Acute Coronary Syndrome: GP Essentials

1. Spencer Toombes FRACP Acute Coronary Syndrome: GP Essentials

3. Learning Plan... • Challenges of assessing patients with chest pain... • Terminology & Pathophysiology • ECG interpretation • Use of Troponin • Risk Assessment • Inpatient management - how and when to transfer • Post-discharge management

4. 5 min task in pairs: • For each of the following scenarios... What is the most likely diagnosis? What is this patient’s risk of having an Acute Coronary Syndrome?

5. 68 yo man: • Complaining of intermittent central chest pain. • Previous ischaemic heart disease: Coronary angiogram 2 years ago showed 40% LAD and 30% RCA stenosis. • Managed medically. • Has noticed over the past 2 months that he needs to use his GTN spray whenever he exerts himself.

6. The same 68 yo man: • What if he had received a stent 5 months ago?

7. 68 yo woman: • Recent sharp, stabbing pain adjacent to her left sternum. • There doesn’t seem to be a clear precipitant. • She feels a bit washed out, but otherwise reasonably well. …but she is a Type II diabetic.

8. 46 yo man: • 10 minutes of central chest heaviness after he finished mowing the lawn • Associated with pallor and breathlessness • His wife thought he looked ill and talked him into coming up to your practice. • Positive family history, heavy smoker.

9. Differential Diagnosis of Chest Pain: (Includes biliary)

10. Prevalence of MSK chest Pain:Depends on the site at which you study!

11. Cardiac Oesophageal 28% 14% 60% 37% 10% 23% 100% 100% 49% 35% 5% 18% 33% 12% Back 12% Back 33% Cardiac vs Oesophageal Chest Pain:is not distinguished by Site of Radiation Bennett et al. Lancet. 1966

12. More difficulties in evaluating the Patient with Chest Pain: • Intensity of Pain - no indication of severity. • Nature of Pain - no indication of diagnosis: • 5-19% acute coronary syndromes ‘sharp’ or pleuritic. • Physical Signs - no indication of diagnosis: • 15% AMI patients have chest wall tenderness. • ‘Atypical’ Presentations: • Up to 25% patients with ACS do not present with “classical” chest pain.

13. Terminology: define in pairs... • Acute Coronary Syndrome (ACS) • Stable angina • Unstable angina • Myocardial ischaemia • Q wave infarction • Non-Q wave infarction • STEMI... STEACS • Non-STEMI... Non-STEACS

14. Pathophysiology:Components of atheroma plaque -

15. Pathophysiology:Safe or Stable plaque: • little cholesterol content • thick fibrous cap • low risk of rupture The proportion of the lumen occluded determines the degree of exercise related ischaemia, and the severity of symptoms.

16. Safe Plaque - Chronic Stable Angina

18. Pathophysiology:Unsafe / Unstable Plaque • Lotsof Low Density Lipoprotein Cholesterol • Thin fibrous cap • Lots of inflammation: • Activated T cells, Macrophages, Foam Cells • Mediators: Cytokines and C reactive protein HIGH RISK OF RUPTURE

19. Unsafe Plaque - Potential for trouble!

21. Acute Coronary Syndromes:Plaque rupture: Acute clot formation.

22. ACS / Dynamic Clot formation:Spectrum of Possible Outcomes - • Dynamic Partial Occlusion: No damage • Worsened Angina pain, possible ECG change • No cardiac enzyme rise • Dynamic Partial Occlusion: Some damage • Worsened Angina pain, probable ECG change • Rise in cardiac troponin, +/- creatinine kinase • Complete Occlusion: • Full thickness myocardial infarction • ST segment elevation, Q wave formation if not treated

25. Chest Pain: Getting the basics right... • Rapid assessment. • Observed environment. • Aspirin 300mg. • ECG within 10 minutes of presentation.

26. 12 Lead ECG interpretation: • STEMI: requires immediate reperfusion • Everything else: still requires risk assessment.

34. Or maybe it looks like this...

36. Cardiac Troponin Complex: Tnl TnC TnT Ca++ Tropomyosin Actin

37. Cardiac Troponin: • Exquisitely sensitive marker of myocardial distress... not necessarily muscle necrosis • Onset 4-6, peak 24-36 hours, offset 7 days • Normal initial troponin is NOT reassuring • Normal 12 hour troponin is quite reassuring

38. Risk Stratification using ECG & Tn testing(mod. from NEJM 337:1648-53)

39. Troponin T and probability of death Lindahl NEJM 2000 343:16;1139-47

40. Practice Points: Troponin • Don’t necessarily mean ACS... • Pulmonary embolus • Left ventricular failure • Renal failure • Sepsis • True false positives related to assay • Immune cross reactivity

41. Practice Points: Troponin GENERALLY DO NOT ORDER IN GENERAL PRACTICE

42. Diagnosis of ACS evolves over time… Presentation of ACS (clinical presentation, initial ECG) Working diagnosis STEMI NSTEACS Time Evolution of ECG and biomarkers Myonecrosis confirmed Myonecrosis not confirmed Final diagnosis STEMI NSTEMI Unstable angina ACS = acute coronary syndromes; ECG = electrocardiogram; STEMI = ST-segment-elevation myocardial infarction; NSTEACS = non-ST-segment elevation acute coronary syndromes; NSTEMI = non-ST-segment elevation myocardial infarction Acute Coronary Syndrome Guidelines Working Group. Med J Aust 2006;184(8 Suppl):S9-29.

43. 68 yo man: • Complaining of intermittent central chest pain. • Previous ischaemic heart disease: Coronary angiogram 2 years ago showed 40% LAD and 30% RCA stenosis. • Managed medically. • Has noticed over the past 2 months that he needs to use his GTN spray whenever he exerts himself.

44. 68 yo woman: • Recent sharp, stabbing pain adjacent to her left sternum. • There doesn’t seem to be a clear precipitant. • She feels a bit washed out, but otherwise reasonably well. …but she is a Type II diabetic.

45. 46 yo man: • 10 minutes of central chest heaviness after he finished mowing the lawn • Associated with pallor and breathlessness • His wife thought he looked ill and talked him into coming up to your practice. • Positive family history, heavy smoker.

46. For each of these patients: What is their risk of having an Acute Coronary Syndrome?

49. These patients can be managed with upgrade to their anti-anginal medications and outpatient referral for cardiac investigation.

50. These patients generally require emergency admission to a monitored environment, and aggressive drug therapy including parenteral anticoagulants.