Background: The limitations of visual angiographic assessment in coronary artery disease are well known. When intermediate lesions are submitted for functional assessment, there is a reclassification in the initial therapeutic decision in up to 33% of patients. Additional diagnostic modalities have been developed, such as the instantaneous wave-free ratio (iFR) evaluation, to characterize these patients with intermediate lesions better.
Methods: This prospective single-center study investigated the prognosis of intermediate coronary stenoses assessed by the iFR. Consecutive patients from January 2017 to January 2020, whose iFR was assessed in our hospital and had one or more moderate coronary lesions were included. Patients were divided into Group A (deferred lesions [65 patients with 93 assessed lesions]) and Group B (revascularized lesions [25 patients with 37 lesions]).
Results: There was no difference in demographic characteristics and clinical symptoms at presentation between the groups. The radial artery approach was performed in both groups, with crossover rates of the arterial access of 4.61% in Group A and 4% in Group B, although this was not statistically different. The volume of contrast used (p = 0.001) and fluoroscopy time (p = 0.05) were higher in Group B than in Group A. The average duration of late follow-up was 390.1 + 289.1 days, with no significant difference between the groups (p = 0.202). The variables associated with the need for new urgent revascularization and death (cardiac and non-cardiac) were not different between the groups (p = 0.689 and p > 0.999, respectively). There was no case of infarction in either group.
Conclusion: Our study showed the safety of the iFR-based invasive physiology method in patients deferred from coronary revascularization in daily clinical practice. Both groups of patients had low rates of adverse cardiac events and death at the late follow-up.
What is Known:
• Fractional flow reserve evaluation is the gold standard diagnostic modality to measure the pressure gradient between the chosen lesion and the aortic root.
• The instantaneous wave-free ratio uses principles similar to that of the fractional flow reserve but does not require adenosine.
What the Study Adds:
• The instantaneous wave-free ratio is a safe and effective diagnostic measure in a real-world setting.
• Both patients deferred and those recommended for revascularization showed low rates of adverse cardiac events and death using the instantaneous wave-free ratio as an indicator.