Relative cerebral blood volume is associated with collateral status and infarct growth in stroke patients in SWIFT PRIME

Abstract

We aimed to evaluate how predefined candidate cerebral perfusion parameters correlate with collateral circulation status and to assess their capacity to predict infarct growth in patients with acute ischemic stroke (AIS) eligible for endovascular therapy. Patients enrolled in the SWIFT PRIME trial with baseline computed tomography perfusion (CTP) scans were included. RAPID software was used to calculate mean relative cerebral blood volume (rCBV) in hypoperfused regions, and hypoperfusion index ratio (HIR). Blind assessments of collaterals were performed using CT angiography in the whole sample and cerebral angiogram in the endovascular group. Reperfusion was assessed on 27-h CTP; infarct volume was assessed on 27-h magnetic resonance imaging/CT scans. Logistic and rank linear regression models were conducted. We included 158 patients. High rCBV ( p = 0.03) and low HIR ( p = 0.03) were associated with good collaterals. A positive association was found between rCBV and better collateral grades on cerebral angiography ( p = 0.01). Baseline and 27-h follow-up CTP were available for 115 patients, of whom 74 (64%) achieved successful reperfusion. Lower rCBV predicted a higher infarct growth in successfully reperfused patients ( p = 0.038) and in the endovascular treatment group ( p = 0.049). Finally, rCBV and HIR may serve as markers of collateral circulation in AIS patients prior to endovascular therapy.

Clinical trial registration: Unique identifier: NCT0165746.

Trial registration: ClinicalTrials.gov NCT01657461.

Keywords: Acute ischemic stroke; cerebral blood volume; collateral circulation; perfusion imaging; thrombectomy.

Figure 1.

Boxplots showing the distributions of (a) the rCBV values across cerebral collateral categories as assessed by CTA in the core laboratory (p = 0.08 for all categories and p = 0.008 for excellent vs. poor collaterals) and (b) the rCBV values across cerebral collateral categories as assessed by cerebral angiography in the endovascular group (p = 0.01).

Figure 2.

Boxplots showing the distributions of (a) the HIR values across cerebral collateral categories as assessed by CTA in the core laboratory (p = 0.1 for all categories and p = 0.03 for excellent vs. poor collaterals, respectively) and (b) Boxplots showing the distributions of the HIR values across cerebral collateral categories as assessed by cerebral angiography in the endovascular group (p = 0.5).