Acute Ischemic Stroke Treatments
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This policy governs medical necessity and coverage for selected endovascular, pharmacologic, and adjunctive treatments for acute ischemic stroke (AIS) and medically refractory delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage for Aetna members.
No material clinical or coverage changes in this revision.
Coverage Criteria and Evidence Summary
Endovascular stent retriever therapy (medically necessary)
Endovascular therapy with a retrievable stent is considered medically necessary when ALL of the following are met:
Applies to retrievable stent devices (e.g., Solitaire FR, Trevo)
Intra-arterial spasmolytic/calcium-channel blocker infusion (medically necessary)
Intra-arterial infusion of spasmolytics or calcium-channel blockers is considered medically necessary when ALL of the following are met:
Examples: papaverine, intra-arterial nicardipine; used when hemodynamic augmentation fails
Experimental / Investigational (Not Covered)
The following procedures and therapies are considered experimental and investigational (therefore not covered):
Identified as experimental/investigational in policy; not covered for indications listed
Stent retriever thrombectomy — AHA/ASA 2015 Class I criteria
Endovascular therapy with a stent retriever is recommended when ALL of the following are met (per AHA/ASA 2015; Class I; Level A):
Per Powers et al., 2015 AHA/ASA guideline criteria
Endovascular therapy when IV tPA contraindicated or for other vessel occlusions
Endovascular therapy may be reasonable (lower level evidence) when ALL of the following are met:
Based on lower-level evidence per Powers et al., 2015
Endovascular therapy for symptomatic, medically refractory cerebral vasospasm
Endovascular treatment for cerebral vasospasm is considered reasonable when ALL of the following are met:
Guidelines support angioplasty and/or selective intra-arterial vasodilator therapy as reasonable rescue therapy; prophylactic angioplasty is not recommended
Coverage-relevant evidence conclusions
Summary coverage-relevant conclusions from evidence:
Evidence summary supports nimodipine use
Recanalization benefits noted; functional outcome evidence variable
Interpretive evidence summaries
Therapy-specific evidence summaries
Coverage considerations based on presented evidence:
Subgroup hypothesis-generating
Considered investigational/not medically necessary
Not recommended outside trials
Further study needed
Investigational
Guideline‑disfavored
Limited evidence, specialized use only
Promising but investigational
Evidence summaries and interpretive criteria (informational)
Background evidence summaries and investigational status; no explicit coverage criteria are provided in these sections. Key interpretive points for clinicians:
Informational
Informational
Informational
Investigational outside select contexts
Use uncertain; evidence context dependent
Investigational and not generalizable
Acute stenting + tirofiban — evidence context
Acute intracranial stenting with concomitant IV tirofiban:
Evidence limited; reported parent artery patency 85.7% and mRS ≤2 in 71.4% at 3 months in the series
Governor vessel acupuncture — reported findings
Governor vessel acupuncture (GV Ac):
Systematic review of 18 RCTs (1,543 patients) suggested improvements but trials had methodological limitations and limited generalizability
Thrombectomy ± IV alteplase — evidence synthesis
Mechanical thrombectomy with vs without IV thrombolysis — trial evidence:
Interpretation depends on non‑inferiority margins, alteplase dosing, populations, and workflow times
Documentation of times and alteplase dosing important for applicability
Fingolimod adjunct — preliminary evidence
Fingolimod plus standardized treatment:
Preliminary evidence; larger trials needed
MSC-CM — preclinical data
Mesenchymal stem cell–conditioned medium (MSC-CM):
Preclinical data only; clinical translation not established
PTAS for BAS — candidate selection and outcomes
Percutaneous transluminal angioplasty with stenting (PTAS) for basilar artery stenosis (BAS):
Technical success often high but clinical outcomes and complication risks variable; randomized trials lacking
PTAS candidate selection (evidence-based criteria)
Descriptive criteria from cited studies and guidance (not formal coverage decision language):
Based on pooled cohort analyses and expert guidance; randomized evidence lacking
Endovascular recanalization candidate selection
Descriptive criteria from a single-center SNOVA series:
Series reports mean lesion length and outcomes; evidence limited and single‑center
The policy distinguishes medically necessary use of intra‑arterial spasmolytics or calcium‑channel blockers from other indications. Infusion into intracranial arteries is considered medically necessary only for patients with medically refractory symptomatic delayed cerebral ischemia (vasospasm) after aneurysmal subarachnoid hemorrhage. Infusion for other indications is identified in the policy scope as experimental/investigational and not covered.
