Early neurological deterioration (END) after thrombolysis occurs in 10% acute ischemic stroke (AIS) patients, and its mechanism remains unclear in majority of cases, named as unexplained END. We tested the hypothesis that penumbra/infarct growth beyond the initial penumbra might be the cause of unexplained END. We reviewed the database of AIS patients who received reperfusion therapy. Unexplained END was defined as ≥ 2-point increase of NIHSS from baseline to 24 h, without straightforward causes. For each unexplained END patient, we extracted 2 matched controls based on 4 clinical and radiological characteristics which were strongly associated with unexplained END. We defined extra-penumbra and extra-infarct as penumbra and infarct growth at 24 h beyond baseline penumbral tissue and then investigated the relationship between extra-penumbra and extra-infarct and the presence of unexplained END. Finally, 44 unexplained END patients and 88 matched controls were included. The volume of both extra-infarct (OR, 1.032 per 1-mL increase; p = 0.018) and extra-penumbra (OR, 1.070 per 1-mL increase; p < 0.001) were associated with the presence of unexplained END, while the absence of recanalization was associated with the presence of either extra-infarct or extra-penumbra (OR, 3.291; p = 0.001). Moreover, 51.4% cases with extra-penumbra at 24 h finally progressed to infarct at 7 days, and they underwent higher increase of NIHSS from 24 h to 7 days than those that did not progress to infarct at 7 days (4.0 vs 1.0; p = 0.017). Penumbra/infarct growth beyond the initial penumbra is involved in the unexplained END in AIS patients receiving reperfusion therapy.
Keywords: Early neurological deterioration; Imaging; Perfusion; Reperfusion therapy.