ECONOMIZING VEIN-GRAFT SURVEILLANCE PROGRAMS

Objectives: To investigate the effectiveness of two alternative vein-g raft surveillance strategies. In the first strategy surveillance was r estricted to patients with a possible higher risk of significant steno sis development, i.e. those with a moderate stenosis identified early after the operation. In the second strategy the effects of reducing th e number of duplex tests per patient was examined. Patients and Method s: In a prospective study in three vascular surgical departments 300 p atients (300 femoropopliteal or distal grafts) underwent duplex survei llance during the first year after the operation. The duplex-derived P SV-ratio was considered to represent the degree of stenosis. Arteriogr aphic confirmation of suspected stenoses was routinely obtained, and p atients without a suspected graft stenosis underwent a consented arter iogram during the first postoperative year. The decision to perform a graft revision was taken on the basis of an arteriographic stenosis of at least 70% diameter reduction. In the first strategy graft categori es were defined on the basis of the first postoperative duplex examina tion: grafts with a PSV-ratio < 1.5, grafts with a PSV-ratio < 1.5-2.0 , grafts with a PSV-ratio of 2.0-2.5, grafts with PSV-ratios 2.5-3.0, and grafts with PSV-ratios > 3.0. The primary patency rate at 12 month s was compared for these categories. In the second alternative strateg y the number of examinations and the percentage of event causing de no vo stenoses were analysed per surveillance interval. Results: The pres ence of moderate abnormalities at the initial duplex scan did not iden tify patients with a high risk of an event, as initial PSV-ratios of 1 .5-2.0 and 2.0-2.5 (early mild-moderate lesions) had comparable 12-mon th primary patencies to patients with a PSV-ratio < 1.5 (completely no rmal grafts): (63%, 73%, and 71%, respectively). The interval incidenc e of event causing de novo stenoses was 8% of the total number of dupl ex tests performed at 3 months, and 8% at 6 months after the operation . In patients who had no previous intervention for stenosis and had a normal bypass during the first 6 months postoperatively, a sharp drop in this incidence was seen at 9 and 12 months, with event causing de n ovo stenoses observed in only 2% and 1% of all duplex tests. Conclusio ns: All patients should be included in a surveillance program, as the presence of a normal vein graft at the first duplex examination does n ot rule out the subsequent development of graft stenosis. The duration of the surveillance period may be restricted to the first 6 months af ter operation in patients who have a normal bypass during that time pe riod, as only few stenoses will be missed by this policy.