Coronary circulation: Pressure/flow parameters for assessment of ischemic heart disease

Area of Science:

• Cardiovascular Physiology
• Medical Imaging
• Interventional Cardiology

Background:

• Coronary circulation assessment utilizes invasive and non-invasive parameters.
• Metrics like fractional flow reserve (FFR) and coronary flow reserve (CFR) guide revascularization and risk stratification.
• Various indices, including instantaneous wave-free ratio (iFR) and PET absolute myocardial blood flow, serve similar clinical purposes.

Purpose of the Study:

• To present basic principles of commonly used coronary circulation metrics.
• To discuss the potential strengths and weaknesses of these indices.
• To improve the appreciation of clinical information provided by each metric.

Main Methods:

• Review of invasive and non-invasive physiological parameters for coronary circulation assessment.
• Discussion of metrics such as FFR, CFR, iFR, hyperemic stenosis resistance, and PET absolute myocardial blood flow.
• Analysis of basal condition measurements including iFR, Pd/Pa, and basal stenosis resistance (BSR).

Main Results:

• Commonly employed metrics are dichotomized into 'normal' and 'abnormal' categories.
• Dichotomized indices may not always yield consistent results, potentially causing confusion.
• Understanding the principles and limitations of each metric is crucial for accurate interpretation.

Conclusions:

• A clear understanding of coronary physiological metrics is essential for clinical practice.
• Appreciating the strengths and weaknesses of each index enhances diagnostic accuracy.
• This review aims to provide a comprehensive overview for informed clinical decision-making.