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Carotid Stenting: Unanswered Questions and Future Directions

Carotid Stenting: Unanswered Questions and Future Directions. Rod Samuelson, Elad Levy, LN Hopkins University at Buffalo Neurosurgery October 2006. LN Hopkins, MD Potential Conflicts. Consultant & research support: Boston Scientific, Cordis, Medtronic, Guidant Financial interests:

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Carotid Stenting: Unanswered Questions and Future Directions

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  1. Carotid Stenting: Unanswered Questions and Future Directions Rod Samuelson, Elad Levy, LN Hopkins University at Buffalo Neurosurgery October 2006

  2. LN Hopkins, MD Potential Conflicts Consultant & research support: Boston Scientific, Cordis, Medtronic, Guidant Financial interests: Boston Scientific EPI, Cordis, J&J, Micrus, Endotex, Access Closure Inc

  3. Carotid StenosisWhat do We Know? In LOW RISK Patients: • CEA is of benefit (greater for Sx pts) • CEA of more benefit with severe stenosis • CEA of more benefit in elderly • CEA must be done safely

  4. Carotid StenosisWhat do We Know? In Asymptomatic Low Risk Patients • CEA is better than medical therepy • CEA prevents strokes in women (ACST) • CEA prevents disabling strokes (ACST) • CEA prevents fatal strokes (ACST)

  5. Carotid StenosisWhat do We Know? In Elderly Patients: • Stroke risk is much higher in elderly pts • CEA greatly benefits elderly low risk pts • CEA risk is increased in elderly patients

  6. Carotid StenosisWhat do We Know? • Definition of High Risk for CEA • CAS risk = CEA in High Risk pts • CAS & CEA risk is higher in elderly pts and in symptomatic pts

  7. Unanswered Questions • Should we treat Symptomatic low risk pts with CAS or CEA? • Embolic protection no/ yes/ what type? • Which is better: Open or Closed cell stents • What training is best for CAS

  8. Unanswered Questions • What is High Risk for CAS ? • Should we treat elderly pts with CAS ? • Are high risk (CEA) pts at higher risk for stroke ?? • The “3% Rule” ????

  9. A Few Helpful Facts…

  10. Asymptomatic Carotid Stenosis and Risk of Stroke Study (ACSRS) Asymptomatic Patients with Medical CoMorbidities And Severe Stenosis… Stroke rate up to 6% per year !! The “3 % Rule” does not apply to High Risk pts Kakkos,Nicolaides et al Int Angiol ’05, 24, 221-30

  11. Elderly Patients(75-79)NASCET Analysis • Absolute risk reduction(ARR) overall = 17% • ARR in pts 75-79 = 30%

  12. Some Stroke Facts… • Only 1/3 of strokes are preceded by TIA Caplan et al • Many TIA’s are never diagnosed Castaldo, Tool et al, Arch neurol, 1997 • Many Stroke are never diagnosed

  13. Stroke Facts… • Silent infarcts (CT&MRI) noted in 12-70% of asx pts (ACST) Halliday • Silent infarcts seen in 15% of ACAS patients

  14. Other “Non Symptom” Symptoms • Neurocognitive function impaired in asymptomatic patients. Raabe, SIR March ’06 • Dizzyness ???

  15. High Risk CAS • Not the same as for CEA • Are CEA and CAS complementary ? • What are identified CAS risk factors? • How to make CAS SAFER ?

  16. Current CAS Results (D/S/MI)High Risk Registries • CAPTURE 6 • CREATE 6 • BEACH 5 • CABERNET 4 • CASES 5

  17. Current CAS ResultsOutliers, But RPCT • SPACE 7 • EVA 3S 10

  18. CAPTURE STROKE COHORT: Summary- Capture 3500 patients • Overall stroke rate = 4.8% • Major stroke rate = 2.0% • Minor stroke rate = 2.9% • Ipsilateral stroke rate= 4.0% • Non-ipsilateral stroke rate= 0.9% (18% of all strokes)

  19. CAPTURE STROKE COHORT: Summary of Strokes • Stroke rate in high risk population is 4.8% • Major stroke rate = 2.0% • Non-ipsilateral represents 18% of strokes of a cumulative 0.9% rate • No non-ipsilateral strokes reported during the procedure • 38% of strokes occurred after 24 hours • 78% of strokes occurred post-procedure and post-discharge

  20. CAPTUREGender & Symptoms • DSMI overall Sx pts 12.2 Asx 5.3 (.0001) • DS (F Worse) Sx F <80 vs Sx M <80 (.03)

  21. CAPTURE Post Market Registry3000 ptsFDA Selection CriteriaOctogenarians • Age > 80 713/3000 pts(24%) • Independent predictors DSMI @ 30 days… • DSMI = 9.4(>80) vs 5.2(<80) • Calcification (mod+) OR 1.39 • Predilitation for filter OR 3.22 stroke alone OR 4.02 • Multiple stents OR 1.77 >80 stroke alone OR3.14

  22. CAPTURE STROKE COHORT: Questions • Why do many strokes occur after the procedure (78%) or after 24 hours (38%)? Would Closed Cell stents be better?? • Why do 18 % occur in a vessel that has not been manipulated? • Does the answer lie in? • Arch Type, calcification and overall plaque morphology • Improved technical equipment • Medical therapy before and after the procedure

