Intracranial Stenting–SAMMPRIS Criteria

In follow-up from today’s morning report, regarding an elderly patient with multiple symptoms from a high-grade intracranial stenosis,  following are the inclusion and exclusion criteria from the SAMMPRIS study’s methods paper. Note that having multiple recent events followed by return to baseline is not among the exclusions. “Progressive neurological signs” was a contraindication. Age > 80 was an exclusion.

The point I’d like to make is that if your patient wouldn’t have met the criteria for inclusion in an intervention trial, especially a negative one, it doesn’t follow that they are part of a subgroup that does benefit from the intervention. That patient / subgroup might indeed benefit, or might be harmed. In particular, “instability” might suggest a benefit from early intervention, but could also be associated with high peri-procedural risk, as seen with emergent carotid endarterectomy. Advanced age is usually associated with higher peri-procedural risk. This is not to say that one must always rely on randomized studies for all decisions to pursue intervention–most of medicine is lacking such. However, when the best data we have suggest that a procedure is harmful, we must be very careful when choosing to recommend that procedure to our individual patient.


  1. TIA or non-severe stroke within 30 days of enrollment attributed to 70–99% stenosis * of a major intracranial artery (carotid artery, MCA stem (M1), vertebral artery, or basilar artery)
    • *
      may be diagnosed by TCD, MRA, or CTA to qualify for angiogram performed as part of the study protocol but must be confirmed by catheter angiography for enrollment in the trial
  2. Modified Rankin score of ≤ 3
  3. Target area of stenosis in an intracranial artery that has a normal diameter of 2.00 mm to 4.50 mm
  4. Target area of stenosis is less than or equal to 14 mm in length
  5. Age ≥ 30 years and ≤ 80 years.
    • Patients 30–49 years are required to meet at least one additional criteria (i-vi) provided in the table below to qualify for the study. This additional requirement is to increase the likelihood that the symptomatic intracranial stenosis in patients 30–49 years is atherosclerotic.


1. Tandem extracranial or intracranial stenosis (70%–99%) or occlusion that is proximal or distal to the target intracranial lesion (NOTE: an exception is allowed if the occlusion involves a single vertebral artery proximal to a symptomatic basilar artery stenosis and the contralateral vertebral artery is supplying the basilar artery)
2. Bilateral intracranial vertebral artery stenosis of 70%–99% and uncertainty about which artery is symptomatic (e.g. if patient has pontine, midbrain, or temporal – occipital symptoms)
3. Stenting, angioplasty, or endarterectomy of an extracranial (carotid or vertebral artery) or intracranial artery within 30 days prior to expected enrollment date
4. Previous treatment of target lesion with a stent, angioplasty, or other mechanical device, or plan to perform staged angioplasty followed by stenting of target lesion
5. Plan to perform concomitant angioplasty or stenting of an extracranial vessel tandem to an intracranial stenosis
6. Presence of intraluminal thrombus proximal to or at the target lesion
7. Any aneurysm proximal to or distal to stenotic intracranial artery
8. Intracranial tumor (except meningioma) or any intracranial vascular malformation
9. CT or angiographic evidence of severe calcification at target lesion
10. Thrombolytic therapy within 24 hours prior to enrollment
11. Progressive neurological signs within 24 hours prior to enrollment
12. Brain infarct within previous 30 days of enrollment that is of sufficient size (> 5 cms) to be at risk of hemorrhagic conversion during or after stenting
13. Any hemorrhagic infarct within 14 days prior to enrollment
14. Any hemorrhagic infarct within 15 – 30 days that is associated with mass effect
15. Any history of a primary intracerebral (parenchymal) hemorrhage (ICH)
16. Any other intracranial hemorrhage (subarachnoid, subdural, epidural) within 30 days
17. Any untreated chronic subdural hematoma of greater than 5 mm in thickness
18. Intracranial arterial stenosis due to arterial dissection, Moya Moya disease; any known vasculitic disease; herpes zoster, varicella zoster or other viral vasculopathy; neurosyphilis; any other intracranial infection; any intracranial stenosis associated with CSF pleocytosis; radiation induced vasculopathy; fibromuscular dysplasia; sickle cell disease; neurofibromatosis; benign angiopathy of central nervous system; post-partum angiopathy; suspected vasospastic process, suspected recanalized embolus
19. Presence of any of the following unequivocal cardiac sources of embolism: chronic or paroxysmal atrial fibrillation, mitral stenosis, mechanical valve, endocarditis, intracardiac clot or vegetation, myocardial infarction within three months, dilated cardiomyopathy, left atrial spontaneous echo contrast, ejection fraction less than 30%
20. Known allergy or contraindication to aspirin, clopidogrel, heparin, nitinol, local or general anesthesia
21. History of life-threatening allergy to contrast dye. If not life threatening and can be effectively pretreated, patient can be enrolled at physician’s discretion
22. Active peptic ulcer disease, major systemic hemorrhage within 30 days, active bleeding diathesis, platelets < 100,000, hematocrit < 30, INR > 1.5, clotting factor abnormality that increases the risk of bleeding, current alcohol or substance abuse, uncontrolled severe hypertension (systolic pressure > 180 mm Hg or diastolic pressure > 115 mm Hg), severe liver impairment (AST or ALT > 3 x normal, cirrhosis), creatinine > 3.0 (unless on dialysis)
23. Major surgery (including open femoral, aortic, or carotid surgery) within previous 30 days or planned in the next 90 days after enrollment
24. Indication for warfarin or heparin beyond enrollment (NOTE: exceptions allowed for use of systemic heparin during stenting procedure or subcutaneous heparin for deep vein thrombosis (DVT) prophylaxis while hospitalized)
25. Severe neurological deficit that renders the patient incapable of living independently
26. Dementia or psychiatric problem that prevents the patient from following an outpatient program reliably
27. Co-morbid conditions that may limit survival to less than 3 years
28. Pregnancy or of childbearing potential and unwilling to use contraception for the duration of this study
29. Enrollment in another study that would conflict with the current study.

About Justin A. Sattin

I'm a vascular neurologist and residency program director. I created this blog in order to share some thoughts with my resident and other colleagues, and to foster my own learning as well.
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