Individualized intravenous thrombolytic strategy for acute ischemic stroke with large vessel occlusion on the era of mechanical thrombectomy: cases report

A 67-year-old male presented with sudden left limbs deficit was admitted to our hospital at 33 min after symptom onset. Non-contrast head CT was performed immediately (multimodal CT scan was not available at that time) and revealed no intracranial hemorrhage but with high- density on the right middle cerebral artery (MCA) M1 segment (Fig. 1a). The National Institute of Health Stroke Scale (NIHSS) scored 14, and the patient was treated with IVT (rtPA 0.9 mg/kg × 78 kg) that followed by digital subtraction angiography (DSA). The first image of DSA showed that the right MCA M1 segment was occluded with a score of American Society of Interventional and Therapeutic Neuroradiology collateral grading (ACG) system 3 (Fig. 1b and c). However, the M1 segment was recanalization 6 min after the first DSA image, and the residual thrombus had immigrated to the M2 segment (Fig. 1d and e). Fortunately, the vessel achieved complete recanalization after another 5 min without any endovascular treatment in the whole process (Fig. 1f). Therefore, IVT was terminated in advance with a total dose of 42 mg (3/5 standard-dose, 0.54 mg/kg individually). The door-to-needle time (DNT), door-to-puncture time, onset-to-needle time, and onset-to-reperfusion time were 30 min, 58 min, 63 min, and 106 min, respectively. Immediate result of Dyna-CT scan (Artis zee biplane, Siemens, Germany) confirmed no intracranial hemorrhage (Fig. 1g), and the NIHSS score decreased to 1 at 24 h. However, asymptomatic intracranial hemorrhage in the infarction area was detected by the non-contrast CT imaging at 24 h, with class 3 of the Heidelberg Bleeding Classification [17] (Fig. 1h). Finally, the modified Rankin Score (mRS) of the patient at 90 days was 0.

An 80-year-old male presented with sudden slurred speech and weakness of the right limbs was sent to our hospital at 102 min after the symptom onset. The pre-procedure NIHSS score was 14 and a multimodal CT was performed. There was no intracranial hemorrhage and significant infarcted territory on non-contrast CT imaging. However, the CT angiography showed occlusion of the upper branch of left MCA M1 segment with lower perfusion that was revealed by cerebral blood volume and cerebral blood flow on CT perfusion (Fig. 2a–c). The patient received stenting of the responsible artery to assist coil embolization of an unruptured bifurcation aneurysm 2 months ago (Fig. 2d) and took aspirin (Bayer, Germany) 100 mg/day before stroke. As the patient was still within the thrombolytic time window, we administered rtPA (0.9 mg/kg × 60 kg) and performed DSA immediately. The DSA showed that the part of forward blood flow had recovered, but thrombus was still on the ostium of the artery (Fig. 2e). Then, IVT was continued and the occluded artery was recanalized to modified thrombolysis in cerebral infarction (mTICI) 3 (Fig. 2f and g) 15 min later without any endovascular intervention. Then, we stopped IVT when the total dose of rtPA was 45 mg (5/6 standard dose, 0.75 mg/kg individually). But the symptom was not improved, and the NIHSS score was still 14. The DNT, door-to-puncture time, onset-to-needle time, and onset-to-reperfusion time were 35 min, 63 min, 137 min, and 182 min, respectively. Non-contrast CT imaging showed hemorrhagic transformation (HT) with class 2 of the Heidelberg Bleeding Classification and PH2 of ECASS II [18] at 24 h (Fig. 2h). The location of HT was similar with the lower perfusion territory on the CT perfusion scan before IVT. Although the intracranial hemorrhage was absorbed within 1 week, clinical symptoms were not recovered, and the mRS was 4 at 90 days.