title: Intensive blood flow monitoring following femoro-distal bypass: can early outcome be reliably predicted?
abstract: Forty-two femoro-distal vein grafts were studied in the early post-operative period for up to 1 week using a newly developed Doppler monitoring system designed to make frequent, automatic assessments which were stored on tape. Thirty-three grafts remained patent at 1 month with clinical improvement but in nine cases, all performed for critical ischaemia, reconstruction was unsuccessful with six grafts thrombosing and three remaining patent without clinical improvement (haemodynamic failure). The system was shown to provide good quality data, subsequent analysis of which with respect to the time-averaged mean velocity (TAMV) and pulsatility index (PI) revealed good separation between successful and failed grafts. In 30/33 cases a good result was predicted by the early establishment of hyperaemic flow (TAMV greater than 10 cm s-1, PI less than 2), whereas in three a "low flow" state was observed (TAMV less than 10 cm s-1, PI 2-3) which also resulted in a successful outcome. Graft thrombosis was heralded by the rapid development of high pulsatility (PI greater than 6) or a progressive departure from initial hyperaemia towards more pulsatile flow within a few days. Haemodynamic failure was associated with poor flow (TAMV less than 10 cm s-1) accompanied by a PI greater than 3.5. Intensive post-operative monitoring with this new system offers a means whereby early graft outcome can be reliably predicted and also has the potential to study the effects of any intervention used to salvage high risk grafts.
authors.affiliation: Department of Surgery, Leicester Royal Infirmary, U.K.
authors.forename: J A
authors.initials: JA
authors.lastname: Brennan
authors.forename: A J
authors.initials: AJ
authors.lastname: Thrush
authors.forename: D H
authors.initials: DH
authors.lastname: Evans
authors.forename: P R
authors.initials: PR
authors.lastname: Bell
mesh_terms: D001783:Blood Flow Velocity; D005268:Femoral Vein / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D011182:Postoperative Care; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D014463:Ultrasonography; D014654:Vascular Patency