A single-center, prospective, randomized, open-label, blinded end-point clinical trial of instantaneous wave-free ratio (iFR) guidance strategy impact on clinical outcomes in multivessel acute coronary syndrome (ACS) patients.

The "all-comers" study population consists of hemodynamically stable de novo ACS patients with a stenosis of 50% and more by visual estimation in at least two separate coronary arteries with Thrombolysis in Myocardial Infarction (TIMI) flow ≥ 2 and willing to sign a patient informed consent. ACS diagnosis established by angina pectoris symptoms and/or ECG changes and/or hs-troponin I levels. The use of drug-eluting stents is mandatory in both treatment groups. In the intervention strategy group, patients are treated by the iFR-guided percutaneous coronary intervention (PCI) in one stage. In the control group, patients are treated in accordance with the standard practice of angiography-guided staged approach.

Inclusion Criteria:

• 18 years of age and older
• willing to give informed consent
• hemodynamically stable de novo acute coronary syndrome patients with a stenosis of 50% and more by visual estimation in at least two separate coronary arteries
• adequate coronary flow, Thrombolysis in Myocardial Infarction (TIMI) flow ≥ 2
• sinus rhythm

Exclusion Criteria:

• inability to give consent;
• younger than 18 years of age
• atrial fibrillation rhythm at the time of inclusion
• with significant valve disease
• in cardiogenic shock
• with reduced kidney function - eGFR < 30 (mL/min/1.73m2);
• with congenital heart defects
• with acute pulmonary artery embolism;
• with isolated left main ostial stenosis;
• on active oncologic treatment or toxic cardiomyopathy;
• revascularization by PCI is not possible due to other comorbidities or patient denial of treatment.