Infection Rate Exceeds 11% After Open Abdominal Aortic Surgery

DENVER — Open abdominal aortic surgery had an 11.4% rate of in-hospital postoperative infectious complications—the highest incidence for any type of elective vascular surgery—in a large national study.

This national rate will strike many surgeons as being higher than the rates they have experienced, but that's because it includes postoperative urinary tract infections, pneumonia, and sepsis, as well as the surgical site infections surgeons tend to focus on, Dr. Todd R. Vogel said at the Vascular Annual Meeting.

The study underscored the major economic consequences of infectious complications arising after elective vascular surgery. Hospital charges for affected patients were more than three times as great as those of patients without such complications, noted Dr. Vogel of the Robert Wood Johnson Medical School, New Brunswick, N.J.

He presented an analysis of 870,778 elective vascular surgical procedures performed in adults at U.S. hospitals during 2002–2006. The data came from the Nationwide Inpatient Sample of the Agency for Healthcare Research and Quality.

The overall in-hospital postoperative infectious complication rate was 3.7%. The rate, adjusted for age, gender, race, and comorbid conditions, varied widely by procedure type, with the 1.7% incidence associated with carotid endarterectomy being lowest.

The study showed that the 11.4% infectious complication rate for open abdominal aortic surgery was substantially higher than for aorta-iliac-femoral bypass surgery (8.9%), and the rate for thoracic endovascular aneurysm repair (5.7%) was twice that of endovascular abdominal aneurysm repair (2.8%), Dr. Vogel noted.

Pneumonia, which occurred in 6.6% of patients following open abdominal aortic surgery, was the most common infectious complication associated with that procedure. In contrast, urinary tract infection was the most common infectious complication after thoracic endovascular aneurysm repair and endovascular abdominal aneurysm repair, affecting 2.9% and 1.3% of patients, respectively.

Infectious complications following elective vascular surgery were significantly more common in women than in men, in blacks versus white or Hispanic patients, and in octogenarians versus younger individuals. Rates were higher at urban hospitals, large medical centers, and—contrary to conventional wisdom—teaching hospitals.

Mean hospital length of stay was 13.8 days in patients with infectious complications and 3.5 days in those without. Hospital charges averaged $37,834 in those who experienced such complications, compared with $11,851 in patients who did not.

Several audience members raised the possibility of coding errors in this huge national database, but Dr. Vogel minimized the likely impact of any such mistakes. “If you look globally at the infectious complication rates, you can see there's a problem in terms of race, a problem for women; and there's a problem in terms of the rate for open aortic aneurysm surgery,” he said.

Dr. Ronald M. Fairman, an audience member, noted that the Nationwide Inpatient Sample doesn't track readmissions. As a result, a patient undergoing femoral-popliteal bypass or another typically short-stay operation could develop an infectious complication requiring readmission soon after discharge, yet it wouldn't be listed as a postop infectious complication.

“So your figures could actually be an underestimate of the true infection rate,” said Dr. Fairman, professor and chief of vascular surgery at the University of Pennsylvania, Philadelphia.