Intraoperative Evaluation of Right Ventricular Mechanics in a Pressure-Overload Swine Model

Objectives: Assessment of right ventricular (RV) mechanical performance during open chest surgery is typically based on invasive methods and subjective evaluations. This study developed a porcine model of acute progressive RV pressure overload to evaluate hemodynamic changes and validate the 3D-video kinematic assessment of the Videocardiograph (VCG). Methods: Seven healthy Landrace pigs were instrumented under fluoroscopic guidance with Swan-Ganz and RV conductance catheters. Following a median sternotomy, pulmonary artery banding (PB) was performed in two stages to induce minimal (PBmin) and maximal (PBmax) pressure overload. In a proof-of-concept experiment, different PB steps were performed to record both videos for the VCG and invasive pressure-volume assessments (PV-loop). Additionally, these videos were subjectively evaluated by five consultant surgeons, similar to clinical routine. Results: PBmax significantly increased end-systolic pressure from baseline (21.17±3.31mmHg vs 39.85±7.82mmHg, p=0.001) and led to RV dilation, reduced ejection fraction (52.80±10.36% vs 33.99±9.88%, p=0.012), and decreased myocardial efficiency. In the proof-of-concept experiment, visual evaluations were highly variable among the cardiac surgeons, resulting in only a moderate reliability of their assessments (ICC=0.59 for RV-function; ICC=0.60 for filling status). VCG-derived epicardial z-axis displacements, systolic timing, diastolic velocity and volume demonstrated excellent relationships with PV-loop data. Conclusions: This study established a porcine model of progressive RV pressure overload with robust PV-loop assessment. VCG-derived epicardial kinematics reliably quantified RV mechanical activity and correlated with gold-standard hemodynamic measurements. This non-invasive, cost-effective method shows promise for early detection of acute RV dysfunction in the operating room and warrants further clinical investigation.