Box 2 – Procedure for patients with STEMI who are for thrombolysis rather than PCI

If PCI is not possible or delayed, thrombolytic therapy should be considered as soon as possible.

Definite indications:

  • Pain <12 hours, ST elevation of at least 1mm in limb leads or 2mm in precordial leads.
  • ST elevation, ongoing pain 12-24 hours.

Probable indications:

  • High clinical suspicion with LBBB
  • Doubt about time of onset, high clinical suspicion, “stuttering” onset, or widespread ECG changes.

Uncertain indications:

  • Profound ST depression - in the presence of ST segment depression only, pooled data from clinical trials have failed to show benefit from the administration of thrombolytic therapy in patients with acute MI. Some of these patients will have true posterior MI, who will benefit from reperfusion therapy. This is usually associated with inferior ST elevation, but this may be subtle.

In the presence of a normal ECG, alternative diagnoses should be sought (e.g. aortic dissection, pericarditis, pulmonary embolus, peptic ulcer disease), and thrombolytic therapy not given. The 12 lead ECG must be repeated frequently if the clinical suspicion is high and pain continues.

If indicated, prescribe and administer tenecteplase in addition to all other drugs in Box 1 (provided there are no contraindications). Note, patients who are hypertensive should not receive thrombolysis until BP is controlled - see below for further advice.

Tenecteplase single weight adjusted IV bolus over 10 seconds
Weight Weight (imperial) Dose (units) Dose (mg) Volume
<60kg <9st 6lb 6,000 units 30mg 6ml
60–69.9kg 9st 6lb–11st 7,000 units 35mg 7ml
70–79.9kg 11st 1lb–12st 8lb 8,000 units 40mg 8ml
80–89.9kg 12st 9lb–14st 2lb 9,000 units 45mg 9ml
>90kg >14st 2lb 10,000 units (max dose) 50mg (max dose) 10ml

N.B. Tenecteplase must not be administered in a line containing glucose due to incompatibility. Alteplase or streptokinase can be used as an alternative if supplies of tenecteplase are unavailable - contact your clinical pharmacist or Medicines Information (see Appendix 6 for contact details) for further advice.

Hypertension and Thrombolysis

Patients who are hypertensive (systolic >200mmHg or diastolic >100 mmHg) should not receive thrombolysis for acute MI until their BP is controlled using the following measures:

  1. Analgesia: Morphine IV 2.5-5mg if patient is in pain or distress.
  1. IV nitrates: Commence as soon as the need for thrombolysis is recognised if the patient is hypertensive.
    • Start glyceryl trinitrate infusion 1mg/ml at 10 to 20 micrograms/minute (equates to 0.6 to 1.2 ml/hour), then increased gradually until the desired BP is attained to allow thrombolysis.
    • BP should be rechecked every five minutes and if BP has not reduced to a level to allow thrombolysis, the infusion should be increased every 5 to 10 minutes until the desired BP is obtained.
    • Normal range is 10 to 100 micrograms/minute (equates to 0.6 to 6ml/hour).
  1. Intravenous beta-blocker: Should be added in patients who are still hypertensive despite 100 micrograms/minute of IV nitrates unless there are contra-indications to beta-blockers. Use either:
    • Metoprolol IV 5mg every 2 minutes to maximum of 15mg. If necessary 15minutes after IV dose, give metoprolol 50mg orally
    • or labetalol IV infusion at 15mg/hour and double dose at 30 minute intervals until BP controlled, patient develops symptomatic bradycardia or maximum dose of 120mg/hour attained.

 

Guideline reviewed August 2023
Page updated October 2023



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