Fiberscope-Based Measurement of Coaptation Height for Intraoperative Assessment of Mitral Valve Repair

Abstract

Background Restoring adequate coaptation height is a key principle of mitral valve (MV) repair. This study aimed to evaluate the utility of fiberscope (FS) technology to assess MV coaptation height for intraoperative use. Methods Ex-vivo testing was performed on five adult porcine hearts. The left atrium (LA) was resected, and the left ventricle (LV) was pressurized retrograde to 27 ± 1mm Hg. An endoscope was inserted into the LV apex, centered under the MV orifice. An FS system (Milliscope II camera, LED light source, and 0.7 mm diameter × 15 cm long) 90° semirigid scope with 1.2 mm focal length) was mounted above the MV annulus in a custom alignment and measuring fixture. Three blinded measurements were taken at two locations on each MV, A2 and P2 segment, from the top of coaptation to the leaflet edge identified by the FS. Accurate positioning was verified using the LV endoscope. A control (metal rod of similar thickness) was used for comparison, with coaptation height recorded when the control was seen via the endoscope. Results Coaptation heights were similar for the control and FS methods across all hearts at A2 (11.6 ± 2.6 mm control vs 11.8 ± 2.2 mm FS) and P2 (13.3 ± 2.6 mm control vs 13.4 ± 2.9 mm FS) segments, with similar measurement variability (control SD 0.1-1.0 mm; FS SD 0.1-0.9 mm). One outlier was excluded from analysis (n = 19/20). The maximum absolute difference and percent error between measurement methods were less than 1.1 mm (median [IQR], 0.6 [0.3-0.9] mm) and less than 14% (4.1 [2.2-7.6]%). Conclusions Utilization of a miniaturized FS enabled precise and accurate quantification of MV coaptation. This technique is promising for evaluating post-repair valve competence and coaptation height.