Impact of prior intravenous thrombolysis on first-line thrombectomy strategy. A secondary analysis of the VECTOR...

Whether prior intravenous thrombolysis (IVT) modifies the relative efficacy of first-line thrombectomy strategies remains uncertain, and no randomised trial has specifically addressed this question. Leveraging the randomised design of the VECTOR trial, a multicentre trial comparing first-line contact aspiration (CA) vs CA plus stent retriever (SR + CA) in patients with anterior LVOs and a positive susceptibility vessel sign, we assessed whether IVT status modified the association between thrombectomy strategy and reperfusion outcomes.

We performed a secondary analysis of the VECTOR trial, in which patients were stratified according to prior IVT use. The primary outcome was near-complete or complete reperfusion (expanded thrombolysis in cerebral infarction [eTICI] 2c-3) after ≤ 3 passes with the assigned first-line technique and before rescue therapy. Secondary outcomes included first-pass reperfusion, complete reperfusion after ≤ 3 passes, final reperfusion at the end of the procedure and functional outcomes at 90 days.

Between 26 November 2019 and 14 February 2022, 521 patients were included in VECTOR. Of these, 288 (55%) received IVT before thrombectomy. The effect of first-line strategy on the primary outcome did not differ according to IVT status (P for heterogeneity = .28). Among IVT-treated patients, eTICI 2c-3 after ≤ 3 passes occurred in 88/144 patients (61.1%) assigned to SR + CA vs 74/144 (51.3%) assigned to CA (aOR, 1.50 [95% CI, 0.91-2.45]). Among patients without IVT, corresponding rates were 64/119 (53.9%) vs 61/114 (53.6%) (aOR, 1.00 [95% CI, 0.58-1.72]). Interaction tests were non-significant for all other angiographic, clinical and safety outcomes except final complete reperfusion, which favoured CA in patients without IVT (P for heterogeneity = .019).

Prior IVT did not significantly modify the effect of first-line strategy on early reperfusion, and both CA and SR + CA remained valid approaches irrespective of IVT status. The isolated interaction for final complete reperfusion, favouring CA in patients without IVT, was exploratory and may reflect chance. A hypothesis-generating mechanism is plausible in this SVS-positive, red blood cell-rich phenotype: CA applied to an intact clot may favour en-bloc retrieval, an advantage attenuated once alteplase softens the thrombus. These results, obtained almost exclusively under alteplase and in an MRI-selected population with mandatory balloon guide catheter use, may not extend to tenecteplase or CT-selected patients.

In this secondary analysis of the VECTOR trial, prior IVT did not significantly modify the association between first-line thrombectomy strategy and successful reperfusion. The observed angiographic differences remain exploratory and warrant further investigation.