Outcomes and practice patterns in patients undergoing lower extremity bypass

Abstract

Background: The appropriate application of endovascular intervention vs bypass for both critical limb ischemia (CLI) and intermittent claudication (IC) remains controversial, and outcomes from large, contemporary series are critical to help inform treatment decisions. Therefore, we sought to define the early and 1-year outcomes of lower extremity bypass (LEB) in a large, multicenter regional cohort, and analyze trends in the use of LEB with or without prior endovascular interventions.

Methods: The Vascular Study Group of New England database was used to identify all infrainguinal LEB procedures performed between 2003 and 2009. The primary study endpoint was 1-year amputation-free survival (AFS). Secondary endpoints included in-hospital mortality and morbidity, including major adverse cardiac events. Trend analyses were conducted to identify annual trends in the proportion of LEBs performed for an indication of IC, in-hospital outcomes, including mortality and morbidity, and 1-year outcomes, including AFS. Analyses were performed on the entire cohort and then stratified by indication.

Results: Between 2003 and 2009, 2907 patients were identified who underwent LEBs (72% for CLI; 28% for IC). The proportion that underwent LEB for IC increased significantly over the study period (from 19% to 31%; P < .0001). There was a significant increase over time in the proportion of LEBs performed after a previous endovascular intervention among both CLIs (from 11% to 24%; P < .0001) and ICs (from 13% to 23%; P = .02). Neither in-hospital mortality nor cardiac event rates changed significantly among either group. There was no significant change in 1-year AFS in patients with IC (97% in 2003 and 98% in 2008; P for trend .63) or in patients with CLI (73% in 2003 and 81% in 2008; P = .10).

Conclusions: Over the last 7 years, significant changes in patient selection for LEBs have occurred in New England. The proportion of LEBs performed for ICs as opposed to CLIs has increased. Patients are much more likely to have undergone prior endovascular interventions before undergoing a bypass. In-hospital and 1-year outcomes after LEB for both IC and CLI have remained excellent with no significant changes in AFS.

Figure 1

Inpatient trends in use of medical therapies.

Figure 2

Annual proportion of infrainguinal lower extremity bypasses for claudication and for critical limb ischemia, p=0.001

Figure 3. Univariate effect of additional sites to the Vascular Study Group of New England on annual proportion of infrainguinal lower extremity bypasses for intermittent claudication, 2003 to 2009

In order to protect the anonymity of sites as they were added, the analyses were performed as comparisons between year groups to assess the effect of adding new centers over time.

Figure 4. Percentage of patients with history of endovascular intervention prior to infrainguinal lower extremity bypass

P for trend=0.0204 for intermittent claudication, p for trend for critical limb ischemia <.0001.

Figure 5

Inpatient trends in complications and mortality.

Figure 6. Trends in use of cardioprotective medications (beta blockers, statins, or antiplatelet agents) and in-hospital operative myocardial infarction/dysrhythmia, among the total cohort

P for trend <0.0001 for cardioprotective medications, p for trend =.4384 for MI/dysrhythmia.

Figure 7

Inpatient trends in mean lengths of stay.