​A Comparative Study of Changes in Left Ventricular Function after Mitral Valve Replacement in Patients with Severe Rheumatic Mitral Regurgitation with and without Mild Mitral Stenosis

ABSTRACT

Introduction: Presently off- pump CABG has proved itself tobe a safe, cheaper and effective alternative of on- pump CABG.However, it requires manipulation, displacement, positioning& mechanical stabilization of the heart during grafting whichmay cause haemodynamic alteration. Study was done withthe objective of finding out the changes in Central VenousPressure (CVP); Mean Arterial Pressure (MAP); MeanPulmonary Arterial Pressure (MPAP); Right Ventricular EndDiastolic Pressure (RVEDP) & Left Ventricular End DiastolicPressure (LVEDP) while grafting the anterior, lateral &inferior surfaces of heart during off-pump CABG.Material and methods: Over one year time, 50 patients withLVEF ≥40%, undergoing off-pump CABG were monitoredfor the above parameters at various stages of their operation,namely- 1. During manipulation & shunt introduction,2.During anastomosis without shunt, 3.During anastomosiswith shunt & 4.After anastomosis; while grafting the anterior,lateral & inferior surfaces of heart. These results werecompared with the baseline values of CVP, MAP, MPAP,RVEDP & LVEDP, to look for statistical significance.Results: During manipulation & shunt introduction; CVP(mmHg) significantly increased during Ramus grafting - 12±1.8(p<0.047); and also during OM grafting – 12.6±1.9 (p<0.045),when compared to a baseline value of 9±1.8. The MAP(mmHg) was significantly decreased during manipulation &shunt introduction in Diagonals - 70±5.8 (p<0.046), Ramus- 70±5.8 (p<0.048), OMs - 65±5.8 (p<0.028) & in the Rightterritory - 69±5.9 (p<0.032); as compared with baselineMAP of 76±11.7. During anastomosis without shunt also, theMAP(mmHg) significantly decreased while grafting LAD- 70±3.8 (p<0.048), Diagonals - 68±3.8 (p<0.039), OMs –71.8±4.8 (p<0.039) & Right sided arteries 70.8±4.6 (p<0.039),as compared with baseline MAP values. The MPAP(mmHg)was significantly increased – 18.3±3.7 (p<0.047) as comparedto the baseline value of 16±2.4 during manipulation & shuntintroduction in the OMs.Conclusion: During OPCABG there will be significantalterations in haemodynamics mostly due to mobilizationof the heart, which is necessary to visualise the targetvessels properly & stabilisation of the concerned areawith stabiliser. However, by observing the haemodynamicvariations constantly & by making necessary mechanical &pharmacological adjustments, unnecessary conversion to Onpump technique can be avoided.