NCT02073422

FAMOUS-NSTEMI MRI Sub-Study

Fractional Flow Reserve Versus Angiographically Guided Management to Optimise Outcomes in Unstable Coronary Syndromes - A 3.0 Tesla Stress Perfusion MRI Sub-Study (FAMOUS-NSTEMI MRI)

• Status: Completed
• Phase: —
• Study type: Observational
• Enrollment: 106 (actual)
• Sponsor: NHS National Waiting Times Centre Board · Academic / Other
• Sex: All
• Age: —
• Healthy volunteers: Not accepted

Summary

BACKGROUND: Non-ST-segment elevation myocardial infarction (NSTEMI) is the commonest type of acute coronary syndrome (ACS) and has a poor long-term prognosis. Guidewire-based coronary pressure measurement of the myocardial fractional flow reserve (FFR) is validated for measuring the severity of a coronary lesion narrowing in patients with stable angina. FFR measurement in patients with a recent ACS has theoretical limitations and is not fully validated. AIM: To prospectively assess heart muscle blood flow and injury with guide-wire based methods at the time of the clinically-indicated angiogram and compare these results with those from a stress perfusion MRI scan in medically-stabilised NSTEMI.. HYPOTHESIS: 1) FFR measured invasively will correspond closely with findings from stress perfusion MRI, 2) MRI will provide clinically-relevant information on heart muscle injury, function and salvage, 3) Guidewire-derived measurements of coronary microvascular function will be associated with the MRI findings. DESIGN: The MRI study will be performed in patients who give informed consent in the FAMOUS-NSTEMI clinical trial (NCT registration 01764334). All of the clinical data for these participants will be available to link with the MRI results.

Detailed description

BACKGROUND: Non-ST elevation myocardial infarction (NSTEMI) is the commonest type of acute coronary syndrome (ACS) and has a poor long-term prognosis. Guidewire-based coronary pressure measurement of the myocardial fractional flow reserve (FFR) is a prognostically-validated invasive method for measuring coronary lesion severity in patients with stable coronary artery disease. FFR measurement in patients with unstable coronary disease has theoretical limitations and is not fully validated in NSTEMI. AIM: To prospectively evaluate ischaemia and infarction with adenosine stress perfusion cardiac MRI in medically-stabilised NSTEMI patients in whom FFR has been measured. METHODS: In the FAMOUS-NSTEMI clinical trial (NCT registration 01764334), medically-stabilised patients with recent NSTEMI will have lesion-level ischaemia measured with FFR in all coronary artery stenoses amenable to revascularisation, as clinically appropriate. Consecutive study participants will be invited to have an adenosine (140 µg/kg/min) stress 3.0 Tesla cardiac MRI scan to assess myocardial perfusion on up to three occasions: 1) before coronary angiography, 2) within 10 days post coronary angiography and finally, 3) 6 months after hospital admission. MRI will also assess myocardial pathophysiology including ischaemia, oedema, haemorrhage and infarct scar. MRI will provide the reference dataset. Guidewire-derived parameters were obtained and assessed blind to the MRI results. The primary outcome is the correspondence between the presence or absence of an inducible-myocardial perfusion defect and FFR ≤ or \> 0.80 in the MRI scans at baseline or post-angiography. Secondary outcomes include the correlation between measures of infarct severity as revealed by MRI (infarct size, myocardial salvage, microvascular obstruction, myocardial haemorrhage, myocardial strain) and invasive measures of coronary function (1) coronary collateral supply (fractional coronary collateral supply), (2) microcirculatory resistance (index of microvascular resistance), and (3) vasodilator capacity (resistive reserve ratio). The project was funded by the British Heart Foundation and Chief Scientist Office. The pressure wires were provided through a restricted grant from St Jude Medical. The funders of the study have no involvement in the study design, analysis, interpretation, or presentation of the results. VALUE: This study will provide clinically important information on the relationships between coronary artery and microcirculatory function measured invasively and ischaemia and MI pathologies, as revealed by non-invasively by MRI.

Conditions

• NonST Elevation Myocardial Infarction

Interventions

Type	Name	Description
DEVICE	Fractional flow reserve	Guidewire-based index of coronary artery stenosis severity measured when coronary microvascular resistance is minimised by administration of a vasodilator drug.
OTHER	Magnetic resonance imaging	Cardiac magnetic resonance imaging at 3.0 Tesla, including perfusion MRI at rest and during pharmacological stress with intravenous adenosine (140-210 ug/kg/min).

Timeline

• Start date: 2011-10-01
• Primary completion: 2014-06-10
• Completion: 2016-12-10
• First posted: 2014-02-27
• Last updated: 2024-10-29

Locations

1 site across 1 country: United Kingdom