EXERCISE DOPPLER-ECHOCARDIOGRAPHY IN CONJUNCTION WITH RIGHT HEART CATHETERIZATION FOR THE ASSESSMENT OF MITRAL-STENOSIS

Rationale: A new diagnostic approach is reported, which combines Doppl er echocardiography and a thermodilution technique for the calculation of mitral Valve area at rest and during exercise. This method was app lied to determine the magnitude of mitral va Ive reserve (= exercise-i nduced increase of mitral va Ive area) and to assess the hemodynamic r elevance of mitral stenosis. Methods: 69 patients with mitral stenosis were included in this study. A Swan-Cant catheter was used to measure exercise hemodynamics and transvalvular flow by a thermodilution tech nique. The mean transmitral flow velocity v(mean) was determined by co ntinuous wave Doppler. Measurements were performed simultaneously at r est and during stepwise bicycle ergometry. Effective mitral valve area was calculated according to the continuity equation method (MVA(CE) = Flow/V-mean). Results: A significant exercise-induced increase of mit ral Valve area was found in the total group (rest --> 25 W: 1.1 +/- 0. 3 --> 1.3 +/- 0.4 cm(2), p < 0.001). Two subgroups were defined accord ing to the presence or absence of mitral Valve reserve: Delta MVA grea ter than or equal to 20 %: group A (n = 30); Delta MVA < 20 %: group B (n = 39). Both groups did not differ with regard to mitral valve area at rest. However, the increase of cardiac output and stroke volume wa s significantly higher in group A than in group B. An effective mitral valve area at 25 W of less than 1.2 cm(2) had an 80 % sensitivity and an 83 % specificity to detect a severe mitral stenosis. Conclusions: Because the presence and extent of mitral valve reserve cannot be pred icted under resting conditions measurements under flow-increasing inte rventions are necessary. Our data demonstrate that exercise Doppler in conjunction with right-sided cardiac catheterization is most useful t o determine mitral valve reserve and to assess the hemodynamic relevan ce of mitral stenosis.