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Acute Coronary Syndromes

Acute Coronary Syndromes. Adam Oster, R4. Dr. Gill Curry, FRCP Core Rounds. July 8, 2004. Topics. Master of the ECG Evidence for various therapeutic interventions NSTEMI Risk Stratification Thrombolysis AMI in LBBB Pre-hospital lytics Cardiogenic shock. ACS Rounds.

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Acute Coronary Syndromes

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  1. Acute Coronary Syndromes Adam Oster, R4. Dr. Gill Curry, FRCP Core Rounds. July 8, 2004.

  2. Topics • Master of the ECG • Evidence for various therapeutic interventions • NSTEMI Risk Stratification • Thrombolysis • AMI in LBBB • Pre-hospital lytics • Cardiogenic shock

  3. ACS Rounds 55M with atypical chest pain for 60mins

  4. Hyperacute T waves

  5. Hyperacute T waves • Early sign of infarct • Normal T <7mm • Hyperacute >8mm • Ischemic are more symmetric • Upgoing side still slopes up gradually • Other Causes; • Hyperkalemia (steep and sharp) • LVH • LBBB

  6. Master of the ECG • Progression of changes…

  7. STE

  8. Evolving STEMI

  9. Evolving STEMI

  10. Post-STEMI 3 weeks

  11. Case

  12. Case

  13. Case

  14. Role of the 15 lead • Inferior MI • RV infarct occurs in 25% of inferior MIs • Different therapeutic and resuscitation needs • Posterior MI • Dorsal region of LV • Usually LCX or RCA-posterior descending branch

  15. Limitations of the ECG • Specificity approx 50% for ischemia • The normal or non-diagnostic ECG

  16. Special ECGs

  17. LM Disease

  18. Wellens’ Syndrome

  19. Wellens’ Syndrome: T Wave Inversion

  20. Pope et al.Missed Diagnoses of Acute Cardiac Ischemia in the Emergency Department. New England Journal of Medicine vol. 342, no. 16, 2000. • 10 689 patients • Data collected for 30d (hospitalised patients) or at 24 to 72hrs for non-hospitalised patients • Outcomes assigned by physicians at study sites using pre-defined criteria

  21. Pope et al.Missed Diagnoses of Acute Cardiac Ischemia in the Emergency Department. New England Journal of Medicine vol. 342, no. 16, 2000. • Final Diagnosis • 1866 (17%) ACI • 894 (8.5%) AMI • 972 (9%) unstable angina • 21% non-ischemic cardiac problem • 55% non-cardiac

  22. Pope et al.Missed Diagnoses of Acute Cardiac Ischemia in the Emergency Department. New England Journal of Medicine vol. 342, no. 16, 2000. • 22 missed unstable angina (2.26%) • MC diagnosis; • stable angina, atypical chest pain

  23. Pope et al.Missed Diagnoses of Acute Cardiac Ischemia in the Emergency Department. New England Journal of Medicine vol. 342, no. 16, 2000. • 19 missed AMIs (2.1% of 894) • MC diagnosis; • non-cardiac chest pain, pulmonary conditions and stable angina

  24. Pope et al.Missed Diagnoses of Acute Cardiac Ischemia in the Emergency Department. New England Journal of Medicine vol. 342, no. 16, 2000. • Factors associated with non-hospitalisation for patients with missed ACI • female • <55 • non-white • chief complaint of SOB • normal ECG • 30d adjusted risk of mortality 1.7 times higher if not hospitalised (95% CI 0.7 to 5.2)

  25. AMI Mortality

  26. 3 Cases of Chest Pain; • 50M with 1hr of RSCP. No known CAD. • No DM/HTN/FHx. Smoker. • ECG normal. 10hr TnT neg • 65F with 120mins RSCP. No known CAD. • T2DM/HTN/recent non-smoker. • ECG non-specific. 10hr TnT neg. • 74M with 3hrs RSCP • prior 4xCABG, daily ASA. • ECG nil acute, TnT positive

  27. ACS Risk Stratification

  28. Thrombolysis in Myocardial Infarction (TIMI):Risk Stratification • Antman et al. JAMA. 2000. Vol. 284, No.7. • TIMI RS based on data from TIMI 11b (N=3910) and ESSENCE (N=3171) • Test cohort (TIMI UFH) • Validation cohort (TIMI and ESSENCE enoxaparin groups and ESSENCE UFH) • TIMI RS derived in test cohort

  29. TIMI Risk StratificationAntman et al. JAMA. 2000. Vol. 284, No.7. • Endpoints • all-cause death, new or recurrent MI or UR at 14d post-randomisation • Eligibility (1 of following) • admitted patients who presented within 24hrs with symptoms of unstable angina/NSTEMI • transient STE or STD or 0.05mV (TIMI) or 0.01mV (ESSENCE) • known CAD* • increased Troponin

  30. TIMI Risk StratificationAntman et al. JAMA. 2000. Vol. 284, No.7 • All patients received ASA • randomised to enoxaparin or UFH • Derivation cohort; • tested 12 candidate variables age ST deviation at least 3 CAD risk factors >2 anginal events in 24hrs significant coronary stenosis use of ASA in last 7d prior MI elevated cardiac markers prior CABG prior history of CHF prior PTCA

