Background: Fractional flow reserve (FFR) is defined by the maximal coronary flow ratio with and without stenosis.
Aims: We hypothesized that guiding catheter intubation in coronary ostia during FFR measurements may underestimate FFR value by limiting the increase of coronary flow during maximal hyperaemia.
Methods: Between June 2013 and January 2014, we prospectively included all patients with i.v. adenosine FFR measurements. FFR was measured with the guiding catheter intubated in the coronary ostia (FFRint) and extubated in the aorta (FFRext). We calculated the ratio between coronary ostium assessed by quantitative coronary angiography and guiding catheter surfaces, defined as the free ostial lumen ratio.
Results: In total, 151 lesions in 104 patients were included; 121 lesions and 88 patients were eligible for analysis. Mean±SD FFRext was significantly lower compared with FFRint; 0.82±0.08 and 0.84±0.08, respectively (P<0.001). Revascularization indication changed in 14 patients (16%). The difference induced by guiding extubation correlated significantly with the free ostial lumen ratio (R2=0.06, P=0.008).
Conclusion: FFR value is significantly lower when the guiding catheter is extubated. The smaller the coronary ostium, the greater the difference observed between FFRext and FFRint. Guiding extubation during FFR measurements changed the revascularization indication in 16% of cases.
Keywords: Catheter guide; Coronary stenosis; Fractional flow reserve; Guiding catheter; Sténose coronarienne.
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