Improvement in coronary haemodynamics after percutaneous coronary intervention: assessment using instantaneous...

Area of Science:

• Cardiovascular Medicine
• Interventional Cardiology
• Physiology

Background:

• Assessing the significance of coronary artery stenosis is crucial for guiding percutaneous coronary intervention (PCI).
• Fractional flow reserve (FFR) is a gold standard for evaluating stenosis severity, but the instantaneous wave-free ratio (iFR) offers a simpler, non-hyperemic alternative.
• Understanding how iFR reflects hemodynamic changes post-PCI compared to FFR is essential for clinical practice.

Purpose of the Study:

• To evaluate the ability of iFR to detect hemodynamic improvements following PCI.
• To compare the post-PCI performance of iFR with FFR and resting Pd/Pa.
• To determine if iFR can serve as a reliable indicator of successful PCI.

Main Methods:

• A prospective observational study involving 112 patients with significant coronary stenoses (FFR ≤ 0.80) undergoing elective PCI.
• Intracoronary pressure measurements (iFR, Pd/Pa, FFR) were taken before and after PCI, with hyperemia induced by adenosine.
• Validated, automated algorithms were used for calculating iFR, Pd/Pa, and FFR values.

Main Results:

• PCI significantly improved all hemodynamic indices: FFR increased from 0.66 to 0.89, iFR from 0.75 to 0.94, and Pd/Pa from 0.83 to 0.96.
• The change in iFR after PCI (ΔiFR) was comparable to the change in FFR (ΔFFR) (0.20 vs. 0.22, p=0.25).
• Both ΔFFR and ΔiFR demonstrated a significantly larger dynamic range than resting ΔPd/Pa, even in patients with risk factors like diabetes and hypertension.

Conclusions:

• Both iFR and FFR accurately reflect hemodynamic changes induced by PCI.
• iFR and FFR exhibit a greater dynamic range in assessing hemodynamic shifts post-PCI compared to resting Pd/Pa.
• iFR shows potential as an objective tool for documenting hemodynamic improvements after PCI, mirroring FFR's utility.