Author + information
- Ankita Gore1,
- Jung-Min Ahn2,
- Marcel van 't Veer3,
- Allen Jeremias4,
- Stuart Watkins5,
- Colin Berry6,
- Keith Oldroyd5,
- Barry Hennigan7,
- Aaron Crowley8,
- Akiko Maehara9,
- Gary Mintz9,
- Nils Johnson10,
- Seung-Jung Park2,
- Johan Svanerud11 and
- Ziad Ali12
- 1Columbia University/Cardiovascular Research Foundation, New York, New York, United States
- 2Asan Medical Center, Seoul, Korea, Republic of
- 3Catharina Hospital, Eindhoven, Netherlands
- 4St. Francis Hospital, Roslyn, New York, United States
- 5West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, U.K., Glasgow, United Kingdom
- 6British Heart Foundation Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, U.K, West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, U.K.,, Glasgow, United Kingdom
- 7Golden Jubilee National Hospital, Glasgow, Scotland, United Kingdom
- 8Cardiovascular Research Foundation, Queens, New York, United States
- 9Cardiovascular Research Foundation, New York, New York, United States
- 10Department of Cardiology, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, Texas, United States
- 11Coroventis Research AB, Uppsala, Sweden
- 12NewYork-Presbyterian Hospital/Columbia University Medical Center, New York, New York, United States
iFR requires sensitive landmarking of the pressure waveform to identify the “wave-free period” of diastole, where it is assumed that the maximal flow and minimal resistance occurs during rest. However this may not be obligatory in all clinical scenarios, particularly assessment of the right coronary artery (RCA) where peak flow may occur late in systole or early in diastole.
This was a retrospective study designed to compare the diagnostic utility of iFR to FFR for the physiological assessment of left coronary artery (LCA) vs RCA disease. FFR and iFR were available in 646 raw waveform measurements (522 LCA, 124 RCA). Diagnostic accuracy (DA), sensitivity (Sn), specificity (Sp), negative predictive value (NPV) and positive predictive value (PPV) of iFR (≤0.89) were compared to FFR (≤0.80).
The median FFR was 0.82 (IQR 0.12) and iFR 0.92 (IQR 0.09). iFR correlated to FFR (R2=0.54, iFR = 0.67 X FFR +0.36, P<0.001) with a mean bias of 0.100 (95% Limits of agreement -0.028, 0.23). Overall, diagnostic performance of iFR compared to FFR was DA 80.8%, Sn 69.3%, Sp 88.8%, PPV 81.1%, NPV 80.6%. While diagnostic accuracy of iFR versus FFR was preserved in the RCA, sensitivity was markedly reduced compared to the LCA (40.6% vs 73.2%, P<0.001) while specificity was improved (96.6% vs 86.4%, P<0.001) (Figure).
Compared to FFR, the sensitivity of iFR is significantly reduced in the RCA vs. LCA. Further investigation to determine the mechanism and clinical impact of this discordance is warranted.
IMAGING: Physiologic Lesion Assessment