  31. TIMI Risk StratificationAntman et al. JAMA. 2000. Vol. 284, No.7 • Derivation cohort • 7 variables remained statistically significant after multivariate analysis • Age >65 • at least 3 CAD RF • STD • severe anginal symptoms • prior stenosis >50% • use of ASA over previous 7d • elevated serum cardiac markers

  32. TIMI Risk StratificationAntman et al. JAMA. 2000. Vol. 284, No.7 • Small numbers of patients in extreme risk scores required combining • criteria of known stenosis >50%, insensitive to missing data and remained a significant predictor

  33. TIMI Risk StratificationAntman et al. JAMA. 2000. Vol. 284, No.7 • Validation Phase • different rate of increase for rate of composite endpoint in UFH vs enoxaparin • merged the databases • TIMI RS and treatment were both significant predictors of risk of the composite endpoint

  34. TIMI Risk StratificationAntman et al. JAMA. 2000. Vol. 284, No.7 • Predicting the individual components of the composite endpoint • all statistically sig.

  35. TIMI Risk StratificationAntman et al. JAMA. 2000. Vol. 284, No.7 • Caveats and Critique • tested on admitted patients with unstable angina/NSTEMI • Validation Phase not prospective • cohort who qualified for enrolment in a phase III study; ?generalisabilty to all-comers with chest pain • enrolment criteria for TIMI 11b changed during the trial • duration of treatment different between UFH (3-8d) and enoxaparin (8d or hospital discharge) • elevated CKMB was both a predictor of an endpoint as well as part of the definition of an endpoint • CKMB was the marker in TIMI but now use Troponin without study to prove similarly predictive

  36. TIMI Risk StratificationAntman et al. JAMA. 2000. Vol. 284, No.7 • Support • consider using on chest pain patients to be admitted • simple to use and to communicate to consultants • cannot use to determine who is at low risk • cannot use to determine who is safe for discharge

  37. How Predictive are Routine Historic Features? • Goodacre et al. How Useful are Clinical Features in the Diagnosis of Acute, Undifferentiated Chest Pain? Academic Emergency Medicine, vol. 9, no. 3, 2002. • Prospectively evaluated 893 CPOU (normal ECG, no CHF or arrhythmia) • ST seg monitoring, troponin T >6hrs, +/-EST or thallium • F/U at 3d and 6mo, 12mo • Endpoints: AMI at presentation and ACS (AMI at any time, pos. EST cardiac death, arrhythmia, revascularisation procedure) • Assessed predictive power of routine historic features

  38. Goodacre et al. How Useful are Clinical Features in the Diagnosis of Acute, Undifferentiated Chest Pain? Academic Emergency Medicine, vol. 9, no. 3, 2002. Features Predictive of AMI:

  39. Goodacre et al. How Useful are Clinical Features in the Diagnosis of Acute, Undifferentiated Chest Pain? Academic Emergency Medicine, vol. 9, no. 3, 2002. Features Predictive of ACS:

  40. Once Risk Stratified…What to give? • ASA • Heparin/LMWH • hirudin • Bblocker • CCB • Nitro • Morphine • O2 • Lytic • Clopidegril (plavix) • G2b3a • Bed Rest

  41. NSTEMI • Acute rupture of plaque • Fibrin and platelets • Incomplete occlusion of CA • ?chlamydial • Inflammatory reaction • Shear forces

  42. Pharmacology...Better Living Through Chemistry

  43. O2 • Makes intuitive sense since imbalance between O2 demand of myocardium and supply • Hypoxemia in AMI most likely caused by V/Q mismatch from LV dysfunction • Evidence to support routine use is weak • Reduces amount of STE in precordial leads with anterior MI • Madias, et al. Circulation 1976.

  44. Anti-Platelet Therapy • ASA • Clopidegril • 2b3a

  45. ASA • ISIS-2 • Randomised AMI to “normal therapy” or ASA or streptokinase • Reduction in mortality with ASA or strepto • ASA RRR 23% • NNT 20 to save 1 life in STEMI • Benefit and risk profile better than thrombolytic since you can give ASA to virtually all with ACS

  46. ASA • NSTEMI • RRR 50% • ARR 3% • NNT death/MI 30

  47. ASA ASA: • 160-325mg to chew ASAP • All trials have shown mortality benefit that extends to 2 years • Contraindications: • Allergy?? • Active bleeding (GI, retinal) • Hemophilia

  48. Putting it all together…

  49. Anti-platelet therapy Clopidogrel • CAPRIE (1996), RCT ASA vs Plavix (N=19,185) • 3 year ischemic stroke, MI or death ARR = 0.5% (NNT = 200) • Plavix equal to ASA but increased side effects (diarrhea, rash, GI bleed)

  50. Anti-platelet therapy Clopidogrel: • CURE trial (2001) RCT Plavix + ASA vs ASA • UA/NSTEMI within 24 hr • Death, MI, or stroke 3 and 12 month ARR = 2.2% (NNT = 45) • Excess in major bleed of 1% (NNH = 100) • Risk of bleed with CABG increased in 1st 5 days • Recommended in UA/NSTEMI when noninvasive course is anticipated • BOTTOM LINE: appears to work but not for us to start in the ED

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