Edge-to-edge repairs of P2 prolapsed mitral valves in isolated swine hearts

Background and aim of the study: The study aim was to determine if mitral stenosis occurred after edge-to-edge (E2E) repair of P2 mitral valve prolapse. Methods: Six swine hearts were reanimated and videoscopes placed to view the mitral valve from the left atrium and left ventricle. Image analyses provided measures of the valve annulus area, orifice area, and regurgitant area. Hemodynamic data were collected (heart rates, left ventricular (LV) pressures, left atrial pressures, maximal LV dP/dt, and maximal LV - dP/dt) from three groups: (i) native functioning valve (Normal); (ii) mitral valve following excision of strut chordae from the P2 region (Prolapse); and (iii) following E2E repair. Results: The mitral valve annulus areas were unaffected by the creation of prolapses, or following repairs (Normal 10.50 ± 4.22 cm²; Prolapse 9.41 ± 3.70 cm²; E2E 9.66 ± 3.37 cm ²; p <0.01), with similar decreases in annulus areas throughout the cardiac cycles, measured at 15 ± 3%. The orifice areas did not change with the creation of prolapses, but decreased following repairs (Normal 4.49 ± 2.70 cm²; Prolapse 4.13 ± 2.16 cm²; E2E 1.99 ± 1.19 cm²; p = 0.12). The regurgitant areas increased following induced prolapse, and returned to near-normal levels upon repair (Normal 0.20 ± 0.16 cm²; Prolapse 0.73 ± 0.35 cm ²; E2E 0.12 ± 0.10 cm²; p <0.01). The max LV dP/dt measures did not decrease significantly, whereas max LV -dP/dt measures were decreased. Conclusion: In this acute assessment of E2E repair of surgically induced mitral valve P2 prolapses, it was observed that a placed A2-P2 (Alfieri) stitch did not change the annulus area, but caused a significant decrease in the orifice area while successfully eliminating regurgitation, but without causing stenosis.