The effect of chordal preservation on late outcome after mitral valve replacement: a randomized study.

Postoperative survival, hemodynamic status and exercise tolerance with or without posterior chordal preservation were compared in a case-limited prospective randomized manner in 100 patients who underwent isolated mitral valve replacement with size 29mm or 31mm St. Jude Medical prostheses. The preoperative clinical and hemodynamic parameters were comparable in the two groups. The mean follow up was 293.3 months for those with and 263.1 months for patients without chordal preservation. Right heart cardiac catheterization was performed in every patients at the end of the follow up period and it demonstrated significantly better results with than without chordal preservation (cardiac index 2.81 +/- 0.47 vs. 2.63 +/- 0.52, p < 0.05; pulmonary arterial pressure 30 +/- 11 mmHg vs. 37 +/- 13 mmHg at 30 Watts bicycle exercise, p < 0.01; end-diastolic volume index 75 +/- 22 vs. 86 +/- 38 ml/m2, p < 0.02; and maximum exercise tolerance 1.8 +/- 0.3 vs. 1.2 +/- 0.5 Watt/kg, p < 0.01). Actuarial freedom from complications was 78.1 +/- 4.2% with and 70.7 +/- 6.2% without chordal preservation (p < 0.02). In particular, patients with severe mitral regurgitation benefited from the preservation of the posterior mitral leaflet with its chordal and papillary structure (p < 0.001).