Ver el código de «Non-ST-elevation myocardial infarction»

==Background==
*Also known as NSTEMI
*33% with confirmed MI have no chest pain on presentation (especially older, female, [[DM]], [[CHF]])
*5% of NSTEMI will develop [[Cardiogenic Shock]] (60% mortality)
*Age >65 with 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

{{MI Types by Causation}}

==Clinical Features==
{{Clinical features ACS}}

==Differential Diagnosis==
{{Chest Pain DDX}}

==Evaluation==
*Non-STEMI ECG + positive troponin
*CK-MB and myoglobin are not helpful<ref>AHA ACA - NSTEMI ACS Guidelines 2014[http://circ.ahajournals.org/content/130/25/e344 View Online]</ref>
*Angiography indicated for:
**Recurrent angina/ischemia with or with out symptoms 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 within previous 6 mo
**Prior CABG

==Management==
*Dual antiplatelet therapy and antithrombotic therapy is mainstay of treatment
*Medical management vs cath determined by level of risk for future cardiovascular events

===[[Antiplatelets]]===
*[[Aspirin]]
**Recommended dose is 325 mg chewed
**Reduces death from MI by 12.5 → 6.4%
**Should be used in all ACS unless contraindicated (eg [[Anaphylaxis]])
**In pts with true ASA allergies, substitute [[Clopidogrel]]<ref>CAPRIE Steering Committee.. A randomised, blinded, trial of clopidogrel versus aspirin in patients at risk of ischaemic events (CAPRIE). CAPRIE Steering Committee. Lancet. 1996 Nov 16;348(9038):1329-39.</ref>
*[[Clopidogrel]] (see drug link for specific age and indication-related dosages)
**Give in addition to ASA
**Mortality benefit with NSTEMI (CURE trial: Decrease in cardiovascular death, MI, or stroke by 9.3-11.5%)
**Main risk and contraindication is bleeding
*GPIIb/IIIa Inhibitors
**[[Eptifibatide]], [[abciximab]], [[tirofiban]]
**Benefit only for patients undergoing PCI
**Administer at time of PCI, not in the ED

===Antithrombotics===
*Give [[heparin]] or [[enoxaparin]] along with ASA (Class 1A evidence)
*[[Enoxaparin]] (Lovenox)
**1mg/kg subq BID
**AHA recommends for moderate & high risk [[Unstable angina]]/NSTEMI unless CABG within 24hr
**Safer than UFH
**ESSENCE trial showed 20% decrease in death, MI or urgent revascularization with LMWH
**Adjust for CrCl<30ml and extremes of weight
**No need to monitor labs
*Unfractionated [[Heparin]]
**Bolus 60-70u/kg (max 5000) followed by infusion of 12-15u/kg/hr (max 1000/hr), goal ptt 45-75s
**Consider if patient likely to undergo PCI/CABG within 24hr of admission or in setting of renal failure
*[[Hirudins]]
**Approved only for patients with [[HIT]]

===Other===
*[[Oxygen]]
**Use only if SpO2 <90%
*[[Nitroglycerin|Nitrates]] (decrease preload)
**Administer sublingual [[nitroglycerin]] every 5 min x3 for continuing ischemic pain and then assess need for IV [[nitroglycerin]] (AHA ACA Level I)
**Use cautiously in inferior MI or if on sildenafil
**Not shown to decrease MACE
*[[Analgesia]]
**[[Morphine]], [[Fentanyl]], or other opioid (AHA ACA Level IIb)
**Do not use NSAIDs other than ASA (AHA ACA Level III: Harm)
**Complete absence of pain is likely not feasible - aim for pain level <5
*[[Beta blockers|β-blockers]]
**Start PO dose within 24 hours (Do not give IV β-blocker in ED (AHA ACA Level III: Harm))
**Goal HR is 50-60
**Contraindicated if HR<50 or SBP<90, acute CHF, low flow state, or PR>240ms
**Decreases inotropic and chronotropic response to catecholamines
**Use [[diltiazem]] if cannot use beta-blocker ([[nifedipine]] clearly harmful)
*[[ACE inhibitor]]
**Start short-acting ([[captopril]]) within 24 hours of admission
**Reduces RR of 30 day mortality by 7%
**Those with recent MI (especially anterior) and LV dysfunction benefit most
*[[Transfusion]]
**Transfuse to keep hemoglobin >10
*[[Thrombolytics]]
**''Not indicated'' (only useful for [[STEMI]])

