Cutting second-order chords does not prevent acute ischemic mitral regurgitation

Article; Proceedings Paper

关键词: VALVE REPLACEMENT;    MECHANICS;    APPARATUS;    TENDINEAE;    INSIGHTS;    COMPLEX;    REPAIR;   

DOI  :  10.1161/01.CIR.0000138396.24335.6a

来源: SCIE

【 摘 要 】

Background-Cutting anterior mitral leaflet second-order chordae has been proposed for repair in ischemic mitral regurgitation (IMR). We examined the efficacy of such chordal cutting in preventing acute IMR. Methods and Results-Six sheep underwent radiopaque marker placement (left ventricle, mitral annulus, papillary muscles [PMs], and leaflets). The largest second-order chord from each PM was encircled with exteriorized wire snares. Three-dimensional marker coordinates were obtained with biplane videofluoroscopy before and during acute ischemia (80 seconds of mid-circumflex occlusion). Color Doppler transesophageal echocardiography was used to grade MR on a 0 to 4+ scale. Data were acquired immediately before and after dividing second-order chordae. Slope of the end-diastolic volume-stroke work relationship (PRSW) was calculated to assess systolic function. Chordal cutting increased anterior leaflet inflection angle (155 +/- 12 versus 162 +/- 9 degrees; P=0.03), resulting in a flatter leaflet, but did not increase effective leaflet length (1.97 +/- 0.24 versus 2.08 +/- 0.23 cm; P=0.15); PRSW decreased (63+/-15 versus 56 +/- 12 mrnHg; P=0.008). Both before and after chordal cutting, ischemia caused: Septal-lateral annular dilation (P=0.005), posterior PM displacement away from the mid-septal annulus (P=0.06), increased leaflet tenting area (P=0.001), and increased leaflet tenting volume (P=0.002). Before chordal cutting, MR increased significantly during ischemia (0.5 +/- 0.3 versus 1.7 +/- 0.4; P<0.001), and IMR increased similarly even after the second-order chords were cut (0.7 +/- 0.4 versus 1.9 +/- 0.9; P<0.001). Conclusions-Cutting second-order chordae resulted in LV systolic dysfunction and neither prevented nor decreased the severity of acute IMR, septal-lateral annular dilation, leaflet tenting area, or leaflet tenting volume.

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