After large-vessel occlusion (LVO), blood flow to the ischemic penumbra largely depends on collateral perfusion. Intraprocedural BP reductions have been associated with infarct growth and unfavorable functional outcome. We hypothesized that patients with poor collateral circulation assessed using CT perfusion and CTA imaging are at increased risk for infarct progression associated with intraprocedural BP reductions.

To examine the relationship between poor collateral circulation and sensitivity to blood pressure (BP) reductions during endovascular therapy (EVT).

We prospectively enrolled 111 patients with LVO stroke who underwent EVT at two comprehensive stroke centers. Volumes of arterial tissue delay >10 seconds (ATD10) were estimated with RAPID software; in accordance with previous studies, malignant perfusion profile was defined as ADT10 >100 ml. Collaterals were independently scored on CTA images using the Miteff and rLMC systems. BP reduction was defined as the difference between admission BP and lowest intraprocedural BP; both systolic blood pressure (SBP) and mean arterial pressure (MAP) reductions were measured. Infarct progression was defined as the difference between follow-up MRI infarct volume and RAPID-assessed CBF<30% core infarct volume.

Seventy-nine patients (mean age 69±14, 47F, mean NIHSS 16) who were successfully revascularized (TICI 2B/3) were included in analysis. Mean baseline MAP was 106±19 mmHg; median MAP reduction was 21 (IQR 5-37). Malignant perfusion profile (n=21) was an independent predictor of infarct progression after adjusting for age, sex, admission NIHSS, and time to EVT (mean 40 vs. 22 ml, p=0.019). A significant interaction was found between SBP reduction and both malignant profile (p=0.01) and collateral status (p=0.03, Miteff; p=0.07, rLMC). For every 10 mmHg MAP reduction, patients with poor versus excellent collaterals experienced an average infarct growth of 7 ml versus 1 ml, respectively.

Patients with malignant perfusion profiles and poor collaterals are at significantly higher risk of infarct progression related to intraprocedural BP reduction.