Ahoy. Is That a Large Vessel or Small Vessel That I See Ahoy! Is That a Large Vessel or Small Vessel That I See? Margaret Tremwel MD PhD Stroke Program Medical Director Washington Regional Medical Center Fayetteville, AR

Arkansas has one of the highest death rates from stroke in the nation (7th place in 2017)

Our Challenge For persons with a large vessel occlusion (LVO) that requires thrombectomy, time is spent with Initial triage in the field to arrival at SRH and PCS for tpa and then Obtaining post tpa CTA to determine if transfer to endovascular center vs hospital that provides post tpa ICU care and then Transfer to endovascular center

Our Challenge M1, ICA, and tandem ICA/M1 thrombi are associated with low likelihood of thrombolysis with tpa alone; may need endovascular treatment More distal M2/M3 thrombi have a higher likelihood of partial or complete recanalization with tpa alone Patients with significant penumbra have better outcomes with successful endovascular therapy The vulnerability of ischemic tissue that is not yet dead (penumbra) varies from person to person. This can not be determined by CT or CTA. NIHSS is the best method to predict vessel occlusion but not penumbra

Our Advantages State wide registry available to assist hospitals and EMS track and improve processes and patient outcomes related to stroke care Training available for EMS and hospital personnel pertaining to care of suspected stroke patients Telestroke consultation services available in nearly all hospitals

Our Advantages Developing a system of care to provide ‘state of the art’ stroke care for all our residents We have several Primary Stroke Centers (PSC) in Arkansas providing post tpa ICU care UAMS as a Comprehensive Stroke Center is available 24/7 for endovascular treatments

endovascular thrombectomy, and Our Challenge Time is still the BEST predictor of good outcome in persons receiving thrombolysis with tpa, endovascular thrombectomy, and combined thrombolysis and thrombectomy

Our Challenge Some hospitals provide post thrombolytic neuro-ICU care and some provide both ICU care and endovascular treatment. Some patients may need post thrombolytic care only and others with large vessel occlusion (LVO) require additional endovascular treatment. These destinations may be different destinations Travel costs

Our Challenge How and when do we triage or transfer a patient to the SRH or PSC vs Endovascular Center? Constellation of stroke symptoms can give us a clue to vascular etiology of stroke Time from symptom onset: 0-6 hr: presence of penumbra is assumed. All LVO can be treated endovascularly 6-24 hours: need to demonstrate penumbra by imaging

Our Challenge Availability of CT angiography at the transferring hospital Efficiency of SRH or PSC Door to needle time Efficiency of Endovascular Center Door to start of thrombectomy (groin puncture)

Symptoms Associated with Small vs Large Vessel Stroke Small Vessel: Fiber tract abnormality Large Vessel: cortical abnormality with or without fiber tract abnormality Hemiparesis Hemibody numbness Isolated ataxia Aphasia Monocular visual loss Neglect Gaze deviation Bilateral symptoms (except numbness) Visual loss Acute confusion ( but present in many metabolic and neurologic disorders)

Characteristics of a Scale that Accurately Predicts LVO Need a high rate of correctly identifying LVO (Sensitivity (%) = true positive rate). This is the proportion of people with LVO that have a positive test result; ability to identify all LVOs Need a high rate of correctly identifying absence of LVO (Specificity (%) = true negative rate. This is the proportion of people without an LVO that have a negative test result; ability to correctly identify no LVO

Characteristics of a Scale that Accurately Predicts LVO Positive predictive value is the proportion of patients with a positive test result who have the condition (LVO) Negative predictive value is the proportion of patients with a negative test result who do not have the condition (LVO). It is not the probability of having an LVO despite a negative test result. The goal is 30% over-triage for EMS identification of stroke in the field(AHA policy for development of system of care)

Scales for triage in the ER Patients assessed at SRH without CT angiography NIHSS has the largest validation for predicting LVO when administered by MD or trained nursing Threshold >10 has sensitivity 73% and specificity 74% Threshold > 6 has sensitivity 87% and specificity 52%

Cortical Symptoms are More Suggestive of LVO and Thrombectomy Cohort of 543 patients acute stroke in all vascular distributions and stroke mimics Catagorized by symptom and whether patient had LVO as determined by imaging Determined the likelihood of each stroke symptom to predict LVO and thrombectomy Stroke. 2018;49:2323-2329.

