🫀 Mirza's Cardiology Notes

Acute Coronary Syndrome (ACS)

7 min read

  • On initial evaluation, you will want to determine the likelihood symptoms represent ACS?
    • High, Intermediate, Low
      • As described in the Chest Pain guidelines, we can describe these patients CP as being “Cardiac”, “Possibly Cardiac”, “Non-Cardiac”
      • Search alternative etiologies in low-likelihood patients
    • Tools:
      • History, Exam, ECG, Biomarkers (serial)
      • Scores: AHCPR, AHA/ACC Risk, HEART Score, etc
    • What is the risk of a bad outcome?
      • An ECG will be normal in 1/3 of patients, so it is important to repeat 15-30 minutes.
      • Consider additional leads (posterior, RV).
      • Telemetry.
  • Posterior leads (V7-V9) should be obtained in patients with suspected left circumflex occlusion particularly in the setting of isolated ST-segment depression ≥0.5 mm in leads V1–V3.

Figure source: 1

Management

Parenteral anticoagulation

  • Continue until revascularization to reduce ischemic events (Class 1)
  • If STEMI treated with lytics 🩸, continue for duration of hospital stay (max of 8 days) or until revascularization performed (Class 1)
  • If no plan for invasive approach, enoxparin preferred (Class 1) or fondaparinux is an alternative (Class 1)

Heparin

  • Initial therapy: Loading dose 60 IU/kg (max 4,000 IU), with initial infusion 12 IU/kg per h (max 1,000 IU/h) adjusted to therapeutic aPTT range of 60-80 s.
  • To support PCI: In patients who have received prior anticoagulant therapy, additional UFH as needed to achieve an ACT 250-300 s.
    • In patients who have not received prior anticoagulant therapy, 70-100 IU/kg initial bolus to achieve target ACT of 250-300 s.
  • With fibrinolytic therapy: loading dose 60 IU/kg (maximum 4,000 IU) with initial infusion 12 IU/kg per h (maximum 1,000 IU/h) adjusted to therapeutic aPTT range.

Bivalirudin

  • To support PCI: 0.75 mg/kg bolus, 1.75 mg/kg per h IV infusion during the PCI procedure.
  • Post-PCI infusion for PPCI: 1.75 mg/kg per h for 2-4 h post-PCI.
  • In patients with CrCl <30 mL/min, reduced infusion to 1 mg/kg per h.

Enoxaparin

  • Initial therapy: 1 mg/kg subcutaneous every 12 h. Reduce dose to 1 mg/kg per d subcutaneous if CrCl <30 mL/min.
  • To support PCI: for previous treatment with enoxaparin, if the last subcutaneous dose was administered 8-12 h earlier or if only 1 subcutaneous dose of enoxaparin has been administered, an IV dose of 0.3 mg of enoxaparin should be given. If the last dose was administered within the previous 8 h, no additional enoxaparin should be given.
    • For patients who have not received prior anticoagulant therapy, 0.5-0.75 mg/kg IV bolus.
  • With fibrinolytic therapy: if age <75 y, 30 mg IV bolus, followed in 15 min by 1 mg/kg subcutaneous every 12 h (maximum 100 mg for the first 2 doses).
    • If age >75 y: no bolus, 0.75 mg/kg subcutaneous every 12 h (maximum 75 mg for the first 2 doses).
  • ⚠️ Regardless of age, if CrCl <30 mL/min: 1 mg/kg subcutaneous every 24 h

Fondaparinux

  • Initial therapy: 2.5 mg subcutaneous daily.
  • With fibrinolytic therapy: 2.5 mg IV, then 2.5 mg subcutaneous daily starting the following day. Contraindicated if CrCl <30 mL/min.
  • ⚠️ Fondaparinux should not be used to support PCI because of the risk of catheter thrombosis

Anti-platelets

Aspirin

  • Loading dose 162-325 mg orally. Aspirin (nonenteric coated) should be chewed, when possible, to achieve faster onset of antiplatelet action. Loading dose should be administered for patients already on aspirin therapy.
  • Maintenance dose 75-100 mg orally daily (nonenteric coated)

P2Y12 Inhibitors

![[Acute Coronary Syndrome ACS-1744552912776.webp]]

Ticagrelor

  • Loading dose 180 mg orally
  • Maintenance dose 90 mg orally twice daily

Prasugrel

  • Loading dose 60 mg orally
  • Maintenance dose
    • 10 mg orally daily if body weight ≥60 kg and age <75 y
    • 5 mg orally daily if body weight <60 kg or age ≥75 y (use caution)
  • ⚠️ Avoid prasugrel if pt has a hx of stroke or TIA (Class 3)