Guideline guidance and the policy caution against routine prophylactic angioplasty: international guidance either recommends against routine prophylactic angioplasty or issues no recommendation. Endovascular rescue (angioplasty or intra‑arterial vasodilators) is described as reasonable only for symptomatic, medically refractory vasospasm, and the timing and triggers for prophylactic or routine angioplasty remain unclear.
The evidence synthesis indicates that tirilazad did not improve mortality or poor outcome when added to standard care for aneurysmal SAH, and therefore is not effective for that indication. Likewise, the document states that intravenous calcium antagonists are not recommended for routine practice, with oral nimodipine remaining the only calcium‑channel antagonist supported for post‑SAH use.
The American Heart Association guidance cited in the policy does not recommend the use of sonothrombolysis (microbubbles combined with ultrasound) as an adjunct to IV fibrinolysis. The policy therefore treats sonothrombolysis as a guideline‑disfavored adjunctive therapy pending stronger evidence of safety and clinical benefit.
The policy notes uncertainty in guideline statements regarding the safety and efficacy of intravenous glycoprotein IIb/IIIa inhibitors (e.g., tirofiban) administered during endovascular stroke treatment. While small case series of acute stenting with concomitant tirofiban are described, the document highlights methodological limitations and does not provide explicit payer‑level exclusions for IV IIb/IIIa agents in the excerpts reviewed.
Evidence for governor vessel (GV) acupuncture is limited to randomized trials performed in China. The policy and cited systematic review note methodological limitations (risk of bias, lack of blinding, single‑country data) that restrict generalizability and preclude routine coverage based on current evidence.
Many interventions reviewed lack randomized trial evidence that is broadly generalizable. The policy emphasizes that numerous studies are retrospective, single‑center, or population‑specific (for example, cohorts from China), limiting applicability of results to wider patient populations and supporting continued classification of such approaches as investigational outside specific study contexts.
The policy explicitly lists multiple procedures and treatments as experimental/investigational (not covered) for the indications addressed. Examples called out in the scope and coding sections include acute stenting with concomitant tirofiban, cerebrolysin, defibrinogen therapies (ancrod, batroxobin), erythropoietin, glycoprotein IIb/IIIa antagonists, sphenopalatine ganglion stimulation, transcranial ultrasound devices (CLOTBUST‑HF), transdermal glyceryl trinitrate, microbubbles with ultrasound sonothrombolysis, and normobaric oxygen therapy.
Use of mechanical embolectomy devices other than modern stent retrievers, or expansion of neurothrombectomy outside clinical trial settings, is described as premature. The policy cites prior uncertainty about whether older devices provided net clinical benefit over IV rt‑PA and recommends that broader adoption be supported by randomized data before routine coverage is expanded.
Randomized trials cited in the policy have not uniformly demonstrated that endovascular therapy is superior to IV tPA for acute ischemic stroke. Assessments summarized in the document therefore caution that routine, unrestricted use of endovascular approaches may be premature and that some randomized trials were stopped for futility, supporting a cautious coverage stance outside guideline‑specified indications.
The policy summarizes systematic reviews and randomized trials showing that cerebrolysin has not demonstrated consistent clinical benefit for functional recovery after acute ischemic stroke and that some analyses suggest an increased risk of serious adverse events. As a result, routine administration of cerebrolysin is not supported by the available RCT evidence and is considered investigational or not medically necessary.
Sphenopalatine ganglion stimulation (SGS) is not established as standard management. A large randomized sham‑controlled trial reported no significant benefit in the overall population but a positive signal in a cortical‑involvement subgroup; trial results are therefore mixed and SGS is considered investigational outside of specific trial contexts.
