Novel Method to Detect Pitfalls of Intracoronary Pressure Measurements by Pressure Waveform Analysis

Potential pitfalls of fractional flow reserve (FFR) measurements are well-known drawbacks of invasive physiology measurement, e.g., significant drift of the distal pressure trace may lead to the misclassification of stenoses. Thus, a simultaneous waveform analysis of the pressure traces may be of help in the quality control of these measurements by online detection of such artefacts as the drift or the wedging of the catheter. In the current study, we analysed the intracoronary pressure waveform with a dedicated program. In 130 patients, 232 FFR measurements were performed and derivative pressure curves were calculated. Local amplitude around the dicrotic notch was calculated from the distal intracoronary pressure traces (δdP_n/dt). A unidimensional arterial network model of blood flow was employed to simulate the intracoronary pressure traces at different flow rates. There was a strong correlation between δdP_n/dt values measured during hyperaemia and FFR (r = 0.88). Diagnostic performance of distal δdP_n/dt ≤ 3.52 for the prediction of FFR ≤ 0.80 was 91%. The correlation between the pressure gradient and the corresponding δdP_n/dt values obtained from all measurements independently of the physiological phase was also significant (r = 0.80). During simulation, the effect of flow rate on δdP_n/dt further supported the close correlation between the pressure ratios and δdP_n/dt. Discordance between the FFR and the δdP_n/dt can be used as an indicator of possible technical problems of FFR measurements. Hence, an online calculation of the δdP_n/dt may be helpful in avoiding some pitfalls of FFR evaluation.