OBJECTIVES

We used myocardial fractional flow reserve (FFR(myo)) and coronary flow reserve (CFR) to estimate cut-off values for assessment of the functional severity of coronary stenosis and myocardial ischemia, and we tested the usefulness of coronary blood hemodynamic measurements before and after plain old balloon angioplasty (POBA) and coronary artery bypass graft surgery (CABG).

BACKGROUND

Fractional flow reserve and CFR are useful for assessing the functional severity of coronary artery stenosis, coronary microvascular dysfunction, and myocardial ischemia during cardiac catheterization in adults. However, there have been no reports on the use of these measurements in children with Kawasaki disease (KD).

METHODS

The study group included 128 patients with 314 coronary branches. The subjects were classified into three groups: normal coronary group, with 206 branches; abnormal coronary artery without ischemia group, with 58 branches; and ischemia group, with 50 branches.

RESULTS

In each branch, CFR and FFR(myo) were significantly lower in the ischemia group than in the other groups. Cut-off values for assessing the functional severity of coronary stenosis and CFR were approximately equal to those obtained for adults (CFR: <2.0; FFR(myo): <0.75). We obtained very high sensitivity and specificity for estimating myocardial ischemia using CFR and FFR(myo) (CFR: 94.0% and 98.5%, respectively; FFR(myo): 95.7% and 99.1%, respectively). Both CFR and FFR(myo) were reliable indicators of coronary hemodynamics before and after POBA and CABG.

CONCLUSIONS

Together, CFR and FFR(myo) provide a useful index for assessing the functional severity of coronary artery stenosis and myocardial ischemia and estimating the effectiveness of POBA and CABG in children with KD, the same as they do for adults.