Assessment of Mitral Valve Resistance Index by Echocardiography in Mitral Stenosis Before and After Balloon Mitral Valvotomy and Its Hemodynamic Implications

Abstract

INTRODUCTION: Valvular stenosis is common cardiac disease with greater morbidity and mortality especially in developing countries like India. Echocardiography is considered as an important and simple tool to evaluate valve stenosis .Almost all cases of mitral stenosis are due to rheumatic heart disease. Assessment of severity of mitral stenosis by echocardiography utilizes many parameters using 2D echo, M mode, and Doppler methods. Conventional methods include mitral valve orifice area determination by planimetry and pressure half time method, pressure gradient determinations with Bernoulli’s equation, and mitral leaflet separation index. But the common problem that occurs in all these measurements is that, only anatomic information alone is provided to the clinician. In most of the situations, clinical decisions are made by assessing the functional or hemodynamic status of the valve lesions irrespective of the choice of management. This fact is further strengthened by many observations that, for given mitral valve orifice area, different hemodynamic profiles found to be present. Hence therapeutic judgments have to be contemplated based on functional or hemodynamic status of the patients. AIM OF THE STUDY: 1. To assess mitral valve resistance index in mitral stenosis by echocardiography before and after balloon mitral valvotomy. 2. To study the relationship between systolic pulmonary artery pressure and mitral valve resistance both before and after percutaneous mitral commissurotomy. 3. To study the correlation between severity of mitral stenosis and mitral valve resistance. METHODOLOGY: STUDY DESIGN: This study has been confirmed by the Ethic Committee of Madras medical college, Tamilnadu Dr MGR medical University and all the participants were informed of its objectives before the study and signed a letter of consent in accordance with the Helsinki Declaration Standards. PATIENTS PROFILE: This is a prospective cohort study. During a period of 6 months, 20 patients with pure Mitral Stenosis who were referred and eligible for percutaneous commissurotomy of mitral valve who agreed to undergo 2D and Doppler echocardiographic examination. It was made sure that they have an adequate tricuspid regurgitant jet for systolic PAP calculation was detectable both before and after valvotomy, were prospectively recruited in this study. INCLUSION CRITERIA: 1. Patients with symptomatic rheumatic mitral stenosis undergoing balloon mitral valvotomy. 2. Adequate tricuspid regurgitation jet. EXCLUSION CRITERIA: 1. LA thrombus, 2. More than mild MR, AS, AR and pulmonary stenosis, 3. CAD requiring surgical revascularization, 4. Poor echocardiographic window, 5. Critically ill patients, 6. Organic tricuspid valvular disesase. 5CONCLUSIONS: 1. Mitral valve resistance index is a strong and independent predictor of systolic pulmonary artery pressure both before and after percutaneous balloon mitral valvotomy in mitral stenosis patients. 2. Mitral valve resistance also correlates with severity of mitral stenosis in our study. 3. Because of inherent limitations of conventional echocardiographic parameters in evaluation of MS, valve resistance can be an adjunct tool in assessment of severity. 4. In our study, among conventional indices, trans mitral mean gradient better correlates with hemodynamic status than mitral valve area