BACKGROUND

Current guidelines for ischaemic stroke treatment recommend a strict, but arbitrary, upper threshold of 185/110 mm Hg for blood pressure before endovascular thrombectomy. Nevertheless, whether admission blood pressure influences the effect of endovascular thrombectomy on outcome remains unknown. Our aim was to study the influence of admission systolic blood pressure (SBP) on functional outcome and on the effect of endovascular thrombectomy.

METHODS

We used individual patient data from seven randomised controlled trials (MR CLEAN, ESCAPE, EXTEND-IA, SWIFT PRIME, REVASCAT, PISTE, and THRACE) that randomly assigned patients with anterior circulation ischaemic stroke to endovascular thrombectomy (predominantly using stent retrievers) or standard medical therapy (control) between June 1, 2010, and April 30, 2015. We included all patients for whom SBP data were available at hospital admission. The primary outcome was functional outcome (modified Rankin Scale) at 90 days. We assessed the association of SBP with outcome in both the endovascular thrombectomy group and the control group using multilevel regression analysis and tested for non-linearity and for interaction between SBP and effect of endovascular thrombectomy, taking into account treatment with intravenous thrombolysis.

FINDINGS

We included 1753 patients (867 assigned to endovascular thrombectomy, 886 assigned to control) after excluding 11 patients for whom SBP data were missing. We found a non-linear association between SBP and functional outcome with an inflection point at 140 mm Hg (732 [42%] of 1753 patients had SBP <140 mm Hg and 1021 [58%] had SBP ≥140 mm Hg). Among patients with SBP of 140 mm Hg or higher, admission SBP was associated with worse functional outcome (adjusted common odds ratio [acOR] 0·86 per 10 mm Hg SBP increase; 95% CI 0·81-0·91). We found no association between SBP and functional outcome in patients with SBP less than 140 mm Hg (acOR 0·97 per 10 mm Hg SBP decrease, 95% CI 0·88-1·05). There was no significant interaction between SBP and effect of endovascular thrombectomy on functional outcome (p=0·96).

INTERPRETATION

In our meta-analysis, high admission SBP was associated with worse functional outcome after stroke, but SBP did not seem to negate the effect of endovascular thrombectomy. This finding suggests that admission SBP should not form the basis for decisions to withhold or delay endovascular thrombectomy for ischaemic stroke, but randomised trials are needed to further investigate this possibility.

FUNDING

Medtronic.