Management of Acute Ischemic Stroke at 12 Hours with Proximal Anterior Circulation Occlusion
The most appropriate next step is combined tPA and mechanical thrombectomy (Option D), provided the patient meets specific imaging criteria demonstrating salvageable tissue with a small to moderate infarct core. 1
Rationale for Combined Therapy at 12 Hours
At 12 hours from symptom onset, this patient falls beyond the standard 4.5-hour window for tPA alone but remains within the extended window for mechanical thrombectomy when salvageable tissue is demonstrated. 1 The American Heart Association explicitly recommends combined tPA and mechanical thrombectomy for patients with proximal anterior circulation occlusion and a small to moderate ischemic core, with the strong indication based on tissue viability rather than time alone. 1
Patients eligible for both IV alteplase and endovascular thrombectomy should receive both treatments in parallel, with IV thrombolytics initiated while simultaneously preparing the angiography suite. 2
The landmark trials that established thrombectomy efficacy (MR CLEAN, ESCAPE) included 83.7-91.5% of patients who received IV thrombolytics alongside mechanical intervention, demonstrating the benefit of combined therapy. 1, 2
The adjusted odds ratio for improved functional outcomes with combined therapy versus medical management alone is 1.67 (95% CI 1.21-2.30). 2
Critical Imaging Requirements Before Proceeding
Advanced perfusion imaging is essential to confirm salvageable tissue before proceeding with treatment at 12 hours. 1 The patient must meet one of the following criteria:
DAWN criteria: Clinical-imaging mismatch with age <80 years, NIHSS ≥10, and core <31 mL, OR NIHSS ≥20 and core <51 mL. 1
DEFUSE-3 criteria: Ischemic core <70 mL, mismatch ratio ≥1.8, and mismatch volume ≥15 mL. 1
ASPECTS ≥6 on non-contrast CT to confirm small to moderate infarct core. 1
Why Not the Other Options
Observation (Option C) is inappropriate because this patient has a proximal anterior circulation occlusion with salvageable tissue at 12 hours, which represents a clear indication for intervention. 1
tPA alone (Option A) is insufficient because IV alteplase achieves recanalization in less than 50% of large vessel occlusions, with particularly poor results in proximal occlusions. 2
Mechanical thrombectomy alone (Option B) is suboptimal because patients receiving combined therapy had higher odds of achieving eTICI ≥2b recanalization (OR = 1.34,95% CI: 1.10-1.63) compared to thrombectomy alone. 3 Additionally, patients bridged with IV tPA required fewer passes before successful recanalization (1.6 vs 2.4 passes, p = 0.037) and achieved better functional outcomes (mean mRS 3.4 vs 4.4 at 90 days, p ~ 0.01). 4
Technical Implementation
Do not delay endovascular treatment while waiting for response to IV tPA - this is a Class III recommendation (harmful). 5, 2 Every 30-minute delay in recanalization decreases the chance of good outcome by 8-14%. 5
Door-to-groin puncture time should be minimized, with target times under 110 minutes from arrival. 2
Stent retrievers are the preferred device (Class I, Level of Evidence A), achieving TICI 2b/3 recanalization in approximately 59-87.8% of cases. 5, 2
The procedural goal should be TICI 2b/3 reperfusion to maximize functional outcomes. 1, 5
Critical Contraindications at 12 Hours
Do not proceed with thrombectomy if imaging shows: 1
- ASPECTS of 0
- No perfusion mismatch
- Large established infarct core (>70 mL by DEFUSE-3 criteria or not meeting DAWN criteria)
Post-Procedure Management
Maintain blood pressure ≤180/105 mmHg for 24 hours after thrombectomy to optimize outcomes and reduce hemorrhagic complications. 1, 5
Monitor closely for hemorrhagic transformation in the immediate post-procedure period. 1
The symptomatic intracranial hemorrhage rate with combined therapy is approximately 9%, with no significant difference between patients receiving tPA before thrombectomy versus thrombectomy alone (6.7% vs 9.9%, p > .99). 6