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Leeds Nuffield Hospital – November 2006 www.johnperrins.com Case Studies in Cardiology Over-Active Implantable Devices!! Dr John Perrins MD FRCP FACC Consultant.

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Presentation on theme: "Leeds Nuffield Hospital – November 2006 www.johnperrins.com Case Studies in Cardiology Over-Active Implantable Devices!! Dr John Perrins MD FRCP FACC Consultant."— Presentation transcript:

1 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Case Studies in Cardiology Over-Active Implantable Devices!! Dr John Perrins MD FRCP FACC Consultant Cardiologist – Leeds UK Member Committee of Safety of Devices

2 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Case Studies  An angioplasty balloon which gets stuck inside a heart artery  A Pacemaker lead which stabs the patient through the heart

3 Leeds Nuffield Hospital – November 2006 www.johnperrins.com 83 87 PCI centres Angiography only Centres UK PCI CENTRES 2005

4 Leeds Nuffield Hospital – November 2006 www.johnperrins.com PCI vs Isolated CABG Numbers (UK) 1991 to 2005 2005 data: Ludman

5 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Coronary angiography

6 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Normal Right Coronary Artery

7 Leeds Nuffield Hospital – November 2006 www.johnperrins.com The problem

8 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Angioplasty and Stenting

9 Leeds Nuffield Hospital – November 2006 www.johnperrins.com An Actual PCI Procedure

10 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Boston Scientific Taxus Express Stent System MDA/2004/033, MDA/2004/036  Failure of some balloons to deflate following stent insertion.  Very large product recall complicated by shelf life and large stocks  UK recall approx 15000 units- extended to 16,000 taxus and 23,000 express stents in 2004/36 notice.  2 Deaths + 25 severe myocardial infarctions worldwide

11 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Taxus Express Balloon Design Inflation/deflation port Balloon At high pressure the inflation/deflation tube partially collapses inside the balloon preventing complete emptying of the balloon

12 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Taxus Express consequences  Very expensive to the company  Boston produced a new manufacturing step which they say eliminates the problem  MHRA says it has reviewed corrective action by the company  Taxus superseded by a new stent the Taxus Liberte which Boston says is unaffected.

13 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Taxus Express  Who should the User believe?  Should the Trust have a view as to a particular company’s overall propriety?  Is follow up required from this notification  Are your supplies departments included in the MDA alert cascade?  I personally only use a Boston Stent if there is no other alternative available.

14 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Inventory control – Yorkshire Heart Centre  6 Cardiac Catheter Laboratories  4000 Interventions per year  96 % stent usage, 1.7 stents per case  50% of cases are acute transfers  800 separate consumable stock items  Many have short use by dates  £30-50,000 spend per day on intervention  Approx £1,000,000 stock held

15 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Dual Chamber Pacemaker Insertion Pacing rate / million Leeds PCT’s– Age corrected 2005 Network average 359 National average 411

16 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Dual-Chamber Pacing Atrial ‘J’ Lead ‘Straight’ Ventricular Lead

17 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Bipolar Pacing Lead Construction Outer insulation Outer coil (Anode) Inner insulation Inner coil (Cathode )

18 Leeds Nuffield Hospital – November 2006 www.johnperrins.com IS-1 / VS-1 Bipolar Lead Connector Sealing Rings Terminal Pin Proximal Ring

19 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Fixation Mechanisms Active fixation Screw-in lead Passive fixation Tined tip Passive fixation Finned tip

20 Leeds Nuffield Hospital – November 2006 www.johnperrins.com The Inside View

21 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Atrial “J” Lead

22 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Pacemaker Lead Positioning

23 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Telectronics Accufix J retention wire Problem  MDA Hazard (94)24 November 1994  MDA Technical Note No54 November 1994  MDA Safety Alert No 55 May 1995  MDA Technical Note No59 October 1995  MDA Pacemaker Technical Note No64 Sep 1996  MDA Safety Alert No 69 October 1997  MDA Safety Alert No 72 August 1998

24 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Accufix Retention Wire – Solid rectangular section stainless steel Bipolar Conductor Retention wire is separate and insulated from the main conductors

25 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Accufix Retention Wire – Solid rectangular section stainless steel Bipolar Conductor Retention wire fractures and gradually extrudes outside of the wire body

26 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Accufix lead problem  Wire fracture very difficult to see  Very high quality X-ray screening needed in a digital cardiac cath lab.  Wire fracture has no effect on lead performance so no simple way to detect it

27 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Early Fracture

28 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Near full extrusion

29 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Accufix lead Problem  Extruded wire could puncture through heart into the aorta  Initially 6 Deaths and 13 serious injuries in the USA from Tamponade (Blood around the heart)  Initially occurred months or even years after implant  But removal of pacemaker leads carries a risk

30 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Accufix Initial advice  All product withdrawn  All leads to be screened in cath lab 6 monthly  Consider explant of obviously faulty leads  ? Explant all leads  2 Deaths in US from lead explantation

31 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Telectronics  J-wire was used in other leads  Warnings extended to all Telectronics leads with a J- wire, company initially notified only one lead type.  Companies Never disclose everything!!!  Telectronics company dissolved  Accufix foundation set up to handle litigation and limit liability  This problem stimulated new devices and technologies for pacemaker lead removal

32 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Accufix – Personal Experience  124 leads Implanted  23 Extracted  No Deaths  30 leads STILL IMPLANTED!!  Last MDA technical note 1998  I no longer screen the leads but some do

33 Leeds Nuffield Hospital – November 2006 www.johnperrins.com Conclusions  What is the likely duration of a Device Alert?  Should recalls call into question manufacturer’s reputations ?  Who should make those judgements ?  How do you know if an alert is a balanced risk re action or inaction ?  Please talk to your clinicians more in cardiology.  High risk areas are cardiology, interventional radiology, theatres and ITU.  We all need more detailed information from MHRA Alerts which should either be longer or have a technical appendix  Never believe anything anyone tells you!

34 Leeds Nuffield Hospital – November 2006 www.johnperrins.com SOD’S Law for Devices If it can ******* break Then it will ***** break Nobody likes bad news Therefore Hazard warnings are always too late The Scale of the problem is always underestimated The solution is always over optimistic


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