Intraoperative evaluation of right ventricular mechanics in a pressure-overload swine model

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 three- dimensional (3-D) video kinematic assessment of the videocardiograph (VCG). 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 (PB_min) and maximal (PB_max) 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). In addition, these videos were subjectively evaluated by five consultant surgeons, similar to clinical routine. PB_max significantly increased end-systolic pressure from baseline (21.1 ± 3.3 mmHg vs. 39.8 ± 7.8 mmHg, P = 0.001) and led to RV dilation, reduced ejection fraction (52.8 ± 10.3% vs. 33.9 ± 9.8%, 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. 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 noninvasive, cost-effective method shows promise for early detection of acute RV dysfunction in the operating room and warrants further clinical investigation.NEW & NOTEWORTHY This study established a porcine model of acute right ventricular pressure overload using pulmonary artery banding to assess intraoperative RV mechanics. Hemodynamic changes were measured using pressure-volume (PV) loops and compared with 3-D video kinematic analysis from the videocardiograph (VCG). VCG-derived kinematic parameters correlated well with invasive PV loop data, whereas surgeons' visual assessments were highly variable. The findings suggest that VCG offers a reliable, noninvasive method for intraoperative RV function monitoring, warranting further clinical evaluation.