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World J Cardiol. Apr 26, 2026; 18(4): 116033 Published online Apr 26, 2026. doi: 10.4330/wjc.v18.i4.116033
Quantitative flow ratio virtual pullback index predicts focal coronary artery disease identified on wire-based pullback pressure gradient
Zhi Hao Teoh, Tom Wardill, Michael Zhang, Joseph O’Brien, Derek P Chew, Brian Ko, Dennis T L Wong
Zhi Hao Teoh, Tom Wardill, Michael Zhang, Joseph O’Brien, Derek P Chew, Brian Ko, Dennis T L Wong, Monash Heart, Victorian Heart Hospital, Monash Health, Melbourne 3168, Victoria, Australia
Joseph O’Brien, Derek P Chew, Brian Ko, Dennis T L Wong, Victorian Heart Institute, Monash University, Melbourne 3168, Victoria, Australia
Author contributions: Teoh Z, Wardill T, and Zhang M contributed to data acquisition, performed data analyses and wrote the manuscript; Teoh Z and Wong DTL designed the study; O’Brien J, Chew DP, Ko B, and Wong DTL critically reviewed the manuscript and gave critical suggestions on revision; Wong DTL was responsible for the overall contact and acts as the guarantor; all authors read and approved the final manuscript and agreed to submit it for consideration for publication.
Institutional review board statement: The study protocol was approved by the Local Human Research Ethics Committee (No. RES-22-0000-067Q-83745).
Informed consent statement: Informed consent was waived due to the retrospective design of the study and the use of anonymized clinical data, in accordance with institutional and ethical guidelines.
Conflict-of-interest statement: All authors declare no conflict of interest in publishing the manuscript.
Data sharing statement: The data that support the findings of this study are available from the corresponding author upon reasonable request. All authors confirm accountability for all aspects of the work, including full data access upon reasonable request, integrity of the data, and accuracy of the data analysis, and ensure that any questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
Received: November 3, 2025 Revised: December 29, 2025 Accepted: February 27, 2026 Published online: April 26, 2026 Processing time: 164 Days and 19.7 Hours
Abstract
BACKGROUND
Wire-based pressure pullback gradient (PPG) is the reference method for differentiating focal from diffuse coronary artery disease (CAD). However, it requires invasive instrumentation and hyperaemia. The quantitative flow ratio (QFR)-derived PPG [QFR virtual pullback (QVP) index] is a non-invasive alternative.
AIM
To evaluate the correlation between QVP index and PPG, and to explore the diagnostic performance of QVP index for identifying focal CAD.
METHODS
We retrospectively studied 74 patients (86 vessels) who underwent coronary angiography, fractional flow reserve (FFR), wire-based PPG, angio-based QFR and QVP index between December 2021 and October 2023. The primary analysis focused on FFR-significant lesions (FFR ≤ 0.75, n = 31), as these are clinically relevant for guiding percutaneous coronary intervention. QVP index was calculated from the maximal QFR drop over 20 mm and the length of the epicardial segment with the greatest reduction. Focal disease was defined by PPG > 0.73.
RESULTS
QFR was strongly correlated with FFR (r = 0.84, P < 0.001). In FFR significant vessels (FFR ≤ 0.75, n = 31), QVP index showed a moderate correlation with PPG (r = 0.45, P = 0.01). QVP index demonstrated excellent intra-observer and inter-observer variability with intraclass correlation coefficients of 0.918 (P < 0.001) and 0.932 (P < 0.001), respectively. QVP index predicted focal disease (defined as PPG > 0.73) with area under the curve of 0.73 (P = 0.02). A retrospectively derived threshold of QVP index > 0.53 yielded 90% sensitivity and 53% specificity (P = 0.04), though this cut-off was derived from the same dataset and should be regarded as hypothesis-generating.
CONCLUSION
QVP index correlates with PPG in FFR-significant lesions and may help to identify focal CAD patterns. However, these findings are hypothesis-generating and derived from a small, retrospective, single-centre cohort without external validation. Prospective multicentre studies are needed to validate cut-offs and determine whether QVP index provides incremental clinical value beyond existing physiological and imaging tools.
Core Tip: Quantitative flow ratio virtual pullback index is a non-invasive, high-sensitivity tool that accurately predicts focal coronary artery disease, offering an alternative to pressure pullback gradient for percutaneous coronary intervention decision-making without the need for hyperemia or further invasive procedures.
