Angina Pectoris, Unstable/Non ST Elevation Myocardial Infarction (NSTEMI)

Description

Diagnosis

Medicine Treatment

Referral

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ICD 10 code: I21.4/ I21.9/I22.0-1/I22.8-9/I24.8-9/I25.6/I25.8-9

DESCRIPTION

Unstable angina is a medical emergency and if untreated can progress to NSTEMI.
Presents as chest pain or discomfort similar to stable angina but with the following additional characteristics:

• Angina at rest or minimal effort
• Angina occurring for the first time, particularly if it occurs at rest
• Prolonged angina > 10 minutes, not relieved by sublingual nitrates
• The pattern of angina accelerates and gets worse

DIAGNOSIS

• Made from good history
• ECG may show ST segment depression, transient ST segment elevation or T wave inversion
• Normal ECG does not exclude the diagnosis. For this reason, history is of paramount importance.

MEDICINE TREATMENT

• Oxygen 40% via facemask, if saturation < 94% or if in distress

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CAUTION

Do not administer oxygen to acutely ill patients who are not hypoxic (SPO2 ≥ 96%)

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LoE:IIb¹⁶

ADD

• Aspirin, oral, 150 mg as a single dose (chewed or dissolved) as soon as possible

LoE:Ia¹⁷

ADD

• Nitrates, short acting, e.g.:
• Isosorbide dinitrate, sublingual, 5 mg immediately as a single dose
  • May be repeated at 5-minute intervals for 3 or 4 doses

LoE:lVb¹⁸

ADD

• Morphine 10 mg diluted with 10 mL of water for injection or sodium chloride 0.9%, slow IV (Doctor prescribed)
  • Start with 5 mg; thereafter slowly increase by 1 mg/minute up to 10 mg
  • Can be repeated after 4–6 hours if necessary, for pain relief
  • Beware of hypotension

Continuation of aftercare treatment initiated at higher level of care:

Continue therapy with appropriate lifestyle modification and adherence support.

• Aspirin, oral, 150 mg daily (continued indefinitely in absence of contraindications)

LoE:Ia¹⁹

When clinically stable without signs of heart failure, hypotension, bradydysrhythmias or asthma:

• Cardio-selective beta-blocker, e.g.: (Doctor initiated)
• Atenolol, oral, 50 mg daily

AND

• HMGCoA reductase inhibitors (statins), e.g.:
• Rosuvastatin, oral, 10 mg at night

LoE:Ia²⁰

Patients on protease inhibitor:

• Atorvastatin, oral, 10 mg at night

LoE:Ia²¹

Patients on amlodipine (and not on a protease inhibitor):

• Simvastatin, oral, 10-20 mg at night

LoE:IVb²²

If patient complains of muscle pain:

Reduce dose e.g.:

• If simvastatin 20 mg not tolerated, reduce to 10 mg

OR

Refer for further management

LoE:IIIb²³

AND

If there is cardiac failure or LV dysfunction (Doctor initiated):

• ACE-inhibitor, e.g.:
• Enalapril, oral, target dose 10 mg 12 hourly (usually titrated from 2.5 mg 12 hourly)

LoE:IVb²⁴

Angioedema is a potentially serious complication of ACE-inhibitor treatment and if it occurs it is a contraindication to continued therapy or to re-challenge.

REFERRAL

Urgent

• All suspected or diagnosed cases

Click here for the pdf.

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Standard Treatment Guidelines and Essential Medicines List for South Africa, Primary Healthcare, 2020-2024_Version 1.0_1 November 2024

Chapter 4: Cardiovascular Conditions_4.3 Angina Pectoris, Unstable/Non ST Elevation Myocardial Infarction (NSTEMI)