title: Duplex ultrasound diagnosis of failing stent grafts placed for occlusive disease.
abstract: OBJECTIVE
  We previously showed that duplex ultrasound (DU) imaging is beneficial in the diagnosis of failing vein and prosthetic grafts performed for arterial occlusive disease. The purpose of this study was to evaluate whether DU imaging can reliably diagnose failing stent grafts (ie, covered stents) placed for arterial occlusive disease.
  
  
  METHODS
  Between July 1, 2005, and June 30, 2013, we placed 142 stent grafts in 92 arterial segments (1.5 stent grafts/stenotic artery) for lower extremity occlusive disease in patients who also underwent at least one DU surveillance study documenting a patent stent graft. Stent grafts were placed in 29 iliac and 52 femoropopliteal arteries and in 11 failing infrainguinal bypass grafts. Stent grafts used were Viabahn (W. L. Gore and Associates Inc, Flagstaff, Ariz) in 116 (82%), Wallgraft (Boston Scientific, Natick, Mass) in 23 (16%), Fluency (C. R. Bard Inc, Tempe, Ariz) in 2 (1%), and iCast (Atrium, Hudson, NH) in 1 (1%). Mean follow-up was 16 months (range, 1 week-86 months). Postoperative DU surveillance was performed in our Intersocietal Accreditation Commission accredited noninvasive vascular laboratory at 1 week, then every 3 months the first year, and every 6 months thereafter. DU measured peak systolic velocities (PSVs) and velocity ratio of adjacent PSVs (Vr) every 5 cm within the stent graft and adjacent arteries.
  
  
  RESULTS
  We retrospectively classified the following factors as "abnormal DU findings:" focal PSVs >300 cm/s, uniform PSVs <50 cm/s throughout the graft, and a Vr >3.0. Fifteen of 20 patients with one or more of these abnormal DU findings underwent prophylactic intervention (n = 8) or occluded without intervention (n = 7), whereas only two of 72 with normal DU findings occluded (P = .0001). Excluding the eight patients who underwent prophylactic intervention, seven of 12 patients with abnormal DU findings occluded without intervention vs two of 72 with normal DU findings (P = .0001).
  
  
  CONCLUSIONS
  These findings suggest that follow-up DU surveillance can predict failure of stent grafts placed for lower extremity occlusive disease. Focal PSVs >300 cm/s, Vr >3.0, and most importantly, uniform PSVs <50 cm/s throughout the stent graft were statistically reliable markers for predicting stent graft thrombosis.
authors.affiliation: Section of Vascular Surgery, Pennsylvania Hospital, Philadelphia, Pa.
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Troutman
authors.affiliation: Section of Vascular Surgery, Pennsylvania Hospital, Philadelphia, Pa.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Madden
authors.affiliation: Section of Vascular Surgery, Pennsylvania Hospital, Philadelphia, Pa.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Dougherty
authors.affiliation: Section of Vascular Surgery, Pennsylvania Hospital, Philadelphia, Pa. Electronic address: kcalligaro@aol.com.
authors.forename: Keith D
authors.initials: KD
authors.lastname: Calligaro
mesh_terms: D001157:Arterial Occlusive Diseases / Q000000981:diagnostic imaging / Q000601:surgery*; D001783:Blood Flow Velocity; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation*; D057510:Endovascular Procedures / Q000009:adverse effects / Q000295:instrumentation*; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D035002:Lower Extremity / Q000098:blood supply*; D011237:Predictive Value of Tests; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012039:Regional Blood Flow; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012307:Risk Factors; D015607:Stents; D013927:Thrombosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D013997:Time Factors; D016896:Treatment Outcome; D018616:Ultrasonography, Doppler, Duplex; D014654:Vascular Patency