A strong relationship exists between the volume of surgery performed and outcomes from both open and endovascular aortic repairs (EVAR), according to a study published online Sept. 22, ahead of print in Circulation: Cardiovascular Quality and Outcomes.
Peter J.E. Holt, PhD, from the department of outcomes research at St George's Vascular Institute in London, and colleagues sought to quantify the relationship between the annual caseload and outcomes from elective endovascular (EVR) or open repair of abdominal aortic aneurysms ( AAAs) in England between 2005 and 2007.
Researchers, after obtaining patient data from the Hospital Episode Statistics, examined the case-mix between hospitals of different sizes using observed and expected values for in-hospital mortality. Outcome measures included in-hospital mortality and hospital length of stay.
Between 2005 and 2007, a total of 57,587 patients were admitted to hospitals in England with a diagnosis of AAA, and 11,574 underwent AAA repair, according to the authors. There were 7,313 elective AAA repairs, of which 78 percent were open and 22 percent were EVR.
The authors wrote the in-hospital mortality rates were 5.63 percent for all elective AAA repairs with rates of 6.18 percent for open repair and 3.77 percent for EVR.
Holt and colleagues reported that high-volume aneurysm services were associated with significantly lower mortality rates overall (0.991), for open repairs (0.994) and EVR (0.989). Large endovascular units had low mortality rates for open repairs.
According to the authors, “These data support the concept that abdominal aortic surgery should be performed in specialized units that meet a minimum volume threshold.”
Holt and colleagues noted that for patients identified with AAAs by the screening program, appropriate care necessitates “elective aneurysm repair at the lowest possible operative mortality rate, which under current practice would include limiting the treatment . . . to high volume hospitals experienced in [EVAR].” They recommended that good cut-off points for hospital volume may be eight EVAR procedures per year and 15 surgical AAA repairs per year.