Beneficial effects of nicorandil versus enalapril in chronic rheumatic severe mitral regurgitation: Six months follow up echocardiographic study

Background and aim of the study: It is possible that vasodilator therapy ma y retard left ventricular (IV) dilatation and functional deterioration in c hronic mitral regurgitation (MR). The study objectives were to evaluate com paratively the efficacy of nicorandil (a new, balanced vasodilator)and enal april therapy on IV volume, mass and function in mildly symptomatic, chroni c rheumatic severe MR. Methods: Eighty-seven mildly symptomatic rheumatic patients with severe MR were enrolled in this prospective, randomized study. All patients underwent serial echocardiography study at entry, and again at six months. Eighty pa tients completed the study. Results: At six months, the nicorandil and enalapril patient groups each ha d a significant reduction in LV end-systolic volume index (57.4 +/- 24.8 ve rsus 43.2 +/- 20.7 ml/m(2), p = 0.003; 50.0 +/- 19.0 versus 40.4 +/- 14.2 M l/m(2), p = 0.006, respectively) and LV mass index (218.0 +/- 88.0 versus 1 88.0 +/- 76.0 g/m(2), p = 0.05; 217.2 +/- 48.0 versus 186.2 +/- 45.0 g/m(2) , p = 0.002 respectively). Both nicorandil and enalapril caused significant improvement in ejection fraction (63.8 +/- 7.0 versus 71.0 +/- 6.7%, p <0. 0001; 63.2 +/- 6.9 versus 67.5 +/- 6.4%, p = 0.002, respectively) and a red uction in IV end-systolic stress (152.9 +/- 29.0 versus 126.0 +/- 25.0 dyne /cm(2), p = 0.001; 150.0 +/- 30.2 versus 138.0 +/- 29.0 dyne/cm(2), p = 0.0 02, respectively). However, nicorandil caused a greater reduction in absolu te IV end-systolic volume index (13.3 +/- 10.1 versus 9.6 +/- 5.9 ml/ml, p = 0.02), and a greater improvement in absolute ejection fraction (7.2 +/- 4 .7 versus 4.2 +/- 2.6%, p = 0.0005) than enalapril. Conclusion: It is concluded that nicorandil is equivalent to enalapril in i mproving IV volume, mass, endsystolic stress and ejection fraction in mildl y symptomatic chronic rheumatic severe mitral regurgitation over a period o f six months.