Abstract 17509: The Influence of Chronic Total Occlusion Recanalization on Fractional Flow Reserve Value of Collateral Donor Artery

Abstract

Background: Although recent guidelines recommend the use of fractional flow reserve (FFR) measurements to make decisions for patients with multi-vessel disease and borderline lesions, the presence of a concomitant chronic total coronary occlusion (CTO) may alter the FFR of the interrogated vessel due to collateral circulation. The purpose of this study was to investigate the change in donor artery FFR associated with PCI of a concomitant CTO. Methods: Nineteen consecutive patients who underwent PCI for CTO lesions were prospectively enrolled. All patients underwent myocardial stress perfusion scintigraphy before PCI. An intracoronary pressure/temperature sensor-tipped wire was advanced through a guiding catheter to a point 7cm distal from the ostium of both non-target arteries. At steady-state hyperemia, hemodynamics including FFR and the hyperemic mean transit time (Tmn), which are inversely proportional to coronary flow velocity, were calculated before and immediately after PCI. Coronary blood flow (CBF) was calculated as 1/Tmn х π х (diameter/2) 2 . Coronary wedge pressure was also measured after 30 s of balloon occlusion within the stented segment of the target arteries after PCI. Results: The average FFR values of the donor artery before PCI were 0.89±0.09. None of patients had signs of ischemia in the territory of the donor arteries, even though five patients had an FFR value of <0.80 in the donor arteries. After the successful recanalization of the target arteries, FFR values in the donor artery increased to 0.95±0.06 (mean difference, 0.06 [0.04 to 0.09]: p <0.001). On the other hand, CBF in the donor artery significantly decreased from 35.5±15.7 to 25.7±13.8 (p=0.02). No linear correlation was identified between the change of FFR in the donor artery and coronary wedge pressure in the occluded artery (r= -0.05, p= 0.78). Conclusions: Revascularization of a CTO lesion provides moderate increase in the FFR value of the collateral donor artery as a result of the reduction of coronary blood flow. Therefore, the hemodynamic significance of intermediate stenosis in the donor artery by FFR should be carefully evaluated in the presence of CTO.