title: Outcome and clinical significance of delayed endoleaks after endovascular aneurysm repair.
abstract: OBJECTIVE
  Endovascular aneurysm repair (EVAR) is considered the standard therapy for most patients with abdominal aortic aneurysm (AAA). Endoleak is a well-known EVAR-related complication that requires long-term follow-up. However, patient follow-up is often challenging outside clinical trials. We sought to evaluate the incidence and the effect of delayed endoleaks in a Veterans Administration (VA) health care system where long-term follow-up is ensured.
  
  
  METHODS
  We retrospectively evaluated 213 consecutive patients who underwent EVAR at a referral Veterans Administration medical center. Age, aneurysm size, patency of lumbar and inferior mesenteric arteries, and follow-up evaluations were recorded. Type of endoleak, date of detection, and intervention were also documented. Patients who had <1 year of follow-up were excluded. The χ(2) test, Student t-test, Mann-Whitney test, and Spearman correlation were used for data analysis.
  
  
  RESULTS
  The analysis included 183 patients with a mean follow-up of 53 months (range, 12-141 months); of these, 48 patients (26%) had endoleaks, and 31 (17%) had aneurysm progression. The mean diagnosis time for nontype II (n = 14) endoleaks was 45 months (range, 3-127 months), and 71% were diagnosed >1 year after EVAR. All except one nontype II endoleak received prompt secondary interventions, and the one without intervention presented with aneurysm rupture. An isolated type II endoleak was detected in 34 patients at an average of 14.4 months (range, 0-76 months) after EVAR, 41% of which were detected >1 year after EVAR. Patients without a documented endoleak had a significant decrease in aneurysm size at the latest computed tomography evaluation compared to the preoperative size (4.8 vs 5.7 cm; P < .001), whereas those with isolated type II endoleak had an increase at the latest computed tomography follow-up compared to preoperative size (5.8 vs 5.7 cm). Importantly, 59% of the patients with a type II endoleak had significant AAA enlargement (0.8 cm), and delayed type II endoleak was significantly associated with sac enlargement compared to type II endoleaks detected early. No significant correlation was seen between the diameter of inferior mesenteric artery or lumbar to AAA enlargement among the patients with a type II endoleak. Secondary interventions in 12 patients with isolated type II endoleak resulted in overall aneurysm stabilization or regression.
  
  
  CONCLUSIONS
  This long-term outcome study demonstrated that delayed endoleaks appearing >1 year after EVAR contributed to most of the overall endoleaks and were significantly associated with aneurysm sac growth. This study underscores that type II endoleak is not benign and that vigilant lifelong surveillance after EVAR is critical.
authors.affiliation: Department of Surgery Stanford University, Stanford, Calif; Surgical Service, Veterans Administration Palo Alto Health Care System, Palo Alto, Calif. Electronic address: weizhou@stanford.edu.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhou
authors.affiliation: Duke University School of Medicine, Durham, NC.
authors.forename: Eddie
authors.initials: E
authors.lastname: Blay
authors.affiliation: Department of Surgery Stanford University, Stanford, Calif.
authors.forename: Vinit
authors.initials: V
authors.lastname: Varu
authors.affiliation: New York Medical College, Valhalla, NY.
authors.forename: Syed
authors.initials: S
authors.lastname: Ali
authors.affiliation: Department of Radiation Oncology, Stanford, Calif.
authors.forename: Michelle Qiushuang
authors.initials: MQ
authors.lastname: Jin
authors.affiliation: St. Jude Medical, Sunnyvale, Calif.
authors.forename: Lisa
authors.initials: L
authors.lastname: Sun
authors.affiliation: Department of Surgery, Kyung Hee University Hospital, Gangdong, Seoul, Korea.
authors.forename: Jin Hyun
authors.initials: JH
authors.lastname: Joh
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000175:diagnosis / Q000401:mortality / Q000601:surgery*; D001027:Aortography / Q000379:methods; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects* / Q000401:mortality; D016009:Chi-Square Distribution; D018450:Disease Progression; D018572:Disease-Free Survival; D057286:Electronic Health Records; D057867:Endoleak / Q000175:diagnosis / Q000209:etiology* / Q000401:mortality / Q000628:therapy; D057510:Endovascular Procedures / Q000009:adverse effects* / Q000401:mortality; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014481:United States; D014493:United States Department of Veterans Affairs