Several interventions discussed in the policy are supported only by small single‑center series, preliminary meta‑analyses with small sample sizes, or preclinical data. Examples include acute intracranial stenting with concomitant tirofiban (small retrospective series), fingolimod adjunctive therapy (small RCTs/meta‑analysis), and mesenchymal stem cell–conditioned medium (preclinical datasets), which the policy identifies as requiring larger, higher‑quality trials before routine coverage.
Trials that established benefit of mechanical thrombectomy largely excluded posterior circulation strokes, limiting generalizability. The document notes that endovascular interventions for vertebrobasilar occlusions remain of uncertain benefit except in selected populations and when performed at centers with appropriate expertise, and randomized evidence for posterior circulation disease is limited.
Billing Codes and Time Windows
| 37184 | Primary percutaneous transluminal mechanical thrombectomy, noncoronary, arterial or arterial bypass graft, including fluoroscopic guidance and intraprocedural pharmacological thrombolytic injection(s); initial vessel. |
| 37185 | Second and all subsequent vessel(s) within the same vascular family (List separately in addition to code for primary mechanical thrombectomy procedure). |
| 61645 | Percutaneous arterial transluminal mechanical thrombectomy and/or infusion for thrombolysis, intracranial, any method, including diagnostic angiography, fluoroscopic guidance, catheter placement, and intraprocedural pharmacological thrombolytic injection(s). |
| 38206 | Blood-derived hematopoietic progenitor cell harvesting for transplantation, per collection; autologous. |
| 38232 | Bone marrow harvesting for transplantation; autologous. |
| 38241 | Hematopoietic progenitor cell (HPC); autologous transplantation. |
| 97810 | Acupuncture |
| 97811 | Acupuncture |
| 97812 | Acupuncture |
| 97813 | Acupuncture |
| 97814 | Acupuncture |
| J0885 | Injection, epoetin alfa, (for non-ESRD use), 1000 units. |
| J0887 | Injection, epoetin beta, 1 microgram, (for ESRD on dialysis). |
| J0888 | Injection, epoetin beta, 1 microgram, (for non ESRD use). |
| J2265 | Injection, minocycline HCl, 1 mg. |
| J3246 | Injection, tirofiban HCl, 0.25 mg. |
| Q4081 | Injection, epoetin alfa, 100 units (for ESRD on dialysis). |
| I63.00-I63.9 | Cerebral infarction [acute ischemic stroke]. |
| I67.82 | Cerebral ischemia [medically refractory symptomatic delayed cerebral ischemia]. |
| I67.841-I67.848 | Cerebral vasospasm and vasoconstriction [medically refractory symptomatic delayed cerebral ischemia]. |
Prior Authorization, Documentation, and Provider Responsibilities
Prior authorization: thrombectomy criteria
Prior authorization may be required for mechanical thrombectomy (endovascular thrombectomy) for acute ischemic stroke. Prior authorization requests should confirm key clinical and imaging criteria consistent with guideline-based selection for thrombectomy.
- Confirm anterior circulation proximal large-vessel occlusion (internal carotid artery or MCA M1 ± M2) or other treated occlusion per plan guidance
- Document evidence of salvageable brain tissue (advanced perfusion imaging showing small core/target mismatch) and ASPECTS ≥6 where applicable
- Establish NIHSS ≥6 and pre-stroke mRS 0–1 when applicable to selection criteria
- Treatment initiated (groin puncture) within recommended time window (typically ≤6 hours; consider extended-window criteria per imaging up to 12–24 hours where supported)
- If IV alteplase was administered, document dosing and timing relative to thrombectomy (onset-to-treatment and door-to-puncture times)
Prior authorization for endovascular therapy
Prior authorization may be requested or required for endovascular therapies beyond standard, guideline-supported indications. For interventions where randomized trials have not shown clear superiority to IV tPA or where evidence is limited, prior authorization should document rationale and supporting clinical/imaging data.
