CLEAR LVO
(2022)Objective
To determine whether advanced imaging selection (CT perfusion or MRI) is associated with reperfusion without functional independence (RFI), symptomatic ICH, or mortality in stroke patients treated with thrombectomy in the extended time window (6–24 hours).
Study Summary
• Imaging modality (CT vs CTP vs MRI) did not impact RFI, sICH, or mortality
• Age, NIHSS, and prestroke disability were key predictors of poor outcomes
Intervention
Multicenter retrospective cohort of 715 patients from the CLEAR registry with proximal anterior circulation occlusion stroke treated with thrombectomy 6–24 hours after last seen well. All had mTICI 2c–3 reperfusion. Compared outcomes based on imaging modality used for selection (CT, CTP, or MRI).
Inclusion Criteria
• NIHSS ≥6
• ICA or M1/M2 occlusion
• Prestroke mRS 0–2
• Time-last-seen-well to treatment 6–24 hours
• mTICI 2c or 3 reperfusion
Study Design
Arms: CT vs CTP vs MRI imaging selection
Patients per Arm: 229 CT, 341 CTP, 145 MRI
Outcome
• No difference in RFI by imaging type (adjusted OR CTP vs CT 1.11 [0.68–1.81] p=0.664; MRI vs CT 0.73 [0.49–1.08] p=0.115)
• sICH not associated with imaging (CTP vs CT 0.77 [0.31–1.94]; MRI vs CT 0.71 [0.22–2.25]); hypertension predicted sICH (OR 2.41 [1.16–5.03] p=0.019)
• Mortality not associated with imaging (CTP vs CT 1.48 [0.77–2.83]; MRI vs CT 1.04 [0.67–1.63]); age, NIHSS, prestroke mRS, and transfer predicted mortality (transfer OR 2.32 [1.65–3.27] p<0.0001)
Bottom Line
Imaging modality (CT, CTP, MRI) did not influence the likelihood of RFI, sICH, or mortality after thrombectomy in the extended window. Risk was more dependent on age, stroke severity, and prestroke disability.
Major Points
- Multicenter retrospective analysis of 715 patients with anterior circulation stroke treated with thrombectomy 6–24 hours from last seen well
- All patients achieved mTICI 2c or 3 reperfusion
- 50.9% experienced RFI (mRS 3–6 at 90 days)
- No significant difference in RFI by imaging modality (CT, CTP, MRI)
- Older age, higher NIHSS, and higher prestroke mRS predicted both RFI and mortality; longer TLSW-to-puncture independently predicted RFI (but not mortality), and transfer to a comprehensive stroke center predicted both
- Hypertension was associated with symptomatic ICH
Study Design
- Study Type
- Multicenter retrospective cohort
- Randomization
- No
- Blinding
- Unblinded
- Sample Size
- 715
- Follow-up
- 90 days
- Centers
- 15
Primary Outcome
Definition: Reperfusion without functional independence (mRS 3–6 at 90 days after mTICI 2c/3)
| Control | Intervention | HR/OR | P-value |
|---|---|---|---|
| 50.9% overall | No difference by imaging modality (CTP vs CT adj OR 1.11 [0.68–1.81]; MRI vs CT 0.73 [0.49–1.08]) | - (CTP vs CT: 1.11 (0.68–1.81); MRI vs CT: 0.73 (0.49–1.08)) | CTP vs CT p=0.664; MRI vs CT p=0.115 |
Limitations & Criticisms
- Retrospective, nonrandomized design
- Imaging modality choice was site-dependent and not standardized
- No data on patients not undergoing thrombectomy
- No core/perfusion imaging parameters included
- No adjustment for postprocedural variables like infarct size or anesthesia
Citation
Stroke. 2022;53:3594–3604. doi:10.1161/STROKEAHA.122.039476