Deferred revascularization of left main stenosis based on instantaneous wave-free ratio: Long-term clinical outcomes from the PHYNAL registry.

Background: An accurate assessment of intermediate left main (LM) stenoses is crucial for revascularization decision-making. However, data on LM revascularization strategy according to instantaneous wave-free ratio (iFR) are limited. This study aimed to evaluate the safety of deferring LM revascularization according to iFR.

Methods: The PHYNAL study is a prospective, multicenter registry that included consecutive patients with intermediate LM stenosis who underwent coronary physiology assessment. Patients in whom the treatment strategy (revascularization versus deferral) was based on the iFR cutoff of 0.89 were considered for the current subanalysis. The primary endpoint was major adverse cardiac events (MACE), a composite outcome including all-cause death, non-fatal myocardial infarction (MI), and target lesion revascularization (TLR). Secondary endpoints were cardiac death and each component of the primary endpoint.

Results: The study population consisted of 240 patients: 188 in the deferred and 52 in the revascularized groups. At a median follow-up of 24 months (IQR: 21 to 25 months), MACE occurred in 19 patients (10 %) in the deferred and 8 patients (16 %) in the revascularized groups (HR: 1.56; 95 % CI: 0.67 to 3.60; p = 0.30) with no significant difference. Rate of all-cause death was 5 % in the deferred versus 12 % in the revascularized groups (p = 0.1), cardiac death 3 % versus 8 % (p = 0.2), non-fatal MI 1 % versus 2 % (p = 0.4), and TLR 5 % versus 2 % (p = 0.5).

Conclusions: Deferring LM revascularization according to iFR is safe. Patients in whom LM revascularization is deferred based on iFR have comparable clinical outcomes to patients who undergo LM revascularization according to iFR.