No-reflow phenomenon in acute ischemic stroke: an angiographic evaluation

Background Futile recanalization (FR) is de fined as a poor 90-day outcome or lack of neurological improvement at 24 h despite successful recanalization in acute ischemic stroke (AIS) with large vessel occlusion (LVO) treated by mechanical throbectomy (MT). The No-reflow phenomenon (NRP) could be a possible cause of FR, but its evidence in AIS patients is scarce. Methods We retrospectively analyzed 185 digital subtraction angiographies (DSA) of AIS patients with anterior circulation LVO after endovascular treatment. To better define NRP, we designed a score called the modified capillary index score (mCIS). The score is obtained by dividing the middle cerebral artery territory in three segments. For each segment, we gave 2 points if the capillary blush was present without any delay, 1 if delayed, and 0 if absent. The primary endpoint was to use mCIS to identify NRP on post-interventional DSA and to test whether this marker may predict FR and failure of early neurological improvement (fENI). The secondary endpoint was to search for a correlation between NRP, lesion volume, and hemorrhagic transformation. We used the ROC curve to define mCIS ≤ 3 as the cut-off and marker of NRP. Results NRP was present in 35.1% of patients. NRP predicted fENI at 24 h (aOR 2.825, 95% CI 1.265–6.308, P = 0.011) and at 7 days (aOR 2.191, 95% CI 1.008–4.762, P = 0.048), but not 90-day FR. Moreover, NRP predicted hemorrhagic transformation (aOR 2.444, 95% CI 1.266–4.717, P = 0.008). Conclusions The modified capillary index score (mCIS) seems useful in identifying NRP in AIS. In addition, mCIS was able to predict NRP that correlated with early clinical outcome and hemorrhagic transformation of the ischemic lesion. An external validation of the score is warranted. Graphical Abstract