SCVS 2023: DAPT shows higher survival rate in patients with low WIfI scores, study indicates

C.Y. Maximilian Png presents during SCVS 2023

A retrospective cohort study presented at the 2023 Society for Clinical Vascular Surgery (SCVS) Annual Symposium in Miami (March 25–29) has found lower-extremity bypass patients who received dual antiplatelet therapy or anticoagulation (DAPT/AC) postoperatively had a higher 30-day survival rate.

“We have limited contemporary evidence to support increasing antithrombotic therapies after bypass,” C.Y. Maximilian Png, MD, a vascular surgery resident at Massachusetts General Hospital stated, providing background for their research in conversation with Vascular Specialist on his return from presenting the data at SCVS. The authors set about identifying optimal antithrombotic management of patients after lower-extremity bypass through a restriction analysis of wound, ischemia and foot infection (WIfI) scores.

At a single hospital system, Png and colleagues extracted data from infrainguinal bypass procedures completed between January 2018–2021, assigning preoperative WIfI scores to each individual case through the associated documentation. Excluding patients with wound scores of two or three, ischemia scores of zero or one, or foot infection scores of three, Png’s study singularly concerned patients at “[low] risk” of a negative outcome, such as major amputation, who may “theoretically benefit the most” from increased therapy, he said.

Based on the type of antithrombotic regimen on discharge, demographics, comorbidities, type of bypass, 30-day rates of graft occlusion, major amputation, mortality and major adverse limb events (MALEs) were analyzed. “The WIfI scoring system has already been clinically validated and associated with amputation risk,” Png said. “The next challenge is to figure out how to get the most out of this valuable tool, and we thought one use of it could be to help differentiate patients who would benefit from increased anti-thrombotic medication therapy.”

Including 191 procedures in the study, Png et al found 66 (34.6%) patients were discharged on single antiplatelet therapy (SAPT), compared with 125 (65.5%) who were discharged on either DAPT or AC. The only difference that the authors identified between the two groups was a higher prevalence of atrial fibrillation in the DAPT/AC group.

At 30 days, Png and colleagues observed no significant difference in postoperative reintervention or graft occlusion rates, however the DAPT/AC group had a significantly lower rates of mortality (2.2% vs. 9.1%, P<0.05), major amputation (1.6% vs. 7.6%, P <0.05) and MALE. Reflecting on their Kaplan-Meier analysis, the authors determined that MALE-free survival were higher amongst DAPT/AC patients compared with the SAPT group.

Despite drawing this conclusion from their analysis, Png made clear that their results cannot be generalized to the rest of the PAD population, as this work was done in a select group of patients. And although they illuminate an alternate treatment path which diverts from the contemporary hesitance to prescribe DAPT or AC therapies postoperatively, Png said, more research must be done.

“If you ask any researcher if more research should be done, we’ll always say yes. Our study has several limitations, including selection bias and its lack of granularity regarding the types of antiplatelet and anticoagulation medications, but if you’re to get anything out of our study it’s that there truly is no one-size-fits-all solution.”


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