title: Comparison of surveillance versus aortic endografting for small aneurysm repair (CAESAR): results from a randomised trial.
abstract: BACKGROUND
  Randomised trials have failed to demonstrate benefit from early surgical repair of small abdominal aortic aneurysm (AAA) compared with surveillance. This study aimed to compare results after endovascular aortic aneurysm repair (EVAR) or surveillance in AAA <5.5 cm.
  
  
  METHODS
  Patients (50-79 years) with AAA of 4.1-5.4 cm were randomly assigned, in a 1:1 ratio, to receive immediate EVAR or surveillance by ultrasound and computed tomography (CT) and repair only after a defined threshold (diameter ≥5.5 cm, enlargement >1 cm /year, symptoms) was achieved. The main end point was all-cause mortality. Recruitment is closed; results at a median follow-up of 32.4 months are here reported.
  
  
  RESULTS
  Between 2004 and 2008, 360 patients (early EVAR = 182; surveillance = 178) were enrolled. One perioperative death after EVAR and two late ruptures (both in the surveillance group) occurred. At 54 months, there was no significant difference in the main end-point rate [hazard ratio (HR) 0.76; 95% confidence interval (CI) 0.30-1.93; p = 0.6] with Kaplan-Meier estimates of all-cause mortality of 14.5% in the EVAR and 10.1% in the surveillance group. Aneurysm-related mortality, aneurysm rupture and major morbidity rates were similar. Kaplan-Meier estimates of aneurysms growth ≥5 mm at 36 months were 8.4% in the EVAR group and 67.5% in the surveillance group (HR 10.49; 95% CI 6.88-15.96; p < 0.01). For aneurysms under surveillance, the probability of delayed repair was 59.7% at 36 months (84.5% at 54 months). The probability of receiving open repair at 36 months for EVAR feasibility loss was 16.4%.
  
  
  CONCLUSIONS
  Mortality and rupture rates in AAA <5.5 cm are low and no clear advantage was shown between early or delayed EVAR strategy. However, within 36 months, three out of every five small aneurysms under surveillance might grow to require repair and one out of every six might lose feasibility for EVAR. Surveillance is safe for small AAA if close supervision is applied. Long-term data are needed to confirm these results.
  
  
  BACKGROUND
  This study is registered, NCT Identifier: NCT00118573.
authors.affiliation: Vascular Surgery Unit, Department of Cardioscience, Hospital S. Camillo-Forlanini, Piazza C. Forlanini, Rome, Italy. piergiorgio.cao@gmail.com
authors.forename: P
authors.initials: P
authors.lastname: Cao
authors.forename: P
authors.initials: P
authors.lastname: De Rango
authors.forename: F
authors.initials: F
authors.lastname: Verzini
authors.forename: G
authors.initials: G
authors.lastname: Parlani
authors.forename: L
authors.initials: L
authors.lastname: Romano
authors.forename: E
authors.initials: E
authors.lastname: Cieri
mesh_terms: D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000401:mortality* / Q000473:pathology / Q000601:surgery*; D001019:Aortic Rupture / Q000453:epidemiology; D016063:Blood Loss, Surgical; D001807:Blood Vessel Prosthesis; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D007902:Length of Stay; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D018615:Ultrasonography, Doppler, Color; D018616:Ultrasonography, Doppler, Duplex