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TARDIS: TCD sub-study

TARDIS: TCD sub-study. TARDIS Investigator Meeting, Nottingham, UK Alice King. Overview. Background Rationale Schedule Method Headset & trans-temporal set-up Equipment & settings Artefact Storage and analysis Interested? Questions. T rans C ranial D oppler.

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TARDIS: TCD sub-study

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  1. TARDIS: TCD sub-study TARDIS Investigator Meeting, Nottingham, UK Alice King

  2. Overview • Background • Rationale • Schedule • Method • Headset & trans-temporal set-up • Equipment & settings • Artefact • Storage and analysis • Interested? • Questions TARDIS TCD sub-study

  3. TransCranial Doppler TCD allows examination of: • Intracranial circulation (arteries e.g. MCA, PCA, ACA, BASILAR) MOVING RBCs reflect/scatter ultrasound back ↓ FREQUENCY shift ↓ ↑ Speed = ↑ Shift ↓ 128 pt Fast Fourier Transform ↓ 3D pulsatile blood flow with cardiac cycle DIRECTION and VELOCITY (y axis) + ve shift = Flow towards probe • ve shift = Flow away from probe TIME (xaxis) Signal INTENSITY - colour spectrum (z axis) • Dynamic cerebrovascular patho-physiology • e.g. Autoregulation, CO2 reactivity, cerebral vasospasm, intra-op monitoring & ES detection TARDIS TCD sub-study

  4. Micro Embolic Signal Detection Gaseous ES = bubbles (e.g. from cavitation, decompression or surgery) Solid ES = thrombi, platelet aggregates and particulate atheroma ↓ Acoustic impedance ES > surrounding blood ↓ scatter/reflect ultrasound waves @ interface Emboli Blood Ratio (EBR) ↓ Large ↑ in the received ultrasound intensity ↓ Visual FFT- high intensity, short duration, unidirectional Acoustic - chirp Frequency focused in blood flow spectra Video of ES, observed in blood flow on Fast Fourier Transform Human observer remains gold standard for ES detection TARDIS TCD sub-study

  5. Rationale • EMBOLIC stroke > 50% ALL stroke • Arise from: Heart OR Large arteries – carotid stenosis • Risk recurrent stroke is HIGH • Secondary prevention  ANTI-THROMBOTICS • Clinical trials evaluate regimens & novel therapies • Endpoints • Stroke - 4% per annum •  25% with new treatment • SAMPLE SIZE 14178 • Sensitive surrogate marker – present in 50% •  30% with new treatment • SAMPLE SIZE 242 TARDIS TCD sub-study

  6. ES are a surrogate marker • Stroke/TIA outcome infrequent • ES detected by TCD = Surrogate marker • ES are more frequent in acute stroke/TIA • ES are predominantly asymptomatic • Predict risk • In vivo TARDIS TCD sub-study • BEFORE vs. AFTER treatment • DUAL vs.TRIPLE ANTI-PLATELET • ES repeatedly shown to be attenuated by anti-thrombotic therapy • E.g. CARESS (symptomatic carotid stenosis) A + C > A alone TARDIS TCD sub-study

  7. ES are frequent in acute stroke • ES have been consistently shown in acute ischaemic stroke • 9.3 - 71% patients (Daffertshofer et al 1996, Babikian et al 1994, Babikian et al 1997, Del et al 1997, Grosset et al 1994, Koennecke et al 1998, Forteza et al 1996, Tong et al 1995, Lund et al 2000, Iguchi et al 2007, Droste et al 2000, Gao et al 2004, Ghandehari et al 2002, Goertler et al 2002, Serena et al 2000, Valton et al 1998 & Kaposzta et al 1999) • Most frequent • large artery stroke • cardio-embolic stroke TARDIS TCD sub-study

  8. Carotid stroke in evolution TARDIS TCD sub-study

  9. Carotid stroke in evolution TARDIS TCD sub-study

  10. Carotid stroke in evolution TARDIS TCD sub-study

  11. Carotid stroke in evolution TARDIS TCD sub-study

  12. Carotid stroke in evolution TARDIS TCD sub-study

  13. Carotid endarterectomy ES common in post-op period TARDIS TCD sub-study

  14. Asymptomatic embolism is probably much more common TARDIS TCD sub-study

  15. Stroke/TIA Stroke ALONE ES predict risk stroke/TIA: acute stroke – 8 studies, n=737 TARDIS TCD sub-study

  16. CARESS: Study Design Randomised, double-blind, placebo-controlled >50% symptomatic carotid stenosis N = 230 screened; 110 MES positive included D0 D1 D7 ± 1 D-1 Clopidogrel 75 mg o.d. Clopidogrel 300 mg Clopidogrel R ASA 75 mg o.d. to all patients from D1 to D7±1 Screening Placebo Placebo Placebo o.d. MES detection MES detection MES detection Markus et al Circulation 2005 TARDIS TCD sub-study

