Preoperative and postoperative echocardiographic grade of mitral regurgitation (MR). Preoperative MR grades were severe and moderate 20 and 5 patients, respectively. Mitral valves were repaired using rough-zone trimming (RZT). All grades improved to below mild MR grades within early postoperative period of 30 days. By mid-term (>12 months), 13 of 14 patients had better than mild MR. Only one patient worsened to moderate MR because of progressive sclerotic valve changes.