Carotid Artery Stenting (CAS) Carotid Artery Stenting for Stroke Risk Reduction Matthew A. Corriere MD, MS, RPVI Assistant Professor of Surgery Department of Vascular and Endovascular Surgery Rationale: Stroke risk reduction Proposed advantages of CAS vs. CEA -? Less invasive -? Lower risk of adverse outcomes Stroke Death Procedural morbidity Cranial nerve injury MI -? Cost Pathophysiology Plaque characteristics: relevant concepts carotid bulb Rich source of emboli Embolic risk related to plaque burden plaque usually located on the surface opposite the flow divider low shear stress stagnant flow and recirculation prolonged exposure to circulating atherogeneic metabolites Concerning features Low density plaque Greater lipid content Intra-plaque hemorrhage Progression of stenosis Ulcerated luminal surface HMG-CoA ( statin ) therapy associated with fibrous remodeling and plaque stabilization American Heart Association Guidelines - Asymptomatic Patients For treatment of 60% or greater stenosis - Perioperative stroke/death must be less than 3% - Symptomatic Patients For treatment of 50% or greater stenosis - Perioperative stroke/death must be less than 6% - No proven indications beyond these thresholds Technical Considerations Biller et al, Circulation 1998 1
Technical Considerations Brief Summary of Carotid Stent placement - Technical Performance Update on Contemporary Trial Results CREST Update on Duplex US Surveillance Criteria Technical Considerations - Operative Technique Vascular Access Angiography Stent Placement Completion Studies - Postoperative Care - Surveillance Sheath Access Femoral (preferred) Brachial Common Carotid Radial Technical Considerations: Aortic arch Anatomy Common carotid distally CAS: Arch branch access Aortic arch classification Level I Level II Level III 2
Aortic arch classification by segment of origin ( Surf and Turf ) Schneider PA, Bohannon WT, Silva MB. Carotid Interventions. New York: Marcel Dekker, 2004. IIB Technical considerations Arch aortogram Selective angiography Cannulation of target CCA Complete angiography (AP and Lateral) - Carotid Bifurcation - Intracranial circulation Cerebral Angiography 3
Technical Considerations - Sheath Placement Selective cannulation ECA engagement preferable Exchange for stiff guidewire Track 90cm 6F sheath into CCA Often the hardest part of the case Establish cerebral protection Cerebral Protection Devices Distal filter Flow reversal (proximal occlusion) Distal balloon occlusion Technical Considerations - Final arteriography - Lesion crossing 0.014 or 0.018 systems - Embolic protection standard of care - Pre-dilation as necessary - Self-expanding stent placement Abbott X-Act & Accu-link Cordis Precise - Post-dilation as necessary - Retrieval of DEP device -Completion angiography Distal micro-embolization during carotid intervention (TCD) Gupta N, CorriereMA, Dodson TF, et al. Journal of Vascular Surgery, 2010 Peri- and Postoperative Care - Preoperative measures for renal protection prn Hydration? N-Acetylcysteine? Bicarbonate prn - Early heparinization - Postoperative ICU or Acute Care for 24 hours - Anti-platelet therapy 4
Surveillance - For restenosis and adverse events Early Post-CAS Six month intervals for two years Yearly thereafter - Duplex at each visit Questions of diagnostic cut-points Carotid Endarterectomy Carotid Endarterectomy Excellent Durability Excellent stroke protection 60-70% risk reduction Safe Contemporary Carotid Intervention Trials CREST results CREST Randomized Blinded Asymptomatic or symptomatic carotid stenosis >70% Acculink Stent/Distal filter embolic protection CAS (n=1262) CEA (n=1240) Age 69 69 Female - % 36 34 Asymptomatic - % 47 47 Hypertension - % 86 86 Diabetes - % 30 30 Dyslipidemia - % 82 85 Current smoker - % 26 26 5
