title: Predicting aneurysm enlargement in patients with persistent type II endoleaks.
abstract: OBJECTIVE
  The clinical significance of type II endoleaks is not well understood. Some evidence, however, indicates that some type II endoleaks might result in aneurysm enlargement and rupture. To identify factors that might contribute to aneurysm expansion, we analyzed the influence of several variables on aneurysm growth in patients with persistent type II endoleaks after endovascular aortic aneurysm repair (EVAR).
  
  
  METHODS
  In a series of 348 EVARs performed during a 10-year period, 32 patients (9.2%) developed type II endoleaks that persisted for more than 6 months. Variables analyzed included those defined by the reporting standards for EVAR (SVS/AAVS) as well as other endoleak characteristics. Univariate, receiver operating characteristic curve, and Cox regression analyses were used to determine the association between variables and aneurysm enlargement.
  
  
  RESULTS
  The median follow-up period was 26.5 months (range, 6-88 months). Thirteen patients (41%) had aneurysm enlargement by 5 mm or more (median increase in diameter, 10 mm), whereas 19 (59%) had stable or shrinking aneurysm diameter. Univariate and Cox regression analyses identified the maximum diameter of the endoleak cavity, ie, the size of the nidus as defined on contrast computed tomography scan, as a significant predictor for aneurysm enlargement (relative risk, 1.12; 95% confidence interval, 1.04-1.19; P =.001). The median size of the nidus was 23 mm (range, 13-40 mm) in patients with aneurysm enlargement and 8 mm (range, 5-25 mm) in those without expansion (Mann-Whitney U test, P <.001). Moreover, receiver operating characteristic curve and Cox regression analyses showed that a maximum nidus diameter greater than 15 mm was particularly associated with an increased risk of aneurysm enlargement (relative risk, 11.1; 95% confidence interval, 1.4-85.8; P =.02). Other risk factors including gender, smoking history, hypertension, need of anticoagulation, aneurysm diameter, type of endograft used, and number or type of collateral vessels were not significant predictors of aneurysm enlargement.
  
  
  CONCLUSIONS
  In patients with persistent type II endoleaks after EVAR, the maximum diameter of the endoleak cavity or nidus is an important predictor of aneurysm growth and might indicate the need for more aggressive surveillance as well as earlier treatment.
authors.affiliation: Division of Vascular Surgery, Department of Surgery, Montefiore Medical Center, Albert Einstein College of Medicine, 111E 210th Street, Bronx, NY 10467, USA.
authors.forename: Carlos H
authors.initials: CH
authors.lastname: Timaran
authors.forename: Takao
authors.initials: T
authors.lastname: Ohki
authors.forename: Soo J
authors.initials: SJ
authors.lastname: Rhee
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Veith
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Gargiulo
authors.forename: Hisako
authors.initials: H
authors.lastname: Toriumi
authors.forename: Mahmood B
authors.initials: MB
authors.lastname: Malas
authors.forename: William D
authors.initials: WD
authors.lastname: Suggs
authors.forename: Reese A
authors.initials: RA
authors.lastname: Wain
authors.forename: Evan C
authors.initials: EC
authors.lastname: Lipsitz
mesh_terms: D000368:Aged; D001014:Aortic Aneurysm / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy; D001019:Aortic Rupture / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy; D015331:Cohort Studies; D004621:Embolization, Therapeutic / Q000295:instrumentation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D017537:Mesenteric Artery, Inferior / Q000000981:diagnostic imaging / Q000503:physiopathology; D011183:Postoperative Complications / Q000209:etiology / Q000401:mortality / Q000628:therapy; D011237:Predictive Value of Tests; D012008:Recurrence; D012086:Reoperation; D012680:Sensitivity and Specificity; D016019:Survival Analysis; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014654:Vascular Patency / Q000502:physiology