Anti-Thrombotic Therapy in Atrial Fibrillation Medicolegal Issues in Cardiology

1. Anti-Thrombotic Therapy in Atrial FibrillationMedicolegal Issues in Cardiology Dr Miles WH Behan Consultant Cardiologist Royal Infirmary of Edinburgh Clinical Negligence Conference Edinburgh 29th April 2019

2. Anti-Thrombotic Therapy in Atrial Fibrillation and Myocardial Infarction • Atrial Fibrillation • Background • Antithrombotic Therapy • Medicolegal Issues

3. Atrial fibrillation

4. ATRIAL FIBRILLATION • AF is caused by abnormal electrical impulses firing in the atria, overriding the heart's natural pacemaker, which can no longer control the rhythm of the heart • Commonest cardiac arrhythmia • 1-2% population • 25% over 40’s will have episode • Much commoner >75 years • Major cause of morbidity

5. Epidemiology of Atrial Fibrillation Prevalence of AF by age and sex3 Prevalence in Scotland considered to be ~1.71% 1 In the UK the prevalence increases with age and men tend to be more commonly affected than women2,3 In the UK 85% of people are diagnosed with AF aged ≥ 65 years4 AF is becoming more prevalent due to the rising population4 AF= all types of atrial fibrillation; ISD = Information Services Division Scotland; NICE=National Institute for Health and Care Excellence ISD QOF data 2014/2015 http://www.isdscotland.org/Health-Topics/General-Practice/Quality-And-Outcomes-Framework/2014-15/Register-and-prevalence-data.asp accessed on 25.09.17; NICE Clinical Guideline 180. Atrial fibrillation: the management of atrial fibrillation – methods, evidence and recommendations. June 2014; Davis et al. Eurospace 2012;14:1553‒1559; NICE. Support for commissioning anticoagulant therapy. Commissioning guide 49. Published 14 May 2013

6. Prevalence of Atrial Fibrillation in Scotland Numbers of patients on general practice QOF registers for atrial fibrillation with crude rates per 100 patients, by NHS Board 2014/2015¹ AF = all types of atrial fibrillation 1. ISD QOF data 2014/2015 http://www.isdscotland.org/Health-Topics/General-Practice/Quality-And-Outcomes-Framework/2014-15/Register-and-prevalence-data.asp accessed on 25.09.17

7. AF: morbidity and mortality • AF independently increases the risk of mortality and morbidity due to: • Stroke and thromboembolism1 • Congestive heart failure1 • Impaired quality of life1,2 • In the general population, AF is responsible for 20% of all strokes3 • AF-related stroke is associated with increased morbidity and mortality1: High healthcare cost and public health burden1 1. Lip et al. Lancet 2012;379:648–61; 2. Thrall et al. Am J Med 2006;119:448.e1–448.e19; 3. Marini et al. Stroke 2005;36:1115–9.

8. Atrial Fibrillation is associated with significant clinical burden • Risk of stroke in AF and non-AF patients1 2-year age adjusted incidence of stroke/1000 • Mortality at 1-year after ischaemic stroke in AF and non-AF patients2 • 50 • Strokes in AF • Non-AF strokes • 40 • 5x • 30 • AF patients have a near 5-fold increased risk of ischaemic stroke • Fatal, • 27.1% • Fatal, • 49.5% • Non-fatal, • 50.5% • 20 • Non-fatal, • 72.9% • 10 • 0 • AF patients • Non-AF patients • Risk ratio 4.8 In Scotland in 2016 2,315 ischaemic stroke patients had AF on admission3 639 (27.6%) were on anticoagulation at onset of the cerebrovascular event3 This data appear to show that many patients with AF are still not receiving anticoagulants to help reduce their risk of future stroke3 AF=all types of atrial fibrillation Wolf et al. Stroke 1991;22:983‒988; 2. Marini et al. Stroke 2005;36:1115‒1119; 3. NHS National Services Scotland, Scottish Stroke Improvement Programme Report 2017.

9. AF CAUSES

10. AF TERMS Paroxysmal, persistent and permanent all have the same thrombotic risk

11. SYMPTOMS • The most obvious symptom of AF is a fast and irregular heartbeat (palpitations) – usually over 100 beats a minute • Other symptoms: • Tiredness • Breathlessness • Dizziness • Angina • The way the heart beats in AF reduces the heart's efficiency and performance – this can result in low blood pressure and heart failure

12. ECG ATRIAL FIBRILLATION

13. ASSESSMENT

14. STROKE RISK- CHADSVASC SCORE • 1-year risk of stroke by score (0-0.84%, 1-1.75%, 2-2.69%, 3- 3.2%) • Warfarin for score ≥1 • Aspirin only for patients unable to tolerate OAC • Score 0 need no treatment

15. HASBLED SCORE Predicts bleeding risk (ICH) Score ≥ 3 patients should be anticoagulated with caution and remain under regular review

16. SIGN GUIDELINES

17. WARFARIN • Introduced 1948 • Vitamin K antagonist (prothrombin and factor VII) • Pesticide against rats and mice • Found to be safe for prevention of thromboembolism • Clinically approved in USA 1954 • Wisconsin Alumini Research Foundation (+arin) • Shortcomings: • Interactions • Monitoring • Bleeding

18. NOACs Simulium (black fly) NAPc2 (dog hookworm) Hirudin (Medicinal leech)) Rhodniin (Assassin bug) Draculin (vampire bat) Tick anticoagulant peptide AntiXa inhibitors Anti-thrombin inhibitors

19. NEW ORAL ANTIOCOAGULANTS

20. SIGN GUIDELINES

21. ATRIAL FIBRILLATION- MEDICOLEGAL ISSUES

22. CASE Mr A

23. CASE Mr A

24. CASE Mr B

25. CASE Mr B

26. ATRIAL FIBRILLATION • Common condition • Increasingly recognised • Major morbidity with strokes • Clear guidelines for treatment • New drugs available • Medicolegal issues