Comparison of Prehospital Findings to Predict LVO No LVO (N=362) SEN SPE PPV NPV ACC hemiparesis 153 170 0.85 (0.78-0.89) 0.53 (0.48-0.58) 0.47 (0.43-0.53) 0.87 (0.82-0.91) 0.64 Any cortical symptom 165 108 0.91 (0.86-0.95) 0.70 (0.65-0.75) 0.60 (0.54-0.66) 0.94 (0.90-0.97) 0.77 Aphasia 85 65 0.47 (0.40-0.55) 0.82 (0.78-0.86) 0.57 (0.48-0.65) 0.76 (0.71-0.80) 0.70 Neglect gaze deviation 137 0.76 (0.69-0.82) 0.68 (0.61-0.74) 0.87 (0.83-0.90) 0.80 Cortical symptom and hemiparesis 142 67 0.79 (0.72-0.84) 0.88 (0.84-0/92) Cortical symptom or hemiparesis 176 212 0.97 (0.93-0.99) 0.41(0.36-0.47) 0.45 (0.40-0.51) 0.97 (0.92-0.99) 0.60 Stroke. 2018;49:2323-2329.

Comparison of Prehospital Findings to Predict Thrombectomy MT (n=109) No MT (n=434) SEN SPE PPV NPV ACC hemiparesis 95 228 0.87 (0.79-0.93) 0.48 (0.43-0.52) 0.29 (0.25-0.35) 0.94 (0.89-0.96) 0.55 Any cortical symptom 98 175 0.90 (0.82-0.95) 0.60 (0.55-0.64) 0.36 (0.30-0.42) 0.96 (0/93-0.98) 0.66 Aphasia 44 106 0.40 (0.31-0.50) 0.76 (0.71-0.80) 0.29 (0.22-0.37) 0.84 (0.79-0.87) 0.69 Neglect gaze deviation 87 115 0.80 (0.71-0.87) 0.74 (0.69-0.78) 0.43 (0.36-0.50) 0.94 (0.90-0.96) 0.75 Cortical symptom and hemiparesis 89 120 0.82(0.73-0.88) 0.72 (0.68-0.77) 0.94 (0.91-0.96) 0.74 Cortical symptom or hemiparesis 104 284 0.95 (0.90-0.98) 0.35 (0.30-0.39) 0.27 (0.23-0.32) 0.97 (0.92-0.99) 0.47 Stroke 2018;49:2323-2329.

Cortical Symptoms are More Suggestive of LVO and Thrombectomy Cortical symptoms alone are a reliable indicator of LVO For LVO: Sensitivity 90% and specificity 70% For thrombectomy: sensitivity 90% and specificity 60% Motor symptoms alone For LVO: Sensitivity 85% and specificity 53% For thrombectomy: 87% and specificity 48% Stroke. 2018;49:2323-2329.

Comparison of Stroke Scale to Predict LVO #patient hemorrhage # items Items cutoff sen spe acc 3I-SS 171 NO 3 LOC ,gaze, motor 4 0.67 0.92 0.86 CPSSS 303 LOC, gaze, arm weakness 2 0.83 0.40 FAST-ED 727 6 Face palsy, arm weakness, speech, gaze, neglect > 4 0.80 0.89 0.79 LEGS 181 Leg weakness, eyes/visual fields, gaze, speech 0.69 0.81 0.77 RACE 357 YES Face palsy, arm motor, leg motor, head and gaze deviation, aphasia, agnosia > 5 0.85 0.68 0.82 PASS 3127 LOC, gaze palsy/deviation, arm weakness > 2 0.66 0.74 VAN 62 Arm weakness, visual disturbance, aphasia, neglect No 1.0 0.90 Stroke 2018;49:2323-2329.

