Upfront perfusion imaging may extend thrombectomy window in acute ischaemic stroke due to LVO

Upfront perfusion imaging may extend time window for endovascular thrombectomy (EVT) beyond 24 hours in patients with acute ischaemic stroke due to large vessel occlusion (LVO-AIS), according to data presented at AIM 2023.

“[Upfront] perfusion imaging helps identify candidates for reperfusion surgery beyond the conventional time window. Time is no longer a boundary [for EVT in LVO-AIS],” said Dr Sze-Ho Ma of Department of Medicine and Therapeutics, the Chinese University of Hong Kong (CUHK).

Upfront perfusion imaging may predict EVT effectiveness in LVO-AIS patients. In a study in 100 LVO-AIS patients selected with pre-EVT imaging ≤6–24 hours of symptom onset, 52 achieved functional independence (modified Rankin Scale [mRS] score, 0–2) at 90 days. Without upfront imaging, only 22 of 100 patients treated ≤12 hours of symptom onset achieved 90-day functional independence. [Int J Stroke 2020;22:377-386; Stroke 2018;49:90-97]

“EVT may benefit [selected] LVO-AIS patients within a time window of nearly 2 days from symptom onset,” Ma noted. In a systematic review and meta-analysis of 7 studies involving 569 LVO-AIS patients with a mean onset-to-puncture (OTP) time of 46.2 hours, 32 percent of patients achieved functional independence at 90 days. The rate of symptomatic intracranial haemorrhage (sICH) was 6.8 percent, with a mortality rate of 27.2 percent. [JAMA Netw Open 2023;6:e2311768]

“LVO-AIS patients with established large infarcts may gain functional recovery from EVT-based therapy,” Ma highlighted. In the randomized, multicentre ANGEL-ASPECT trial of 456 Chinese LVO-AIS patients with a median baseline infarct core volume of 62 mL, the rate of 90-day mRS score of 0–2 was 30 percent with EVT plus medical management vs 11.6 percent with medical management alone (relative risk, 2.62; 95 percent confidence interval; 1.69–4.06). The sICH rate was 6.1 percent vs 2.7 percent, and mortality rate was 21.7 percent vs 20.0 percent. [N Engl J Med 2023;388:1272-1283] Similar results were reported in studies in Japan, America and Europe. [N Engl J Med 2022;386:1303-1313; N Engl J Med 2023;388:1259-1271]

EVT is also effective for AIS due to occlusion of the basilar artery or M2 segment of middle cerebral artery. [N Engl J Med 2022;387:1361-1372; N Engl J Med 2022;387:1373-1384; Ann Neurol 2022;91:629-639; Stroke Vasc Interv Neurol 2023;0:e000664]

“[At Prince Wales Hospital in Hong Kong,] EVT is available for LVO-AIS patients [with salvageable penumbra] and those unable to tolerate intravenous tissue plasminogen activators [tPAs] within 4.5 hours of symptom onset. Additional EVT criteria include mRS score of 0–1 and National Institutes of Health Stroke Scale >6, with optional use of upfront CT perfusion,” Ma said. “Introduction of this EVT protocol since 2020/2021 resulted in a 43 percent shorter door-to-puncture time and 30 percent higher 90-day functional independence.”

“While EVT may provide benefits within an extended window after LVO-AIS onset, timely AIS management remains important,” Ma concluded. “Each hour of OTP delay reduces the likelihood of achieving functional independence by 7.7 percent and discharge to home by 10 percent.” [Circulation 2018;138:232-240; Stroke 2023;54:733-742]