N. K. Le1,2, N. Chervu1,3, T. Coaston1,2, S. Mallick1, A. Vadlakonda1,2, K. Joachim1,2, P. Benharash1,3 1David Geffen School Of Medicine, University Of California At Los Angeles, Cardiovascular Outcomes Research Laboratories (CORELAB), Los Angeles, CA, USA 2David Geffen School Of Medicine, University Of California At Los Angeles, Los Angeles, CA, USA 3David Geffen School Of Medicine, University Of California At Los Angeles, Department Of Surgery, Los Angeles, CA, USA
Introduction:
While the radial artery (RA) and right internal mammary artery (RIMA) are acceptable conduits in multi-arterial graft coronary bypass surgery (CABG), differences in short-term outcomes and resource utilization remain largely uncharacterized. We therefore used a national database to analyze the acute clinical and financial outcomes associated with the utilization of each conduit.
Methods:
All adult hospitalizations for first-time, isolated, multi-arterial CABG were tabulated from the 2016-2020 Nationwide Readmissions Database. Only patients with a left internal mammary artery conduit and either RA (RA-CABG) or RIMA (RIMA-CABG) conduit were included. Patients who received both RA and RIMA grafts were excluded.
The primary outcome was in-hospital mortality. Secondary endpoints included perioperative complications, postoperative length of stay (LOS), hospitalization costs, and 30-day nonelective readmissions. Mixed regression models were developed to examine the association between RIMA or RA utilization and the outcomes of interest. Due to our large sample size, the significance of intergroup difference was defined as a standardized mean difference (SMD) ≥ 0.10 in place of p-values.
Results:
Of an estimated 62,044 patients, 36,108 (58.2%) received RA-CABG. The proportion of RA-CABG cases increased from 49.5% in 2016 to 64.5% in 2020 (p=0.02). Compared to RIMA-CABG, RA-CABG patients were similar in age (61.7 years ± 9.5 vs 60.7 ± 10.3, SMD=0.099), female distribution (16.6 vs 14.9%, SMD=0.09), and had a higher median Elixhauser Comorbidity Index (4 [3, 5] vs 3 [2, 5], SMD=0.25). Patients receiving RA-CABG were more likely managed at metropolitan teaching hospitals (89.7 vs 82.2%, SMD=0.26). Moreover, RA-CABG were more often elective (50.8 vs 47.9%, SMD=0.103) and on-pump (82.3 vs 77.4%, SMD=0.22), but had a similar number of vessels bypassed (3 [3, 4] vs 3 vessels [3, 4], SMD=0.05).
After adjustment, RA-CABG was associated with reduced odds of mortality, prolonged ventilation (>24 hours), and infectious complications, compared to RIMA-CABG (Figure 1B). RA utilization was also linked with marginally shorter LOS (β -0.04, 95% Confidence Interval (CI) [-0.06, -0.02]), similar costs (β 0.79, 95% CI [-0.80, 2.39]), and reduced likelihood of 30-day nonelective readmission, with RIMA as reference (Figure 1B).
Conclusion:
Patients receiving RA conduits appear to have superior acute clinical outcomes, similar costs, and reduced 30-day readmission rates following multi-arterial CABG, compared to RIMA. As the proportion of RA-CABG increases, propsective studies examining the long-term outcome differences of specific conduits are warranted.