HEMODYNAMIC EVALUATION OF TTK CHITRA HEART VALVE BY DOPPLER ECHOCARDIOGRAPHY-AT MITRAL AND AORTIC POSITION

Artificial heart valves are engineered devices used for replacing diseased or damaged natural valves of the heart. Most commonly used for replacement are mechanical heart valves and biological valves. Rheumatic disease continues to be a major indication for valvular heart surgery in India. TTK Chitra heart valve prosthesis (CHVP) is a tilting disc artificial heart valve designed and developed by Sree ChitraTirunal Institute for Medical Sciences and Technology (SCTIMST). It has an ultra-high-molecular-weight polyethylene disc, Haynes-25 alloy (Haynes International Inc., USA)cage, and polyester suture ring.1-4Distinguished features of TTK Chitra valve which highlight it amongst prosthetic heart valves are Complete Structural Integrity, Absence of cavitations related damage, silent operation, Rotatable within the sewing ring to assure its freedom to rotate if repositioning is required, Low profile. Because of its low cost and proven efficacy, it has a high potential for more widespread use in developed countries. In the present work 60 cases have been studied. The study population consist of 60 consecutive patients who had undergone T.T.K Chitra valve replacement either in mitral and aortic position or both and will undergo routine follow up in Cardiothoracic surgery OPD and have been subjected to a routine follow-up echocardiographic examination. So far, various clinical studies have been reported but homodynamic studies especially with Doppler Echocardiography are far and few. This paper presents experimental observation and analysis with the TTK Chitra valve in mitral and aortic positions and also an in-vivo hemodynamic assessment of the valve with focus on echocardiographic characteristics. We have studied the Doppler echocardiographic parameters of the normally functioning CHVP in the mitral position & aortic position to make reference for these parameters and to assess whether derivation of MVA using the CE and more commonly used PHT method is comparable in the functional assessment of this tilting disc prosthesis. The statistical analysis of data and inferences drawn revealed that the average mean gradient of T.T.K. Chitra valve in Mitral position was 5.14±2.19.There was significant correlation between size of the valve used and mean gradient across the valve in Mitral position of T.T.K. Chitra prosthesis (P valve 0.001). Mean gradient was inversely proportional to the size of the valve. Average mean gradient of T.T.K. Chitra valve in aortic position is 15.78±6.41.The correlation between size of the valve used and Mean gradient in Aortic position was statistically signification, P valve 0.004. The average peak velocity of T.T.K. Chitra valve in Mitral position was 2.03±1.45mmHg.There was significant correlation between size of the Valve used and Peak Velocity across the valve in Mitral position of T.T.K. Chitra prosthesis. (P valve 0.001). Peak velocity was inversely proportional to size of the valve. The average peak velocity of T.T.K. Chitra valve in Aortic position was 3.05±1.51mmHg.There correlation between size of the valve used and Peak Velocity across the valve in Aortic position of T.T.K. Chitra prosthesis was statistically insignificant. In aortic position the peak gradient, mean gradient and peak velocity of T.T.K. Chitra valve were 26.5±10.33mmHg. 15.77±6.41mmHg and 3.05±1.51m/s respectively. Peak gradient and peak velocity did not correlate well with the size of the valve in Aortic position. (P>0.224, P>0.101) but mean gradient decreases significantly with increase in the size of the valve, P<0.004. In the present study 60 cases that had undergone valve replacement by T.T.K. Chitra prosthesis either in mitral position or at aortic position and attendance the cardiothoracic OPD for routine follow-up and having ejection fraction more than 50% were included. Those who had undergone valve replacement other than T.T.K. Chitra valve and those who had left ventricular dysfunction were excluded from the study. The age group of patients ranged from 9 – 50 years with mean age 27.7±10.1. The maximum distribution of cases was in the 3rd to 4th decade (61.6%). These findings were comparable to Pawan et al5 (mean age 26±5year) and Namboodiri et al6. Where the mean age was 38.8±10.5 year and Joshi et al was 30.98±9.3year. Rheumatic heart disease was the commonest etiological factor for valve replacement in this study; none of the patient had degenerative valve disease. The finding was comparable to Namboodiri et al6. Where 95% of the patient had RHD as the etiology for valve replacement. The striking features of these patients profile were young age (27.7±10.1) and late presentation. There were 68.3% males and 31.6% female patients. There was a male preponderance with a male to female ratio is 2.1:1. These finding are comparable to study conducted by N.Namboodri et al(6) which had male 57.5% and female 42.5%. Out of 60 patients 38 out of 60 (55%) had mitral valve pathology alone and had MVR and 36.6% had DVR (MVR+AVR) and only 2% had AVR alone. This findings was comparable to N.Namboodri et al (70) where 78 (58.7%) had mitral valve replacement (MVR). The T.T.K. Chitra valve on the merits of efficiency performance and low cost and proven efficacy, it has a high potential for more widespread use in India and developing countries.