Abstract 005: Outcomes of Heparin Induced Thrombocytopenia Type II in Aneurysmal Subarachnoid Hemorrhage Patients
Authors: Subah Galadu , Lui Aiden K. , Lin Fangyi , Hosein‐Woodley Rasheed , Uddin Anaz , Naftchi Alexandria , Soldozy Sauson , Gandhi Chirag D. , Al‐Mufti Fawaz 
Published: March 2024

Introduction
Heparin‐induced thrombocytopenia (HIT) is a rare complication characterized by a decreased platelet count and hypercoagulability following heparin and light‐molecular weight heparin administration. Both anticoagulants can be used intraoperatively and postoperatively for DVT prophylaxis in patients undergoing subarachnoid hemorrhage (SAH) treatment. Patients with SAH are an understudied population in terms of assessing incidence and impact of HIT. This study aims to investigate the incidence, complications, and outcomes of SAH patients who develop HIT.

Methods
ICD‐9‐CM and ICD‐10‐CM codes were used to query the National Inpatient Sample for patients with SAH between 2010 and 2019. Subgroup analysis was stratified by HIT development. SAH severity was determined using the National Institute of Health Stroke Scale as a template. Patients from both groups were assessed for baseline clinical characteristics, comorbidities, interventions, complications, and outcomes. Cohorts containing ten or fewer patients must only be described qualitatively. Descriptive statistics, multivariate regressions, and propensity score‐matching were all performed using IBM SPSS 28.

Results
76,387 patients were diagnosed with SAH between 2010 and 2019. 166 (.22%) had developed HIT in response to anticoagulant administration. The incidence of HIT was higher in patients who were younger (58.04 vs 61.39, p = 0.01), obese (0.4% vs 0.2%, p < 0.01), on long‐term anticoagulant use (10.84% vs 5.72%, p < 0.01), and had an implanted cerebrospinal fluid drainage device (p < 0.01). Patients with HIT were associated with higher SAH severity (1.42 vs 1.06, p < 0.01). Through both the complete cohort and propensity score‐matched cohort, patients with HIT were associated with higher rates of endovascular coiling, external ventricular drain placement (p < 0.01), and ventriculoperitoneal shunt placement (p < 0.01). HIT patients had significantly higher rates of deep vein thrombosis (p < 0.01), pulmonary embolism (p < 0.01), central venous sinus thrombosis (p = 0.01), pneumonia (p < 0.01), urinary tract infection (p < 0.01), acute kidney injury (p < 0.01), and cerebral vasospasm (p < 0.01). Patients who develop HIT had a longer length of stay (LOS) (24.04 vs 10.48, p < 0.01). HIT continued to be a significant predictor of having an above average LOS (OR: 6.799, CI: 3.985 ‐ 11.6, p < 0.01) when controlling for age, SAH severity, and significant comorbidities.

Conclusion
Our study revealed that younger SAH patients with various comorbidities are more prone to developing HIT, leading to higher rates of thrombotic events, acute kidney injury, and nosocomial infections, which can significantly prolong their hospital stay. Considering the extended postoperative recovery period for SAH, investigating the causes of HIT can facilitate earlier detection and prevention of thrombotic complications. This nationwide, multicenter, retrospective study provides valuable insights for clinicians on how to prevent and manage HIT in patients with subarachnoid hemorrhage.