The effects of complete versus incomplete mitral valve repair in experimental mitral regurgitation

Masayoshi Nagatsu, Kazuaki Ishihara, Michael R. Zile, Hiroyuki Tsutsui, Hirofumi Tagawa, Gilberto DeFreyte, Ryuhei Tanaka, George Cooper, Blase A. Carabello

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Abstract

Severe mitral regurgitation (regurgitant fraction 0.75 ± 0.02) was created in eight dogs by our closed-chest chordal rupture technique. After 3 months of chronic mitral regurgitation all indices of contractile function were depressed. Mitral valve repair was then attempted. Postoperative regurgitant fraction was reduced compared with the preoperative value in all eight dogs. Concomitantly, forward cardiac output increased in all dogs and pulmonary capillary wedge pressure fell in all dogs. However, in some dogs, significant regurgitation persisted despite repair. Postoperative regurgitant fraction ranged from 0% to 60%. Postoperative residual regurgitant fraction was related significantly to postoperative cardiac output (r = 0.99), pulmonary capillary wedge pressure (r = 0.77), ejection fraction (r = 0.75), and two indices of contractile function—the mass-corrected end-systolic stress volume relationship (r = 0.87) and end-systolic stiffness (r = 0.93). In general, these parameters returned to their normal values before mitral regurgitation when postoperative regurgitant fraction was less than 30%. Myocytes isolated from the ventricles at the end of study also demonstrated normal contractile function when regurgitant fraction was less than 30%.

Original languageEnglish
Pages (from-to)416-423
Number of pages8
JournalJournal of Thoracic and Cardiovascular Surgery
Volume107
Issue number2
DOIs
Publication statusPublished - Jan 1 1994
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Surgery
  • Pulmonary and Respiratory Medicine
  • Cardiology and Cardiovascular Medicine

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