Doppler ultrasonography screening of poor-grade subarachnoid hemorrhage patients increases the diagnosis of deep venous thrombosis.

BACKGROUND: Prophylactic anticoagulation greatly decreases the prevalence of deep venous thrombosis (DVT) in neurosurgical patients. Using Doppler ultrasonography (USG), recent studies demonstrate a 1% DVT detection rate following microsurgery or endovascular treatment for aneurysmal subarachnoid hemorrhage (aSAH). We hypothesize that reported statistics underestimate the DVT detection rate in this high risk cohort by accounting for only symptomatic thromboses. This study utilizes Doppler USG to examine the prevalence of DVT in a large population of aSAH patients and attempts to identify a high-risk subgroup within this cohort.
METHODS: We retrospectively examined 178 aSAH patients who underwent screening lower extremity Dopplers (LEDs) and 57 who did not undergo screening LEDs. All received pharmacologic and mechanical DVT prophylaxis. We analysed DVT prevalence within these two groups and compared rates to the literature. We then segregated patients according to Hunt-Hess grade and determined DVT prevalence within subgroups.
RESULTS: Patients who underwent LED screening demonstrated a 3.4% (6/178) DVT rate, compared to 0% (0/57) in the unscreened cohort. Our screening protocol yielded a thrombosis rate almost triple that reported in the literature (3.4% versus 1.2%). A significantly greater (p<0.05) percentage of screened Hunt-Hess III-V patients (6.5%, 6/93) had positive LEDs compared to Hunt-Hess I-II patients (0%, 0/85).
CONCLUSION: These data suggest that while pharmacologic prophylaxis lowers the prevalence of symptomatic DVTs in aSAH patients, the number of asymptomatic DVTs remains significant, particularly in patients with formidable neurological deficits. While a formal cost-effective analysis is warranted, our data suggest that screening high-risk patients may increase the diagnosis of asymptomatic DVTs and potentially prevent serious medical complications.