Peter Kayaert1, Mathieu Coeman1, Benny Drieghe1, Johan Bennett2, Keir McCutcheon2, Jo Dens3, Claudiu Ungureanu4, Carlo Zivelonghi5, Pierfrancesco Agostoni5, Yoann Bataille6, Quentin de Hemptinne7, Sofie Gevaert1, Michel De Pauw1, Steven Haine8,9. 1. Department of Cardiology, Ghent University Hospital, Ghent, Belgium. 2. Department of Cardiovascular Medicine, University Hospital Leuven, Leuven, Belgium. 3. Department of Cardiology, Ziekenhuis Oost-Limburg, Genk, Belgium. 4. Department of Cardiology, Jolimont Hospital, La Louvière, Belgium. 5. Hartcentrum, Ziekenhuis Netwerk Antwerpen Middelheim, Antwerp, Belgium. 6. Department of Cardiology, Jessa Hospital, Hasselt, Belgium. 7. Department of Cardiology, CHU Saint Pierre, Brussels, Belgium. 8. Department of Cardiology, Antwerp University Hospital, Antwerp, Belgium. 9. Department of Cardiovascular Diseases, University of Antwerp, Antwerp, Belgium.
Abstract
OBJECTIVES: The study aimed to demonstrate through instant wave-free ratio (iFR) measurements that myocardium distal to a chronic total occlusion (CTO) is ischemic, that ischemia is reversible by PCI, and that iFR assessment after PCI can be used to optimize PCI results. BACKGROUND: The greatest benefit of revascularization is found in patients with low fractional flow reserve. In patients with CTOs, iFR measurement may be more appropriate to evaluate ischemia as it does not require maximal microvascular vasodilation, which may be hampered by microvascular dysfunction. METHODS: The iFR was measured in 81 CTO patients, both pre- and post-PCI in 63 patients, and only post-PCI in the following 18 patients. A pressure wire pullback was performed post-PCI if iFR ≤0.89. RESULTS: The first 63 patients all had significant ischemia distal to the CTO with a median iFR of 0.33 [0.22; 0.44], improving significantly post-PCI to a median iFR of 0.93 [0.89;0.96] (p < .001). In the complete cohort, the median iFR post-PCI was 0.93 [0.86;0.96] but still ≤0.89 in 23 patients (30%). 12 of these patients had further PCI optimization because of a residual focal pressure gradient on pullback, after which only two had a final iFR ≤0.89. CONCLUSIONS: In CTO patients with an indication for PCI, iFR consistently demonstrated profound myocardial ischemia. Successful PCI immediately relieved ischemia in 70% of patients. In the remaining 30% of cases, a manual iFR pullback proved helpful in guiding further optimization of the PCI result.
OBJECTIVES: The study aimed to demonstrate through instant wave-free ratio (iFR) measurements that myocardium distal to a chronic total occlusion (CTO) is ischemic, that ischemia is reversible by PCI, and that iFR assessment after PCI can be used to optimize PCI results. BACKGROUND: The greatest benefit of revascularization is found in patients with low fractional flow reserve. In patients with CTOs, iFR measurement may be more appropriate to evaluate ischemia as it does not require maximal microvascular vasodilation, which may be hampered by microvascular dysfunction. METHODS: The iFR was measured in 81 CTO patients, both pre- and post-PCI in 63 patients, and only post-PCI in the following 18 patients. A pressure wire pullback was performed post-PCI if iFR ≤0.89. RESULTS: The first 63 patients all had significant ischemia distal to the CTO with a median iFR of 0.33 [0.22; 0.44], improving significantly post-PCI to a median iFR of 0.93 [0.89;0.96] (p < .001). In the complete cohort, the median iFR post-PCI was 0.93 [0.86;0.96] but still ≤0.89 in 23 patients (30%). 12 of these patients had further PCI optimization because of a residual focal pressure gradient on pullback, after which only two had a final iFR ≤0.89. CONCLUSIONS: In CTO patients with an indication for PCI, iFR consistently demonstrated profound myocardial ischemia. Successful PCI immediately relieved ischemia in 70% of patients. In the remaining 30% of cases, a manual iFR pullback proved helpful in guiding further optimization of the PCI result.