Association of perfusate oxygenation with cardiovascular disorder in tetralogy of fallot children: A nested case-control study.

Background: Little is known regarding whether hyperoxic reoxygenation was associated with higher risk of cardiovascular disorder following tetralogy of Fallot repair.

Methods: We performed a nested case-control study among patients aged 1 month-18 years undergoing complete repair of tetralogy of Fallot in 2012-2018. We measured the highest perfusate oxygenation (PpO2) during aortic occlusion in 107 cardiovascular disorder cases and in 321 controls matched 1:3 to the cases on date of surgery, sex, and area of residence. We analyzed the association between PpO2 and outcome using multivariable conditional logistic regression adjusted for covariates. We further identified and integrated the risk covariates to build prediction nomograms.

Results: Cases had higher percentage of exposure to PpO2 > 200 mmHg (86.0% vs. 76.1%, p = .019) than controls. Patients with PpO2 > 200 mmHg had an increased risk of cardiovascular disorder compared to those with PpO2 ≤ 200 mmHg (odd ratio [OR] = 2.075, 95% confidence interval [CI] = 1.035, 4.158, p = .039) adjusted for matching, clinical and procedural covariates. Categorical PpO2, lower body mass index, lower SpO2, untreated minor aortopulmonary collateral arteries, high immediately postoperative central venous pressure, and longer cardiopulmonary bypass time were independent risk factors for cardiovascular disorder (all p < .05). Combining PpO2 nomogram slightly improved discrimination compared with covariate-based nomogram alone for training cohort (area under receiver operating characteristic curve [AUC] = 0.768 vs. 0.761) and for internal validation (AUC = 0.759 vs. 0.753).

Conclusion: Our findings suggest association exists between high PpO2 during aortic occlusion and cardiovascular disorder risk, and nomogram integrating clinical and procedural factors may be useful in management of patients with tetralogy of Fallot.