Hamilton, ON - A new economic analysis of elective endovascular repair of abdominal aortic aneurysms (EVAR) in high-risk patients suggests that the minimally invasive approach is a cost-effective strategy compared with open surgical repair [1].

The investigators, led by Dr Jean-Eric Tarride (McMaster University, Hamilton, ON), also showed that the average one-year costs for EVAR and open surgery were nearly identical, despite the significantly more expensive endovascular procedural costs, which include the $10 000 endograft. Patients undergoing endovascular repair spent less time in the hospital—7.7 days compared with 16 days for those treated with traditional open surgery—and this translated into lower nonprocedural costs. Despite similar baseline characteristics, there was also less morbidity associated with the endovascular approach.

The results of the study are published in the October 2008 issue of the Journal of Vascular Surgery.

The Canadian Society for Vascular Surgery recommends EVAR for patients with suitable anatomy at intermediate and high risk for perioperative morbidity with open repair, while open repair is the current standard for those at low risk. Previous economic analyses of EVAR vs open surgery concluded that the endovascular approach was not cost-effective, but the studies focused on all comers and not just those at high risk. In this review, Tarride and colleagues evaluated the cost-effectiveness of EVAR compared with open surgery in high-risk patients only.

In this nonrandomized study, demographic, medical, healthcare-resource utilization, and quality-of-life data were collected over a period of one year following elective abdominal aortic aneurysm (AAA) repair. Two effectiveness measures were used in this economic evaluation: number of life-years gained (LYGs) and number of quality-adjusted life-years (QALYs). QALYs, which combine duration of life with quality of life, are a measure commonly used in economic evaluations.

Data were collected on 192 high-risk patients undergoing surgical repair of an abdominal aortic aneurysm >5.5 cm at the London Health Sciences Center, in Ontario. Of these patients, 140 underwent endovascular repair of the aneurysm while 52 had open repair surgery. The 30-day postoperative complication rates were lower in those undergoing EVAR, with mortality rates of 0.7% for those undergoing endovascular repair and 9.6% for those undergoing open surgery. Hospital lengths of stay, intensive care unit (ICU) admissions, and ICU lengths of stay were also shortened with EVAR.

At one year, the total costs of the two treatments were similar, although there were differences in how the money was spent. Initial hospitalization costs were less with EVAR than with open surgery, but follow-up medical costs were higher with the endovascular approach. In terms of postprocedural surveillance, EVAR patients have a computed tomography (CT) scan and are seen by the surgeon at one, three, six, and 12 months postoperatively, while open repair requires only a single postoperative visit at four to six weeks. At one year, all-cause mortality was lower in EVAR patients—7.1% vs 17.3%—and there were no differences in terms of quality of life.

In terms of the cost-effectiveness analysis, point estimates at one year showed that EVAR "dominated" open surgical repair, as EVAR was less costly and more effective than open surgery in terms of LYGs and QALYs. The investigators note that when bootstrap techniques were used to deal with the sampling uncertainty associated with the trial, there was more uncertainty regarding the QALYs and less uncertainty regarding the life-years gained.

To summarize the uncertainty with the data, the authors used cost-effectiveness acceptability curves to show the probability that a treatment is cost-effective for several threshold values. "If society were willing to pay $50 000 per life-year gained or per quality-adjusted life-year gained, the probability of EVAR being cost-effective was found to be 0.76 and 0.55, respectively," they write.

Sensitivity analyses examining several different mortality scenarios allowed investigators to extrapolate the findings out to five years, and these data showed that EVAR was cost-effective.

The provincial Ministry of Health and Long-Term Care requested the cost-effectiveness study in order to provide evidence to support policy recommendations regarding the use of EVAR in Ontario and approved funding for the procedure based on interim results of this study and the clinical-outcomes data, which will be published soon.