Role of flowmetry in tactics of bypass grafting for myocardial bridge of the anterior descending artery.

The purpose of the study was to analyse the remote results of bypass grafting for myocardial bridges. Our retrospective single-centre study included a total of 17 patients subjected to coronary bypass grafting of the anterior descending artery (ADA) in connection with a detected myocardial bridge (MB). All patients underwent assessment of the coronary bypass grafts (CBG) by means of intraoperative flowmetry - transit time flow measurement (TTFM), as well as angiographic control of the CBGs in the remote period. The duration of follow up amounted to 72 months. Six patients were found to have pronounced retrograde blood flow accompanied by an elevated index of peripheral resistance (Pi) and decreased mean volumetric blood flow velocity (Qmean) below the threshold values. Compression of the ADA proximal to the anastomosis appeared to be followed by improvement of blood flow parameters, in connection with which the shunted artery was ligated with monofilament polypropylene suture 4/0. According to the findings of coronary bypass angiography (CBA) the following results were obtained: 4 occluded grafts were revealed in the group of patients in whom ligation of the ADA was not performed. In patients subjected to ADA ligation in connection with pronounced retrograde blood flow, all bypass grafts were competent. The cumulative probability of freedom from graft occlusion was significantly higher in the group of patients subjected ADA ligation proximal to the anastomosis (Log Rank=0.032).