title: Significant sac retraction after endovascular aneurysm repair is a robust indicator of durable treatment success.
abstract: OBJECTIVE
  The principal aim of this study was to demonstrate that significant sac retraction (SSR) was a predictive marker of durable success after endovascular aortic repair (EVAR). If verified, follow-up (FU) of patients with SSR may become unnecessary. In addition, the clinical features of the patients and aneurysms were analyzed to identify predictive factors of SSR.
  
  
  METHODS
  A group of 371 patients treated by EVAR had a complete clinical exam, computed tomography (CT) scan, and duplex scan follow-up. Data were collected prospectively and analyzed retrospectively. We assessed the difference between the largest diameter of the aneurysm (D) and the diameter of the stent-graft body (D1) on each postoperative CT scan. SSR was defined as a minimum of 75% reduction of this difference between the first and any of the following CT scans. Treatment success was defined as survival free of aneurysm-related death, type I or III endoleak, aneurysm expansion exceeding 5 mm, rupture, surgical conversion, migration, and graft occlusion. To assess the predictive factors of SSR, we performed a multivariable analysis and a logistic regression of the most significant variables.
  
  
  RESULTS
  SSR was observed in 24.8% (92/371) of the patients after an average of 26 ± 21 months of FU. The mean duration of FU in this group was 50 ± 26 months (vs 45 ± 25 months; P = NS). Survival was significantly longer in the SSR group (96 ± 3 months vs 93 ± 3 months; P < .05). No rupture, surgical, or endovascular conversion was reported in the SSR group. The frequency of type I (2.2% vs 15.4%; P < .001), type II (3.3% vs 29.4%; P < 10(-6)), and secondary interventions (3.3% vs 13.3%;P < .05) was lower in the SSR group. All type I and III endoleaks were diagnosed and treated before SSR detection. Since SSR was detected, treatment success remained until last follow-up in 98.9% (91 of 92) of the patients. The independent predictive factors of SSR were abdominal aortic aneurysm (AAA) diameter < 55 mm (odds ratio [OR] 3.91; 95% confidence interval [CI]: 2.16-7.11), infra renal aorta diameter < 23 mm (OR 2.96; 95% CI: 1.74-5.03), and a proximal neck length > 22 mm (OR 2.41; 95% CI: 1.42-4.10).
  
  
  CONCLUSIONS
  In this series, SSR was accurately predictive of a durable success after EVAR. It occurred mostly in patients with a favorable anatomy. Less intensive follow-up work up seems to be safe in patients with SSR.
authors.affiliation: Department of Vascular and Endovascular Surgery, Henri Mondor Hospital, University of Paris, Creteil, France. docrabih@gmail.com
authors.forename: Rabih
authors.initials: R
authors.lastname: Houbballah
authors.forename: Marek
authors.initials: M
authors.lastname: Majewski
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Becquemin
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000401:mortality / Q000601:surgery*; D001027:Aortography / Q000379:methods; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation / Q000401:mortality; D005602:France; D006801:Humans; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008875:Middle Aged; D016017:Odds Ratio; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012086:Reoperation; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D015607:Stents; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D018616:Ultrasonography, Doppler, Duplex