- All patients with ACS are candidates for antiplatelet and antithrombin therapies.
- STEMI are candidates for reperfusion therapy (fibrinolytic or catheter-based).
- NSTEMI are not candidates for fibrinolytic reperfusion agents but should receive catheter-based therapy when applicable.
- In treating ACS attention should also be paid to exacerbating
factors such as fever, anemia, hypoxemia, hypertension, hypotension,
and arrhythmias.
- If chest pain or hypotension remains refractory, intra-aortic balloon counterpulsation should be considered.
- In general, patients with ACS should undergo diagnostic coronary
arteriography to evaluate for left main disease, triple vessel disease,
proximal LAD disease or lesions amenable to PCI.
- Cocaine-induced ACS should be treated with intravenous
nitroglycerin and a calcium channel blocker (e.g., diltiazem,
verapamil) and coronary arteriography should be considered. There is
evidence that β-adrenergic blockade can enhance cocaine-induced
coronary artery vasoconstriction.
|
Agent |
Dosage |
Indications |
Comments |
MONA(Morphine, O2, NTG, ASA) |
See below |
All patients with ACS. |
Bedrest, IV access, telemetry, obtain serial ECGs and cardiac enzymes |
Morphine sulfate |
Initially 2–4 mg IV then increments of 2–8 mg IV q5–15 min prn pain |
If pain not relieved with NTG then give until pain and anxiety relief is obtained or hypotension occurs |
Reduces sympathetic tone; reduces preload; reduces myocardial O2 demand |
Oxygen |
Initially 4 L/min by nasal cannula or 28% by venti-mask (adjust to maintain SaO2 >90%) |
Maximize O2 delivery to ischemic myocardium |
SaO2 should be maintained over 90% and preferably over 95% |
Nitrates (Contraindicated in patients on sildenafil or other PDE 5 inhibitors and patients with RV infarctions) |
Nitroglycerin |
SL: 0.4 mg q5min ×3 Spray: 1–2 metered sprays (0.4 mg NTG/spray) onto or under the tongue; may repeat in 3–5 min, ×3 IV: 20 µg/min then titrate to effect (pain relief and/or to lower BP 10% to 20% if not hypotensive) Topical: 1–2 inches of 2% ointment q6h or equivalent patches |
Nitrate preparations for acute use; initial pain relief; coronary vasodilation; reduces preload (predominant) and afterload |
Causes headache; may increase myocardial O2 demand by causing unintended tachycardia or hypotension; rapid tachyphylaxis |
Isosorbide dinitrate |
10–60 mg PO q4–6h |
Useful for chronic management |
Daily nitrate-free interval may ameliorate tachyphylaxis to antianginal effects |
Aspirin (ASA) |
Immediate: 162–325 mg tablet (chewed or ground up) then 75–162 mg PO qd PCI:
75–325 mg prior to (300–325 mg at least 2 h and preferably 24 h before
PCI if not on daily ASA) then 325 mg qd for at least 1 m if BMS, 3 m if
sirolimus-eluting and 6 m if paclitaxel- eluting then 75–162 mg
indefinitely |
All patients with ACS without ASA allergy Effective for primary and secondary MI prevention |
Irreversibly inhibits prostaglandin cyclo-oxygenase, preventing formation of platelet aggregating factor thromboxane A2 Immediate antiplatelet effect; reduces mortality |
Clopidogrel |
ACS: Initially 300 mg PO then 75 mg PO qd PCI:
300 mg PO before PCI (preferably 6 h prior), then 75 mg PO qd for at
least 1 m if BMS, 3 m if sirolimus-eluting and 6 m if
paclitaxel-eluting and ideally up to 12 m if bleeding risk not high |
As a substitute for ASA in individuals with true ASA allergy May be beneficial when added to daily ASA in NSTEMI (CURE trial) In addition to ASA for planned PCI |
Inhibitor of ADP-induced platelet aggregation May be associated with increased risk of bleeding in patients undergoing CABG within 5–7 d of receiving clopidogrel |
Heparin (UFH) |
If adjunct to fibrinolytic
agents: 60 U/kg IV bolus (max 4,000 U) then 12 U/kg/h infusion (max
1,000 U/h) for at least 48 h (maintain aPTT 1.5–2.0 × control) otherwise 60–70
U/kg IV bolus (max, 5,000 U) then 12–15 U/kg/h infusion (max 1,000 U/h)
