New Criteria Define Limb Revascularization Results

By Mitchel L. Zoler

PALM BEACH, FLA. -- A refined definition of successful revascularization of critical limb ischemia showed that fewer than half of the 331 patients at one center had a complete response to bypass surgery, Dr. Spence M. Taylor said at the annual meeting of the Southern Surgical Association. The definition tested in this study required patients to meet four criteria after surgery for the outcome to be considered successful:

• Was graft patency achieved so that the wound healed?
• Was the affected limb retained for at least 1 year after surgery?
• Did patients maintain their ambulatory status for at least 1 year?
• Did patients survive for at least 6 months?

Although a substantial number of the patients met at least one of these criteria, only 44% met all four, said Dr. Taylor, a professor of vascular surgery at the University of South Carolina, Columbia.

"A combined definition of success probably provides a better representation of the outcomes of patients with critical limb ischemia who are treated with surgery," Dr. Taylor said.

He and his associates applied their new definition to all patients with critical limb ischemia who underwent revascularization at Greenville Hospital between January 1998 and December 2004. The average age of the 331 patients in the study was 66 years. All patients included had Rutherford type III limb ischemia, with either a chronic ulcer or gangrene. The analysis excluded those patients with rest pain and claudication.

The large number of revascularization failures "is not an indictment of surgical revascularization. It's an indictment of the way we evaluate success," said Dr. David L. Cull, a collaborator on the study and a vascular surgeon at Greenville Hospital.

"Unless we evaluate success appropriately, we can't select the patients who will benefit most from surgery," said Dr. Cull.

"My sense, based on our experience, is that it's not the vascular surgery that leads to revascularization failure but the underlying disease itself," he added.

In another part of their analysis, the investigators evaluated several clinical characteristics as possible risk factors for unsuccessful revascularization. A multivariate analysis showed that four baseline clinical features were independent predictors of worse outcomes: impaired ambulation before surgery, need for infrainguinal bypass, end-stage renal disease, and gangrene (see box).

A fifth baseline measure, hyperlipidemia, predicted better outcomes.

These five features interacted in an additive fashion. For example, patients with impaired ambulation, a need for infrainguinal bypass, and end-stage renal disease had just a 7% chance of fulfilling all four criteria for success after bypass surgery.

Patients who had all four negative features had a 150-fold increased risk of revascularization failure and just a 3% chance of having a successful outcome.