genetically Modified Porcine to Human Xenotransplant

Introduction: Our medical center performed the first genetically modified cardiac xenotransplant in human and performed longitudinal invasive and noninvasive hemodynamic measurements throughout the recipient’s hospitalization. We hypothesized that echocardiographic derived hemodynamic assessments would correlate with invasive measurements within the cardiac xenotransplant. Methods: Transthoracic echocardiography (TTE) and right heart catheterizations were performed in the cardiac xenotransplant. Retrospective analysis of TTE and invasive hemodynamics were analyzed to assess correlation between various parameters. The following invasive hemodynamics were measured or calculated: right atrial pressure (RAP), pulmonary artery systolic and diastolic pressures (PASP, PADP), pulmonary vascular resistance (PVR), pulmonary artery pulsatility index (PAPi), cardiac output (CO), cardiac index (CI), right ventricular stroke work index (RVSWI) and cardiac power output (CPO). TTE measurements and calculations included: RAP based on inferior vena cava size and collapsibility, PASP calculated via tricuspid regurgitation velocity (TRV), PADP based on end diastolic pressure gradient, right ventricular outflow time-velocity integral (TVI RVOT), PVR (TRV/TVI RVOT x 10 + 0.16) PAPi, CO (using left ventricular outflow tract (LVOT) velocity-time integral and LVOT area), CI (from TTE-derived CO), CPO and RVCPI {4x(TRV)} x TAPSE as a surrogate of RVSWI. Results: Pearson correlation for RVSWI and RVCPI using invasive measurements obtained at the time of TTE was -0.095 and at time of mixed venous blood gas (mVBG) was 0.963. Mean absolute difference in time between mVBG and TTE was 4h 59 min. Pearson correlation for catheter-based continuous CO (CCO) monitoring with TTE was 0.965. Conclusion: In a retrospective analysis of porcine cardiac xenotransplant function, there was a strong correlation between directly measured hemodynamics with TTE, particularly when mVBG was obtained.