Intraoperative assessment of in situ saphenous vein arterial grafts using pulsed Doppler spectral analysis

D. F. Bandyk, R. A. Jorgensen and J. B. Towne

Errors in anastomotic construction, retained competent valves, and arteriovenous fistulas can cause both early and delayed failure of in situ saphenous vein arterial grafts. Pulsed Doppler spectral analysis of midstream flow was compared with arteriography in 50 consecutive in situ saphenous vein bypasses for the detection of unsuspected technical error. Based on spectral changes in the velocity waveform indicating flow disturbance, intact valve cusps could be distinguished from arteriovenous fistulas, and technically unsatisfactory anastomoses were identified. Competent valve cusps were identified in nine (5%) of 180 valve-incision sites, and six anastomoses (6%) were judged unsatisfactory. The presence of severe flow disturbance was always associated with an anatomic defect on arteriography. Incision of missed valve cusps and anastomotic revisions corrected associated flow disturbances. Doppler flow analysis readily located high-flow arteriovenous fistulas, thereby reducing operative time and the need for multiple arteriograms. The high sensitivity of this method (no false-negative assessments) makes it an ideal screening test, resulting in the selective use of operative arteriography.