Recent years have seen progress in combating critical limb ischemia (CLI) in the United States, but the progress has been mixed and appears to be driven by increasing numbers of minimally invasive percutaneous (endovascular) procedures.

So suggests a new comprehensive analysis of a nationwide hospital sample of nearly 650,000 patients conducted from 2003 to 2011.

“We found that rates of surgery for CLI are going down while rates of endovascular procedures are going up,” says Mehdi Shishehbor, DO, MPH, PhD, Director of Endovascular Services at Cleveland Clinic. “Meanwhile hospital admissions for CLI have remained constant even as rates of amputation and death from CLI have gone down. This suggests there’s something at work other than improved medical therapy for CLI.”

Dr. Shishehbor led the Cleveland Clinic-conducted analysis, which was just published in Journal of the American College of Cardiology and will also be presented at the 65th Annual Scientific Session of the American College of Cardiology (ACC.16) in Chicago in early April.

A comprehensive, contemporary look at CLI management

CLI — defined as the presence of ulcers, gangrene or rest pain plus peripheral artery disease (PAD) — affects an estimated 10 million U.S. adults and is a major cause of pain, immobility, diminished quality of life, amputation and death.

A significant rise in endovascular revascularization as a treatment for CLI, accompanied by a decrease in surgical revascularization, prompted Dr. Shishehbor and his colleagues to undertake their analysis to more closely examine this trend and its potential associations with changes in CLI outcomes and resource utilization.

They obtained their data from the federal government’s Nationwide Inpatient Sample for 2003-2011, which contains discharge-level data from some 8 million hospitalizations annually across more than 1,000 hospitals. The database is designed to represent a 20 percent stratified sample of all U.S. hospitals.

They identified 642,433 admissions with CLI during this period and assessed these admissions for two primary end points, in-hospital mortality and amputation, as well as two secondary end points, length of stay (LOS) and hospitalization cost.

Key findings

The researchers’ key findings are reflected in the figure below and include the following:

• The annual rate of CLI admissions remained relatively constant (at ~150/100,000 population) throughout the 2003-2011 period despite a progressive increase in the rate of admissions for PAD. “The rise in PAD might be secondary to the rise in prevalence of cardiovascular risk factors, which we observed,” notes Dr. Shishehbor. “An increase in the rate of PAD-related admissions, with the constant rate of CLI-related admissions, might suggest early detection of PAD, leading to improved PAD management and the relative stabilization of CLI rates.”
• The proportion of patients with CLI undergoing surgical revascularization declined significantly during the study period (from 13.9 percent in 2003 to 8.8 percent in 2011) while the proportion undergoing endovascular treatment rose significantly (from 5.1 percent to 11.0 percent).
• There was a steady and significant decline in rates of in-hospital death and major amputation across the study period among patients with CLI as well as a significant overall decline in mean length of stay. Despite these improvements, mean hospitalization cost remained unchanged throughout the study period.
• Compared with surgical revascularization, endovascular treatment of CLI was associated with significantly lower in-hospital mortality, mean LOS and mean hospitalization cost — even after adjustment for potential confounders — despite statistically comparable rates of major amputation.

Study takeaways

“We found that endovascular procedures were associated with lower mortality, lower cost and lower length of stay compared with surgical revascularization in this large cohort of patients with CLI,” says Dr. Shishehbor. “While we cannot say it’s causation, these findings imply that endovascular treatment appears to be safer and less costly than surgical procedures for these patients.”

When asked what surprised him most about the study’s findings, Dr. Shishehbor points to the constant rate of patients admitted with CLI throughout the nine-year period.

“We had thought the decrease in amputation and mortality over time was a result of improving medical therapy, but that would lead you to expect a decrease in CLI admissions over time, which didn’t happen,” he explains. “Of course, good medical therapy is extremely important, but the data suggest that good medical therapy needs to be combined with our increasingly effective use of endovascular procedures to make further progress in CLI outcomes.”

Dr. Shishehbor can be reached at 216.636.6918 or shishem@ccf.org.