Clopidogrel

  • Loading dose
    • 300 mg orally if age ≤75 y; Initial dose 75 mg orally if age >75 y;
  • Maintenance 75 mg orally daily

P2Y12 Inhibitors if Coronary Artery Bypass Graft (CABG)-bound

![[Acute Coronary Syndrome ACS-1744553201227.webp]]

IV Glycoprotein IIb/IIIa inhibitors

  • Examples: Eptifibatide (Integrilin), Abciximab (ReoPro), and Tirofiban (Aggrastat)
  • Typically administered for 18-24 hours ⏱️
  • Use in patients with ACS with PCI who have large thrombus burden, no-reflow, or slow flow
  • Can be given IV or intracoronary to “improve procedural success and reduce infarct size” (Class 2a)

Oxygen

  • Only give oxygen if confirmed hypoxia, i.e. O2 sat < 90%, with goal to increase sat to ≥ 90%
  • 🚫 Routine O2 supplementation has a Class 3 recommendation

Anti-Anginal Therapy

  • SLN 0.3 or 0.4 mg every 5 min as needed up to a total of 3 doses (if hemodynamically stable and SBP ≥90 mmHg)
  • IV nitroglycerin (start at 10 μg/min and titrate to pain relief and hemodynamic tolerability) if persistent angina refractory to oral nitrates or if ACS accompanied by HTN or pulmonary edema
    • ⚠️ Avoid use in suspected RV infarction, SBP <90 mm Hg or a change in SBP >30 mm Hg below baseline.

Pain control

  • Morphine IV 2-4 mg; may repeat if needed every 5-15 min. Doses up to 10 mg may be considered.
  • Fentanyl IV 25-50 μg; may repeat if needed. Doses up to 100 μg may be considered.

Beta-blockers

  • If no contraindication, guidelines recommend “early (<24 hours) initiation of oral beta-blocker therapy is recommended to reduce risk of reinfarction and ventricular arrhythmias” (Class 1)

ARB

  • Indications (Class 1)

MRA

  • Indications (Class 1)
    • LVEF ≤40%
    • HF Sx
    • DM

Hyperlipidemia

See Secondary Prevention

Non-STE ACS

- TIMI ***, GRACE ***
- DAPT: ASA, ***
- AC: heparin gtt (per ACS protocol)
- Metoprolol tartrate ***
- SLN PRN
	- If refractory, consider nitroglycerin gtt
- *** Supplemental oxygen if O2 < 90
- Telemetry
- NPO at midnight for possible cath
  • ED risk assessment scores have only modest predictive value
    • TIMI score
    • 🌟 GRACE risk score (>140 are considered high-risk, <90 have a <3% risk)
StrategyFactors associated with strategy selection
Immediate invasive (within 2 h)Refractory angina
Signs or symptoms of HF or new or worsening mitral regurgitation
Hemodynamic instability
Recurrent angina or ischemia at rest or with low-level activities despite intensive medical therapy
Sustained VT or VF
Ischemia-guided strategyLow-risk score (eg, TIMI [0 or 1], GRACE [<109])
Low-risk Tn-negative female patients
Patient or clinician preference in the absence of high-risk features
Early invasive (within 24 h)None of the above, but GRACE risk score >140
Temporal change in Tn
New or presumably new ST depression
Delayed invasive (within 25—72 h)None of the above but diabetes mellitus Renal insufficiency (GFR <60 mL/min/1.73 m2
Reduced LV systolic function (EF <40%)
Early postinfarction angina
PCI within 6 mo
Prior CABG
GRACE risk score 109–140; TIMI score ≥2

Figure source: 1

STE-ACS

Footnotes

  1. Amsterdam EA, Wenger NK, Brindis RG, Casey DE Jr, Ganiats TG, Holmes DR Jr, Jaffe AS, Jneid H, Kelly RF, Kontos MC, Levine GN, Liebson PR, Mukherjee D, Peterson ED, Sabatine MS, Smalling RW, Zieman SJ. 2014 AHA/ACC Guideline for the Management of Patients with Non-ST-Elevation Acute Coronary Syndromes: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 2014 Dec 23;64(24):e139-e228. doi: 10.1016/j.jacc.2014.09.017. Epub 2014 Sep 23. Erratum in: J Am Coll Cardiol. 2014 Dec 23;64(24):2713-4. PMID: 25260718. ↩ ↩2

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