Methods	Study design: Intention to treat. Method of randomisation: The randomisation procedure was created with equal probability of assignment to each of the treatment groups by means of a computer-generated random-number code Concealment of allocation: Unblinded.
Participants	Country: United States. Number: 728. Sex: Men (n = 631) and women (n = 97). Age: 40 - 90 years. Inclusion criteria: Patients with small (4.0-5.0 cm) AAAs. Patients were excluded from the study if they had evidence of symptoms referable to the aneurysm, an abdominal or thoracic repair, an aneurysm originating ≤ 1.0 cm from the most distal main renal artery, life expectancy of < 3 years, inability to provide informed consent, predicted noncompliance with the protocol, Society of Vascular Surgery (SVS) score > 2 with the exception of age and controlled hypertension, baseline serum creatinine level > 2.5 mg/dL, or when the patient did not meet the indications for use of the endograft device
Interventions	Treatment: Surgery, n = 366 of whom 322 had immediate EVAR surgery: 4 underwent open surgery, 6 underwent repair outside of the 30-day window of randomisation, 9 were withdrawn per patient request, 10 were withdrawn per physician request for deteriorating health status between randomisation and scheduled repair, 2 were treated with an endograft device that was not in the protocol, and 13 received no repair for reasons not specified Surveillance, n = 362 of whom 100 had aneurysm repair when met the criteria listed below Patients assigned to early EVAR underwent aneurysm repair ≤ 30 days of randomisation while patients assigned to surveillance were seen at 1 month, 6 months, and every 6 months thereafter for a minimum of 36 months and a maximum of 60 months after operation. Patients were offered aneurysm repair when symptoms thought referable to the aneurysm developed, when the diameter of the aneurysm reached 5.5 cm, or when the aneurysm enlarged ≥0.5 cm between any two 6-month assessments
Outcomes	Primary: To determine whether early endovascular repair of aneurysms 4.0-5.0 cm in diameter is superior to surveillance with respect to the frequency of rupture or aneurysmrelated death Secondary: N/A
Notes
Risk of bias
Bias	Authors’ judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	The randomisation procedure was designed to provide equal probability of assignment to each of the treatment groups by means of a computer-generated random-number code
Allocation concealment (selection bias)	Unclear risk	Concealment of allocation: Unblinded
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Cannot blind participants
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Unlikely given the study outcome (mortality) and low lost of follow-up rate. Vital status was assessed using the same methodology for both patients in the immediate repair group and patients in the routine ultrasound surveillance group - in case misclassification occurred this would have been non-differential and its impact on the study results would be limited
Incomplete outcome data (attrition bias) All outcomes	Low risk	Unlikely given the study outcome (mortality) and low lost of follow-up rate
Selective reporting (reporting bias)	Low risk	Authors published findings on the main study outcome of this review
Other bias	High risk	Conflicts of interest: The study was funded by Medtronic Vascular, which now holds the trial database. The funding source was not specified in the report of trial results, butwas specified in the 2009 paper describing the rationale and protocol for the study (PIVOTAL). In addition, two members of the research team were acknowledged as paid consultants of Medtronic