Effects of low versus high inspired oxygen fraction on myocardial injury after transcatheter aortic valve implantation: A randomized clinical trial

BACKGROUND: Oxygen therapy is used in various clinical situation, but its clinical outcomes are inconsistent. The relationship between the fraction of inspired oxygen (F(I)O(2)) during transcatheter aortic valve implantation (TAVI) and clinical outcomes has not been well studied. We investigated the association of F(I)O(2) (low vs. high) and myocardial injury in patients undergoing TAVI. METHODS: Adults undergoing transfemoral TAVI under general anesthesia were randomly assigned to receive F(I)O(2) 0.3 or 0.8 during procedure. The primary outcome was the area under the curve (AUC) for high-sensitivity cardiac troponin I (hs-cTnI) during the first 72 h following TAVI. Secondary outcomes included the AUC for postprocedural creatine kinase-myocardial band (CK-MB), acute kidney injury and recovery, conduction abnormalities, pacemaker implantation, stroke, myocardial infarction, and in-hospital mortality. RESULTS: Between October 2017 and April 2022, 72 patients were randomized and 62 were included in the final analysis (n = 31 per group). The median (IQR) AUC for hs-cTnI in the first 72 h was 42.66 (24.82–65.44) and 71.96 (35.38–116.34) h·ng/mL in the F(I)O(2) 0.3 and 0.8 groups, respectively (p = 0.066). The AUC for CK-MB in the first 72 h was 257.6 (155.6–322.0) and 342.2 (195.4–485.2) h·ng/mL in the F(I)O(2) 0.3 and 0.8 groups, respectively (p = 0.132). Acute kidney recovery, defined as an increase in the estimated glomerular filtration rate ≥ 25% of baseline in 48 h, was more common in the F(I)O(2) 0.3 group (65% vs. 39%, p = 0.042). Other clinical outcomes were comparable between the groups. CONCLUSIONS: The F(I)O(2) level did not have a significant effect on periprocedural myocardial injury following TAVI. However, considering the marginal results, a benefit of low F(I)O(2) during TAVI could not be ruled out.