Non-ST-elevation myocardial infarction: Difference between revisions
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##Decreases progression from UA to MI by 13% | ##Decreases progression from UA to MI by 13% | ||
##Decr inotropic and chronotropic response to catechols | ##Decr inotropic and chronotropic response to catechols | ||
##Use | ##Use dilt if can't use beta-blocker (nifedipine clearly harmful) | ||
#ACE Inhibitor | #ACE Inhibitor | ||
##start short-acting (captopril) w/in 24hr of admission | ##start short-acting (captopril) w/in 24hr of admission |
Revision as of 00:49, 19 June 2014
Background
- 33% w/ confirmed MI have no CP on presentation (esp older, female, DM, CHF)
- 5% of NSTEMI will develop Cardiogenic Shock (60% mortality)
- Age >65 w/ MI and anemia had 33% reduction in 30 day mort if transfused to keep HCT >30
- Association between quantity of troponin and risk of death
- NSTEMI includes Type 2 -Type 5 biomarker elevations
Types of Myocardial Infarction
- Type 1: Ischemic myocardial necrosis due to plaque rupture ( ACS)
- Type 2: Ischemic myocardial necrosis due to supply-demand mismatch, e.g. coronary spasm, embolism, low or high blood pressures, anemia, or arrhythmias.
- Type 3: sudden cardiac death (no cTr values)
- Type 4: procedure related, post PCI or stent thrombosis ( cTr > 5X Decision Level).
- Type 5 post CABG (cTr > 10X Decision Level).
Treatment
- Dual antiplatelet therapy is key
- ASA + other agent (other agent depends on conservative vs interventional strategy)
- Medical management vs cath determined by level of risk for future cardiovascular events
- ASA + other agent (other agent depends on conservative vs interventional strategy)
Anti-ischemia
- Oxygen
- ACC recs O2 for sats <90% (evidence indeterminant)
- Nitrates
- No mortality benefit
- Use cautiously in inferior MI
- Decreases preload
- B-block to avoid reflex tachycardia
- B-Blockers
- No IV BB in ED, PO w/in 24 H
- Goal HR is 50-60
- Contraindicated if HR<50 or SBP<90, acute CHF or PR>240ms
- Decreases progression from UA to MI by 13%
- Decr inotropic and chronotropic response to catechols
- Use dilt if can't use beta-blocker (nifedipine clearly harmful)
- ACE Inhibitor
- start short-acting (captopril) w/in 24hr of admission
- Reduces RR of 30 day mort by 7%
- Those w/ recent MI (esp ant) and LV dysfunction benefit most
- Transfusion
- Transfuse to keep Hb>10
- Magnesium
- Reduces pain and theoretically can decr HR, SBP and O2 demand
- Correct hypomag
Antiplatelet
- ASA
- Recommended dose is 325mg chewed
- Reduces death from MI by 12.5-6.4%
- Should be used in all ACS unless contraindicated
- Clopidogrel
- Give in addition to ASA
- 300mg
- 600mg if going to PCI (superior in preventing post-proc MI)
- Mortality benefit with NSTEMI
- Main risk and contraindication is bleeding
- CURE trial: Decr in CV death, MI or stroke by 9.3-11.5%
- Give in addition to ASA
- GPIIb/IIIa Inhibitors
- Eptifibatide, abciximab, tirofiban
- Benefit only for pts undergoing PCI
- Administer at time of PCI, not in the ED
Antithombotics
- Give heparin or enoxaparin along w/ ASA (Class 1A evidence)
- Enoxaparin
- AHA recommends for moderate & high risk UA/NSTEMI unless CABG w/in 24hr
- 1mg/kg subq BID
- Safer than UFH
- ESSENCE showed 20% decrease in death, MI or urgent revasc w/ LMWH
- Adjust for CrCl<30ml and extremes of weight
- No need to monitor labs
- Unfractionated Heparin
- Consider if pt likely to undergo PCI/CABG within 24hr of admission
- Bolus 60-70u/kg (max 5000) followed by infusion of 12-15u/kg/hr (max 1000/hr), goal ptt 45-75s
- Hirudin
- Approved only for pts w/ HIT
Thrombolytics
- Only useful for STEMI
Angiography
- Indicated for:
- Recurrent angina/ischemia w/ or w/o sx of CHF
- Elevated troponins
- New or presumably new ST-segment depression
- High-risk findings on noninvasive stress testing
- Depressed LV function
- Hemodynamic instability
- Sustained V-tach
- PCI w/in previous 6 mo
- Prior CABG
Prognosis
NSTEMI TIMI Score[1]
- Used to estimate percent risk of all-cause mortality, new/recurrent MI, or need for revascularization at 14 days
- Age >65 yrs (1 point)
- Three or more risk factors for coronary artery disease: (1 point)
- family history of coronary artery disease
- hypertension
- hypercholesterolaemia
- diabetes
- current smoker
- Use of aspirin in the past 7 days (1 point)
- Significant coronary stenosis (stenosis >50%) (1 point)
- Severe angina (e.g., >2 angina events in past 24 h or persisting discomfort) (1 point)
- ST-segment deviation of ≥0.05 mV on first ECG (1 point)
- Increased troponin and/or creatine kinase-MB blood tests (1 point)
points | % risk of mortality, MI, or need for revascularization |
---|---|
0 | 5% |
1 | 5% |
2 | 8% |
3 | 13% |
4 | 20% |
5 | 26% |
6 | 41% |
See Also
External Links
Sources
- EM Practice Guidelines