Scenarios for Traige EMS triage of patients with suspected stroke and direct transfer to endovascular hospital vs stroke ready hospital No one scale is superior: need more studies For a good test, the probability of positive LVO could be > 50% depending on the underlying true prevalence, but probability of LVO with a negative test could be > 10%

Future Direction Need studies to evaluate validity of LVO identification scales when administered by EMS Need decision analysis studies to estimate cost and benefit of triage in the field by EMS to endovascular hospital vs at SRH/PSC. Need to develop thoughtful triage and transfer policies sensitive to patient need for thrombolytic vs endovascular treatment. Policies for triage from the field and/or transfer from the SRH or PCS should emphasize delivery of patients to the closest hospital that provides the needed services

Future Direction The receiving hospitals that provide tpa, provide post tpa and endovascular care should demonstrate and publish clinical excellence as achieved through accreditation from highly recognized certification programs Policies should always emphasize that time to recanalization is the single best predictor of good outcome

Time is Brain 1 minute = 2 million dead neurons 10 minute delay = reduces a patients disability free lifetime 40 days. 10 minute delay = increases health cost $10,000 1 minute = reduces a patients life 1 week Significant time delays on average 2 hours could be prevented if EMS send patients with severe signs of stroke directly to a comprehensive stroke center.

Symptoms of Stroke Sudden Onset: Numbness or weakness of face, arm or leg, especially on one side of the body Confusion, trouble speaking or understanding Trouble seeing in one or both eyes Trouble walking, dizziness, loss of balance or coordination Severe headache with no known cause

Scales Designed to Assist Determination of LVO NIHSS: considered the gold standard NIH-EMS: shortened NIHSS emphasizing LOC, motor for face, arm and leg, and dysarthria. 0-29 pt scale NIH-EMS > 6 sensitivity 70.3% and specificity 80.7% NIH > 9 sensitivity of 69% specificity of 85% Not much data repeated to confirm results

Scales Designed to Assist Determination of LVO CPSSS: Cincinnati Prehospital Stroke Severity Scale Measures conjugate gaze deviation(2), abnormal LOC (1 any abnormality in LOC questions or commands), severe arm weakness ( 1 for inability to maintain arm raised against gravity. Total score 4. With a cutoff of > 2, 70% sensitivity and 86.8% specificity

Scales Designed to Assist Determination of LVO FAST Plus Test Measures facial palsy (0-1), Arm motor function(0-1), Positive if score 1 or 2 for FAST FAST Plus evaluates severe weakness arm or leg (0-1) Sensitivity of 93% and specificity 47% Greater than 50% false positives

Scales Designed to Assist Determination of LVO Rapid Arterial Occlusion Evaluation Scale (RACE) Based on NIHSS items: facial palsy (0-2), arm and motor function (0-2), leg motor function (0-2), gaze abnormality (0-1) and aphasia or neglect (0-2). Total score 9. RACE scale > 5, sensitivity 85% and specificity 68%.

Scales Designed to Assist Determination of LVO Prehospital Acute Stroke Severity Scale (PASS) 3 NIHSS scores: LOC (month and age), gaze palsy/deviation, and arm weakness. Total score 3. Score > 2 is positive, sensitivity 66%, specificity 83%

Scales Designed to Assist Determination of LVO Stroke vision, aphasia, neglect (VAN) assessment Mild, moderate or severe arm weakness. If any weakness: vision disturbance: absent or double Aphasia: expressive, receptive, both Neglect: forced gaze or can not track to one side, unable to feel on one side, ignoring one side or recognize ones own arm, Patient must have weakness and 1 or all of above to be positive Sensitivity 100% Specificity 90% Needs large group repeated studies

Scales Designed to Assist Determination of LVO FAST-ED: Field Assessment Stroke Triage for Emergency Destination Facial palsy (0-1), Arm Weakness (0-2), Speech Change (0-2), Time (document decision making- no points), Eye Deviation (0-2), Denial/Neglect (0-2) Total 9 points. Score > 3 sensitivity 71% and specificity 78%. Score > 4 sensitivity 60% and specificity 89% (higher prevalence of M1 occlusion Score < 4 had high prevalence of M2 occlusion