Clinical implications of guiding catheter extubation during fractional flow reserve measurements.

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) and extubated in the aorta (FFR). 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 was significantly lower compared with FFR; 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 (R=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 and FFR. Guiding extubation during FFR measurements changed the revascularization indication in 16% of cases.