승모판협착증에서 운동능력을 결정하는 혈역학적인 인자 ; Exercise Doppler Echocardiography 를 이용한 연구 = Factors Determining thc Exercise Capacity in Patients with Mitral Stenosis - Hemodynamic Study Using Exercise Doppler Echocardiography

다국어 초록 (Multilingual Abstract)

Objectives: Objective assessment of degree of functional impairment in patients with valvular heart disease is crucial in the clinical decision-making. The present study was designed to examine the use of formal exercise testing in the evaluation of mitral stenosis (MS) ancl to determine hemodynamic factors associated with exercise tolerance in patients with MS. Methods: In 37 patients with MS (26 females, age of 51±10yrs), Doppler measurement of transmitral gradient (MG) and pressure gradient between right ventricle and atrium using turbulent jets of tricuspid regurgitation (PGTR) was performed before and immediately after maximum symptom-limited treadmill exercise (EX) according to Bruce protocol. Results: Mean mitral valve area (MVA) was 0.97±0.33㎠ (0.5-1.9) and number of patients with severe MS (MVA<1.0㎠) were 25/37. TR was present in 35/37 at rest and immediately after EX, PGTR could be measured in 86% (32/37). Mean EX time was 422±188 sec (112-760) and MG increased from 11±5 to 27±10mmHg (p<0.001) and PGTR form 31±13 to 61±30mmHg (p<0.001). Using a linear regression, factors associated with prolonged EX time were male gender, increased mobility of leaflet, low MG, small pre- and post-EX TR jets, low pre-and post-EX PGI'R, and appropriate increase of heart rate during EX; among them, low post-EX PGTR (p=0.000) and heart rate increase with EX (p=0.005) were the significant independent factors. In patients with tight MS with average MVA of 0.8±0.15㎠, the range of PGTR increase with EX was from 10 to 100mmHg. Patients with post-EX PGTR more than 60mmHg had larger jets of TR at rest, and higher basal MG and pre-EX PGTR compared to the others. Conclusion: Exercise Doppler echocardiography is technically simple and an important addition to the noninvasive evaluation of patients with MS. Increase of PGTR with EX rather than MVA at rest per se is the important determining factors for EX capacity in patients with MS, and it can be predicted by severity of TR at rest and pre-EX PGTR.