The Weekend Effect in Lower Extremity Bypass
Kirsten Dansey, MD1, Nicholas Swerdlow, MD1, Rens Varkevisser1, Thomas O’Donnell, MD1, Thomas O’Donnell, MD1, Doug Jones, MD2, Kristina Giles3, Raul Guzman, MD1, Marc Schermerhorn, MD1.
1Beth Israel Deaconess Medical Center, BOSTON, MA, USA, 2Boston Medical Center, BOSTON, MA, USA, 3University of Florida, Gainesville, FL, USA.
OBJECTIVES: The ‘weekend effect’ has been described in the literature as higher complication rates following surgery on weekends versus weekdays. However, data regarding outcomes following lower extremity bypass (LEB) on weekends is limited.
METHODS: We performed a retrospective analysis of prospectively collected data from all patients undergoing LEB for chronic limb-threatening ischemia (CLTI) or acute limb ischemia (ALI) in the Vascular Quality Initiative between 2003 and 2017. Our primary outcome was the combined endpoint of in-hospital major adverse limb event (MALE; major amputation or revascularization) or 30-day mortality. We performed mixed effects logistic regression clustering at the level of the center and the surgeon to compare outcomes on the weekend vs weekdays.
RESULTS: We included 32,261 LEB procedures, of which 1020 (3.2%) were performed on the weekend. For CLTI, 501 LEBs (2.6%) were performed on the weekend. In unadjusted analysis, the rate of combined mortality plus MALE was 23% on the weekend compared to 16% on weekdays (P<.001). The 30-day mortality rate was 3.2% vs. 2.2%, respectively (P=.12), and the rate of MALE was 20% vs. 14% (P<.001). For ALI, 441 LEBs (10.6%) were performed on the weekend. In unadjusted analysis, the rate of combined mortality plus MALE was 33% on the weekend compared to 21% on weekdays (P<.001). The 30-day mortality rate was 6.6% vs. 3.6%, respectively (P=.002), and the rate of MALE was 28.4% vs. 18.5% (P<.001). After multivariable adjustment (for baseline characteristics, weekend surgery for CLTI and ALI were both associated with higher odds of combined mortality plus MALE compared to weekday surgery (CLTI: OR 1.3, 95% CI 1.02-1.6, P=.04; ALI: OR 1.3 95% CI 1.0-1.4, P=.04).
CONCLUSIONS: Rates of 30-day mortality or MALE for patients undergoing LEB for CLTI or ALI were higher following procedures performed on the weekend. The worse outcomes in patients with ALI who underwent an operation on the weekend likely reflect a cohort of people who were too sick to delay revascularization. However, the need for CLTI revascularization on a weekend is more likely to reflect OR availability which should prompt re-evaluation of weekday resources for these complex patients. 
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