Browsing by Author "Sivasankaran, Sivasubramonian"

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    Doppler echocardiographic assessment of TTK Chitra prosthetic heart valve in the mitral position
    (EUROPEAN JOURNAL OF ECHOCARDIOGRAPHY, 2008)
    Aims TTK Chitra heart valve prosthesis (CHVP), a tilting disc mechanical heart valve of tow cost and proven efficacy, has been in use for the last 15 years. Although various studies substantiating its long-term safety and efficacy are available, no study had assessed its echocardiographic characteristics. The purpose of this study was to determine the normal Doppler parameters of CHVP in the mitrat position and to assess whether derivation of mitrat valve area (MVA) using the continuity equation (CE) and more commonly used pressure half-time (PHT) method is comparable in the functional assessment of this tilting disc mitral prosthesis.Methods and results Doppler echocardiography was performed in 40 consecutive patients with CHVP in the mitrat position. All patients were clinically stable, without evidence of prosthetic valve dysfunction such as significant obstruction or regurgitation, enclocarditis, left ventricular dysfunction (ejection fraction <40%), or significant aortic regurgitation. Valve sizes studied included 25, 27, and 29 mm. Mitrat valve area was derived both by the PHT method and by the CE, using the stroke volume measured in the ventricular outflow tract divided by the time-velocity integral of CHVP jet. The peak Doppler gradient ranged from 5 to 21 (mean 11.0) mmHg, and the mean gradient ranged from 1.7 to 9.2 (mean 4.1) mmHg. Mean gradient negatively correlated with an increase in the actual orifice area (ACA) derived from the valve orifice diameter given by the manufacturer (r = -0.45, P = 0.004). Mitral valve area calculated by both PHT and CE increased significantly with an increase in the ADA (r = 0.42, P = 0.007 and r = 0.32, P = 0.046, respectively). Mitrat valve area by the CE averaged 1.55 +/- 0.36 cm(2) (range 0.85 cm(2) for a 25 mm valve to 2.41 cm(2) for a 29 mm valve) and was smaller than by PHT (mean 2.04 +/- 0.41 cm(2), range 1.40-3.14 cm(2); P = 0.0001; t-test), irrespective of whether PHT is less than or >110 ms.Conclusion The Doppler parameters obtained with CHVP in the mitrat position are comparable with those obtained with the different prosthetic valves in common use. In the selected group of patients with CHVP, assessment of MVA by the PHT method is comparable with that by the CE. Areas by both methods were smaller than the AOA provided by the manufacturer, as seen in other similar design valves.
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    Natural History of Aortic Valve Disease Following Intervention for Rheumatic Mitral Valve Disease
    (JOURNAL OF HEART VALVE DISEASE, 2009)
    Background and aim of the study: A significant proportion of patients who require interventions for rheumatic mitral valve (MV) disease have coexisting aortic valve (AV) disease. To date, little is known of the natural history of AV disease in these patients.Methods: The details of a cohort of 200 patients (146 females, 54 males; mean age at MV intervention 30.3 +/- 9.9 years) with rheumatic heart disease were retrospectively reviewed. The patients had undergone an index MV intervention (either closed or balloon mitral valvotomy) or MV replacement between 1994 and 1996, and received long-term regular follow up examinations. The clinical and echocardiographic data at entry and at follow up were noted. Patients were allocated to two groups, based on whether the AV disease was absent (group I, n = 98) or present (group 11, n = 102) at baseline. The AV disease was categorized as thickening only (group IIA), isolated aortic regurgitation (AR) (group IIB), or combined aortic stenosis (AS) and AR (group IIC). No patient had isolated AS at baseline.Results: The mean follow up period was 9.3 +/- 1.07 years, during which 10 patients in group I developed new AV disease, which included AV thickening only (n = 2), trivial-mild AR (n = 7) and mild AS with trivial AR (n = 1). Of 16 patients in group IIA, 11 developed isolated AR, and one patient progressed to have mild AS and AR. Among 69 patients in group IIB, 22 (31.9%) developed AS, and all had either mild (n = 8) or moderate (n = 14) AR with mild AS. Group IIC included 17 patients with mild combined AV disease at baseline, except for moderate AS and moderate AR in one patient each. Among 16 patients with mild AS in group IIC, six progressed to moderate AS and two to severe AS. AR became moderate in 10 patients and severe in one patient. The two patients who progressed to severe AS requiring AV replacement had mild AS at baseline. No patient who developed new combined AV disease had lesions with severity more than mild AS or moderate AR. On logistic regression analysis of the variables predisposing to progression of AV disease, such as age, gender, history of rheumatic fever (RF) and recurrence, and interval from RF episode to symptom onset, only the initial AV gradient was identified as being statistically significant (beta coefficient 0.528, SE = 0.17, p < 0.0001).Conclusion: Patients with no or mild AV disease at the time of MV intervention rarely develop severe AV disease, and seldom require AV surgery over the long-term follow up. The presence of mild AS at baseline is predictive in the minority of cases where AV disease will progress relatively more rapidly.