- Specify the device/technique planned (stent retriever vs aspiration vs other device) and evidence of device-specific benefit if available
- Provide imaging confirming proximal occlusion, infarct core size, and collateral status supporting endovascular approach
- Document contraindications to IV thrombolysis or failure of IV therapy if endovascular therapy is being offered as alternative
Cerebrolysin prior authorization guidance
Cerebrolysin is considered experimental/investigational for acute ischemic stroke and prior authorization is expected to include documentation of investigational status and clinical justification if requested. Trials and systematic reviews have not demonstrated clear functional benefit and have signaled possible increased serious adverse events.
- State that Cerebrolysin is listed as investigational in the policy and is generally not covered
- Include trial data or rationale only for exceptional/clinical-trial enrollment situations
Prior authorization: none specified
For several investigational interventions (for example: acute stenting with concomitant tirofiban, microbubbles with ultrasound sonothrombolysis, transdermal glyceryl trinitrate for acute AIS, normobaric oxygen, many neuroprotective agents), the policy does not specify routine prior-authorization pathways — these are considered experimental/investigational and may be denied. Providers must follow plan provisions and submit full clinical rationale when seeking coverage.
- Treatments labeled experimental/investigational are at high risk of denial if submitted without compelling, plan-approved evidence or clinical trial context
- Prior authorization is determined by the member's plan and contract terms; contact plan for case-specific guidance
PTAS — prior authorization expectations
Percutaneous transluminal angioplasty with stenting (PTAS) for basilar artery stenosis is generally considered only for severe, symptomatic basilar artery stenosis refractory to optimal medical therapy; prior authorization requests should document severity and prior medical management.
- Document percent stenosis (typically ≥50–70%) and location (basilar artery)
- Provide history of symptomatic events (TIA/stroke) attributable to the lesion
- Confirm failure or intolerance of dual antiplatelet therapy and other optimal medical management prior to PTAS request
Prior authorization determined by member plan
Whether prior authorization is required and the specific administrative process for any procedure is ultimately determined by the member’s plan benefits. Providers must follow the member’s plan provisions and check payer-specific prior authorization portals or contact the plan for verification.
- Verify member eligibility and benefit coverage prior to scheduling
- Follow Aetna plan-specific prior authorization procedures (portal/phone) and include required documentation
Denial risk for experimental/investigational treatments
Procedures and therapies designated as experimental or investigational in this policy are at elevated risk of denial. Submit comprehensive clinical documentation only in exceptional circumstances (e.g., clinical trial participation or prior authorization appeals with new evidence).
- Common investigational items include: Cerebrolysin, acute stenting with tirofiban, EPO, microbubble sonothrombolysis, stem cell therapies, hypothermia for AIS
Guideline-disfavored therapy
Some therapies are specifically disfavored by clinical guidelines (e.g., sonothrombolysis as an adjunct to IV fibrinolysis). Requests for such therapies should include guideline-based justification or be considered non-covered.
- AHA/ASA guidance advises against routine use of sonothrombolysis as an adjunct to IV fibrinolysis
- Document any compelling new evidence or trial enrollment if seeking coverage for guideline-disfavored therapies
No explicit coverage authorization or pr
The policy background includes no universal statement that prior authorization is required for all covered interventions; however, administrative notes indicate that safety concerns and evidentiary limitations exist. Providers should not assume automatic coverage and must follow plan-specific authorization rules.
- Absence of an explicit coverage authorization statement in the CPB does not equate to coverage — verify with the payer
- Clinical Policy Bulletins are partial descriptions and plan terms govern coverage decisions
Candidate selection for PTAS
Candidate selection for PTAS should be carefully documented: PTAS has been used for severe symptomatic basilar artery stenosis in patients who remain symptomatic despite medical therapy.
- Indication typically severe (≥50–70%) symptomatic BAS with recurrent ischemic events
- Preferential use of Wingspan or comparable devices documented in literature; include device planned
Documentation of severity and refractory status
Prior authorization requests must include documentation of percent stenosis and failure of medical therapy for PTAS candidates. The plan requires objective evidence of severity and refractory status before approving invasive interventions.
- Provide angiographic or CTA/MRA measurements of baseline stenosis and post-treatment targets
- Include prior antiplatelet regimen details and documentation of continued ischemic events despite optimal therapy
Clinical documentation requirements
Clinical documentation requirements for endovascular and investigational therapies should include baseline neurologic assessment, imaging confirming occlusion and salvageable tissue, and prior therapies attempted.
