Optimisation of Off-Pump CABG Using Graft Flowmeter, Intra-Operative Tee and Cardiac Markers

Background: Aim: The aim of the present study was to optimize the off pump coronary artery bypass grafting by the use of graft flow meter based on transit time flow principle and revision of grafts when the values are abnormal and there is associated haemodynamic instability as seen on TEE, ECG changes and rise in Trop I levels. Methods: 75 patients undergoing isolated off-pump CABG at LPS Institute of Cardiology and Cardiac Surgery were included in the study from January 2017 to June 2018. The study was conducted on all the cases who were admitted for CABG and who met the inclusion criteria. Results: Out of 75 patients undergoing off pump CABG, 67 were males and 8 were females. The majority of patients (37.3%) were in the age group of 51 – 60 years followed by 32% patients in the age group of 61 - 70 years. Out of the 75 patients 18 were suffering from Diabetes, 28 from hypertension, 12 were both diabetic as well as hypertensive, 3 had previous PTCA, 5 were suffering from COPD. Out of the total 75 patients 46 had triple vessel disease, 22 had double vessel disease and 7 had single vessel disease. 6 had significant LMCA disease. The mean flow with standard deviation in the left coronary territory was 35.54 + 16.35 ml/min and in the right coronary territory was 31.05 +15.12 ml/min with a p value of 0.4 which is not significant. The Pulsatility index (PI) in the left coronary territory was 1.99 + 0.75 and in right coronary territory was 1.94 + 0.81 with a p value of 0.06 which is not significant. Conclusion: The present study concluded that transit time flow measurement is simple, reliable and easy to perform. Low flow and raised PI require reexploration of the anastomosis unless severe spasm of the conduit or poor runoff is strongly suspected. Redoing the distal anastomosis leads to significant improvement in flow and decreases pulsatility index in the presence of anastomotic failure. Mean graft flow of >10 ml/min can be considered satisfactory in Indian population where the native coronary size ranges between 1- 2mm , whereas in Western population it is between 3 to 4mm, cutoff value of >20 ml/min has been described. In this light, heamodynamic stability as assessed by intraoperative ECG and TEE, is important as low flow per se does not signify graft failure.