Impact of Thrombus Length on Outcomes After Intra-Arterial Aspiration Thrombectomy in the THERAPY Trial

Abstract

Background and Purpose-Increasing thrombus length (TL) impedes recanalization after intravenous (IV) thrombolysis.We sought to determine whether the clinical benefit of aspiration thrombectomy relative to IV r-tPA (recombinant tissuetype plasminogen activator) may be greater at longer TL. Methods-THERAPY was a randomized trial of aspiration thrombectomy plus IV r-tPA versus IV r-tPA alone in largevessel stroke patients with prospective TL measurement ≥8 mm. In this post hoc study, we evaluated the association of TL with trial end points and potential endovascular treatment effect, using univariate, multivariable, and multiplicative interaction analyses. Results-TL data were available for all 108 patients (28% internal carotid artery, 62% M1, and 10% M2). Median TL was 14.0 mm (interquartile range, 9.7-19.5 mm). Longer TL was associated with worse outcome (90-day modified Rankin Scale score: odds ratio, 1.24 per 5-mm TL increment; 95% confidence interval, 1.04-1.52; P=0.02), even after adjusting for key outcome predictors (adjusted P=0.004). Longer TL was also associated with more serious adverse events (adjusted P=0.01), more symptomatic hemorrhages (adjusted P=0.03), and increased mortality (adjusted P=0.01). No significant relationship was observed between TL and angiographic reperfusion (modified thrombolysis in cerebral ischemia 2b-3), but greater TL was associated with longer endovascular procedural times (ρ=0.36; P=0.045). Increasing TL was associated with greater aspiration thrombectomy treatment effect (interaction term P=0.03). This might be related to a potentially stronger adverse effect of increasing TL on 90-day modified Rankin Scale for patients treated with IV r-tPA (ρ=0.39; P=0.01) compared with intra-arterial therapy (ρ=0.20; P=0.165). Conclusions-Ischemic stroke patients with longer symptomatic thrombi have worse 90-day clinical outcomes but may have a greater relative benefit of aspiration thrombectomy over IV r-tPA alone. Clinical Trial Registration-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01429350.

Large Vessel Occlusion Secondary to COVID-19 Hypercoagulability in a Young Patient: A Case Report and Literature Review

“…Although there are conflicting data, 13À15 clot length has been associated with decreased reperfusion rate and worse outcome. 16 In fact, the odds ratio for worse outcomes increases by 1.24 for every 5 mm increment over 14 mm. 16 An independent risk factor for stroke (odds ratio 3.4À14.5 17 ) is an inflammation-driven 18 hypercoagulable and vasculopathic state 19 from recent infection, especially respiratory in origin.…”

Clot Burden Score and Collateral Status and Their Impact on Functional Outcome in Acute Ischemic Stroke

“…7,10 Besides, longer thrombi may be more difficult to retrieve, requiring more attempts and prolonging the procedural time. 7,31 Few studies have assessed the relation between collateral status and clot extent and the role of collateral status in the association of clot extent with functional outcome. 13,14 Our findings are in accordance with previous studies in which patients with poor baseline collaterals had longer clots.…”

Does Clot Burden Score on Baseline T2*-MRI Impact Clinical Outcome in Acute Ischemic Stroke Treated with Mechanical Thrombectomy?

“…In the ESCAPE trial, Puetz et al [22] demonstrated an increase in benefit from MT for lower CTA-CBS, i.e., longer thrombus, when compared with higher CTA-CBS. Similarly, in a post hoc analysis of 108 patients included in the THERAPY trial [14], longer thrombi, as defined on CTA, were independently associated with worse clinical outcomes. Furthermore, in adjusted analyses of 90-day ordinal mRS, there was a 33% relative increase in the likelihood of a worse outcome with every 5-mm increase in thrombus length and the relative benefit of MT compared with IVT alone increased with thrombus length [14].…”

“…Amongst factors influencing recanalization success, clot length is an important determinant [10-12], that was scarcely assessed in the recent RCTs. Indeed, if patients were included in case of LVO on computed tomography angiography (CTA), only few studies [13,14] assessed clot length using the CTA-defined clot burden score (CTA-CBS). These analyses demonstrated a direct link between clot length, likelihood of recanalization, final infarct volumes, and 3-month neurological outcome.…”