Valve replacement in rheumatic mitral incompetence: total versus posterior chordal preservation

Abstract

Several studies have shown that mitral valve replacement with total chordal preservation (MVR-TCP) improves left ventricular function when compared with total chordal transection. Few clinical studies, however, have compared this technique to that involving only posterior chordal preservation (MVR-PCP). This study was intended to cover this aspect. A total of 36 consecutive patients with chronic rheumatic mitral incompetence were operated upon by one surgeon and benefited from MVR-TCP (group I). During the same period and along similar selection criteria, 60 patients underwent MVR-PCP (group II) in our department. With the exception of a statistically significant higher preoperative left ventricular ejection fraction (LVEF) percentage and lower fractional shortening (LVFS) percentage in group II patients; both groups were comparable as regarding age, sex distribution New York Heart Association (NYHA) functional class (FC), preoperative left atrial diameter (LAD), left ventricular end-diastolic dimension (LVEDD), left ventricular end-systolic dimension (LVESD) as well as aortic crossclamp and cardiopulmonary bypass times. The means of the differences, between the pre- and postoperative values of NYHA FC and echocardiographic data were compared between both groups. As compared with group II, group I patients showed lower: hospital mortality rate (0 versus 8.3%; P > 0.05); need for positive inotropic support (11.1 versus 20.8%; P > 0.05) and total ICU stay (2.9 ± 0.17 versus 2.2 ± 0.13 days; P < 0.01). In addition, group I patients showed a better NYHA FC improvement (−2.08 ± 0.15 versus −1.93 ± 0.11; P > 0.05) as well as a statistically significant ( P < 0.00001) higher decrease in the LAD (−18.19 ± 0.97 versus −11.59 ± 0.58 mm), LVEDD (−14.44 ± 0.91 versus −6.17 ± 0.05 mm), LVESD (−6.17 ± 0.77 versus −3.23 ± 0.01 mm), LVFS percentage (−0.06 ± 0.01 versus −0.01 ± 0.001%) and a higher increase in the LVEF percentage (8.1 ± 0.9 versus 1.48 ± 0.02%). The smaller mean diameter of the implanted St Jude prosthesis, in group I patients (26.77 ± 0.22 versus 27.43 ± 0.21 mm; P = 0.046), was neither associated with the use of a smaller prosthesis than that predicted for the patient size nor a significantly higher mean transprosthetic pressure gradient. These data suggest that in rheumatic patients with chronic mitral incompetence, MVR-TCP is always feasible: it is associated with lower hospital mortality and morbidity rates and better preservation of the postoperative left ventricular systolic functions when compared with MVR-PCP.