Author + information
- Ricardo Petraco da Cunha,
- Tim van de Hoef,
- Sukhjinder Nijjer,
- Sayan Sen,
- Javier Escaned,
- Martijn Meuwissen,
- Darrel Francis,
- Jan Piek and
- Justin Davies
Recently, two invasive, vasodilator-free indices of coronary disease severity, the instantaneous wave-Free Ratio (iFR) and Baseline Stenosis Resistance (BSR) index, have been proposed as alternatives to fractional flow reserve (FFR). However, outcome studies on BSR and iFR are still lacking. In this study, we estimate iFR and BSR diagnostic performance in the populations of FAME and DEFER studies, landmark trials which have demonstrated the prognostic benefit of physiology-guided coronary revascularisation.
The classification agreement of coronary stenoses between iFR and FFR and between BSR and FFR were established from their original publications, across the whole range of FFR values (0.2 to 1), in 0.05 bands (step 1). The distribution of FFR values in DEFER was obtained from its published reproducibility scatter plot. FAME-like populations were derived using the mean ± SD values described in the original manuscript, assuming it to be normally distributed (step 2). The estimated overall accuracy of iFR and BSR to match the FFR classification of coronary stenoses in both studies was calculated as the sum-product of the per-band agreement (step 1) by the per-band percentage of values in each study (step 2). The accuracy of both baseline indices was adjusted for the measurement variability of FFR.
In both DEFER and FAME studies, BSR and iFR estimated agreement with FFR was very high. DEFER: BSR diagnostic accuracy = 91%; iFR diagnostic accuracy = 92%. FAME: BSR diagnostic accuracy = 91%; iFR diagnostic accuracy = 93%. Disagreements between baseline indices and FFR were predominantly concentrated near the FFR cut-off, where the rate of coronary events is known to be lower.
Adenosine-free indices iFR and BSR would have a very high classification agreement with FFR in the populations of FAME and DEFER studies, possibly deriving similar benefits in patient outcome if they were used to guide revascularisation. Prospective outcome studies need to be performed to confirm this finding.
Poster Sessions, Expo North
Monday, March 11, 2013, 9:45 a.m.-10:30 a.m.
Session Title: Chronic CAD: Genetics and Biomarkers
Abstract Category: 9. Chronic CAD/Stable Ischemic Heart Disease: Basic
Presentation Number: 1282-67
- 2013 American College of Cardiology Foundation