- Baseline NIHSS and pre-stroke mRS
- Imaging modality and findings (CT/CTA, CT perfusion, MRI/DWI, perfusion maps) demonstrating occlusion, infarct core, and penumbra
- Documentation of contraindications to IV thrombolysis if applicable
Required clinical documentation for thrombectomy
Required clinical documentation for thrombectomy prior authorization includes imaging demonstrating a proximal large-vessel occlusion, evidence of salvageable tissue (small infarct core / target mismatch), and a relatively small infarct core on perfusion imaging or ASPECTS.
- CT/CTA or MR/MRA confirming occlusion site
- Perfusion imaging quantifying core and penumbra (e.g., core <70 mL or per local protocol)
- ASPECTS score where applicable and NIHSS score
Suggested documentation elements
Suggested documentation elements for endovascular procedures include details of the occlusion confirmation modality, device to be used, and timing metrics (onset-to-puncture and onset-to-recanalization).
- Modality used to confirm vessel occlusion (CTA, MRA, DSA) and representative images in the record
- Planned device/technique (stent retriever, aspiration, combined), device model if known
- Time metrics: symptom onset, arrival, imaging, IV tPA bolus (if given), groin puncture, and recanalization times
Timing and outcome documentation
Timing and outcome documentation should be available in the medical record for prior authorization and post-procedure review. Include onset-to-treatment intervals and standard outcome measures used in trials.
- Onset-to-door, door-to-needle (IV tPA), door-to-puncture, onset-to-recanalization times
- Outcome measures: NIHSS, modified Rankin Scale (mRS) at discharge and 90 days, Barthel Index where available
- Document any symptomatic intracerebral hemorrhage or procedural complications
Documentation expectations (background)
Documentation expectations from clinical trials and guideline context: records should include trial-like outcome measures (mRS, NIHSS, BI), intracerebral hemorrhage rates, mortality, and procedural details to support medical necessity determinations.
- Include follow-up documentation of 90-day functional outcomes when available
- Record any device-related adverse events, ICH, or re-occlusion events
Stepwise treatment context
When mechanical thrombectomy is considered, document prior use or ineligibility for IV thrombolysis (stepwise treatment context). Provide evidence if endovascular therapy is being used as an adjunct or alternative.
- State whether IV alteplase was administered, contraindicated, or unable to achieve reperfusion
- Show prior non-invasive therapies attempted and responses
Step before higher-cost or experimental options
Consider established, lower-cost, or guideline-supported alternatives before higher-cost or experimental options. Prior authorization reviewers will expect documentation that standard therapies were attempted or contraindicated prior to experimental interventions.
- Document failure or contraindication to IV tPA or optimal medical therapy before escalation
- For therapies with mixed evidence (e.g., EPO), provide rationale and prior treatment course
No step-therapy pathways are defined
The policy does not define formal step-therapy pathways for many investigational or emerging treatments. Providers should not assume a standardized step-therapy sequence and must document clinical rationale when deviating from standard care.
- Tenecteplase and other alternatives are discussed in literature but not codified into formal step-therapy requirements in this CPB
- For PTAS, step-therapy context generally describes PTAS after failure of dual antiplatelet therapy
Clinical Background and Context
Background: Acute ischemic stroke (AIS) is a leading cause of death and disability. Standard acute management includes intravenous thrombolysis with tPA administered within a narrow time window (commonly ≤ 3–4.5 hours) for eligible patients. Endovascular approaches, including mechanical thrombectomy with stent retrievers, are used for large‑vessel occlusions and may extend treatment opportunities for selected patients.
Definitions and Key Terms
Policy Dates and References
Policy status and dates: this Clinical Policy Bulletin is listed as CURRENT. The policy has an effective date of 2009‑07‑10, a last review date of 2023‑11‑07, and a next scheduled review on 2024‑09‑12.
References: The document includes a compiled list of references supporting the evidence summaries and recommendations; the reference list is provided in the policy's References section.
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