Myocardial Ischemia Is Present and Mostly Reversible in Patients With a Chronic Total Occlusion and a Viable Perfusion Territory: The DISTAL CTO Study

Abstract

ACKGROUNDThe highest benefit of revascularization isfound in patients with very low fractionalflow reserve (FFR).In chronic total occlusion (CTO) patients, instant wave-freeratio (iFR, Philips) may be more appropriate to evaluateischemia as it does not require maximal microvascular vaso-dilation, which may be hampered by microvasculardysfunctioninuptoone-halfofCTOpatients.Thestudyaimsto prove through iFR measurements that the myocardiumdistal to a CTO is ischemic and that ischemia is reversible by apercutaneous coronary intervention (PCI).METHODSCTO patients with proven viable myocardium andclinical or other signs of ischemia were prospectively andconsecutively enrolled in 6 Belgian CTO PCI centers. Pd/Paand iFR was measured with a pre-normalized pressure wire(Verrata, Philips) before (advanced through a microcatheter)and after PCI. If iFR was still below 0.90 after stenting, furtheroptimization with intracoronary imaging was performed.RESULTSA total of 38 patients were included. All patientshad significant ischemia distal to the CTO. iFR improvedfrom 0.32 (0.26 to 0.43) to 0.92 (0.89 to 0.96) post-PCI(p<0.001). In total, 23.7% of patients had a suboptimalpost-PCI iFR below 0.90 despite a satisfactory angio-graphic result. After furtheroptimization, only 7.9% had afinal iFR below 0.90 attributed to residual diffuse disease(Figure).CONCLUSIONIn CTO patients selected for PCI based onpresence of viability and ischemia, myocardial ischemiadistal to a CTO was always present and largely reversible. Alow post-PCI iFR helped guide further optimization of theresult