Endovascular Therapy for Acute Ischaemic Stroke in Northern Ireland

Ian Rennie

Interventional Neurologist

On behalf of the Belfast trust stroke team

Belfast Team

Evidence base we rely on ESCAPE trial

• Acute Ischemic Stroke (NIHSS>5)

• 12 Hour window

• No upper age limit

• Good functional status

• CT head: ASPECTS >5 (exclude large core)

• CTA: ICA+M1 or M1 or functional M1 (all M2s)

• CTA moderate to good collaterals

Result summary

• MRS 0-2 at 90 days

• 53.0% in the treatment arm

• 29.3% in the control arm

• NNT= 4 for independence

• We still stick fairly closely to the ESCAPE trail selection criteria

Demographics and Geography

www.ons.gov.uk

Belfast City pop. = 286 000 Belfast Metropolitan Area pop = 585 000 (>33% of NI total) >1.2 million pop. within 30 miles of Belfast (>66% of NI total)

Famous for healthy Lifestyle

IV Thrombolysis rates

Extrapolation of numbers

How many in real l ife? St Georges in London offering service to SW London and Surrey treat on average 2/month

Just because somewhere else has l ittle interest in stroke doesn’t imply lack of need. ?? how many treated in Calgary for s imilar population. I know Bern in Switzerland with about 1.8m population treat 2 per week

If try to ca lculate those that might benefit Guess is better word than calculate

Suitable for IV thrombolysis – 12.6% according to RCP cri teria We can treat patients not suitable for lysis .

Prior Rankin 2 or less – 81% Fair enough

Arrive within 0-3 hours of onset symptoms 80% of thrombolysed Time is not relevant as ESCAPE was up to 12 hrs . As long as ASPECTS good.

Don’t respond to IV thrombolysis - 86%

We don’t wait to see if response

Have proximal vessel occlusion – approx. 25% unresponsive to IV tPA Most large vessel occlusions don’t respond

Reduces the percentage of potentially eligible to about 2% if the total. i.e. about 50/year for Northern Ireland. At best level of NNT that would be 12/yr who avoid disability

We have treated about 50 patients in 1st 4 months 2015 on 5/7 day basis . Simple maths on this would estimate about 210 patients per yr giving 50 who avoid disability. This fits with other other work presented

here

ESCAPE showed 50% mortality reduction by the way.

Early IV trials were negative

• Recent presentation in Northern Ireland

• Took numbers from another hospital

• Guessed population catchments and did come maths

• Suggested the max need in Northern Ireland 12/yr

“homework corrected”

• Interventional cases • 2011 9 • 2012 11 • 2013 32 • 2014 30 • 2015 to date is 38

• Don’t rely on guess work for estimates of numbers

• Try some local research that can be extrapolated

Method/ Premise

• IAT is likely to be beneficial for those with significant stroke secondary to proximal vessel occlusion and minimal early ischaemic change on CT.

• A list of all patients who received IV-tPA alone for acute ischaemic stroke in NI in 2012 and their initial National Institute of Health Stroke Scale (NIHSS) was obtained from the stroke service

Methods

• Three PACS systems covering all Northern Ireland hospitals were used to view the CT brain studies and calculate the Alberta Stroke Program Early CT score (ASPECTS)

• All patients who received IV-tPA alone for acute ischaemic stroke in NI in 2012 were assessed

Methods • Ordinarily CT angiography is required to assess for

proximal vessel occlusion

• CT angiography is not routinely performed outside the tertiary neuroradiology centre

• The presence of a significant proximal vessel occlusion was estimated using a combination of a hyperdense vessel (HDV) and NIHSS

• Patients with low ASPECT score excluded

Conclusion (2012 figures)

• Estimate 100-150 referrals for IAT for acute ischaemic stroke per year in NI

• Approximately 50-75 referrals per million population per year

• Our figures correlates with published estimates

• Cloft et al estimated likely be no more than 20,000 cases per year in the United States1 (63 per million population per year)

1Cloft HJ, Rabinstein A, Lanzino G, Kallmes DF. Intra-Arterial Stroke Therapy: An Assessment of Demand and Available Work Force. AJNR. 2009; 30:453-58

