Home Journal Watch Relation or Influence of RVOTO in the Inflammatory Response to Reoxygenation in Patients with Tetralogy of Fallot

Relation or Influence of RVOTO in the Inflammatory Response to Reoxygenation in Patients with Tetralogy of Fallot

Congenital Heart Disease
Vol.16, No.5, 2021, pp.443-455, doi:10.32604/CHD.2021.015588

Hong Liu, Luyao Ma, Jinghang Li, Bingqi Sun, Siqiang Zheng, Yongfeng Shao

Abstract

Background

This study evaluated differential inflammatory response to cardiopulmonary bypass reoxygenation in tetralogy of Fallot repair. 

Methods

We performed a retrospective study at a cardiovascular center from 2012 to 2018, including 500 patients aged 1 week–18 years who received complete repair of tetralogy of Fallot. Patients were grouped according to tertiles of preoperative RVOT gradient on echocardiography into mild, moderate, and severe stenosis. We measured the highest perfusate oxygenation (PpO2) during aortic occlusion as independent variable. Primary outcome was systemic inflammatory response syndrome (SIRS) within 7 days postoperatively or the time of death or discharge. 

Results

Overall, rate of SIRS was 24.2% without significant differences among three groups (P > 0.05). Older age, male, and smaller indexed left ventricular end-diastolic volume is independent risk factor of SIRS. There were significant interactions between RVOT stenosis and PpO2 on SIRS (P interaction = 0.011): higher PpO2 was associated with a greater SIRS risk among combined moderate and severe stenotic children (OR 1.463 95%CI [1.080, 1.981] per-SD increase, P = 0.014) but not among mild stenotic children (OR 0.900 [0.608, 1.333] per-SD increase; P = 0.600), independent of covariates. 

Conclusion

The association of PpO2 with SIRS was modified by RVOT obstruction severity in tetralogy of Fallot repair. (Clinical Trials gov: NCT03568357)

Keywords

Cardiopulmonary bypass; tetralogy of Fallot; hypoxia/reoxygenation injury; systemic inflammatory response syndrome

Full Article

Commentary

Liu and co-authors have undertaken an interesting and insightful study into the effects of re-oxygenation on the post-operative systemic inflammatory response seen after repair of Tetralogy of Fallot. These cyanotic patients are at risk of oxygen-induced tissue injury when acutely exposed to a higher PaO2 at the time of repair. The authors sought to determine whether there was an association between the severity of RV outflow tract obstruction (RVOTO), highest aortic oxygen tension (PpO2) during cardiopulmonary bypass after application of the aortic cross clamp and the occurrence of a post-operative systemic inflammatory response syndrome (SIRS).

This is a retrospective study including 500 patients who underwent Tetralogy repair over a 7 year period. The overall rate of post-operative SIRS was 24.2% which was similar across groups stratified by severity of RVOTO into mild, moderate and severe. Importantly, patients with more severe RVOTO were older, had higher hemoglobin and hematocrit levels, lower systemic saturations, higher rate of cyanotic spells, smaller indexed LVEDV and higher rates of transannular patch indicating significant baseline differences across groups. Multivariate analysis demonstrated that only older age, male gender and smaller indexed LVED volumes were associated with post-operative SIRS. RVOTO severity was not related to PpO2 as a continuous variable for the risk of post-operative SIRS when RVOTO severity was triple stratified. If the moderate and severe RVOTO groups were combined into a “major” group an association between PpO2, RVOTO severity and risk of SIRS could be demonstrated. This finding suggests that variables other than RVOTO severity and PpO2 are more relevant to the risk of post-operative SIRS such as older age at time of repair and underdevelopment of the LV due to delayed presentation.

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