Non-hyperaemic pressure ratios to guide percutaneous coronary intervention.

Area of Science:

• Cardiovascular medicine
• Interventional cardiology
• Physiology

Background:

• Fractional flow reserve (FFR) is guideline-recommended for guiding revascularisation, improving patient outcomes.
• Limited FFR adoption is attributed to procedural complexity and discomfort from hyperaemic agents.
• Non-hyperaemic pressure ratios (NHPRs) were developed as alternatives to FFR.

Purpose of the Study:

• To review the development and evidence supporting non-hyperaemic pressure ratios (NHPRs) as alternatives to FFR.
• To compare the diagnostic performance and clinical utility of various NHPRs.
• To highlight the importance of understanding NHPRs for clinical decision-making.

Main Methods:

• Review of existing clinical guidelines and published studies on FFR and NHPRs.
• Analysis of the mathematical principles and diagnostic equivalence of different NHPRs.
• Discussion of the integration of NHPRs into current pressure wire systems.

Main Results:

• Instantaneous wave-free ratio (iFR) is a well-established NHPR, now guideline-recommended.
• Other NHPRs, including diastolic hyperaemia-free ratio and resting full-cycle ratio, demonstrate mathematical analogy and equivalent diagnostic performance to iFR.
• These NHPRs are widely available in catheter laboratories.

Conclusions:

• NHPRs offer a viable, less invasive alternative to FFR for guiding revascularisation.
• Understanding the nuances and evidence base of different NHPRs is crucial for optimal clinical application.
• The increasing availability and proven performance of NHPRs support their role in routine practice.