Background: Fractional flow reserve (FFR) is considered the standard for the assessment of the physiological significance of coronary artery stenosis. Intracoronary papaverine (PAP) is the most potent vasodilator used for the achievement of maximal hyperaemia. However, its use can provoke ventricular tachycardia (VT) due to excessive QT prolongation. We evaluated the clinical efficacy and safety of the administration of PAP after nicorandil (NIC), a potassium channel opener that prevents VT, for optimal FFR measurement.
Methods: A total of 127 patients with 178 stenoses were enrolled. The FFR values were measured using NIC (NIC-FFR) and PAP (PAP-FFR). We administered PAP following NIC (NIC-PAP). Changes in the FFR and electrogram parameters (baseline versus NIC versus PAP) were assessed and the incidence of arrhythmias after PAP was evaluated. In addition, we analysed another 41 patients with 51 stenoses, which were assessed the FFR using PAP before NIC (PAP-NIC). After propensity score matching, the electrogram parameters between 2 groups were compared.
Results: The mean PAP-FFR was significantly lower than the mean NIC-FFR (0.82 ± 0.11 versus 0.81 ± 0.11, p<0.05). The mean baseline-QTc, NIC-QTc, and PAP-QTc values were 425 ± 37 ms1/2, 424 ± 41 ms1/2, and 483 ± 54 ms1/2, respectively. VT occurred in only one patient (0.6%). Although PAP induced QTc prolongation (p<0.05), the PAP-QTc duration was significantly shorter in NIC-PAP compared to PAP-NIC (p<0.05).
Conclusion: The administration of PAP with NIC may induce sufficient hyperaemia and prevent fatal arrhythmia through reductions in the PAP-induced QTc prolongation during FFR measurement.