ACUTE CORONARY SYNDORME EARLY RISK STRATIFICATION

1. ACUTE CORONARY SYNDORME EARLYRISK STRATIFICATION Sarah Jamison March 2003

2. Overview • Definition of Acute coronary syndrome (ACS) • Factors used to determine risk stratification • History • Examination • ECG changes • Biochemical cardiac markers • Initial management

3. Definitions – Acute coronary syndrome • Any constellation of clinical symptoms that are compatible with acute myocardial ischemia. • It encompasses a spectrum from AMI  NSTEMI UA • NSTEMI – acute process of myocardial ischemia resulting in myocardial necrosis.The initial ECG does not show ST elevation

4. Definitions – Acute coronary syndrome • UA – an acute process of myocardial ischemia that does not result in myocardial necrosis

5. Why be concerned re risk stratification……… • 1) Are the symptoms a manifestation of ACS • 2) Therapy/ site of care will vary dependent on diagnosis • 3) To determine prognosis/short term survival

6. HISTORY

7. History – diagnosing ACS • 5 most important factors that relate to the likelihood of ischemia due to CAD… • 1) Nature of the anginal symptoms • 2)Prior Hx of CAD • 3)Sex • 4)Age • 5)Number of traditional risk factors present • Beware – women and elderly

8. History – diagnosing ACS • High – Chest/L) arm pain as chief symptom,similar to previous angina Known Hx of CAD (including MI) • Intermediate – Chest/L) arm pain as chief symptom Age>70yrs/Male/Diabetes • Low– Probable ischemic symptoms in absence of any of the intermediate likelihood characteristics Recent cocaine use

9. History – short term risk of death or nonfatal MI in unstable angina • High – Accelerating tempo of ischemic symptoms in preceding 48hrs Pain – Prolonged ongoing (>20min) rest pain • Intermediate – Prior MI, peripheral or CVS/CABG/Aspirin use Pain – Prolonged (>20min) rest angina, now resolved, with moderate or high likelihood of CAD. Rest angina (<20min) or relieved with rest or SL NTG

10. History – short term risk of death or nonfatal MI in unstable angina • Low – New onset or progessive angina (Marked limitiation/or inability to carry out any physical activity) over the past 2/52. Without prolonged (>20min) rest pain but with moderate or high likelihood of CAD  In patients that meet diagnostic criteria for UA/NSTEMI, the recent tempo of ischemic symptoms is the strongest predictor of risk of death

11. PHYSICAL EXAMINATION

12. Examination - diagnosing ACS • High – Transient MR, hypotension,diaphoresis, pulmonary oedema • Intermediate – Extracardiac vascular disease • Low – Chest discomfort reproduced by palpation

13. Examination - short term risk of death or nonfatal MI in UA • High – Pulmonary odema, most likely secondary to ischemia New or worsening MR murmur S3 or new/worsening creps Hypotension / Bradycardia / Tachycardia Age > 75yrs • Intermediate – Age >70yrs

14. Examination - short term risk of death or nonfatal MI in UA  Cardiogenic shock occurs in up to 5% of patients with NSTEMI and mortality rates are greater than 60%

15. THE ECG

16. ECG - diagnosing ACS • High – New, or presumably new, transient ST- segment deviation ( 0.05 mV) or T-wave inversion ( 0.2mV) with symptoms • Intermediate – Fixed Q waves / Abnormal ST segments or T waves not documented to be new • Low – T wave flattening or inversion in leads with dominant R waves / Normal ECG

17. ECG - diagnosing ACS • A completely normal ECG in a patient with chest pain DOES NOT exclude the possibility of ACS. - 1-6% of these patients it will be proven that they have had a NSTEMI -  4% will be diagnosed with unstable angina

18. ECG - short term risk of death or nonfatal MI in unstable angina • High – Angina at rest with transient ST-segment changes > 0.05mV Bundle – branch block, new or presumed new Sustained ventricular tachycardia • Intermediate – T wave inversion >0.2mV Pathological Q waves • Low – Normal/unchanged ECG during an episode of chest pain

19. ECG - short term risk of death or nonfatal MI in unstable angina • Risk factors ranked in order for risk of death in patients with ACS • 1) Confounding ECG patterns – bundle branch pattern,paced rhythm, LV hypertrophy • 2) ST segment deviation • 3) Isolated T wave inversion or normal ECG ECG pattern remains an independent predictor of death, after adjusting for clinical findings and biochemical cardiac markers

20. Biochemical cardiac markers

21. Biochemical cardiac markers • Useful in both the diagnosis of myocardial necrosis and estimation of prognosis • Prognosticaly there is a quantitative relationship between the magnitude of elevation of marker levels and the risk of an adverse event

22. BCM - diagnosing ACS • High – Elevated troponins or CK-MB • Intermediate – Normal • Low - Normal

23. A- myoglobin/CK-MB isoforms after AMI B – Cardiac Troponin after AMI C - CK-MB after AMI D – Cardiac Troponin after UA

24. BCM - short term risk of death or nonfatal MI in unstable angina • High– Elevated TnT > 0.1 ng/ml • Intermediate – Slightly elevated TnT (> 0.01 but <0.1 ng/ml) • Low - Normal

25. BCM – Creatine Kinase (CK-MB) • Advantages- Rapid, cost- efficient accurate assays. Able to detect early reinfarction • Disadvantages – Loss of specificity Low sensitivity during very early MI (6hr after sxs onset) or later after sxs onset (>36hr) and for minor myocardial damage

26. BCM – CK-MB isoforms • Advantages – Early detection of early MI (3-6hrs after onset of sxs) • Disadvantages – Specificity profile similar to that of CK-MB Current assays require special expertise (used predominately in research centers)

27. BCM - Myoglobin • Advantages – High sensitivity Useful in early detection of MI (2hrs after onset of sxs) Most useful in ruling OUT a MI • Disadvantages - Very low specificity in setting of skeletal muscle injury or disease Rapid return to normal • Should not be used in isolation

28. BCM – Cardiac Troponins • Advantages - Powerful tool for risk stratification Greater sensitivity and specificity than CK-MB Detection of recent onset of MI up to 2 wks after onset Useful for selection of therapy

30. BCM – Cardiac Troponins • Disadvantages - Low sensitivity in very early phase of MI (< 6hrs after onset of sxs) and requires repeat levels Limited ability to detect late minor reinfarction

31. BCM – Other markers • CRP– Patients without biochemical evidence of myocardial necrosis but who have an elevated CRP are at an increased risk of an adverse outcome • Other – Elevated levels of interleukin-6, serum amyloid A, have similar predictive value as CRP

32. Putting it together - management • Assign patients with chest pain to 1 of 4 groups • 1) Noncardiac • 2) Chronic stable angina • 3) Possible ACS • 4) Definite ACS

34. Putting it together • Most important baseline features assoc with death (Boersma et al) Age Heart rate Systolic BP ST- segment depression Signs of heart failure Elevation of cardiac markers

35. Putting it together • 7 point risk score (Antman et al) Age (>65yrs) More than 3 coronary risk factors Prior angiographic coronary obstruction ST – segment deviation More than 2 angina events within 24hrs Use of aspirin within 7 days Elevated cardiac markers

36. ANY QUESTIONS???????

37. Summary • Risk stratification in ACS involves assessment of History Examination ECG Biochemical cardiac markers • Risk stratification is used in determining management and assessing prognosis

38. Summary • High risk patients – 1.7% risk of death after 30 days • Intermediate patients – 1.2% risk of death after 30 days • Low risk patients – no death after 30 days