title: Limitations of the Outback LTD re-entry device in femoropopliteal chronic total occlusions.
abstract: OBJECTIVE
  Subintimal recanalization for the treatment of femoropopliteal chronic total occlusions (CTO) occasionally requires re-entry devices to access the true lumen distally, but limited information is available on factors predicting the success or failure of these devices. We evaluated the Outback LTD re-entry device (LuMend, Redwood City, Calif; acquired by Cordis Corp, Miami Lakes, Fla).
  
  
  METHODS
  A retrospective review of patients with femoropopliteal CTO from August 2006 to August 2009 was performed. Age, gender, occlusion length, site of re-entry, and the angle of the aortic bifurcation were recorded. Procedural angiograms were used to assign a calcification score (none, mild, moderate, severe) at the re-entry site. Univariate and multivariate logistic regression analyses were used to identify factors predicting failure of re-entry into the true lumen.
  
  
  RESULTS
  Of 249 CTOs treated, the re-entry device was used 52 times (20.9%): 47 superficial femoral artery (SFA) occlusions and 5 combined SFA and popliteal artery occlusions (33 TransAtlantic InterSociety Consensus II type C and 18 type D lesions). Of 48 procedures with available angiograms for review, the target re-entry site was at the adductor canal in 30 (62.5%), the above-knee popliteal artery in 13 (27.1%), behind the knee joint in 4 (8.3%), and the mid-SFA in 2 (4.2%). Patients (54% men) were a mean age of 73.1 years. Re-entry was successful in 34 attempts (64.5%). Causes of failure included inability to re-enter the true lumen in 11 (61.1%), difficulty tracking the device over a wire in 3 (16.7%), acute angle of aortic bifurcation in 2 (11.1%), mechanical failure of the device in 1 (5.6%), and difficulty tracking the device through the lesion in 1 (5.6%). Moderate or severe calcification at the site of re-entry was the only significant predictor of failure (odds ratio, 6.3; 95% confidence interval, 1.45-24.48; P = .01). An aortic bifurcation angle ≥40° did trend toward predicting success (odds ratio, 0.23; 95% confidence interval, 0.05-1.02; P = .054).
  
  
  CONCLUSIONS
  Although the Outback re-entry device can be successful in extending the applicability of endovascular management to difficult femoropopliteal occlusions, it is not uniformly successful in current clinical practice. Significant calcification at the proposed re-entry site is a strong predictor of failure.
authors.affiliation: Division of Vascular Surgery, University of Pittsburgh Medical Center, Presbyterian, 200 Lothrop St, A-1017, Pittsburgh, Pa 15213, USA. shins@upmc.edu
authors.forename: Susanna H
authors.initials: SH
authors.lastname: Shin
authors.forename: Donald
authors.initials: D
authors.lastname: Baril
authors.forename: Rabih
authors.initials: R
authors.lastname: Chaer
authors.forename: Robert
authors.initials: R
authors.lastname: Rhee
authors.forename: Michel
authors.initials: M
authors.lastname: Makaroun
authors.forename: Luke
authors.initials: L
authors.lastname: Marone
mesh_terms: D000368:Aged; D017130:Angioplasty / Q000009:adverse effects / Q000295:instrumentation*; D001157:Arterial Occlusive Diseases / Q000000981:diagnostic imaging / Q000628:therapy*; D002114:Calcinosis / Q000000981:diagnostic imaging; D057785:Catheters; D016009:Chi-Square Distribution; D002908:Chronic Disease; D004867:Equipment Design; D004868:Equipment Failure; D005260:Female; D005263:Femoral Artery / Q000000981:diagnostic imaging; D006801:Humans; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D010414:Pennsylvania; D011150:Popliteal Artery / Q000000981:diagnostic imaging; D011859:Radiography; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D016896:Treatment Outcome