for at least 48 h (maintain aPTT 1.5–2.0 × control) |
For persistent or recurrent
angina; for fibrin-specific lytics; for increased risk of systemic
emboli (e.g., coexisting atrial fibrillation, LV thrombus, large or
anterior MI) |
Enhances the action of antithrombin III Should be avoided in cases of known HIT or whenever a pre-existing coagulopathy would increase risk over perceived benefit |
Bivalirudin |
PCI: 0.75 mg/kg IV bolus
immediately before the procedure then 1.75 mg/kg/h infusion for the
duration of the procedure. Five min after bolus, an ACT should be done,
and if needed an additional bolus of 0.3 mg/kg may be given. |
As an alternative to UFH in patients with ACS undergoing PCI With
“provisional use” of GPI IIb/IIIa (given for complications) as an
alternative to UFH + GPI IIb/IIIa in patients undergoing PCI |
Direct thrombin inhibitor (synthetic analogue of recombinant hirudin) Except in the setting of PCI there are limited data on efficacy and safety Use in conjunction with ASA (325 mg PO); safety and |
Bivalirudin (continued) |
Continuation of the infusion
for up to 4 h postprocedure is optional (after 4 h, an additional
infusion may be continued at 0.2 mg/kg/h for up to 20 h) |
(REPLACE-2 Trial) As a substitute for UFH with known HIT in patients undergoing PCI |
efficacy have not been established when used in conjunction with platelet inhibitors other than ASA |
Enoxaparin (LMWH) |
30 mg IV bolus, then 1 mg/kg
sq bid for 2–8 d (use with ASA 325 mg PO); avoid if age ≥75, serum Cr
> 2 mg/dl in women or >2.5 mg/dl in men |
Adjunctive therapy in ACS (age <75, and without clinically significant renal insufficiency) as an alternative to UFH |
Direct thrombin inhibitor through complex with antithrombin III Avoid if pre-existing coagulopathy would increase risk over perceived benefit |
Fibrinolytic Agents(For contraindications refer to
Table 3.2) |
- Only for STEMI,
including true posterior MI, or presumed new left bundle branch block
and <12 hours from onset (ideally ≤3 h from symptom onset; goal:
door to drug <30 minutes).
- Consider PCI as an alternative based on local resources. In general
PCI preferred if door to balloon <90 minutes, or cardiogenic shock
present or late presentation (>3 hours) or contraindication to
fibrinolysis. If ≤3 hours from symptom onset and PCI without delay then
no preference for either strategy.
- Reteplase and alteplase are not known to be antigenic nor
hypotensive-inducing. Tenecteplase has shown infrequent development of
antibody titer at 30 days and reuse should be undertaken with
precaution. It is also not hypotensive-inducing.
- Tenecteplase, reteplase, and alteplase should be used in
conjunction with ASA 162–325 mg PO and heparin bolus of 60 U/kg (max
4,000 U) then 12 U/kg/h infusion (max 1,000 U/h) for at least 48 hours
(maintain aPTT of 1.5–2.0 times control).
|
Tenecteplase |
IV bolus over 5–15 s <60 kg: 30 mg 60–69 kg: 35 mg 70–79 kg: 40 mg 80–89 kg: 45 mg ≥90 kg: 50 mg |
Greater fibrin specificity then rtPA Give with ASA and heparin (see above) |
Reteplase |
10 U IV over 2 min, then repeat, 30 min later, 10 U IV over 2 min |
Low fibrinolysis (relatively clot-selective) Give with ASA and heparin (see above) |
Alteplase (rtPA) |
>67 kg: 15 mg IV bolus, then 50 mg over 30 min, then 35 mg over 60 min >67 kg: 15 mg IV bolus, then 0.75 mg/kg over 30 min, then 0.5 mg/kg over 60 min |
Low fibrinolysis (relatively clot-selective) Give with ASA and heparin (see above) |
Glycoprotein IIb/IIIa Receptor Inhibitors (GPI IIb/IIIa)
- Platelet aggregation inhibitor; inhibits the integrin GP
IIb/IIIa receptor in the platelet membrane; contraindications include
active bleeding, bleeding diathesis (past 30 days), intracranial tumor,
hemorrhage arteriovenous malformation, aneurysm, recent stroke or major
surgery or trauma (past month), severe hypertension, aortic dissection,
pericarditis, platelets <100,000.
