D-dimer is Valuable for Predicting the Extension of Isolated Distal Deep Vein Thrombosis of the Lower Limb in Neurocritical Patients: A Retrospective Observational Study

Abstract

Background: Isolated distal deep vein thrombosis (IDDVT) of the lower limb and its extension to the proximal deep veins have high incidence rates in patients with acute brain injury (ABI). The objective of the study was to determine the value of dynamic changes in coagulation function in predicting the occurrence and extension of IDDVT.Methods: In this retrospective cohort study, ABI patients during the perioperative period in a neurocritical care unit (NICU) of a university hospital were identified from September 2019 to September 2020. Complete compression ultrasound was used by a senior sonographer to diagnose the occurrence and extension of IDDVT. Coagulation function was recorded at a series of time points during the perioperative period.Results: A total of 245 ABI patients were identified, including 46 acute traumatic brain injury patients, 117 acute hemorrhagic stroke patients, 36 acute ischemic stroke patients and 46 acute aneurysmal subarachnoid hemorrhage patients. Most of the patients were elderly and male, and most had severe cases. The rates of IDDVT occurrence and extension were 62% and 21%, respectively. Age, GCS score at admission, NICU length of stay were risk factors for IDDVT occurrence. None of coagulation indices was a sensitive predictor of IDDVT occurrence. The elevation of D-dimer on days 5-7 was the most valuable predictor of IDDVT extension (the area under the ROC was 0.89, with a 95% CI of 0.82-0.95, and the sensitivity and specificity were 0.86 and 0.81, respectively with the cutoff of 8.9 mg/L).Conclusions: The occurrence and extension of IDDVT are common in ABI patients during the perioperative period, particularly in elderly patients with severe cases. D-dimer level on days 5-7 is the most valuable predictor of IDDVT extension in ABI patients.