Evaluation of Instantaneous Wave-Free Ratio and Fractional Flow Reserve in Severe Aortic Valve Stenosis

Area of Science:

• Cardiology
• Interventional Cardiology
• Physiology

Background:

• Optimal functional evaluation of coronary artery stenosis in patients with severe aortic stenosis (AS) remains unclear.
• Severe AS can affect hemodynamic assessments of coronary stenosis.

Purpose of the Study:

• To evaluate the diagnostic and prognostic utility of instantaneous wave-free ratio (iFR) and fractional flow reserve (FFR) in patients with and without severe AS.

Main Methods:

• Retrospective analysis of 395 lesions in 293 patients with severe AS and 2257 lesions in 1882 patients without severe AS.
• FFR data was available for all patients; iFR was analyzed post hoc in lesions with adequate resting pressure curves.
• Median follow-up of 2 years to assess deferred lesion failure.

Main Results:

• The incidence of iFR ≤0.89 was significantly higher in severe AS patients (66.6%) compared to non-severe AS patients (31.8%).
• FFR ≤0.80 incidence was similar between groups (45.3% vs 43.9%).
• FFR ≤0.80 was associated with deferred lesion failure (aHR 2.71), whereas iFR ≤0.89 was not (aHR 1.31).

Conclusions:

• FFR is less affected by severe AS and demonstrates better prognostic value for coronary artery disease.
• iFR may overestimate functional stenosis severity in severe AS patients and lacks prognostic significance.
• iFR can be useful for excluding significant coronary stenosis in severe AS patients.