Instantaneous Wave-Free Ratio: Novel Adenosine-Free Method to Assess Intracoronary Physiology

Area of Science:

• Cardiovascular Medicine
• Interventional Cardiology
• Physiology

Background:

• Fractional flow reserve (FFR) is established for guiding revascularization in coronary artery disease.
• Borderline lesions and multivessel disease require accurate physiological assessment.
• Noninvasive evaluation is often absent in patients undergoing coronary angiography.

Purpose of the Study:

• To review the concept of coronary physiological assessment.
• To discuss the emergence and utility of the instantaneous wave-free ratio (iFR).
• To explore iFR's application in various clinical scenarios.

Main Methods:

• Review of cornerstone studies on FFR and iFR.
• Discussion of iFR's technical advantages.
• Analysis of iFR's performance in different patient groups.

Main Results:

• iFR is a nonhyperemic pressure ratio measured during diastole.
• iFR offers benefits including no need for vasodilators, speed, and assessment of tandem/diffuse lesions.
• Virtual percutaneous coronary intervention (PCI) using iFR aids in optimizing revascularization.

Conclusions:

• iFR has become a valuable tool in coronary physiology.
• Its advantages make it a practical option for assessing coronary stenosis.
• This review highlights iFR's role alongside FFR in clinical practice.