Pulsed Doppler intraoperative flow assessment and midterm coronary graft patency

Background. This study was designed to assess the value of hemodynamic measurements taken intraoperatively in predicting midterm patency of coronary bypass grafts. Methods. A pulsed Doppler flowmeter was routinely used during operation to determine the hemodynamic parameters of coronary bypass grafts. During a 7-year period, 85 patients underwent angiographic evaluation. As a result, a thorough hemodynamic assessment of 214 grafts (89 arterial and 125 venous) at initial operation was available for analysis. Results. The overall patency rate was 88.3%. The mean flow measured intraoperatively in 168 intact grafts was 60 ± 3 mL/min (range, 9 to 230 mL/min), and the resistance was 1.8 ± 0.1 peripheral resistance units (range, 0.3 to 9.0 peripheral resistance units). The mean flow was 36 ± 5 mL/min (range, 2 to 107 mL/min), and the resistance was 5.9 ± 2.0 peripheral resistance units (range, 0.6 to 46.0 peripheral resistance units) in 25 grafts found occluded at angiographic evaluation. Multivariate analysis identified three independent variables associated with a reduced patency rate: increased resistance as measured in the graft (p = 0.012), increasing interval of control angiography (p = 0.006), and preoperative cardiogenic shock (p = 0.040). Conclusions. The prognosis for midterm patency of aortocoronary bypass grafts depends on the intraoperative hemodynamic status.