- Major benefit in NSTEMI troponin positive group with signs of
persistent or recurrent ischemia (used in addition to aspirin or
heparin).
- Can be used as adjunctive therapy with PCI strategy.
- Eptifibatide and tirofiban preferred in patients with USA/NSTEMI
managed medically and abciximab and eptifibatide preferred in patients
with USA/NSTEMI undergoing PCI. For planned PCI start treatment prior
to procedure as early as feasible.
|
Abciximab |
0.25 mg/kg IV bolus (over 5 min) then 0.125 µg/kg/min (max 10 µg/min) infusion for 12–24 h |
Consider for USA/NSTEMI undergoing PCI |
A murine monoclonal antibody;
readministration may result in hypersensitivity, thrombocytopenia, or
diminished benefit due to formation of human antichimeric antibodies |
Eptifibatide |
0.18 mg/kg IV bolus (max 22.6 mg) then 2 µg/kg/min (max 15 mg/h) infusion up to 72 h |
Consider for USA/NSTEMI undergoing PCI Adjunct to ASA and heparin in high risk USA/NSTEMI managed medically |
If CrCl <50 mL/min or Cr >2 mg/dL, decrease infusion to 1 µg/kg/min (maximum 7.5 mg/h), contraindicated in renal dialysis |
Tirofiban |
0.4 µg/kg/min IV for 30 min then 0.1 µg/kg/min for 12–48 h |
Adjunct to ASA and heparin in high risk USA/NSTEMI managed medically |
CrCl <30 mL/min, decrease dose by half (0.2 µg/kg/min IV for 30 min, then 0.05 µg/kg/min) |
Angiotensin Converting Enzyme—Inhibitors (Refer to
Table 3.4)
- Beneficial in setting of MI regardless of ejection fraction or presence of HF (oral route preferred).
- Avoid IV ACE-I within the first 24 hours of symptom onset due to risk of hypotension.
β-Blocking Agents (Refer to
Table 3.5)
- Indicated as treatment in the setting of ACS.
Statins(Refer to Table 3.6)
- For all patients with ACS without contraindication in first 24
hours. May reduce ACS associated inflammation, and increase nitric
oxide level and thus may be useful irrespective of LDL-C level.
Antiarrhythmic Agents (Refer to
Tables 3.9 and
3.10)
- Do not give prophylactically and avoid Class IC agents.
|
Magnesium sulfate |
1–2 g IV over 30–60 min, then 0.5–1 g IV q1–2 h for up to 24 h |
Prophylactic use in ICU patients with ACS not recommended Some studies suggest reduction in mortality while others do not |
Can cause conduction disturbances; mild hypotension; flaccidity; optimal dose unknown |
Treatment of Complications of ACS Please see the following tables:
- Cardiogenic pulmonary edema and shock (Therapy;
Table 3.3)
- Heart failure (Tables 3.3,
3.4, 3.5)
- Arrhythmia (antiarrhythmic agents
Tables 3.9 and
3.10)
Secondary Prevention After Acute MI
- ASA 75–162 mg PO qd indefinitely
- ACE inhibitor indefinitely (Table 3.4)
- β-blocker indefinitely (Table 3.5)
- Statin indefinitely if LDL-C ≥100 mg/dl (Table 3.6)
|
ACS,
acute coronary syndromes; ADP, adenosine diphosphate; aPTT, activated
partial thromboplastin time; ASA, aspirin; BMS, bare metal stent; BP,
blood pressure; CABG, coronary artery bypass graft; CURE, clopidogrel
in unstable angina to prevent recurrent events; ECG, electrocardiogram;
GPI IIb/IIIa, glycoprotein IIb/IIIa receptor inhibitor; HF, heart
failure; HIT, heparin-induced thrombocytopenia; INR, international
normalized ratio; IV, intravenous; LAD, left anterior descending
coronary artery; LDL-C, low-density lipoprotein-cholesterol; LMWH, low
molecular weight heparin; LV, left ventricle; NSTEMI, non-ST segment
elevation myocardial infarction; NTG, nitroglycerin; O2,
oxygen; PCI, percutaneous coronary intervention; PDE,
phosphodiesterase; PO, by mouth; REPLACE-2, Randomized Evaluation in
PCI Linking Angiomax to Reduced Clinical Events-2; RV, right ventricle;
SaO2, arterial oxygen saturation; STEMI, ST segment
elevation myocardial infarction; UFH, unfractionated heparin; USA,
unstable angina |