Incidence and Risk Model of Venous Thromboembolism in Patients with Aneurysmal Subarachnoid Hemorrhage

OBJECTIVE: Venous thromboembolism (VTE) is a signifi-cant source of morbidity and mortality in hospitalized pa-tients. We describe our experience with VTE prophylaxis and treatment in patients with aneurysmal subarachnoid hemorrhage (aSAH), risk factors for VTE, and a hazard model describing the daily risk of VTE.METHODS: A retrospective cohort study was performed on patients with aSAH admitted from 2014 to 2018. Patients were screened for VTE based on clinical suspicion. De-mographics, perioperative data, and in-hospital data were assessed as risk factors for VTE using survival analysis with death as a competing risk.RESULTS: Among 485 patients, the overall incidence of VTE, deep vein thrombosis, and pulmonary embolism were 5.6%, 4.3%, and 2.3%, respectively. Increasing length of stay in the intensive care unit (hazard ratio [HR], 1.79; P < 0.0001; 95% confidence interval [CI], 1.49-2.16) and ventilation immediately after aneurysm treatment was associated with VTE (HR, 8.87; P < 0.01; 95% CI, 1.86-42.38). Hunt and Hess grade was negatively associated with VTE (HR, 0.61; P [ 0.045; 95% CI, 0.37-1.00) due to its increased association with the competing risk of death (HR, 2.57; P < 0.0001; 95% CI, 1.89-3.49). The adjusted 4-year cumulative incidence for VTE is 11.1% and at mean day of hospital discharge is 5.4%. Treatment of VTEs with anticoagulation and/or inferior vena cava filter placement was not associated with immediate complications.CONCLUSIONS: We describe the largest single -institution cohort of VTEs in aSAH patients. Our hazard model quantifies the cumulative incidence of VTEs during the course of hospitalization. We suggest a standardized protocol for screening, prophylaxis, and treatment of VTEs in this patient population.