  23. CREATE High Risk RegistryEV3 Stent + Spider Filter30 Day Results • 30 day death, stroke and MI 6.2% • Major Stroke 3.5% • Hemorrhage 1.3% • Risk Factors Symptomatic carotid stenosis Renal failure Duration of filter deployment

  24. SPACE TrialRPCT N=1200 Death, Stroke and MI - 30 day CAS 6.8% CEA 6.3% p = 0.09 CEA better in older patients

  25. CAS Risk Factors 1)Symptomatic lesion 2)Sx > age 80 3)Renal Failure 4)Multiple stents 5)Duration Filter deployment 6)Pre dilitation 7)Tortuous/calcified arteries

  26. CASNon Predictors of Risk • Sex ?? CAPTURE • Calcification • Residual stenosis • Filter • Contralateral occlusion • Smoking • Diabetes • Statins

  27. Newer ResultsWhat Do They Mean? • Endarterectomy versus Stenting in Patients with Symptomatic Severe Carotid Stenosis • EVA-3S Trial • New England Journal of Medicine • October 19, 2006

  28. EVA-3S Trial: Results • 30 Day rate of any stroke or death • Endarterectomy = 3.9% • Carotid Stent = 9.6% • Relative Risk of 2.5 (95% CI 1.2 to 5.1) • 30 Day rate of disabling stroke or death • Endarterectomy = 1.5% • Carotid Stent = 3.4% • Relative Risk of 2.2 (95% CI 0.7 to 7.2)*** • Not statistically significant

  29. EVA-3S Trial: Limitations • Distal protection was only “[strongly] recommended” after February 2003 (50% trial duration) • 30 day stroke or death • Without DEP = 25% (5 of 20) • With DEP = 7.9% (18 of 227) • If 7.9% rather than 9.6% is used: • Relative Risk = 2.0 (p = 0.07)

  30. EVA-3S Trial: Limitations • Rates of MI were not assessed • (Reduced rate of MI was one source of benefit identified in the SAPPHIRE Trial) • Only 30 day and 6 month follow up • (Despite trial ongoing since 2000)

  31. EVA-3S Trial: Limitations • Experience bias • Vascular surgeons: • Required 25 CEAs in the year prior to study entry • Endovascular physicians: • Required 12 carotid stents or 35 “supra-aortic stents” with at least 5 carotid stents • Or, Allowed to receive training and credentialing “under supervision” as they enrolled patients in the trial • Allowed to use new stents after only two cases

  32. EVA-3S Trial: Limitations • Enrollment Bias…? • Total CEA case volumes were not discussed • Estimated 15% or less of all patients randomized • Thirty hospitals • Assuming only 1 vascular surgeon per hospital with the enrollment criteria minimum 25 cases/yr • 4.75 years of enrollment = 3562.5 patients

  33. What will CREST teach us that we don’t already know? • CREST: Randomized CAS vs. CEA • Started in 2000, >100 centers • Plans to enroll 2500 patients • Enrollment- around 1700 • 1387 lead-in cases • 789 carotid stents reported in November 2004 • 30 day stroke and death = 4.6% • 30 day MI = 1.1%

  34. What will CREST teach us that we don’t already know? • Differences from EVA-3S • Distal Embolic Protection • MI rates are monitored • Dual antiplatelet therapy in all patients • Long term follow up • More rigorous interventionalist credentialing • CREST is now more important than ever • Challenges to Recruitment are present

  35. Conclusions • CAS and CEA are complementary…the patient must have every technical option • Asymptomatic patients deserve treatment…we don’t know which is best yet • Low-risk patients should be enrolled in further trials! CREST, ACT 1… • We are beginning to understand which pts are at high risk for CAS….AVOID them!!!!

  36. Future Perspectives:The War Against StrokeHow Are We Doing??

  37. Who Will Treat Acute Stroke? • 750,000 CVAs per year and growing • ~ 250 neurointerventionalists • ~ 60 endovascular neurosurgeons • ~ 5 endovascular neurologists • 5,000 interventional cardiologists

  38. How Do We Get There ? • Training • Technology • Collaborating

  39. Barriers • Societal • New Anatomy • Technology

  40. CollaborationSubspecialty Strengths • Neurology • Radiology • Vascular surg • Vascular med • Cardiology • End organ cognitive • Imaging/cath skills • Own CEA market • Cognitive/imaging • Cath/angioplasty skills • Clinicians • Industry partners • Clinical research

  41. We Will Win the War on StrokeAnd…Cardiologists Will Treat Stroke

  42. Simulator Training Model Commercial Pilot • Mandatory yearly training • 60 hours simulated instrument training • 60 hours actual instrument training Col. Chester Griffin Director, Simulator Training AW Certification - USAF

  43. Flight SimulationThree Components • Tactile (haptics) • Procedural • Complications Sound Familiar ??

  44. Mentice Simulator

  45. Illustrative Case • 27 year old female • Cesarean delivery 8 weeks prior • Ground level fall and head impact • No LOC, No seizure • Acute onset right neck and head pain • Left upper extremity weakness • Slurred speech

  46. Illustrative Case • Meds: Oral contraceptives • In ED: NIHSS = 11 • Left facial weakness, dysarthria, left upper extremity weakness, left sided anesthesia • Head CT: no acute trauma • Head CT perfusion…

  47. Original CT Perfusion Time to Peak

  48. Emergent Angiogram

  49. Acute RICA occlusion • Heparin 4000 • ACT >250

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