Association Between Pathophysiological Disease Pattern and an Increase in Absolute Coronary Flow Velocity After Elective Percutaneous Coronary Intervention.

Background: Percutaneous coronary intervention (PCI) aims to restore myocardial perfusion by relieving flow-limiting lesions. While fractional flow reserve (FFR) guides PCI decision-making, the relationship between lesion pathophysiological patterns and post-PCI absolute flow improvement remains elusive. Recent evidence suggests that disease pattern-focal versus diffuse-impacts PCI outcomes. The quantitative flow ratio (QFR)-derived pullback pressure gradient (PPG) offers a wire-free method to characterize these patterns.

Aims: We investigated whether pre-PCI QFR-PPG index predicts absolute coronary flow velocity improvement, assessed by stress-transthoracic Doppler echocardiography (S-TDE), in elective PCI.

Methods: This single-center retrospective analysis included 118 consecutive patients who underwent elective FFR-guided PCI and pre- and post-PCI LAD flow assessment using S-TDE. The study was conducted using the institutional QFR-PPG database registered in the University Hospital Medical Information Network Clinical Trials Registry (UMIN000056097). Pre-PCI QFR-PPG index was calculated to assess its association with post-PCI changes in coronary flow velocity.

Results: Post-PCI hyperemic diastolic peak velocity (hDPV) improved in 81.3% of patients, but 18.6% showed decreased values despite FFR improvement. The median % increase in hDPV was 30.3%. Patients with greater hDPV improvement (> 30%) had significantly lower pre-PCI FFR, lower pre-PCI hDPV, and higher QFR-PPG index. Multivariable logistic regression identified these three indices as independent predictors of flow improvement. ROC analysis and net reclassification improvement (NRI) supported incremental value of the QFR-PPG index over traditional metrics.

Conclusions: Pre-PCI QFR-PPG index, together with FFR and S-TDE-derived hDPV, predicts absolute flow improvement after PCI. This noninvasive, wire-free approach may help optimize revascularization decisions.