Dr. Krishna Prasad A R

The rheumatic mitral disease represents a complex progressive disorder that affects young adults and causes severe morbidity and mortality. Valve replacement with a mechanical valve has been the traditional treatment for these patients. Valve replacement increases longevity but necessitates several lifestyle changes. Improved understanding of the pathophysiology of the disease and standardization of mitral repair techniques, renewed interest is now generated in repairing these complex valves. We review the existing evidence for the repairing rheumatic mitral valve and propose a practical and systematic approach to repair the valve to ensure higher success rates.

Reduced organ perfusion during cardiopulmonary bypass (CPB) is responsible for morbidity associated with cardiac surgery. Non-pulsatile flow and hypothermia during CPB have been shown to cause reduced perfusion. During CPB, cardiac output is directly proportional to the pump flow rate. Therefore, we hypothesised that increasing pump flow during hypothermic CPB would improve organ perfusion and reduce the inflammatory response in the post-operative period. Methods: Ethics committee approval was obtained. Twelve consecutive patients with good or moderate left ventricular function undergoing elective or inpatient coronary artery bypass grafting were included in the study after obtaining informed consent. Patients were randomised to receive either normal flow or higher pump flow (20% more than the usual flow during hypothermia). Hepatic blood flow, cytokines such as interleukins 1β, 6, 8, 10 and 12, tumour necrosis factor-α and complements C3a, C4a and C5a were measured during the peri-operative period. Data were analysed using SPSS (ver.15). Categorical data were compared using the chi-square test and trends in cytokines were compared using a repeated measures ANOVA test. Results: Both the groups were similar in pre- and peri-operative variables. Hepatic blood flow almost doubled in the high-pump-flow group following an increase in the flow rate during hypothermia(p=0.026). The release of serum complement IL-6 and 8 appeared to be reduced in the high-flow group; however, the difference did not reach statistical significance. Conclusions: Higher pump flows during hypothermic CPB increase hepatic blood flow. There was a trend towards attenuation of post-operative inflammatory response; however, larger studies will be needed to confirm these findings.