Acute Coronary Syndromes

Myocardial ischemia typically due to atherosclerotic plaque rupture — coronary thrombosis

Spectrum of Acute Coronary Syndromes




Coronary thrombosis




angina that is new-onset, crescendo, or at rest; usually < 30 min

angina at rest usually nr30 min


: ST depression and/or TWI

ST elevations




Ddx (causes of myocardial ischemia/infarction other than atherosclerotic plaque rupture)

• Nonatherosclerotic coronary artery disease

Spasm: Prinzmetal's variant, cocaine-induced (6% of CP • cocaine use r/i for Ml) Vasculitis: Kawasaki's syndrome.Takayasu's arteritis. PAN. Churg-Strauss. SLE. RA Aortic dissection w/ retrograde extension involving coronary (usually RCA — IMI) Spontaneous coronary artery dissection (often in setting of pregnancy)

• Coronary artery embolism: endocarditis, prosthetic valve, mural thrombus, myxoma

• Fixed CAD but T myocardial O2 demand (eg. T HR. anemia. AS) — "demand" ischemia

• Myocarditis (myocardial necrosis, but not caused by CAD) Clinical manifestations (jama 2005:294 2623)

• Typical angina: retrosternal pressure/pain/tightness • radiation to neck, jaw. or arms precip. by exertion, relieved by rest or NTG; in ACS. new-onset, crescendo, or at rest

• Associated symptoms: dyspnea, diaphoresis. N(V, palpitations, or lightheadedness

• 23% of Mis are initially unrecognized b/c silent or atypical sx (A/C 1973:32:1)

Physical exam

• Signs of ischemia: S*. new MR murmur 2° papillary muscle dysfxn, paradoxical S2

• Signs of heart failure:' JVP. crackles in lung fields. © Sj

• Signs of other areas of atherosclerotic disease: carotid or femoral bruits, i distal pulses Diagnostic studies

Qw or PRWP suggests prior Ml and CAD ✓ ECG at presentation, with A in sx. and at 6-12 h: c/w baseline dx of STEMI in setting of LBBB: s 1 mm STE concordant w/ QRS (Se 73%. Sp 92%) or ¿5 mm discordant (Se 31%. Sp 92%) in any lead (Nip* 1996:334.481)

Localization of Ml

Anatomic area

ECG Leads w/ STE

Coronary Artery



Proximal LAD






Distal LAD. LCx. or RCA






RCA ( 85%). LCx (15%)



Proximal RCA


ST depression Vi-Vi

RCA or LCx

If ECG non-dx and suspicion high, consider additional lateral leads (V7-V») to further assess LCx territory. STE in III >STE in II and lack of STE in I or aVL suggest RCA rather than LCx culprit in IMI.

If ECG non-dx and suspicion high, consider additional lateral leads (V7-V») to further assess LCx territory. STE in III >STE in II and lack of STE in I or aVL suggest RCA rather than LCx culprit in IMI.

Cardiac biomarkers: serial testing at presentation. 6-12 h after sx onset troponin (I or T): most Se & Sp marker; rise & fall in approp. clinical setting is dx of Ml detectable 4-6 h after injury, peaks 24 h. may remain elevated for 7-10 d in STEMI "false -y (non-ACS myonecrosis): myocarditis, toxic CMP. severe CHF, PE or severe resp. distress, cardiac trauma or cardioversion, sepsis. SAH. "demand" ischemia renal failure: ? false © (I clearance, skeletal myopathy) vs. true microinfarctions;

in Pts w/ACS & i CrCI. t Tn — poor prognosis (n£/m 2002:346.2047) CK-MB: less Se & Sp (skel. muscle, tongue, diaphragm, intestine, uterus, prostate) Echocardiogram: new wall motion abnormality (operator & reader dependent) Myocardial perfusion: inject sestaMIBI during sx (no stress): image later

Likelihood of ACS





(any of below)

(no hi£h features.

(no hlghfater features.

any of below)

may have below)


chest or L arm pain

chest or L arm pain

atypical sx (eg. pleuritic.

like prior angina

age >70 y

sharp, or positional pain)


male, diabetes


hypotension. CHF.


pain reproduced on palp.

transient MR


new STD ( 0.5 mm)

old Q waves

TWF/TWI (in leads w/ Rw)

TWI (,-2 mm)

old ST orT wave abnl



• Tn or CK-MB



(Adapted from ACC/AHA 2002 Guideline Update for UA/NSTEMI)

(Adapted from ACC/AHA 2002 Guideline Update for UA/NSTEMI)

Approach to triage

• If hx and initial ECG & biomarkers non-dx. repeat ECG & biomarkers 6-12 h later

• If remain normal and low likelihood of ACS. search for alternative causes of chest pain

• If remain normal and Pt is pain-free, have ruled out Ml. but if clinical suspicion remains for

ACS based on hx. then still need to r/o UA w/ stress test to assess for inducible ischemia; if low risk (age - 70; 0 prior CAD. CVD. PAD; 0 rest angina) can do as outPt w/in 72 h

(0% mortality. <0.5% Ml. Ann ewerg med 2006:47:427); if not low risk, admit and evaluate for ischemia (stress test or cath)

• If ECG or biomarker abnl or high likelihood of ACS based on hx. then admit and Rx as per below


Anti-lschemic Treatment

Nitrates (SL PO, topical, or IV)

