Assessment of TTK Chitra Mitral Prosthetic Valve at Rest and Exercise by Echocardiography

Abstract

BACKGROUND Assessment of prosthetic valve by echocardiography remains an important aspect in prosthetic valve follow up. Changes in transvalvular gradient during increase in heart rate (HR) is a common phenomenon. In this context the study was undertaken to evaluate the transvalvular gradient during simple exertion in TTK Chitra Mitral Valve Prosthesis (TCMVP). The aim of this study was to investigate the normal Doppler parameters like Prosthetic Valve Peak Velocity (PVPV), Prosthetic Valve Peak Gradient (PVPG), Prosthetic Valve Mean Gradient (PVMG), Pressure Half Time (PHT), Effective Orifice Area by Continuity Equation (CE) & Orifice Area PHT of TCMVP, Pulmonary Artery Systolic Pressure (PASP) and its changes with exercise. MATERIALS AND METHODS 70 patients who had undergone mitral valve replacement with TCMVP on routine follow up were taken up for study. Echocardiographic analysis of Prosthetic valve parameters was done. Patients were asked to climb up and down two floors which leads to HR increase and same echo parameters were repeated. Effective Orifice Area by Continuity Equation (CE) and PHT are calculated both at rest and exercise. RESULTS Out of the 70 patients studied, 51 were female & 19 were Male. 16 patients were on 25 M, 37 were on 27 M & 17 were on 29 M TCMVP. PVPV at rest was 1.66±0.25 m/sec and increased to 1.99±0.3 m/sec after exercise. The PVMG at base line and after exercise were 4.61±2 mmHg and 6.03±2.4 mmHg respectively. PASP increases from 26 .5±5 mmHg at to 36.8±6 mmHg after exercise. Effective orifice area by continuity equation is 1.70 cm 2 at rest and 1.80 cm 2 at exercise. Mitral Prosthetic Valve Area calculated from pressure half time at rest is 2.06 cm 2 which changed to 2.46 cm 2 with exercise. The mean gradient of 25M, 27M and 29M valves are 6.6, 4.09 and 3.89 mmHg respectively at rest and increased to 8.23, 5.47 and 5.21 mmHg with exercise. CONCLUSION The basic haemodynamic parameters of TTK Chitra valve of different sizes are comparable with that of other types of prosthetic valves. The gradient across the larger size valves is lower when compared to smaller sized valve. There is a significant elevation of the mean and peak valve gradients with exercise.