R S Kumar

Publications of R S Kumar

• Development of the Chitra tilting disc heart valve prosthesis.

  Authors: G S Bhuvaneshwar, C V Muraleedharan, G A Vijayan, R S Kumar, M S Valiathan

  The Journal of heart valve disease. 08/1996; 5(4):448-58.

  BACKGROUND AND AIMS OF THE STUDY: The high prevalence of rheumatic valvular disease in the young population and the high cost of imports necessitated the development of an Indian valve. TheBACKGROUND AND AIMS OF THE STUDY: The high prevalence of rheumatic valvular disease in the young population and the high cost of imports necessitated the development of an Indian valve. The development of a tilting disc prosthesis was successfully concluded in February 1995, when the third model completed its clinical trial. The tilting disc valve has an integrally machined cobalt alloy cage, an ultra high molecular weight polyethylene disc and a polyester suture ring. The choice of design was based on its superior hydrodynamics and the age distribution of patients, the majority of whom were below 30 years. The polymer-metal combination was selected for its extremely low wear rate and proven durability in the human body. MATERIALS AND METHODS: The hydrodynamic performance was tested under steady and pulsatile flow conditions. The accelerated durability of nine test valves was evaluated at 800-840 cycles/min for over 350 million cycles each. Size 23 mm valves mere implanted in the mitral position of five sheep. In a clinical trial, 306 patients with isolated mitral or aortic valve replacements were followed up for a total of 371 patient years (mean 1.37 years and range 0-4 years). RESULTS: The hydrodynamic performance was comparable to that of proven clinical models. The accelerated testing indicated lifetimes in excess of 50 years and the animal trials showed the valve to be safe. In the clinical trial, there was no incidence of structural failure or paravalvular leak. The linearized rate of late thromboembolism was 6.2%/patient-year (pty), anticoagulant related hemorrhage 0.54%/pty and infective endocarditis 0.54%/pty. At two years, the total actuarial survival was 89.5%. The higher incidence of thromboembolism and the very low incidence of anticoagulant related hemorrhage illustrate the difficulty in the management of anticoagulant therapy in a developing country, while the low incidence of endocarditis reflects their greater resistance to infection. CONCLUSION: These data clearly showed the valve to be safe and comparable to other similar valves in clinical use.

• Open heart surgery in presence of hereditary spherocytosis.

  Authors: A Dal, R S Kumar

  The Journal of cardiovascular surgery. 11/1995; 36(5):447-8.

  A patient with ostium secundum atrial septal defect was operated upon despite having hereditary spherocytosis, without any hemolytic effects of cardiopulmonary bypass. A short bypass time is safe inA patient with ostium secundum atrial septal defect was operated upon despite having hereditary spherocytosis, without any hemolytic effects of cardiopulmonary bypass. A short bypass time is safe in presence of this congenital hemolytic anemia.

• Bidirectional Glenn shunt: a step in the right direction.

  Authors: R Narayan, K G Balakrishnan, V R Pillai, J A Tharakan, T Titus, R S Kumar

  Indian heart journal. 48(4):375-80.

  Bidirectional Glenn (BDG) shunt was carried out in 14 patients (age range 1.5-22 years; mean 9.3 years) for a variety of congenital cyanotic heart diseases with decreased pulmonary blood flow.Bidirectional Glenn (BDG) shunt was carried out in 14 patients (age range 1.5-22 years; mean 9.3 years) for a variety of congenital cyanotic heart diseases with decreased pulmonary blood flow. Postoperative cardiac catheterisation was carried out in 10 patients including successful balloon angioplasty of the shunt and LPA in one patient. There was a significant improvement in oxygen saturation and a drop in haematocrit level at follow-up. Doppler echocardiography studies in 13 patients revealed functioning shunts in all cases with low velocity continuous flow. Thus BDG is a useful palliative procedure and could be undertaken as the first stage of total cavopulmonary connection in high-risk Fontan groups where biventricular repair is not feasible.