Outcomes of Mitral Valve Replacement after Closed Mitral Valvotomy: A Retrospective Cohort Study

Abstract

Background: The incidence of rheumatic fever and rheumatic heart disease still remains high in the developing countries. Mitral stenosis is predominantly due to rheumatic origin and affects females more than males. Historically, closed mitral valvotomy (CMV) was the first effective intervention for mitral stenosis. We studied the immediate and early surgical outcomes of MVR in patients with history of CMV to see whether their disease behaves differently, when compared with patients without prior CMV undergoing MVR. Methods: This single center retrospective cohort study was conducted in Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India. Patients who underwent MVR from January 2008 to December 2012 at our institute were studied. The hospital records of 90 patients were analyzed both in the CMV cohort and also in the non-CMV cohort. Preoperative details, intraoperative parameters, immediate postsurgery echocardiography parameters, and follow-up echocardiography details at 1 year and 5 years were studied. Results: Both the cohorts were similar in age, height, weight, and BSA. In the CMV cohort, 67% were females and in the non-CMV cohort 48% were females. Most of the patients in both the cohorts presented with functional classes 2 and 3. The mean duration between onset of symptoms and MVR in the CMV cohort and the non-CMV cohort was 24.6 years and 6.25 years, respectively. Fifty-nine patients in the CMV cohort had preoperative atrial fibrillation, whereas 47 patients in the non-CMV cohort presented with atrial fibrillation. The mean left atrial (LA) size of patients with sinus rhythm and atrial fibrillation was 46.34 (SE, 0.852) and 55.21(SE, 0.808), respectively. Preoperative echocardiographic assessment revealed a mean ejection fraction of 62% and 63%, mean mitral stenosis gradient of 13 mm Hg and 14.7 mm Hg, mean LA size of 53.2 mm and 50.5 mm, and mean right ventricular systolic pressure of 47.5 mm Hg and 43.6 mm Hg in the post-CMV cohort and in the non-CMV cohort, respectively. The CMV cohort had a longer cardiopulmonary bypass time (111.5 minutes) in comparison with the non-CMV cohort (97 minutes). The aortic cross-clamp time remained similar in both the cohorts. Thirty-six percent of the post-CMV cohort patients had a valve size of 25, and 48% of patients belonging to the non-CMV cohort had a valve size of 27. The percent of moderate-to-severe subvalvar pathology was 88 in both the cohorts. Patients belonging to the post-CMV cohort had a median ventilation time of 16.35 hours, and the patients of the non-CMV cohort had a median ventilation time of 13.75 hours. The duration of ICU stay was 4.41 (SE, 0.188) days and 4.13 (SE, 0.153) days, and length of hospital stay was 8.93 (SE, 0.230) days and 9.13 (SE, 0.313) days in the CMV and the non-CMV cohorts, respectively. Inotropic requirement, measured by the vasoactive inotropic score, was higher in the post-CMV group (11.9), when compared to the other cohort (9.7). Right ventricular (RV) function and pulmonary arterial hypertension assessed in the immediate postoperative period, at 1 year, and at 5 years did not show any significant difference. Conclusion: The percentage of females in the CMV cohort is higher. Delaying the valve replacement by performing a surgical palliative procedure like CMV, is beneficial in female patients in the child-bearing age group so that they can complete the families. The disease process started earlier in the CMV cohort, and they had a longer duration of illness before undergoing MVR. Even with the longer duration of disease, the RV function, LA size, PA pressures, and mitral stenosis gradients were comparable. Therefore, CMV prevented progression of the disease in the CMV group. The mean LA size is significantly higher in patients with atrial fibrillation. The CMV cohort had a longer cardiopulmonary bypass time. The duration of ventilation, ICU stay, and hospital stay were similar in both cohorts. Inotrope requirement was higher in the post-CMV group. RV function and pulmonary arterial hypertension assessed in the immediate postoperative period, at 1 year, and at 5 years did not show any significant difference.