Ultrasound Surveillance of Insitu Bypass Grafts - is it Worth the Effort?

Abstract

Introduction: In surgical fit patients with critical limb ischaemia (CLI) a great saphenous vein bypass is the recommended treatment for long occlusions of the infra-popliteal segment ADDIN EN.CITE ADDIN EN.CITE.DATA 1. Development of vein graft stenosis and bypass failure is observed in as much as 40% within the first 12 months2 and duplex ultrasound (DUS) surveillance has been broadly implemented with the aim to increase patency. ADDIN EN.CITE ADDIN EN.CITE.DATA Nevertheless, the evidence supporting this many DUS examinations are conflicting. ADDIN EN.CITE ADDIN EN.CITE.DATA 2, 3 Most cohorts in the literature are heterogeneous and report on a variety of autogenous vein conduits (insitu vein, reversed vein, arm vein and spliced vein) and indications (claudication or CLI) making generalizability difficult.3 The aim of this study was to describe patency of insitu saphenous vein bypass (ISSVB) in critical limb ischaemia and to analyse the added value of systematic DUS surveillance of in situ saphenous vein bypass. Methods: Single centre study including all patients undergoing ISSVB surgery due to CLI between 2011 and 2015. Postoperative graft surveillance program were offered to all patients, including clinical examination, ABI and DUS at 6 weeks, 3 and 12 months. The study was based on prospective entered data from the Danish Vascular Registry and primary endpoints were re-intervention rate and patency. To avoid idealization of the survival plots we decided to include occlusion, amputation and death as endpoints in both plots and use reintervention as the only variable in the Kaplan Meyer estimates. Results: In total 392 consecutive and treatment naive CLI-patients were revascularized with ISSVB and included in the study. Of those, 326 patients had minimum one follow up visit resulting in 1267 DUS examinations. During the study period, 95 (24%) patients received 143 reinterventions to avoid graft failure, 76 patients (80%) with percutaneous transluminal angioplasty (PTA) and 19 patients (20%) with surgical revision. Only 18 patients (20 reinterventions) were revised solely based on DUS findings (significant stenosis) without simultaneous ischemic symptoms or significant (>15%) decrease in ankle brachial index. Hence, to find one asymptomatic graft stenosis requiring reintervention one need to scan 65 patients (1267:20=65). Occlusion- and amputation-free survival (OAS) after 1, 2 and 3 years was 59.7% (95%-CI: 54.6-64.5), 45.3% (39.6-50.9) and 32.3% (26.4-38.4), respectively (figure 1). Reintervention-, occlusion-, and amputation-free survival (ROAS) after 1, 2 and 3 years was 47.6% (42.5-52.6), 33.5% (28.1-38.9) and 21.1% (16.0-26.7). Conclusion: The KM-plots showed a significant difference between ROAS and OAS until 2½ years postoperatively, indicating a modest (approximately 10%) effect of reintervention on graft stenosis. In this study, every fourth of ISSVB patients received a graft-preserving intervention but very few were driven by routine DUS as most graft lesions were recognised on symptoms and clinical findings. This finding suggests that development of more individualised surveillance programs differentiating between high and low risk patients may be more cost effective. Disclosure: Nothing to disclose