Researchers compare effectiveness of IB and AMP in high-risk patients

Major amputation is often selected over infrainguinal bypass in patients with severe systemic comorbidities because of a presumed decrease in risk of perioperative morbidity and mortality. To investigate this presumption, researchers from the Division of Vascular and Endovascular Surgery at the Brigham and Women's Hospital in Boston undertook a risk-adjusted comparison of early postoperative morbidity and mortality of high-risk patients undergoing infrainguinal bypass and major amputation. Results of this study will be presented today at the Society of Vascular Surgery's 64th Vascular Annual Meeting.

Examining a large database of patients, co-author Neal R. Barshes, MD, MPH said there were 780 in the infrainguinal bypass group and 792 patients in the major amputation group, with no significant differences among the demographic, preoperative or anesthetic variables.  "However, in this risk-adjusted propensity-matched comparison," said Dr. Barshes, "infrainguinal bypass had a lower 30-day postoperative mortality than major amputation (6.5 vs. 10.0 percent for bypass vs. amputation, respectively). While infrainguinal bypass was associated with significantly higher rates of return to the operating room (27.6 vs. 14.1 percent) and a trend toward higher bleeding requiring transfusion (2.1 vs. 0.9 percent), major amputation had higher rates of pulmonary embolism (0 vs. 0.9 percent) and urinary tract infection (2.7 vs. 5.2 percent)."

The study further showed that there was no difference in the overall number of major adverse events or postoperative length of stay between the major amputation and infrainguinal bypass groups. Graft patency was 91 percent at 30 days.

A review of procedural codes from the 2005-2008 National Surgical Quality Improvement Program database was used to identify all patients undergoing either IB or AMP. Propensity score matching was used to obtain the bypass and amputation groups from the high-risk patient subset matched in preoperative characteristics. Patients with systemic or local infections were excluded.

Dr. Barshes said that high risk patients were defined as the American Society of Anesthesiologists (ASA) Class 4 or 5; or ASA 3 with either congestive heart failure within 30 days, myocardial infarction within 6 months, renal failure (serum creatinine was more than 3mg/dL or dialysis-dependence), dyspnea at rest or ventilator dependence.

"Our study shows that the decision to perform infrainguinal bypass or major amputation should depend on well-established predictors of graft patency and functional success rather than presumptions about the perioperative risks associated with the two treatments," said Dr. Barshes.