PC3080: Invasive Mechanical Ventilation and Risk of Hospital-acquired Venous Thromboembolism Among Critically Ill Children: A Mutli-center, Retrospective Cohort Study

Background: Hospital-acquired venous thromboembolism (HA-VTE) is a leading cause of morbidity and mortality among children with an estimated annual incidence of 30 to 106 cases per 10,000 admissions. Routine thromboprophylaxis is recommended for adult patients without contraindication to anticoagulants. Yet, the scarcity of validated HA-VTE risk models in pediatrics limits the capacity to estimate benefit from anticoagulant exposure or outweigh potential complications such as clinically-relevant bleeding. Recent retrospective series suggest invasive mechanical ventilation (MV) independent of other known covariates (e.g., central venous catheterization, hematologic malignancy, acute immobility, and hyperinflammatory conditions) may be a candidate risk factor for HA-VTE (Figure 1). We aimed to estimate the frequencies of, and evaluate associations between, HA-VTE and MV among children hospitalized in the pediatric intensive care unit (PICU).

Methods: We performed a multicenter, retrospective cohort study comparing HA-VTE rates among subjects < 18 years of age hospitalized in the PICU from January 2018 through December 2019 among 47 participating centers, via the Pediatric Health Information Systems registry. We excluded perinatal encounters, those with VTE present at admission, and those with observational status. The primary outcome was the cumulative incidence of HA-VTE during hospitalization including extremity deep venous thrombosis, pulmonary embolism, and organ-specific deep venous thrombosis. Frequencies of HA-VTE were compared using Chi-squared tests. The association between HA-VTE and MV was investigated via multivariable, mixed-effects, logistic regression adjusting for previously described VTE risk factors.

Results: Of the 205,231 PICU encounters identified for study, 70,829 (34.5%) underwent MV. The cumulative incidence of HA-VTE was 2.2% (mean hospital center HA-VTE rate 2.2 ± 0.88% [range: 0.9% to 4.9%]) and was greater among children who received, versus did not receive, MV (4.4% versus 1.1%, p < 0.001). Multivariable logistic regression (Table 1) revealed significant association between MV and HA-VTE (odds ratio 2.51, 95% confidence interval 2.33-2.69; p < 0.001).

Conclusion: In this multicenter, retrospective, registry-based cohort study, HA-VTE was diagnosed in 2.2% of critically-ill children, and after adjustment for central venous catheterization and other known risk-factors, MV independently increased the risk of HA-VTE 2.5-fold. These findings warrant prospective validation to inform the design of future risk-stratified clinical trials of thromboprophylaxis in critically-ill children.