Author + information
- Roberto Scarsini1,
- Gabriele Pesarini2,
- Mattia Lunardi3,
- Anna Piccoli4,
- Claudia Zanetti5,
- Carlo Zivelonghi6 and
- Flavio Ribichini7
- 1University of Verona, Verona, Verona, Italy
- 2Ospedale Civile Maggiore Borgo Trento, Verona, Verona, Italy
- 3Division of Cardiology, Department of Medicine, University of Verona, Verona, Verona, Italy
- 4Division of Cardiology, University of Verona, Verona, Verona, Italy
- 5Division of Cardiology, Department of Medicine, University of Verona, Verona, Venice, Italy
- 6Department of Cardiology, St. Antonius Ziekenhuis, Nieuwegein, Netherlands
- 7University of Verona, Verona, Verona, Italy
Physiology of coronary circulation in patients with aortic stenosis (AS) is not well established, and the behavior of conventional ischemic indexes such as fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) in this setting is unclear. We sought to assess the eventual changes in iFR measurements in patients with severe aortic stenosis (AS) before and after TAVI in coronary lesions with different degree of angiographic severity.
The functional relevance of 145 coronary lesions was assessed by on-line iFR and FFR measurement in 66 patients with severe AS before and after TAVI, during the same procedure. A linear-mixed-model was used to verify interaction of TAVI-effect with iFR measurements. The iFR-FFR classification agreement was calculated for pre- and post-TAVI measurements.
Mean iFR values remained identical before and after TAVI, irrespective of the angiographic severity of the coronary stenosis (0.89±0.12 vs 0.89±0.12, p=0.66). However, individual iFR values varied widely after TAVI and the 0.89 iFR threshold was crossed by 15% of the investigated coronary lesions (27% of patients). Higher iFR variation was related to a higher trans-aortic gradient drop after valve intervention. The diagnostic accuracy of iFR in predicting a FFR≤0.8 was poor (65%) in lesions with severe obstructions, and tended to increase post-TAVI.
Although overall values did not change after TAVI, iFR presented significant and mostly erratic individual variations after the valve replacement. The iFR-delta was influenced by the extent of the trans-aortic gradient drop induced by TAVI. Therefore, caution is advisable in iFR interpretation in presence of severe AS.
IMAGING: FFR and Physiologic Lesion Assessment