Frequency of a large drift caused by pressure wire using optical fibers.

The frequency of a large pressure signal drift (PDs) caused by pressure wire using optical fibers and its effect on fractional flow reserve (FFR)-based decision-making is not clear. We used pressure wires using optical fibers as "workhorse wires" for 95 consecutive lesions. The wire was normalized at the tip of the guiding catheter just before performing the percutaneous coronary intervention (PCI) and was used without re-normalization until the end of the PCI. The drift value at the end of the procedures was evaluated. Four per cent (n = 4) of patients showed a large drift (PD >3 mmHg). Classification discordance between read-out and PD-corrected FFR values was detected in 8 (8%) measurements in total. The decision changed from FFR ≤0.80 to >0.80 in 7 (7%) measurements and vice versa in 1 (1%) measurement. PD showed no effect on decision-making when the FFR read-out value was <0.78 or >0.82. The frequency of large drifts caused by pressure wires using optical fibers was 4%. However, no case showed decision changes when the FFR gray zone was considered.

Residual pressure gradient across the implanted stent: An important factor of post-PCI physiological results.

BACKGROUND: Instantaneous wave-free ratio (iFR) has the potential to improve the accuracy of the prediction of the physiological result of percutaneous coronary intervention (PCI). The aim of this study was to evaluate the accuracy of iFR to predict the final physiological results following PCI, and investigate the factors for failed prediction. METHODS: In 73 lesions, iFR pullback recordings were measured and comparisons were made between the predicted improvement following PCI and the observed result. RESULTS: iFR predicted-observed difference was 0.036±0.037. Multivariate analysis showed residual iFR pressure gradient across the implanted stent (odds ratio, 2.329; 95% confidence interval, 1.408-3.853; p=0.0010) as an independent risk factor for error in iFR prediction. CONCLUSIONS: iFR predicted-observed difference was 0.036±0.037. Residual in-stent iFR pressure gradient following PCI is the only independent risk factor for failed prediction.

Postocclusional Hyperemia for Fractional Flow Reserve After Percutaneous Coronary Intervention.

BACKGROUND: Postocclusional hyperemia caused by balloon occlusion is a potential alternative method of inducing hyperemia for measuring post-percutaneous coronary intervention fractional flow reserve (FFR). The aim of this study was to investigate postocclusional hyperemia as a method of inducing hyperemia. METHODS AND RESULTS: FFR measured by postocclusional hyperemia (FFRoccl) caused by balloon occlusion after percutaneous coronary intervention was compared with FFR measured by drug-induced hyperemia (FFR measured by intravenous ATP; and FFR measured by intracoronary papaverine injection [FFRpap]) in 98 lesions from 98 patients. The hyperemia duration was also measured for FFRoccl and FFRpap. The correlation coefficient between FFRoccl, FFR measured by intravenous ATP (r=0.973; P<0.01), and FFRpap (r=0.975; P<0.01) showed almost identical values to those obtained for the correlation coefficient between FFR measured by intravenous ATP and FFRpap (r=0.967; P<0.01). No clear difference was observed on Bland-Altman analysis. Hyperemia duration was significantly longer with FFRoccl than with FFRpap (70±22 versus 51±25 s; P<0.01). CONCLUSIONS: Strong correlations were found between FFRoccl and FFR measured by intravenous ATP and FFRoccl and FFRpap. Hyperemia caused by FFRoccl was significantly longer than that caused by FFRpap.