Low-dose thrombolytic therapy for heart attack patients

A Randomised Trial to Evaluate the Efficacy of Low-dose Intracoronary Tenecteplase in ST-Elevation Myocardial Infarction (STEMI) Patients With High Microvascular Resistance Post-percutaneous Coronary Intervention (PCI).

Phase 3 Interventional University of Sydney · NCT03998319

This study is testing if a low dose of a clot-busting drug can help heart attack patients recover better after their treatment.

Quick facts

PhasePhase 3
Study typeInterventional
Enrollment445 (estimated)
Ages18 Years and up
SexAll
SponsorUniversity of Sydney Academic / other
Locations22 sites (Bankstown, New South Wales and 21 other locations)
Trial IDNCT03998319 on ClinicalTrials.gov

What this trial studies

This study investigates the effects of low-dose intracoronary thrombolytic therapy using tenecteplase in patients experiencing ST-elevation myocardial infarction (STEMI). After performing angioplasty, the Index of Microcirculatory Resistance (IMR) will be measured to assess microcirculatory damage. Patients with an elevated IMR (>32) will be randomized to receive either the thrombolytic treatment or a placebo. The study aims to evaluate the impact of this therapy on heart muscle damage and overall patient outcomes through follow-up cardiac MRIs and clinical assessments.

Who should consider this trial

Good fit: Ideal candidates are adults over 18 who present with STEMI within 6 hours of symptom onset and have an elevated IMR.

Not a fit: Patients with previous coronary bypass grafting or significant residual lesions in the culprit artery may not benefit from this study.

Why it matters

Potential benefit: If successful, this approach could significantly improve recovery and outcomes for heart attack patients by reducing microcirculatory damage.

How similar studies have performed: Other studies have explored thrombolytic therapies in similar contexts, showing promising results, but this specific approach is novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

1. Adult men and women aged over 18 who present with STEMI within 6 hours of symptom onset. Patients will be eligible if they have symptoms consistent with myocardial ischaemia (chest pain, dyspnoea) for at least 20 minutes accompanied by definite ECGs indicating STEMI as defined by Australian National Heart Foundation (NHF) guidelines
2. Willing and able to comply with all study requirements, including treatment, assessment and clinic visit attendances
3. Able to personally read and understand the Participant Information and Consent Form and provide written, signed and dated informed consent to participate in the study
4. (At time of PCI) Patient has received metallic drug-eluting stent
5. Participant consents to have a 3-7 day (discharge) and 6 month follow up cardiac MRI

Exclusion Criteria:

At the time of screening and/or prior to randomisation, no known;

1. Previous coronary bypass grafting
2. Other residual lesions with ≥50% diameter stenosis in the culprit vessel
3. Prior myocardial infarction in the target territory
4. Presence of contraindications to thrombolytic therapy (including history of stroke and recent brain surgery active internal bleeding; history of cerebrovascular accident; intracranial or intraspinal surgery, or trauma within 2 months; intracranial neoplasm, arteriovenous malformation, or aneurysm; known bleeding diathesis; and severe uncontrolled hypertension)
5. Presence of contraindications to adenosine infusion for IMR measurement including sinus node disease, moderate to severe bronchoconstrictive disease and second or third-degree atrioventricular (AV) block
6. Diagnosis of metastatic disease
7. Concurrent illness, including severe infection that may jeopardise the ability of the patient to undergo the procedures outlined in this protocol with reasonable safety
8. Serious medical or psychiatric conditions that might limit the ability of the patient to comply with the protocol
9. Pregnancy, lactation, or inadequate contraception. Women must be post-menopausal, infertile, or use a reliable means of contraception. Women of childbearing potential must have a negative pregnancy test done within 7 days prior to registration. Men must have been surgically sterilised or use a (double if required) barrier method of contraception.
10. Participation in any investigational study in the previous 30 days

    Other exclusion criteria:
11. (Cardiac MRI cohort only) Presence of contraindications to contrast enhanced MRI including severe claustrophobia, pregnancy, pacemakers, non-MRI compatible aneurysm clips, defibrillators and estimated glomerular filtration rate of \<30mL/min.

    (At time of PCI)
12. Patients who received GpIIb/IIIa treatment prior to IMR measurement
13. Patients who do not undergo primary PCI due to lack of severity of culprit lesion or other reasons.

Where this trial is running

Bankstown, New South Wales and 21 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions STEMIElevated IMRIMRmicrocirculationmicrovascular obstructionmyocardial infarctionphysiologyangioplasty
Last reviewed 2026-06-09 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.