Clinical Review ABC of antithrombotic therapy

Antithrombotic strategies in acute coronary syndromes and percutaneous coronary interventions

BMJ 2002; 325 doi: https://doi.org/10.1136/bmj.325.7377.1404 (Published 14 December 2002) Cite this as: BMJ 2002;325:1404
  1. Derek L Connolly,
  2. Gregory Y H Lip,
  3. Bernard S P Chin

Acute coronary syndromes

All patients suspected of having acute coronary syndrome should be managed as medical emergencies and monitored in the critical care unit. Baseline tests must include 12 lead electrocardiography, chest x ray examination, and venous blood samples for analyses of haemoglobin and markers of myocardial damage, preferably cardiac troponin T or I.

High and low risk patients with suspected acute coronary syndromes

High risk
  • Recurrent or persistent chest pains with associated electrocardiographic changes (ST segment depression or transient ST elevation) despite anti-ischaemic treatment

  • Elevated troponin concentrations

  • Age >65 years

  • Comorbidity, especially diabetes

  • Development of pulmonary oedema or haemodynamic instability within observation period

  • Development of major arrhythmias (repetitive ventricular tachycardia or ventricular fibrillation)

  • Early postinfarction unstable angina

Low risk
  • No recurrence of chest pains within observation period

  • Troponin or other markers of myocardial damage not elevated

  • No ST segment depression or elevation on electrocardiogram (T wave inversion is classified as intermediate risk)

Initial management

Assessment

Patients with persistent ST segment elevation on 12 lead electrocardiography need immediate reperfusion treatment (thrombolysis or intervention). Patients with ST segment depression, inverted T waves, or pseudonormalisation of T waves on the electrocardiogram, but with a clinical history suggesting cardiac ischaemia should receive initial treatment for angina.

This would include aspirin 300 mg followed by a low dose of 75-150 mg daily. In cases of aspirin intolerance, clopidogrel should be used. β Blockers and nitrates should also be given. Rate limiting calcium antagonists can be used if β blockers are contraindicated or are already being used. Ideally, patients should be given low molecular weight heparin (enoxaparin) according to their weight. If low molecular weight heparin is unavailable, unfractionated heparin may be used. A bolus of 5000 U is given, followed by an infusion adjusted to get an activated partial thromboplastin time (APTT) ratio of 1.8 to 2.5. In light of data from the CURE and PCI-CURE study, clopidogrel (given for at least one month …

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