Clinical implications of guiding catheter extubation during fractional flow reserve measurements

Abstract

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 (FFR_int) and extubated in the aorta (FFR_ext). 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 FFR_ext was significantly lower compared with FFR_int; 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 FFR_ext and FFR_int. 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.