Case Studies in Cardiology Over-Active Implantable Devices!!

1. Case Studies in CardiologyOver-Active Implantable Devices!! Dr John Perrins MD FRCP FACCConsultant Cardiologist – Leeds UK Member Committee of Safety of Devices

2. Case Studies • An angioplasty balloon which gets stuck inside a heart artery • A Pacemaker lead which stabs the patient through the heart

3. UK PCI CENTRES 2005 PCI centres 83 Angiography only Centres 87

4. 2005 data: Ludman PCI vs Isolated CABG Numbers (UK)1991 to 2005

5. Coronary angiography

6. Normal Right Coronary Artery

7. The problem

8. Angioplasty and Stenting

9. An Actual PCI Procedure

10. Boston Scientific Taxus Express Stent SystemMDA/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. Taxus Express Balloon Design Balloon Inflation/deflation port At high pressure the inflation/deflation tube partially collapses inside the balloon preventing complete emptying of the balloon

12. 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step which they say eliminates the problem • MHRA says it has reviewed corrective action by the company • Taxus superseded by a new stent the Taxus Liberte which Boston says is unaffected.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. 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. 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. Dual Chamber Pacemaker Insertion Pacing rate / million Leeds PCT’s– Age corrected 2005 National average 411 Network average 359

16. Atrial ‘J’ Lead Dual-Chamber Pacing ‘Straight’ Ventricular Lead

17. Bipolar Pacing Lead Construction Inner insulation Inner coil (Cathode ) Outer coil (Anode) Outer insulation

18. IS-1 / VS-1 Bipolar Lead Connector Sealing Rings Proximal Ring Terminal Pin

19. Fixation Mechanisms Active fixation Screw-in lead Passive fixation Finned tip Passive fixation Tined tip

20. The Inside View

21. Atrial “J” Lead

22. Pacemaker Lead Positioning

23. 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. Accufix Retention Wire – Solid rectangular section stainless steel Retention wire is separate and insulated from the main conductors Bipolar Conductor

25. Accufix Retention Wire – Solid rectangular section stainless steel Retention wire fractures and gradually extrudes outside of the wire body Bipolar Conductor

26. 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. Early Fracture

28. Near full extrusion

29. 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. 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. 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. 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. 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. 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