Acute MI treatment Roger Suss MD CCFP(EM) Lecturer Dept of Family Medicine University of Manitoba

AMI Case study 65 year old man with crushing chest pain for 60 minutes DM, HTN, no allergies BP175/105, HR 115 O2 saturation 97% RA EKG shows anterior STEMI

Pathophysiology of an Myocardial Infarction Chronic plaque Acute rupture and thrombosis Myocardial hypoperfusion/hypoxia Myocardial tissue necrosis Remodeling with scar tissue

Increase pressure Increase oxygen carrying capacity Decrease obstruction/Increase flow Decrease oxygen demand Pathophysiology of an Myocardial Infarction

Increase oxygen carrying capacity Decrease obstruction Decrease oxygen demand Pathophysiology of an Myocardial Infarction Extra oxygen?Extra Hb? Fibrinolytics,PCI (percutaneous coronary intervention) ASA, Heparin, Clopidogrel, GIIb/IIIa inhibitors Nitrates,BetaBlockers, Analgesics,Rest

American Heart Association evidence based guideline 2004/2007 on STEMI and 2007 guideline on NSTEMI Level A = definitely Level B = probably Level C = possibly Class I = should Class II = could Class III = dont

Effectiveness of definitely should treatments 30 day mortality from acute MI ~10% ASA Mortality ARR ~2% NNT 50 ASA and lytics Mortality ARR~4% NNT 25 ASA and PCI Mortality ARR~6% NNT 17 Adding Clopidogrel ARR another~0.5% NNT200 Adding Heparin to ASA NNT unclear

Mortality over time Stenestrand and Wallentin. Arch Intern Med 2003

Effectiveness of Fibrinolytics Mortality from acute MI ~10% ARR 2% NNT 50 Decreasing effectiveness of 0.2% each hour ie by 5 hours ARR 1%

Lytics ARR per 1000

ASA 160mg chewed Definitely shouldUnless –Sensitivity (use clopidogrel instead) –Acute hemorrhage Definitely should add PPI if risk of GI bleeding

Nitroglycerine sl or iv Possibly should for –Pain –Hypertension –Pulmonary edema Probably dont if –Phosphodiesterase inhibitor recently –BP <90 sys –HR 100 –Suspected RV infarct

Bed rest Possibly should

Oxygen Probably should if O2<90% Otherwise possibly could

Morphine (2-4mg q5-15 min) Possibly should for –Pain uncontrolled with NTG and other Tx Contraindications –Sensitivity –Severe hypotension

Heparin Definitely should –UFH if PCI or CABG planned, or if CRI, or after lytics in elderly –Otherwise Enoxaparin Unless acute hemorrhage or high risk In NSTEMI RRR ~33% for death or MI at 5 days. Most of the benefits of the various anticoagulants are short term, however, and are not maintained on a long-term basis. RR [CI]

Clopidogrel 75mg daily Definitely should NNT 167 (COMMIT-CCS2) Definitely could load with 300mg if age <75 Unless CABG considered likely

GP IIa/IIIb inhibitors Probably could (as part of PCI)

Beta Blockers (Metoprolol) Definitely should start orally within 24 hours Definitely dont give acutely if –Shock –Heart failure –Heart block –Active asthma/COPD Probably could give IV acutely if no contraindications Probably should give verapamil or diltiazem as alternatives if active asthma or allergy

Oral ACE inhibitor within 24 hours Definitely should if –Pulmonary edema –LVEF < 40% Unless hypotension or other contraindications ARB if ACE not tolerated

Stop all NSAIDs except ASA Possibly should

Reperfusion (lytics or PCI) (WRHA guidelines) Definitely should if –ST > or = to 0.1mV in 2 adjacent leads or new LBBB –Pain onset <12 hours –Current pain

Reperfusion by PCI (WRHA guidelines) Definitely should if –Can be done in contact to balloon time of <60 min –Cardiogenic shock –Pulmonary edema –Recurrent VF/VT –STEMI dx in doubt –Pain or ST elevation remains >50% at 60 minutes after lytics –Contraindication to lytics Definitely dont use lytics if –High bleeding risk (see list) Probably dont use lytics if –Moderate bleeding risk (see list) –Presenting BP >180/110

Reperfusion by PCI in NSTEMI (AHA) Definitely should if –Cardiogenic shock –Recurrent VF/VT –Ongoing pain/symptoms despite aggressive medical management

Treatment? ASA - yes PCI? Oxygen? NTG sl iv? B blocker? Heparin? Morphine? Clopidogrel? GIIa/IIIb inhibitor?

WRHA STEMI care map

AMI Case study 65 year old man with crushing chest pain for 60 minutes DM, HTN, no allergies BP175/105, HR 115 O2 saturation 97% RA EKG shows anterior STEMI ASA - yes PCI – if can be done in <60 minutes from presentation Otherwise lytics Oxygen – if low NTG sl iv -yes B blocker - yes Heparin - yes Morphine – after NTG Clopidogrel - yes GIIa/IIIb inhibitor - if PCI?

What can go wrong? Hypotension from nitrates Arrhythmias Heart failure/cardiogenic shock Bleeding/CVA

Questions?

Fake MI workshop - Roger Suss What is the likelihood of ACS? What else should be on the differential diagnosis? Are you critical of your colleagues record keeping? Suggest management plan. Are other options reasonable?