Competitive blood flow as a predictor of mammarocoronary artery bypass graft failure: the role of instantaneous wave-free ratio

The objective was to estimate the impact of competitive blood flow on the development of dysfunction of the mammarocoronary artery bypass graft to the anterior interventricular branch of the left coronary artery (MCABG-AIVB), as well as the role of the instantaneous wave-free ratio (iFR) in the development of dysfunction. Methods and materials. The research included 57 patients who were hospitalized between January 2020 and December 2022. Postoperative coronary artery bypass graft was performed for all patients which revealed dysfunction of MCABG-AIVB and a functioning AIVB. Then the iFR of AIVB was measured. Regarding the obtained iFR values, the patients were divided in two groups: group I with a negative iFR value included 40 (70.2 %) patients, and group II with a positive iFR value included 17 (29.8 %) patients. The main endpoint of the study was the development of dysfunctions of mammary conduit due to the presence of competitive blood flow. Results. Among 57 patients, 46 (80.7 %) had complete occlusion of a conduit with the absence of antegrade blood flow; the «string phenomenon» of the internal thoracic artery (ITA) was detected in 11 (19.3 %) patients. Whilst the values of instantaneous wave-free ratio, graft dysfunction occurred significantly more often in vessels with negative iFR than in vessels with the positive value, 40 (70.2 %) versus 17 (29.8 %), respectively (p<0.001). Conclusions. According to the results of the research, the dysfunction of the mammary conduit in most cases was due to the presence of competitive blood flow. The use of iFR before coronary artery bypass graft is necessary in order to assess competitive blood flow and prevent dysfunction of conduits in the long-term period.