===[[Unstable Angina - NSTEMI Guidelines]]===
====Summary of Class I Guidelines====
*[[Aspirin]] should be initiated as soon as possible and continued indefinitely in patients who tolerate it. ([[EBQ:Evidence Levels|Level A]]) 
*[[Clopidogrel]] loading dose should be initiated as soon as possible in patients unable to tolerate aspirin.  ([[EBQ:Evidence Levels|Level B]])
*Medium/High risk patients in whom initial invasive strategy is planned should receive dual therapy (Level A) including aspirin (Level A) and:
**Before PCI one of the following: 
***Clopidogrel ([[EBQ:Evidence Levels|Level B]])
***An IV GP IIb/IIIa inhibitor ([[EBQ:Evidence Levels|Level A]]) preferably eptifibatide or tirofiban. 
**Otherwise during PCI one of the following:
***Clopidogrel ([[EBQ:Evidence Levels|Level A]]) if not started beforehand
***An IV GP IIb/IIIa inhibitor ([[EBQ:Evidence Levels|Level A]]) preferably eptifibatide or tirofiban. 
***[[Prasugrel]] ([[EBQ:Evidence Levels|Level B]])
*If an initial conservative (i.e. noninvasive) strategy is selected, clopidogrel should be added to ASA and anticoagulant therapy as soon as possible after admission. ([[EBQ:Evidence Levels|Level B]])
*If an initial conservative strategy is selected and recurrent symptoms/ischemia, heart failure, or serious arrhythmias subsequently appear, then diagnostic angiography should be performed. ([[EBQ:Evidence Levels|Level A]]). Either an IV GP IIb/IIIa inhibitor ([[EBQ:Evidence Levels|Level A]]) or clopidogrel ([[EBQ:Evidence Levels|Level B]]) should be added to ASA and anticoagulant therapy before diagnostic angiography. ([[EBQ:Evidence Levels|Level C]])
====Summary of Class IIa Guidelines====
*If an initial conservative strategy is selected and patient has recurrent ischemic discomfort with clopidogrel, ASA, and [[anticoagulant]] therapy, it is reasonable to add a GP IIb/IIIa inhibitor before diagnostic angiography. ([[EBQ:Evidence Levels|Level C]])
*If an initial invasive strategy is selected, it is reasonable to omit administration of an IV GP IIb/IIIa inhibitor if [[bivalirudin]] is selected as the anticoagulant and clopidogrel was administered at least 6 hours earlier than planned catheterization or PCI. ([[EBQ:Evidence Levels|Level B]])
====Summary of Class IIb Guidelines====
*If an initial conservative strategy is selected, it may be reasonable to add [[eptifibatide]] or [[tirofiban]] to [[anticoagulant]] and oral antiplatelet therapy.19,20 ([[EBQ:Evidence Levels|Level B]])
*Prasugrel may be considered for administration promptly upon presentation if PCI is planned, before definition of coronary anatomy if both the risk for bleeding is low and the need for CABG is considered unlikely. ([[EBQ:Evidence Levels|Level C]])
*The use of GP IIb/IIIa inhibitors may be considered in high-risk patients already receiving ASA and a thienopyridine who are selected for an invasive strategy, such as those with elevated [[troponin]] levels, diabetes, or significant ST-segment depression, and who are not otherwise at high risk for
bleeding. ([[EBQ:Evidence Levels|Level B]])
*In patients with definite UA/NSTEMI undergoing PCI, the use of a loading dose of clopidogrel of 600mg, followed by a higher maintenance dose of 150mg daily for 6 days, then 75mg daily may be reasonable in patients not considered at high risk for bleeding. ([[EBQ:Evidence Levels|Level B]])
====Summary of Class IIb Guidelines====
*[[Abciximab]] should not be administered to patients in whom PCI is not planned. ([[EBQ:Evidence Levels|Level A]])
*Low risk patients for ischemic events (TIMI risk score 2) or at high risk of bleeding and who are already receiving ASA and clopidogrel, upstream GP IIb/IIIa inhibitors are not recommended. ([[EBQ:Evidence Levels|Level B]])
====Summary of Class III Guidelines====
*In UA/NSTEMI patients with a prior history of stroke or TIA for whom PCI is planned, prasugrel is potentially harmful as part of a dual-antiplatelet therapy regimen.([[EBQ:Evidence Levels|Level B]])

==Disposition==
*Admit

==Prognosis==
{{TIMI Score}}

==See Also==
*[[Unstable Angina - NSTEMI Guidelines]]
*[[Acute coronary syndrome (main)]]
*[[ST-segment elevation myocardial infarction (STEMI)]]
*[[Unstable angina]]
*[[Cocaine-associated chest pain]]

==External Links==
*[http://www.mdcalc.com/timi-risk-score-for-uanstemi/ MDCalc - TIMI Risk Score for UA/NSTEMI]

==References==
<references/>

[[Category:Cardiology]]
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