  17. CARESS: Results - Primary Endpoint Day 7 RRR 37.3% (9.7 - 56.5) p=0.011 24 hr RRR 25.2% (-1.0 - 44.7%) p=0.078 TARDIS TCD sub-study

  18. CARESS:Recurrent cerebral ischaemic events Clopidogrel and ASA (n=51) Placebo and ASA (n=56) TIA Ischaemic stroke TIA / Isch stroke IS / MI / CV Death 8 4 12 4 5 0 5 1 TARDIS TCD sub-study

  19. Stroke/TIA recurrence Yes N = 17 21.6 (28.3) 14.7 (20.3) No N = 85 8.4 (11.1) 5.1 (8.9) p 0.0017 0.0026 MES rate per hour Baseline 24 hr CARESS: MES rate and recurrent events TARDIS TCD sub-study

  20. CARESS:Correlations with any recurrent TIA/stroke R p TCD : MES /hr Baseline Day 7 PLATELET AGGREGATION % max intensity Baseline Day 7 -0.308 0.308 0.119 0.190 0.001 0.002 0.296 0.104 TARDIS TCD sub-study

  21. Schedule Written Informed Consent  TCD – 60 MINUTES Bloods  Randomisation mRS NIHSS  TCD – 60 MINUTES Safety Tolerability  END of TCD sub-study Day 0 Day 3±1 TARDIS TCD sub-study

  22. Method TARDIS TCD sub-study

  23. Method TARDIS TCD sub-study

  24. Method: Set-up • TCD machine ON • Enter patient TARDIS ID & day 0 or day 3 • Monitoring mode • Securely attach headset • Make sure patient is as comfortable as possible! • Trans-temporal identification of the ipsilateral MIDDLE cerebral artery (MCA) • Steps 4/5 interchangeable depending on personal preference BUT ***************Take time to make sure the optimal signal is identified *************** TARDIS TCD sub-study

  25. MCA territory (red) Henry Gray (1821–1865).  Anatomy of the Human Body.  1918. via http://bartleby.com TARDIS TCD sub-study

  26. Trans-temporal identification of MCA TARDIS TCD sub-study

  27. Equipment and Settings • To aid identification of MCA • sample volume to 10mm &  GAIN • WEAR STEREO HEADPHONES • Use M-mode • Optimal signal identified & patient is as comfortable as possible… TARDIS TCD sub-study

  28. Recording • Start recording… • Single channel recoding (Settings menu) • click curve recording on • either by using Doppler menu or REC button and record for 1 hour EXACTLY NB: make sure curve recording and CONTINUOUS SOUNDTRACK are ON there should be a blue dot in top RHS next to speaker icon • Make a note of the settings used - this will help with the follow up! • Depth • Spatial orientation • Sample volume TARDIS TCD sub-study

  29. Artefact Examples: Tapping/touch headset Adjusting probe Chewing Talking Laughing Mackinnon AD, Aaslid R, Markus HS: Long-Term Ambulatory Monitoring for Cerebral Emboli Using Transcranial Doppler Ultrasound. Stroke 2004;35:73-78 TARDIS TCD sub-study

  30. Storage and analysis • Archive the recordings onto CD/DVD • Analysis • Central analysis • Centre for Clinical Neuroscience, SGUL, LONDON • Blinded to treatment and patient identity • Recordings will be immediately check upon receipt • Feedback to centres • Quality control • Constructive criticism of any problems • International consensus criteria, 7dB threshold • 2 EXPERIENCED observers review (PI reviews each ES) TARDIS TCD sub-study

  31. Summary • ES detected by TCD • surrogate marker in vivo • anti-platelet efficacy & prediction of risk • previously shown e.g. in large international CARESS study • TCD non-invasive & painless • Only two 60 min recordings • Only for first 3 days • Central analysis • Support & feedback from experienced centre TARDIS TCD sub-study

  32. Interested???? More centres =  sample size  power • Contact TARDIS co-ordinating centre e.g. details of TCD machine (continuity and analysis) • Send 1 hour TCD test recording on CD/DVD to: Alice King Centre for Clinical Neuroscience St George's University of London Cranmer Terrace London SW17 ORE WE WILL provide feedback: • Quality control • Constructive criticism • START RECRUITING TARDIS TCD sub-study

  33. Thank-you Prof. Hugh Markus Prof. Philip Bath Margaret Adrian TARDIS TCD sub-study

  34. Questions???? Alice King aking@sgul.ac.uk Centre for Clinical Neuroscience St George's University of London Cranmer Terrace London SW17 ORE Tel: 020 8725 2735 or 020 8725 0961 Fax: 020 8725 2950 TARDIS TCD sub-study

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