Intravascular Ultrasound-derived Assessment of Hemodynamically Negative Lesions in NSTEACS Patients

Intravascular Ultrasound-derived Morphometric Assessment of Fractional Flow Reserve Negative Lesions to Predict Cardiovascular Outcomes in Non-ST-segment Acute Coronary Syndrome Patients

This is an observational and prospective cohort study to examine whether the addition of IVUS plaque morphological evaluation to FFR haemodynamic assessment of non-culprit lesions in NSTEACS patients will better predict MACEs.

IMPACT-NSTEACS is a prospective, single-centre and dynamic observational study. The study population consists of NSTEACS patients who undergo FFR in lesions with intermediate to severe angiographic stenosis. Then, FFR-guided PCI is performed, followed by morphological assessment based on IVUS in all FFR-negative lesions (FNLs). After discharge all patients receive optimal medication treatment and are followed up clinically. On the basis of follow-up angiography, MACEs are further adjudicated as occurring at FNLs or not.

Clinical Inclusion Criteria:

1. Moderate to high risk NSTEACS requiring invasive strategy based on current guidelines and local clinical practice.
2. Patient agrees and is able to follow all protocol procedures.

Clinical Exclusion Criteria:

1. STEMI or SCAD.
2. Hemodynamic instability (e.g. cardiogenic shock, refractory ventricular arrhythmias, acute and severe conduction system disease and left ventricular ejection fraction ≤30%).
3. Contraindication for FFR, PCI, IVUS and OMT (e.g. severe allergy to antiplatelet drug or contrast, significant bleed within the past 6 months, bleeding diathesis and serum creatinine ≥2.5 mg/dl).
4. PCI within 6 months or any prior CABG.
5. Anticipated life expectancy <3 year.
6. Pregnancy
7. Unwilling or unable to provide informed consent

Imaging Inclusion Criteria

1. Patients must have at least > 1 de novo lesion in a native coronary segment with a visually estimated diameter stenosis of between 40 and 90 %.
2. Successful FFR-guided PCI performed in all major epicardial coronary arteries (including their branches): PCI for all lesions a) with 40%-90% diameter stenosis and FFR<0.8 and b) with ≥90% diameter stenosis.
3. The FFR-negative lesions must be available for assessment of IVUS.

Imaging Exclusion Criteria:

1. Target lesion reference diameter <2.0 mm.
2. Anatomic conditions precluding FFR and IVUS (e.g. marked calcification or tortuosity, chronic total occlusion or thrombus).
3. After successful FFR-guided PCI, no FNL is left.
4. Any remaining lesion with diameter stenosis ≥90% or FFR<0.8 after PCI.
5. Left main coronary artery lesion.
6. CABG planned by the investigators according to extent and severity of coronary artery disease.