Abstract 12636: Association Between Pre-Operative Specialist Assessment and Adverse Outcomes Among Patients Scheduled for Major Vascular Surgery

Background: The impact of pre-operative specialist assessment on outcomes following high-risk vascular surgery remains uncertain. Our objective was to characterize the association between pre-operative cardiology or general internal medicine (GIM) assessment and post-operative outcomes following scheduled major vascular surgery. Methods: This is a population-based cohort study of all adult scheduled major vascular surgery patients in Ontario, Canada (April 1, 2004-March 31, 2019). Those who underwent an ambulatory cardiology and/or GIM assessment within 6 months prior to surgery were compared to those who did not. The primary outcome was 30-day mortality. Secondary outcomes included 30-day mortality, myocardial infarction or stroke; 30-day cardiovascular death; 1-year mortality; 1-year mortality, myocardial infarction or stroke; and 1-year cardiovascular death. Multivariable cox proportional hazard regression using inverse probability of treatment weighting (IPTW) was used to mitigate confounding by indication. Results: Among 50,228 scheduled major vascular surgery patients, 20,484 underwent pre-operative ambulatory specialist assessment: 11,074 (54.1%) with cardiology, 8,071 (39.4%) with GIM and 1,339 (6.5%) with both. Patients who underwent cardiology or GIM assessment had a higher Revised Cardiac Risk Index (N with Index over 2= 4,989 [24.4%] vs. 4,587 [15.4%], p<0.001) and more frequent pre-operative cardiac testing (N=7,772 [37.9%] vs. 6,113 [20.6%], p<0.001) but had lower crude 30-day mortality (N=551 [2.7%] vs. 970 [3.3%], p<0.001). After application of IPTW, pre-operative specialist assessment remained associated with a lower rate of 30-day mortality (Hazard Ratio [95%CI] = 0.73 [0.65-0.82]) and a lower rate of all secondary outcomes (Figure). Conclusion: Pre-operative ambulatory cardiology or GIM assessment is associated with improved outcomes following scheduled major vascular surgery