Evaluation of intermediate coronary stenoses in acute coronary syndromes using pressure guidewire

Area of Science:

• Cardiology
• Interventional Cardiology
• Diagnostic Tools

Background:

• Fractional flow reserve (FFR) is a key diagnostic tool for guiding myocardial revascularization in stable coronary artery disease.
• Current evidence for FFR primarily includes patients with stable angina, with limited data on acute coronary syndromes (ACS).
• Physiological changes in ACS, such as microvascular dysfunction and sympathetic activation, can impair adenosine-induced hyperemia, potentially leading to false-negative FFR results.

Purpose of the Study:

• To review laboratory and clinical evidence on the application of FFR in both culprit and non-culprit lesions within the context of ACS.
• To explore the utility of the instantaneous wave-free ratio (iFR) as an alternative to FFR in ACS patients.
• To summarize recent data on iFR in stable coronary artery disease and ACS.

Main Methods:

• Literature review of laboratory and clinical investigations.
• Analysis of studies evaluating FFR in stable coronary artery disease and ACS.
• Review of recent data on iFR in both stable and acute coronary syndromes.

Main Results:

• Evidence supporting FFR use is mainly derived from stable angina cohorts.
• Patients with ACS may exhibit blunted responses to adenosine, leading to submaximal hyperemia and potentially false-negative FFR results.
• The instantaneous wave-free ratio (iFR) is emerging as an adenosine-free index for assessing functional stenosis severity.

Conclusions:

• The reliability of FFR in ACS patients requires further investigation due to potential physiological confounders.
• Deferring revascularization based on potentially false-negative FFR in ACS could leave residual risk.
• iFR shows promise as an alternative physiological index for stenosis assessment in ACS, avoiding adenosine-related limitations.