Professor LI Gang's team of East Hospital Affiliated to Tongji University, together with Professor Mark Parsons and Dr. LIN Longting of the University of New South Wales in Australia, found a new imaging indicator, namely "growth rate of infarct core", through the analysis of the world's largest acute stroke perfusion imaging database (INSPIRE). It played a potential role in the selection of vascular recanalization treatment for stroke, and provided a new idea for the selection of early vascular recanalization strategy for acute ischemic stroke.
On September 29, 2021, the research achievement "Stroke Patients With Faster Core Growth Have Greater Benefit From Endovascular Therapy" was published in Stroke, a world-class journal in the field of stroke, and the editor in chief distributed an editorial review at the same time, to fully affirm the breakthrough of this achievement. Professor Li Gang of Dongfang Hospital Affiliated to Tongji University and Professor Mark Parsons of the University of New South Wales in Australia were the co-corresponding authors, and Professor Lin Longting of the University of New South Wales in Australia and master's student Zhang Hao of Tongji University were the co-first authors of the paper.
Stroke is a worldwide health problem. About 13.7 million people worldwide suffer from stroke every year, including 5.8 million deaths, which is the second largest cause of death in the world. In China, stroke has become the first cause of death and disability. Its high incidence rate, disability rate and mortality rate have made it become a serious cerebrovascular disease which seriously affects human health and quality of life. Therefore, it is of great significance to explore suitable and effective treatment. Since the American NINDS trial in 1996 confirmed that intravenous thrombolysis with recombinant tissue plasminogen activator (rtPA) could effectively reduce the disability and improve the prognosis of patients with acute ischemic stroke, intravenous thrombolysis has become the main treatment method of acute stroke. In recent years, with the rapid development of neuroimaging (CT, MR, DSA, etc.), intravascular therapy has become one of the important methods for the treatment of stroke.
In the clinical trials on intravascular therapy, the enrolled patients of the two extended time window thrombectomy trials (DAWN and DIFFUSE3) were selected through perfusion imaging, and the effect of intravascular therapy was better than that of the 0-6-hour thrombectomy trials (ESCAPE, EXTEND-IA, MR CLEAN, REVASCAT, SWIFT PRIME). This "late time window paradox" has attracted the attention of many researchers. It is speculated that the slow growth rate of infarct core in the enrolled patients is the possible reason. Based on the above assumptions, the dynamic concept of infarct core growth rate was introduced into clinical evaluation. However, considering that only a few patients in the control group achieved vascular recanalization in the thrombectomy test with expanded time window, the current hypothesis only discusses the comparison between intravascular therapy and traditional drug therapy (no recanalization). This study extends the hypothesis to the comparison of intravascular therapy and intravenous thrombolytic therapy. Based on the world's largest perfusion image database of acute stroke so far, to explore the modification effect of ultra early (0-4.5h) infarct core growth rate on the effect of intravascular therapy and intravenous thrombolysis in acute stroke.
The results show that compared with intravenous thrombolysis, rapid recanalization brought by intravascular therapy may have better clinical benefits by rapidly inhibiting the growth of infarct core. This explains why patients with faster core growth seem to benefit more from intravascular therapy. Intravenous thrombolysis alone (compared with intravascular therapy) has a lower rate of vascular recanalization, and even if recanalization is achieved, the time from onset to vascular recanalization is relatively prolonged. Delayed recanalization will lead to a significant increase in infarct volume in patients with rapid growth of infarct core. In contrast, patients with slow growth of infarct core will not cause significant increase of infarct volume even if the recanalization time is delayed. Therefore, this study suggests that for patients with rapid growth of infarct core, due to the rapid decline of penumbra, vascular recanalization should be achieved by various means as soon as possible, and intravascular therapy is obviously an important means to achieve this goal.
Professor LI Gang's main research direction is prehospital and in-hospital first aid of cerebrovascular diseases and related cognitive impairment. In recent years, he has continuously explored the direction of first aid and imaging data standardization of stroke. In cooperation with Newcastle University of New South Wales, Australia, he has carried out the construction of international stroke imaging database (INSPIRE) as the leading unit in China. At present, he has also undertaken two international and domestic multicenter clinical studies: INTERACT4 (in cooperation with Professor Craig Anderson, a famous scholar in the field of International Stroke) and OPTIMISTIC.
[Abstract]
PURPOSE: This study aimed to explore whether the therapeutic benefit of endovascular thrombectomy (EVT) was mediated by core growth rate.
METHODS: This retrospective cohort study identified acute ischemic stroke patients with large vessel occlusion and receiving reperfusion treatment, either EVT or intravenous thrombolysis (IVT), within 4.5 hours of stroke onset. Patients were divided into 2 groups: EVT versus IVT only patients (who had no access to EVT). Core growth rate was estimated by the acute core volume on perfusion computed tomography divided by the time from stroke onset to perfusion computed tomography. The primary clinical outcome was good outcome defined by 3-month modified Rankin Scale score of 0–2. Tissue outcome was the final infarction volume.
RESULTS: A total of 806 patients were included, 429 in the EVT group (recanalization rate of 61.6%) and 377 in the IVT only group (recanalization rate of 44.7%). The treatment effect of EVT versus IVT only was mediated by core growth rate, showing a significant interaction between EVT treatment and core growth rate in predicting good clinical outcome （interaction odds ratio=1.03[1.01 - 1.05], P=0.007）and final infarct volume（interaction odds ratio=-0.44[-0.87 - -0.01]）.For patients with fast core growth of >25 mL/h, EVT treatment (compared with IVT only) increased the odds of good clinical outcome (adjusted odds ratio=3.62 [1.21–10.76], P=0.021) and resulted in smaller final infarction volume (37.5 versus 73.9 mL, P=0.012). For patients with slow core growth of <15 mL/h, there were no significant differences between the EVT and the IVT only group in either good clinical outcome (adjusted odds ratio=1.44 [0.97–2.14], P=0.070) or final infarction volume (22.6 versus 21.9 mL, P=0.551).
CONCLUSIONS: Fast core growth was associated with greater benefit from EVT compared with IVT in the early <4.5-hour time window.
