Association between post-PCI vessel fractional flow reserve (vFFR) and optical coherence tomography (OCT) findings:...

Reduced post-PCI fractional flow reserve (FFR) and suboptimal optical coherence tomography (OCT) findings are associated with impaired outcomes. Angiography-derived vessel FFR (vFFR) has emerged as an accurate alternative to pressure-wire based FFR. This study sought to define the association between post-PCI vFFR and OCT findings.

The FAST OCT study included 200 patients with non-ST-elevation acute coronary syndrome (NSTE-ACS) and intermediate to severe coronary artery stenosis. Patients with post-PCI OCT and vFFR evaluation of at least one study vessel were included in this post-PCI sub-analysis. Complete post PCI OCT and vFFR data were available for 109 vessels (100 patients). Median post-PCI vFFR was 0.93 [25th-75th percentile 0.90-0.96], median vessel minimal lumen area (MLA) was 3.48 mm² [25th-75th percentile 2.42-4.89] and median in-stent MLA was 5.37 [25th-75th percentile 4.14-6.82]. In multivariable analysis, post-PCI vFFR was significantly associated with vessel MLA (average decrease of 20.6 % per 0.10 decrease in vFFR (95 % CI -34.6 % to -3.7 %), p = 0.021). The optimal cutoff value of post-PCI vFFR to detect an MLA ≤ 4.5 mm² was 0.92 (sensitivity 60.5 %, specificity 87.9 %). The proximal vFFR gradient showed a good diagnostic performance to detect proximal residual disease (AUC 0.80), whereas the diagnostic performance of the in-stent gradient to detect stent underexpansion was poor (AUC 0.52).

vFFR was significantly associated with MLA and a vFFR ≤ 0.92 had a good specificity to detect an MLA ≤ 4.5 mm². Post-PCI vFFR and segmental gradients may be of interest to identify suboptimal MLA's and proximal disease, but could not identify stent underexpansion.