Assessment of the Potential Unmet Need For Intra-arterial Stroke Therapy

in Northern Ireland Presented to BSNR in 2014 We now think the estimate is slightly conservative (longer time windows /posterior circulation stroke / fluctuating NIHSS etc)

• 36 patients in 7 months on a 5 day service would equate to 86 patients per year with just an increase to working day time Saturday and Sunday

• 100 patients for IA therapy per 1 million population is pretty close

Scotland

• Population 5.2 million

• Estimates of 500+ IA stroke treatments per year

• Similar issues to N I concerning patient access

Hub and Spoke Model

• Currently the most common business model

• Probably started by airlines

• Our current evolving model

Distance: 70 miles Journey Time: 1 hour, 27 minutes Total number of thrombolysed strokes = 22 Number meeting eligibility criteria for thrombectomy = 13 (59.1%)

Out of office hours = 9/13

Distance: 84 miles Journey Time: 1 hour 37 minutes Total number of thrombolysed strokes = 18 Number meeting eligibility criteria for thrombectomy = 7 (38.9%)

Out of office hours = 3/7

How to make this work

• 3 hospitals have regular visiting neuroradiology sessions (1 further hospital has a trained diagnostic Nrad )

• Regular stroke network meetings

• CTA for all eligible stroke with initial CT

• Calls all directed by stroke physicians

• Transfer patients met in CT by stroke team

• Repeat imaging carried out in RVH

• Rapid transfer to angio room

Team getting faster

• 2014 CTA to groin was a mean of 26.2 minutes Groin to Recan was a mean of 48.6 minutes

• 2015 CTA to groin was a mean of 22.14

minutes Groin to Recan was a mean of 38.1 minutes

How to get faster

• Avoid anaesthesia (always contacted )

• No gown etc for patient

• All members of team know their role

• Neuroradiologist doesn’t leave patient and will push from CT

• Stroke consultant talks to family

Case examples

• Cases selected to show our learning points

• Learn from where we did it well

• Where we got lucky

• Where we got it wrong

Case 1 Good

• 74 yr old high NIHSS

• CT at 15:54 CTA at 16:01

• Repeat after transfer at 17:20 CTA at 17:27

• TICA 2a only but NIHSS drop to 4 next day

Initial Imaging

Repeat in RVH

Angio

Lessons

• Get diagnosis of occlusive clot at base hospital

• Repeat imaging always

• Quick assessment and transfer to angiosuite

• This case worked well as list in peripheral hospital was covered by a new consultant who was our trainee the previous week !

Lucky

• 44 yr old female High NIHSS

• Wake up presentation ( last well within 12 hrs)

• Wednesday morning

• CT at 09:17 CTA at 09:30

• Decided to leave alone as a wake up stroke

• Neuroradiology meeting in DGH 10 am

• Neuroradiologist arrives a bit early

• Imaging reviewed

• Discucssed with RVH team

• Transfer ASAP

• CT repeat in RVH 11:35 at our 12hr from well cut off

ASPECTS 8 on transfer

Perfusion still good

Complete occlusion at origin of carotid and multiple Intracranial

M1,A1,P2 occlusions

• NHISS from 20+ to 1 next day

• Final Diagnosis of Takayasu arteritis

• Home on dual antiplatlets for stent and immunosupression for underlying disease

Lessons

• Don’t hope for luck

• Educate DGH stroke teams and radiologists

Bad

• 52 yr old male High NIHSS

• CT at 14:32

• Repeat CT , CTA , CTP at 16:44

• No procedure performed

ASPECTS good at base hospital

Lessons

• Patients are transferred for assessment but not always treatment

• Avoid treating patients who are no longer in a position to benefit

Summary

• Get good reliable data to estimate numbers

• Very rigid patient selection based on imaging

• Work as a team

• All members should be willing to meet patient at hospital door

• Occasional cases are easy but some are the most challenging in neuroradiology especially given time pressure

Summary

• The evidence relates to high volume Neuroradiology centers with well established pathways and experienced operators

• We cannot afford a ‘learning curve’ or the treatment will be discredited

• Don’t reinvent the wheel copy best practice