The rate of infarct core progression in patients with acute ischemic stroke is variable and affects outcome of reperfusion therapy. We evaluated the hypoperfusion index (HI) to estimate the initial rate of core progression in patients with medium vessel occlusion (MeVO) compared to large vessel occlusion (LVO) stroke and within a larger time frame since stroke onset.

Core progression was assessed in 106 patients with acute stroke and CT perfusion. Using reperfusion trial core time criteria, fast progressors had core >70 mL within 6 hours of stroke onset and slow progressors had core ≤70 mL, mismatch ≥15 mL, and mismatch to core ratio ≥1.8 within 6 to 24 hours. The relationship between HI and infarct core progression (core/time) was examined using receiver operating characteristics to determine optimal HI cutoff. The HI cutoff was then tested in the overall cohort, compared between MeVO and LVO, and evaluated in patients up to 24 hours from stroke onset to differentiate fast from slow rate of core progression. HI threshold was assessed in a second independent cohort of 110 patients with acute ischemic stroke.

In 106 patients with acute stroke, 6.6% were fast progressors, 27.4% were slow progressors, and 66% were not classified as fast or slow progressor by reperfusion trial core time criteria. HI >0.5 was associated with fast progression and able to distinguish fast from slow progressors (area under the curve [AUC] 0.94; 95% confidence interval [CI] 0.80–0.99). In MeVO (n = 26) HI >0.5 had a core progression of 0.30 mL/min compared to 0.03 mL/min for HI ≤0.5 (p < 0.001). In LVO (n = 80), HI >0.5 had a core progression of 0.26 mL/min compared to 0.02 mL/min for HI ≤0.5 (p < 0.001). In patients not classified as fast or slow progressor by reperfusion trial criteria, those with HI >0.5 had progression rate of 0.21 mL/min compared to 0.03 mL/min for those with HI ≤0.5 (p < 0.001). Validation in a second cohort of patients with acute ischemic stroke (n = 110; MeVO = 42, LVO = 68) yielded similar results for HI >0.5 to distinguish fast and slow core progression with an AUC of 0.84 (95% CI 0.72–0.97).

HI can differentiate fast from slow core progression in MeVO and LVO within the first 24 hours of acute ischemic stroke. Consideration of core progression rate at time of stroke evaluation may have implications in the selection of patients with MeVO and LVO stroke for reperfusion therapy that warrant further study.

急性缺血性卒中患者的梗塞核心进展率是可变的，并影响再灌注治疗的结果。我们评估了低灌注指数（HI），以估计中血管闭塞（MeVO）患者与大血管闭塞（LVO）卒中患者相比以及卒中发作后较长时间内的核心进展初始率。

对 106 名急性卒中和 CT 灌注患者的核心进展进行了评估。使用再灌注试验核心时间标准，快速进展者在卒中发作 6 小时内核心 >70 mL，缓慢进展者在 6 至 24 小时内核心 ≤70 mL，错配 ≥15 mL，错配与核心比率 ≥1.8。使用接受者操作特征检查 HI 和梗塞核心进展（核心/时间）之间的关系，以确定最佳 HI 截止值。然后在整个队列中测试 HI 截止值，比较 MeVO 和 LVO，并在中风发作后 24 小时内对患者进行评估，以区分核心进展速度快慢。在由 110 名急性缺血性中风患者组成的第二个独立队列中评估了 HI 阈值。

在 106 名急性卒中患者中，6.6% 为快速进展者，27.4% 为慢速进展者，66% 未按再灌注试验核心时间标准分类为快速或慢速进展者。 HI >0.5 与快速进展相关，并且能够区分快速进展者和缓慢进展者（曲线下面积 [AUC] 0.94；95% 置信区间 [CI] 0.80–0.99）。在 MeVO (n = 26) 中，HI >0.5 的核心进展为 0.30 mL/min，而 HI ≤ 0.5 的核心进展为 0.03 mL/min ( p < 0.001)。在 LVO (n = 80) 中，HI >0.5 的核心进展为 0.26 mL/min，而 HI ≤ 0.5 的核心进展为 0.02 mL/min ( p < 0.001)。在再灌注试验标准未分类为快速或慢速进展者的患者中，HI >0.5 的患者的进展率为 0.21 mL/min，而 HI ≤ 0.5 的患者的进展率为 0.03 mL/min ( p < 0.001)。在第二组急性缺血性中风患者（n = 110；MeVO = 42，LVO = 68）中进行的验证对于 HI >0.5 产生了相似的结果，以区分快速和缓慢的核心进展，AUC 为 0.84（95% CI 0.72） –0.97）。

HI 可以在急性缺血性中风的前 24 小时内区分 MeVO 和 LVO 的快速核心进展和缓慢核心进展。在卒中评估时考虑核心进展率可能会对选择 MeVO 和 LVO 卒中患者进行再灌注治疗产生影响，值得进一步研究。