Transit-time flowmetric evaluation of coronary artery bypass graft flow after off- and on-pump myocardial revascularization

Introduction: Incorrect performance of anastomoses to the target coronary arteries often causes coronary artery disease and patient`s death following myocardial revascularization. Coronary graft patency evaluation is obligatory for prevention of peri- and postoperative myocardial ischemia. Aim: The objective of the present study was to comparatively assess the values of mean coronary flow and pulsatility index in arterial and venous grafts in patients after on-pump- and off-pump myocardial revascularization. Materials and Methods: During the period between January 1, 2014 and December 31, 2017, 143 coronary artery disease patients, 111 males at a mean age of 63.29±9.78 years and 32 females at a mean age of 66.43±9.58 years were operated on in the Department of Cardiac Surgery, St. Marina University Hospital of Varna. Myocardial revascularization was performed by using 92 arterial and 65 venous coronary grafts in the on-pump group (ONCAB) and 137 arterial and 45 venous grafts in the off-pump group (OPCAB). Coronary graft blood flow was assessed by means of coronary angiography and transit-time flowmetry (TTFM). Results: There were different values of the mean coronary flow and pulsatility index (PI) in arterial and venous conduits, both intervention types, as well as in males and females. The difference between male and female patients in terms of the mean values of venous grafts is statistically reliable (χ 2 =11.410; р≤0.022 and r=-0.310; p=0.001). The PI values in arterial grafts differed statistically significantly between both intervention types (p=0.003). Much more revisions of arterial and venous conduits on the occasion of insufficient patency were performed in the ONCAP than in the OPCAB group. Conclusion : Based on our results and literature data available, we could recommend the wide application of the method of TTFM for exact recognition of the circulatory disorders in the coronary graft following CAGB in Bulgaria.