Abstract 128: Risk Factors for Hospital-associated Venous Thromboembolism in Critically-ill Children with Cardiac Disease Undergoing Cardiothoracic Surgery or Cardiac Catheter-based Therapeutic Intervention

Abstract

Background: Pediatric hospital-acquired venous thromboembolism (HA-VTE) has dramatically risen in recent years. Children with congenital or acquired heart disease are at particular risk and have not been addressed by recent, novel retrospectively-derived risk scores. Aims: We sought to develop a risk model for HA-VTE in critically-ill children with cardiac disease. Methods: We conducted a retrospective, case-control study of children admitted to the CVICU at All Children's Hospital Johns Hopkins Medicine (St. Petersburg, FL, USA) from January 2006 - April 2013. We identified cases via ICD-9 codes, and employed case validation via review of radiologic records. Two controls were randomly selected for each case. Associations between putative risk factors and HA-VTE were estimated using odds ratios (ORs) and ninety-five percent confidence intervals (95%CIs) from univariate and multivariate logistic regression analyses. Variables with P-values < 0.1 in univariate analyses were included in the multivariate model. A HA-VTE risk score was developed with weighting based on the relative magnitudes of the individual ORs from the multivariate model. Results: After adjustment in a multiple logistic regression, length of stay (LOS) >30 days, cardiac catheterization, and major infection were found to be statistically-significant independent risk factors for HA-VTE in these children. An 8-point risk score was developed in which scores of 0-1, 2-6, and 7-8 yielded HA-VTE risks of < 1%, 1-< 2%, and ≥2%, corresponding to conventional thresholds for instituting no prophylaxis, mechanical prophylaxis, and pharmacological prophylaxis (respectively) in hospitalized adults. Conclusions: LOS >30 days, cardiac catheterization, and major infection are significant independent risk factors for HA-VTE in critically-ill children with cardiac disease leading to the development of a novel HA-VTE risk score in this population. If prospectively validated, this risk score will inform the design of risk-stratified clinical trials of HA-VTE prevention.