b'Scientific Session Abstracts SATURDAY APRIL 20, 2024 23: THE RELATIONSHIP BETWEEN SMOKING CESSATION AND OUTCOMES OF THORACIC ENDOVASCULAR AORTIC REPAIRMarc Farah, BS, Sabrina Straus, BS; Grace Wang, MD, MSCE, FACS;Ann Gaffey, MD, MS; Mahmoud Malas, MD, MHS, RPVI, FACSUniversity of California San Diego, Center for Learning and Excellence in Vascular and Endovascular Surgery (CLEVER), Department of Surgery, Division of Vascular and Endovascular Surgery, UC San Diego, San Diego, CA; Division of Vascular and Endovascular Surgery, Hospital of the University of Pennsylvania, PA; Georgetown University School of Medicine, Washington D.C.Background: Smoking is known to be a strong predictive factor for deleterious outcomes after surgical procedures; however, there is limited research that has focused on the effect of smoking cessation on the outcomes of Thoracic Endovascular Aortic Repair (TEVAR). Using a multi-institutional database, we aimed to determine if smoking cessation was associated with improved outcomes following TEVAR.Methods: Patients undergoing TEVAR in VQI from 2003 to 2023 were categorized into 3 groups: never smokers (NS), those who quit smoking 1 month prior (QS), or current smokers/quit 30 days prior (CS). Primary outcomes include perioperative death, stroke, MI, and spinal cord ischemia (SCI). Secondary outcomes include cardiac and pulmonary complications, prolonged length of stay (2 days), leg and bowel ischemia. A multivariate logistic regression analysis was conducted, controlling for confounding variables. A subanalysis was performed to determine the impact of smoking cessation by TEVAR indication: Thoracic Aortic Aneurysm (TAA) and TypeB Aortic Dissection (TBAD). Long term outcomes were also analyzed using Kaplan-Meier and Cox regression models.Results: We studied 1,435 (30.4%) NS, 1,867 (39.6%) QS, and 1,412 (30.0%) CS. Patients who quit more than 1 month prior were older and had the highest rate of comorbidities including diabetes, MI, and CHF. The multivariate analysis showed that current smokers had no significant difference in odds of perioperative death (aOR=1.40;[95% CI: 0.86-2.25];p=0.2), stroke (aOR=1.19;[95% CI: 0.71-1.99];p=0.5), MI (aOR=1.54;[95% CI: 0.74-3.17];p=0.2), and SCI (aOR=1.52;[95% CI: 0.95-2.45];p=0.083), compared to QS patients [Table I]. However, CS had increased odds of postoperative leg ischemia (aOR=3.75;[95%CI:1.79-8.25];p0.001) and 1-year mortality (aOR=1.34;[95%CI:1.01-1.79] p=0.042) compared to QS patients [Table I]. When stratified by indication, CS TAA patients were not associated with a significant increase in primary postoperative outcomes; however, they had higher rates of leg ischemia (aOR=3.46;[95%CI:1.28-10.1];p=0.017) and 3-year mortality (aOR=1.44;[95%CI:1.02-2.03];p=0.036), when compared to QS TAA patients [Table II]. In TBAD patients, CS had no significant difference in postoperative outcomes, but showed increased odds of 1-year mortality (aOR=2.51;[95%CI:1.17-5.54];p=0.02) compared to QS [Table II]. 68SOUTHERN CALIFORNIA VASCULAR SURGICAL SOCIETY'