1 anginal sx, no J in mortality

p -blockers metoprolol 5 mg IV q5 min x 3 then 25 mg PO q6h titrate to HR 55-60

13% i in progression to Ml (/MM 1988:260:2259) Contraindicoted if HR <55.SBP <100. moderate or severe CHF. 273° AVB. severe bronchospasm

Calcium channel blockers


Consider in Pts who cannot tolerate ß-blockers due to bronchospasm


Consider if persistent sx or pulmonary edema Should not be used to mask persistent CP


Use if necessary to keep S,Oj -90%

Adapted from ACOAHA 2002 Guideline Update for UA/NSTEMI)

Antiplatelet Therapy


162-325 mg PO (1" doie cruthed/chcwd) then 75-162 mg PO qd

50-70% J D/Ml (ncjm 1988,319:1105) If ASA allergy, use Clopidogrel instead (and desensitize to ASA)

Clopidogrel <ADP receptor Mocker)

300 mg PO X 1 - 75 mg PO qd (requires 6 h to steady-state) 600 mg load may be superior (faster and greater pit inhib; ore 2005:111 2099)

Give in addition to ASA if conservative strategy or if PCI planned. 20% 1 CVD/MI/stroke (CURE, nejm


t benefit if given upstream prior to PCI (PCi-CURE. lancet 2001:358527). although need to wait >5 d after d/c Clopidogrel prior to CABG

GP llb/llla inhibitors (GPI) abciximab: 0.25 mg/kg IVB

— 0.125 fjLg/kg/min eptifibatide: 180 p.g/kg IVB (x2qi0' i w/ PCi) - 2 jig/kg/min (i if GO <50) ciroßban: 0.4 ng/kg/min x 30 min

- 0.1 flg/kg/min (1/2 doie If CrCI <30) infusions given 18-24 h post-PCI

Given in addition to oral antiplt Rx(s) In setting of PCI. 50% i D/MI (Capture, loncet

1997:34» 1429; ESPRIT. lancet 2000.356 2037) Consider upstream eptifibatide or tirofiban (not abciximab) if high-risk (• Tn.TRS 4) or refractory sx. 10-20% I D/MI (PURSUIT, ne/m 1998:339:436: PRISM-PtUS. nejm 1998:338 1488). although most benefit peri-PCI (Grc 1999:100:2045)

Anticoagulant Therapy

60 U/kg IVB (max 4000 U) 12 U/kg/h (max 1000 U/h)

titrate to aPTT 50-70 sec

Enoxaparin ltow-moteculi/-weight hep»™) 1 mg/kg SC bid >: 2-8 d (• 30 mg IVB) md noa <M)

Consider instead of UFH. 10% I D/MI (UMA 2004.29189) Benefit greatest if conservative strategy. Can perform PCI on enoxaparin.

Bivalirudin (direct thrombin inhixior)

0.1 mg/kg IVB - 0.25 mg/kg/h at time of PCI: additional 0.5 mg/kg IVB (0.75 mg/kg if not already on bival) — 1.75 mg/kg/h

Use instead of heparin for Pts w/ HIT With invasive strategy, bival alone noninferior to heparin • GPI (non-signif 8% I D/MI/UR) w/ 47% 1 bleeding (ACUiY. ne]M 2006JS5 220J)

2.5 mg SC qd

C/w enox. 17% i mortality & 38% 1 bleeding by 30 d (OASIS-S: nqm 2006:354:1464). However.t risk of cath thromb.;. must supplement w/ UFH if PCI.

Coronary angiography (JACC2WM. 1366)

• Conservative approach selective angiography medical Rx with pre-d/c stress test; angio only if recurrent ischemia or strongly ® ETT

• Early invasive approach routine angiography w/in 24-48 h

Indicated if high risk: recurrent ischemia, 0 Tn. STA.TRS ¿3. CHF. 1 EF. recent PCI <6

mos. sustained VT. prior CABG. hemodynamic instability 25% 1 Ml. 34% i rehosp for ACS. & nonsignif 8% 1 D c/w cons. tfAMA 200S.293 2908) f peri-PCI Ml counterbalanced by U in sponL Ml

Long-term mortality benefit likely only if c/w cons, strategy with low rate of angio/PCI Early invasive approach not found to be superior in ICTUS trial (NEJM 2005;3S3 1095). but results dominated by peri-PCI Ml; post-d/c benefits of INV c/w prior data

TIMI Risk Score for UA/NSTEMI 20C0 2849ÏV

Calculation of Risk Score

Application of Risk Score


Point Score D/MI/URbyl4d


0-1 5%

Age -65 y

1 2 8%

-3 Risk factors for CAD

1 3 13%

Known CAD (stenosis -50%)

1 4 20%

ASA use in past 7 d

1 5 26%


6-7 41%

Severe angina (-2 episodes w/in 24 h)

1 Higher risk Pts (TRS -3) derive t

ST deviation -05 mm

1 benefit from LMWH. GP llb/llla

• cardiac marker (troponin. CK-MB)

1 inhibitors, and early angiography

RISK SCORE - Total points

(0.7) 200M189SI

Figure 1-2 Approach to UAjNSTEMI


©Tn. no ST I. and TRS 0-2 ®Tn ST \ >0.5 mm. or TRS ¿3

Figure 1-2 Approach to UAjNSTEMI


©Tn. no ST I. and TRS 0-2 ®Tn ST \ >0.5 mm. or TRS ¿3

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