Expertise Based Randomized Controlled Trial of Open Versus Endovascular Repair of Abdominal Aortic Aneurysms: A Pilot Study
试验速览
- 阶段
- 3 期
- 入组人数
- 30
- 试验地点
- 1
- 主要终点
- Mortality from the time of randomization until hospital discharge or 30-days after surgery
研究概览
简要总结
Objectives.
To study the feasibility of an expertise-based randomized controlled trial (RCT) testing the role of traditional surgery (OPEN) versus endovascular repair (EVAR) for abdominal aortic aneurysms (AAA).
Study design.
We will conduct an expertise-based RCT comparing OPEN to EVAR of non-urgent abdominal aortic aneurysms in patients referred to vascular surgeons practicing at Hamilton Health Sciences, to determine the rate of death and other complications. Quality of life and status at 6 months will also be recorded. The ultimate goal is to determine the feasibility of conducting a pragmatic expertise-based RCT and to inform a future larger study at a national level.
详细描述
Background. The prevalence in individuals over 65 years of age is 6% (95% Confidence Interval [CI] 5 - 6)(1-4)in men and 1% (95% CI 1 - 2) in women.(5) AAA confers a risk of spontaneous rupture and death: the in-hospital mortality rate of ruptured aneurysms in Ontario was estimated at 40.8%.(6) Prevention of spontaneous rupture is the rationale for surgical intervention. Evidence has established that elective open surgery for AAAs > 5.5cm increases survival(7), but the 30-day perioperative mortality for elective open repair of AAA can be as high as 8%.(8-17) Phase I and II trials have found that endovascular repair is a 'viable and effective treatment' for AAA disease (18;19); the theoretical benefits include avoidance of laparotomy and no aortic clamping.
The results of RCTs (DREAM and EVAR-1)(20;21) have left unanswered the indications for endovascular repair compared with open surgery because of problems with definition of outcomes, lack of statistical power, and surgical expertise (surgeons needed to have done at least 20 surgeries with or without supervision). The only studies addressing the issue of expertise in this field suggests that 60 EVAR need to be done to achieve less than 10% complications (22), and a time interval of less than 10 days between procedures is important to maintain competence and reduce complications.(23) In addition the two RCTs used a conventional design and we have reported that this has intrinsic pitfalls. We argued that in surgery, particularly when a new technique is studied, another approach should be used: the expertise based RCT.(24) Conventional RCTs typically randomize participants to one of two interventions (A or B) and the same clinician give intervention A to some participants and B to others. The expertise based randomized controlled trial, randomizes participants to clinicians with expertise in intervention A or clinicians with expertise in intervention B, and the clinicians perform only the procedure for which they have expertise.
Study Design/Participants
We will conduct an expertise based RCT comparing open repair with EVAR repair of elective infrarenal AAAs. This is a pilot to determine the feasibility of a large pragmatic expertise based RCT of open versus EVAR repair.
We will consider all patients with an AAA determined to require non-urgent repair after assessment by one of the participating surgeons. The second inclusion criterion is that the blinded measurement team must deem a patient to fulfill the anatomic eligibility criteria.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Single Group
- 主要目的
- Treatment
- 盲法
- None
入排标准
- 年龄范围
- 0 Years 至 —（Child, Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •All patients with an AAA determined to require non-urgent repair after assessment by one of the participating surgeons will be considered. Patients must meet two eligibility criteria: Medical and Anatomic.
- •Medical Fitness for surgery will mean that the patient is a candidate for elective open repair, and has none of the exclusion criteria listed below.
- •Anatomic Eligibility will be judged by the endovascular measurement team, and will be based on a score of < 3 on the following scale. (This scale was developed at our centre and is currently being validated.)
- •Neck Length (20 - 15 mm = 1; 14 - 10 mm = 2)
- •Quality of Neck (Thrombus 90 -180 º = 1, 181-270 º = 2; calcification 90 -180 º = 1; 181-270 º = 2)
- •Presence/absence side branches (IMA or lumbar vessels = 1; IMA and lumbar vessels or other = 2)
- •Landing zone (aneurysmal or occlusive disease = 1; aneurysmal and occlusive disease = 2;
- •Degree of calcification of aorta (25 - 50% calcification = 1; > 50% = 2)
- •Access (stenosis = 1; stenosis and tortuosity =2)
- •Stenting of accessory renal arteries necessary
- •Embolization of internal iliac artery necessary
- •Definition of Surgical Experts
- •Expertise in endovascular surgery will be determined by completion of a vascular residency at a credentialed academic centre, a period of study in a formal training programme dedicated to acquiring endovascular expertise, and experience with at least 60 previous EVAR procedures.30
- •Expertise in open aortic repair will require completion of an accredited vascular surgery residency programme and demonstration of expertise by having completed at least 100 consecutive elective AAA repairs in their career.32
- •Endovascular Measurement Team The Endovascular Measurement team consists of at least one vascular surgeon with expertise in endovascular surgery, at least one vascular fellow in his/her first or second year of training and a representative from an endovascular graft specialist who is familiar with graft measurement and deployment. This team, blinded to patient demographics and surgical fitness, will judge anatomic eligibility.
排除标准
- •Exclusion due to Medical Risk: Patients with severe cardiac or respiratory disease that limits their activities of daily living and would make them ineligible for open repair. BMI greater than
- •Any known diagnosis or condition that renders a lift span of less than 2 years based on available and tolerable treatments.
- •Exclusion due to Aneurysm Factors: Patients with ruptured or symptomatic aneurysms requiring urgent surgery. Any aneurysm that extends proximal to the renal arteries (suprarenal), involves the renal arteries or is less than 15mm distal to the level of the lowest renal artery.
- •Exclusion due to Operative Factors: Patients with multiple previous laparotomies making open repair contraindicated due to adhesions (a 'hostile abdomen'). Any patients with stomas or exteriorized bowel. Patients with previous abdominal radiation, Fitz-Hugh-Curtis, or history of other conditions that would render open operative intervention contraindicated.
结局指标
主要结局
Mortality from the time of randomization until hospital discharge or 30-days after surgery
次要结局
- Non-fatal myocardial infarction.
- End organ ischemic event rates (including Renal Failure, Limb ischemia, Bowel ischemia, Non-fatal stroke)
- Reintervention
- Quality of life
- Success of repair
- Mortality at 6 months