Antiplatelet Usage Impacts Clot Density in Acute Anterior Circulation Ischemic Stroke

Abstract

We explored whether clot density in middle cerebral artery (MCA) occlusion is related to clinical variables, stroke etiology, blood constituents, and prestroke medication. We performed a retrospective chart review of patients with acute ischemic stroke of the anterior circulation admitted to two Central European stroke centers. The acquisition of non-contrast enhanced CT (NECT) and CT angiography (CTA) within 4.5 h of symptom onset was obligatory. We assessed the site of MCA occlusion as well as density, area, and length of the clot in 150 patients. The Hounsfield unit values for the clot were divided with contralateral MCA segment to yield relative Hounsfield Unit ratio (rHU). The site of the vessel occlusion (M1 vs. M2) and antiplatelet usage, but not stroke etiology, significantly influenced rHU. We found an inverse correlation of rHU with erythrocyte count (p < 0.001). The multivariate analysis revealed that a higher rHU (i.e., clot being more hyperdense) was more likely with the use of antiplatelets (OR 4.24, CI 1.10–16.31, p = 0.036). Erythrocyte (OR 0.18, CI 0.05–0.55, p = 0.003), and thrombocyte counts (OR 0.99, CI 0.98–0.99, p = 0.029) were associated with odds for more hypodense clots (lower rHU). Our study disclosed that antiplatelet therapy impacts the composition of intracranial clots of the anterior circulation.

Proximal flow to middle cerebral artery is associated with higher thrombus density in terminal internal carotid artery occlusion

“…Briefly, the leptomeningeal collateral pattern was graded by using a three‐category ordinal variable (absent, less, or equal to the unaffected contralateral hemisphere). The methods for the determining MCA thrombus characteristics were reported previously 7, 8. Briefly, we quantified density, area, and length of the thrombus on NECT images and confirmed the findings with the CTA results.…”

“…Brain imaging with NECT was in all cases followed immediately with CTA. Details of the scanners and imaging protocols were reported previously 7, 8. Cervical ICA occlusion was present if the thrombus extended from the carotid bulb to the level of the petrosal bone.…”

“…Several studies confirmed that a higher thrombus density is associated with improved reperfusion rates and better outcome, regardless of systemic or endovascular recanalization techniques 3, 4, 5, 6. Thrombus density can be determined noninvasively on noncontrast enhanced CT (NECT) and was shown to be dependent on source, time, and hematocrit, and is altered by treatment with antiplatelets 7, 8. In patients with ICA occlusion, collateral circulation may play an important role in the severity of ischemic lesions 9.…”

Endovascular Therapy for Tandem Occlusion in Acute Ischemic Stroke: Intravenous Thrombolysis Improves Outcomes

“…The inclusion criteria were acute anterior circulation ischemic stroke within 6 h of symptom onset, ≥18 years of age, CT-angiography (CTA) confirmed TIM occlusion defined as ICA occlusion (extra- or intracranial) combined with occlusion of the MCA (M1 or M2), with a plan to perform stent-retriever based EVT [18]. Details of the scanners and imaging protocols were reported previously [19].…”

“…A repeat computer tomography / magnetic resonance imaging (CT/MRI) within 24 h after the procedure was used to determine the presence of symptomatic intracerebral hemorrhage (sICH). Follow-up CT scans performed between 24 h and 7 days were analyzed to determine the final infarct volume (FIV) using previously reported methodology [7,19]. Additional variables included demographic and laboratory data, as well as the National Institutes of Health Stroke Scale (NIHSS) on admission and at discharge.…”