June 06, 2008

High-Volume Hospitals Better for Abdominal Aortic Rupture Repairs

FRIDAY, June 6 (HealthDay News) -- High-volume hospitals that use endovascular procedures to repair abdominal aortic aneurysms have lower death rates than hospitals that use open surgery, a new report finds.

The study looked at 80,953 Medicare patients who had abdominal aortic aneurysms (AAAs) repaired between 2001 and 2003. Of those patients, an endovascular approach was used in 26,730 of the cases. Patients with ruptured AAAs were excluded from the study. In determining death rates, the researchers included patients who died before being discharged from hospital and those who died within 30 days after surgery.

The study found that the number of any kind of AAA repair done by a hospital was significantly related to death rates, which were 80 percent higher at hospitals in the lowest quartile than in those in the highest quartile.

"We found that the proportion of AAAs repaired by an endovascular approach increased from 27 percent to 39 percent during the study," Dr. Justin B. Dimick, assistant professor at the University of Michigan and staff member of the Michigan Surgical Collaborative for Outcomes Research and Evaluation, University of Michigan Health Systems, said in a prepared statement.

"The highest volume hospitals used the endovascular approach 44 percent of the time compared to 18 percent at the lowest volume hospitals. This greater use of endovascular procedures accounted for 37 percent of the difference in mortality between high- and low-volume hospitals," Dimick said.

Endovascular repair was associated with a much lower in-hospital death rate compared to open surgery (2.5 percent vs. 6.6 percent), and death rates were lower for endovascular repair in both elective (2.1 percent vs. 5.0 percent) and urgent/emergency operations (5.1 percent vs. 11.2 percent).

The findings were published in the June issue of the Journal of Vascular Surgery.

"Our results show that hospital volume is still a valid quality indicator for AAA surgery," Dimick said. "Some researchers used to think endovascular technology would change referral patterns, altering case-mix distribution and potentially diminish the apparent volume effect; our study proves that referral patterns have not altered the impact of volume on outcome. Also, our data shows that high volume hospitals are doing fewer open repairs, but still have very low mortality rates for open repair. These data clearly show that high volume hospitals are performing well despite any changes in referral patterns."

More information

The Society of Interventional Radiology has more about treatments for abdominal aortic aneurysms.

-- Robert Preidt
SOURCE: Society for Vascular Surgery, news release, May 29, 2008
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