CAS CEA (n=1262) (n=1240) Cardiovascular disease - % 41 43 Primary Endpoint 4 years (any stroke, MI, or death within peri-procedural period plus ipsilateral stroke thereafter) Systolic BP, mean mmhg 142 141 CAS vs. CEA Hazard Ratio, 95% CI P-Value % stenosis 70% 85 87 7.2 vs. 6.8% HR = 1.11; 95% CI: 0.81-1.51 0.51 Days from randomization to treatment 6 7 No effect detected for symptomatic status or sex in terms of primary endpoint However women more likely to suffer adverse events after Carotid Stent placement Interaction suggested for age Small short term benefit in HRQOL for CAS but effect gone by 1 year Haz zard Ratio 4 3 2 1 Primary outcome 4 year CEA Superior P interaction = 0.020 Primary Endpoint: peri-procedural components (any death, stroke, or MI within peri-procedural period) CAS vs. CEA Hazard Ratio, 95% CI P-Value 5.2 vs. 4.5% HR = 1.18; 95% CI: 0.82-1.68 0.38 CAS Superior 0 40 50 60 70 80 90 Age (Years) 6
Peri-procedural Stroke and Death CAS vs. CEA Hazard Ratio 95% CI P-Value Stroke 4.4 vs. 2.3% HR = 1.79; 95% CI: 1.14-2.82 0.01 MI 1.1 vs. 2.3% HR = 0.50; 95% CI: 0.26-0.94 0.03 Peri-procedural Stroke CAS vs. CEA Hazard Ratio 95% CI P-Value All Stroke 4.1 vs. 2.3% HR = 1.79; 95% CI: 1.14-2.82 0.01 Major Stroke 0.9 vs. 0.6% HR = 1.35; 95% CI: 0.54-3.36 0.52 Cranial Nerve Palsies Peri-procedural CAS vs. CEA Hazard Ratio, 95% CI P-Value 0.3 vs. 4.7% HR = 0.07; 95% CI: 0.02-0.18 <0.0001 Ipsilateral Stroke after Peri-procedural Period 4 years CAS vs. CEA Hazard Ratio, 95% CI P-Value 2.0 vs. 2.4% HR = 0.94; 95% CI: 0.50-1.76 0.85 Summary Similarity in the Primary Endpoint driven by differences in perioperative stroke and MI More MIs after CEA More strokes after CAS Long term impact of peri-procedural adverse events Myocardial infarction No acute or lasting effects on HRQOL in CREST Associated with significant increase in mortality Even in absence of symptoms or ECG changes Stroke Minor strokes associated with significant HRQOL decrement Associated with significant increase in mortality 7
Physical Component Scale Mental Component Scale Major Stroke vs. None Minor Stroke vs. None MI vs. None -30-20 -10 0 10 20-20 -10 0 10 20 Difference Impact of periprocedural events (stroke/mi) on SF-36 at 1 year adjusting age, sex, symptomatic cerebrovascular disease and baseline SF-36 measures Growth Curve Modeling. CAS Superior CEA Superior Primary Endpoint Stroke Endpoint Stroke + Death Endpoint MI Endpoint Any Death Any Stroke Major Ipsi Stroke Major Non-Ipsi Stroke Minor Ipsi Stroke Minor Non-Ispi Stroke Cranial Nerve Palsy 0.01 0.1 1 10 Hazard Ratio (log scale) CREST: Age-Specific Results - Rates of Stroke/Death Age less than 60: 1.7% Ages 60-69: 1.3% Ages 70-79: 5.3% Ages 80-89: 12.1% - Initial CREST Advisory Age>80 Extreme tortuosity Severe calcification Limited cerebral reserve Wake Forest Hobson Baptist et Medical al, Journal Center of Vascular Surgery 2004 CREST: Restenosis Restenosis ~6% occurrence after both over 2 years Incidence affected by Female gender (HR 1.79)- for both Dyslipidemia (HR 2.07) )- for both Diabetes (HR 2.31) )- for both Smoking (HR 2.26)- only for CEA Close follow-up required Post-Intervention Surveillance 8
Post-intervention surveillance Duplex Surveillance - Complicated by Presence of stent Resultant changes in arterial compliance - Postulated to lead to increased systolic velocities Post-Intervention Surveillance Post-stent restenosis - Diagnostic criteria not the same as for native arteries - Several studies support utility of comparisons to post stent velocities Indicates need for immediate post CAS duplex Every lab must maintain strict QA in this area CREST used criteria of 3m/sec which has been validated by others? 9