PM237 Role of Stress Echocardiography in the Functional Assessement of Prosthetic Mitral Valve

Abstract

Usually, the assessment of prosthetic valves by echocardiography is done at rest. For the patients with prosthetic valves, the echocardiogram taken at rest will not represent the true functional status of the valve. Patient`s day to day activities may induce symptoms. So in order to assess the functional status of the prosthetic valves, it is necessary that stress echocardiogram is done to mimic the daily activities of the patient. So it is assumed that the abnormalities observed under high flow conditions will not be seen at rest as the pressure gradients are related to flow. Resting studies of valve hemodynamics are found to be insufficient to diagnose valve dysfunction sometimes. Earlier, studies were done using cardiac catheterization with special emphasis on changes in prosthetic function observed with various types of physical stress like exercise or drug-induced stress. But these studies suffered from an inability to adequately stress catheterized patients .Moreover the procedures were cumbersome to the patient and also to the physician. With the advent of Doppler echocardiography, it was possible that studies could be done after significant exercise with increased ease and low risk. Using Doppler echocardiography, studies of exercise-induced changes in aortic and mitral prosthetic valve hemodynamics had started coming. AIM OF STUDY: 1. To study about the resting echo profile of patients with prosthetic mitral valve 2. To assess the function of the prosthetic valves by doing stress echocardiography by treadmill exercise and dobutamine infusion. CONCLUSION: 1. This Study helps in comparing the hemodynamic changes noted with stress induced by dobutamine and treadmill exercise.. 2. Normally functioning prosthetic valves in the mitral position can produce significant increases in valvular pressure gradients under conditions of high flow, and thus an estimation of diastolic cardiac flow must be measured before concluding that the valve dysfunction has occurred. 3. Dobutamine produces a greater augmentation in the effective mitral orifice area when compared to exercise. 4. Exercise protocol produces much higher increase in the pressure gradients when compared with dobutamine. 5. An abnormal increase in the pressure gradient without an increase in EOA signifies significant valve dysfunction and these patients should be monitored periodically for further deterioration and further action. Thus this study helps in finding dysfunction of prosthetic valves in the earlier stages itself.