Mechanical Thrombectomy Beyond 24 Hours: Not Recommended for 5 Days
Mechanical thrombectomy cannot be routinely performed up to 5 days (120 hours) after stroke onset; current evidence supports treatment only up to 24 hours for anterior circulation strokes with strict imaging criteria, and beyond 24 hours only on a highly selective case-by-case basis with uncertain benefit.
Evidence-Based Time Windows
Anterior Circulation Large Vessel Occlusions
The strongest evidence supports thrombectomy within 24 hours, not 5 days:
0-6 hours: Class I (strongest) recommendation for mechanical thrombectomy plus best medical management in patients with proximal anterior circulation large vessel occlusion 1
6-24 hours: Class I, Level A recommendation when patients meet strict DAWN or DEFUSE-3 imaging criteria, demonstrating salvageable tissue with favorable perfusion mismatch 2, 3
Beyond 24 hours: No established guideline support for routine thrombectomy at this time window 4
Posterior Circulation (Basilar Artery Occlusion)
Even for basilar artery occlusion, which has the most permissive time windows, 5 days is not supported:
0-12 hours: Class I, Level B-R (indicated) for patients with NIHSS ≥6, PC-ASPECTS ≥6 4
12-24 hours: Class IIa, Level B-R (reasonable) with same criteria 4
- BAOCHE trial showed 46% favorable outcomes versus 24% with medical therapy 3
Beyond 24 hours: Class IIb, Level C-EO (may be reasonable on case-by-case basis only), with tremendous uncertainty about benefit 4
- Isolated case reports exist of basilar thrombectomy >48 hours, but functional outcomes are universally poor when recanalization occurs >9 hours in patients with low NIHSS 4
Real-World Data Beyond 24 Hours
The limited evidence beyond 24 hours shows significantly worse outcomes:
A multicenter registry study (STAR) of 121 patients treated beyond 24 hours showed only 18.8% achieved functional independence at 90 days, compared to 34.9% in the 6-24 hour window (p=0.005) 5
Mortality was significantly higher beyond 24 hours (OR 2.34, p=0.023) 5
While symptomatic hemorrhage rates remained similar, the overall benefit-to-risk ratio deteriorates substantially after 24 hours 5
Critical Pitfalls to Avoid
Do not delay treatment hoping to extend the window:
Each 30-minute delay in recanalization reduces probability of good functional outcome by 8-14% 2
The concept of "tissue window" applies only within the validated 24-hour timeframe with appropriate perfusion imaging 6
Do not proceed beyond 24 hours without:
- Documented large vessel occlusion on CTA 4, 2
- Perfusion imaging demonstrating salvageable tissue 2, 3
- NIHSS ≥6 for posterior circulation 4
- Multidisciplinary discussion acknowledging uncertain benefit and higher mortality risk 5
The 5-Day Question: Why It's Not Feasible
No randomized trial has evaluated thrombectomy at 5 days (120 hours):
- The latest evidence extends only to 24 hours with strict imaging selection 7, 6
- By 5 days, the ischemic core is established, penumbra is lost, and the risk of hemorrhagic transformation increases dramatically
- Even the most permissive case reports for basilar occlusion describe treatment at 48-72 hours maximum, not 5 days 4
The answer is definitively no for routine practice at 5 days, with only the 0-24 hour window supported by high-quality evidence.