INTRAOPERATIVE DETERMINANTS OF INFRAINGUINAL BYPASS GRAFT PATENCY - APROSPECTIVE-STUDY

Objectives: To evaluate a number of currently available methods for in traoperative assessment of infrainguinal bypass grafts (IBG) in terms of defecting technical errors and predicting graft failure. Design: Pr ospective open clinical study. Methods: Forty-nine patients undergoing 54 consecutive IBG were studied. Intraoperatively, the following meas urements were performed: distal pulse palpation (DPP), continuous wave Doppler (CWD) pulse volume recording (PVR), and ultrasonic volume flo wmetry (UVF), followed by intraoperative angiography of the entire gra ft and runoff vessels. The outflow resistance teas graded according to the guidelines of the Society for Vascular Surgery and International Society for Cardiovascular Surgery (SVS/ISCVS runoff score). Graft pat ency was determined noninvasively (PVX, colour Duplex) up to 12 months following surgery Predictive values and likelihood ratios for the int raoperative tests in detecting a technical problem during the bypass p rocedure and in predicting early graft failure were calculated. Result s: There were five immediate revisions for problems detected intraoper atively. Angiography did not identify any additional problems but assi sted in the correct location of the problems detected by the other tes ts. DPP and CWD were highly significant indicators of the need for rev ision with likelihood ratios for a positive test of 14.7 (p < 0.01) an d 12.3 (p < 0.01) respectively PVX did not achieve statistical signifi cance in this respect. None of the intraoperarive tests was a statisti cally significant predictor of early graft failure. The SVS/ISCVS runo ff score, on the other hand, predicted early failure with a PPV of 33% (likelihood ratio for a positive test of 4.9, p < 0.05). None of the grafts with a perfect SVS/ISCVS runoff score (n = 39) failed in the fi rst postoperative month. Conclusions: Simple CWD insonation of graft a nd anastomoses is the best intraoperative indicator for technical inad equacies after IBG. Routine intraoperative angiography is not necessar y and intraoperative anatomical imaging may be reserved for situations in which noninvasive documentation of technical success is absent. Co ntrary to the intraoperative haemodynamic test results, the SVS/ISCVS runoff score is a good predictor of early graft failure.