Pressure wire compared to microcatheter sensing for coronary fractional flow reserve: the PERFORM study.

AIMS: Among technologies used to assess FFR, a monorail, sensor-tipped micro pressure catheter (PC) may be advantageous for delivery and re-assessment. We sought to determine whether the larger cross-sectional area of the PC influences FFR measurements compared to the pressure wire. METHODS AND RESULTS: PERFORM was a single-centre, prospective study designed to determine the precision and accuracy of the PC compared with the pressure wire (PW) for measurement of FFR. Eligible patients had native coronary artery target lesions with visually estimated diameter stenosis of 40-90%. The independently adjudicated primary endpoint was the difference in hyperaemic PW-determined minimal FFR with and without the PC distal to the stenosis. Seventy-four patients (95 lesions) were prospectively analysed between December 2015 and December 2016. Median hyperaemic FFR was 0.84 (IQR 0.78, 0.89) with the PW and 0.79 (IQR 0.73, 0.85) with the PC distal to the stenosis (p<0.001). Such differences led to clinical discordance, whereby the PC decreased the hyperaemic PW-determined FFR from >0.80 to ≤0.80 in 17 of 95 measurements (19%). Median resting Pd/Pa was lower following introduction of the PC compared with the PW alone (0.93 [IQR 0.90, 0.97] versus 0.90 [IQR 0.86, 0.95], p<0.001). Median pressure drift was not different between the PW and the PC (0.01 [IQR -0.01, 0.05] versus 0.01 [IQR 0.00, 0.02], p=0.38). CONCLUSIONS: Introduction of the PC reduced both hyperaemic FFR and resting Pd/Pa compared with the PW alone, leading to re-classifying physiological significance to below the clinical threshold in one out of five assessments.

Clinical validation of the new T- and Y-shape models for the quantitative analysis of coronary bifurcations: an interobserver variability study.

OBJECTIVES: This article presents the results of an interobserver validation study of our new T- and Y-shape bifurcation models including their edge segment analyses. BACKGROUND: Over the last years, the coronary artery intervention procedures have been developed more and more toward bifurcation stenting. Because traditional straight vessel quantitative coronary arteriography (QCA) is not sufficient for these measurements, the need has grown for new bifurcation analysis methods. METHODS: In this article, our two new bifurcation analysis models are presented, the Y-shape and T-shape model. These models were designed for the accurate measurement of the clinically relevant parameters of a coronary bifurcation, for different morphologies and intervention strategies and include an edge segment analysis, to accurately measure (drug-eluting) stent, stent edge, and ostial segment parameters. RESULTS: The results of an interobserver validation study of our T-shape and Y-shape analyses are presented, both containing the pre- and post-intervention analyses of each 10 cases. These results are associated with only small systematic and random errors, in the majority of the cases compliant with the QCA guidelines for straight analyses. The results for the edge segment analyses are also very good, with almost all the values within the margins that have been set by our brachytherapy directive. CONCLUSIONS: Our new bifurcation approaches including their edge segment analyses are very robust and reproducible, and therefore a great extension to the field of quantitative coronary angiography.

SYNTAX score reproducibility and variability between interventional cardiologists, core laboratory technicians, and quantitative coronary measurements.

BACKGROUND: In the Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery (SYNTAX) trial, the SYNTAX score was useful in risk stratifying patients with complex coronary artery disease. The reproducibility of this score may affect its clinical utility. We therefore assessed SYNTAX score interobserver and intraobserver variability among a group of interventional cardiologists (ICs) and an experienced group of angiographic core laboratory (ACL) technicians. METHODS AND RESULTS: After basic training from the SYNTAX score website, 3 ICs and 4 ACL technicians, each working independently, assessed the SYNTAX score of 30 multivessel disease angiograms. The ICs then underwent an intensive training session with ACL technicians, after which the SYNTAX score from 50 additional angiograms were assessed independently by both groups. Interobserver Fleiss κ statistic values were determined. A third assessment was performed using quantitative coronary angiography (QCA). The ACL technician interobserver strength of agreement from both periods was substantial or greater (k=0.82; 95% CI [0.72, 1.00] and 0.84 [0.76, 1.00]) and not different than QCA. The IC interobserver agreement was initially estimated to be at least slight (k=0.33 [0.18, 0.44]), improving to substantial or greater after advanced training (k=0.76 [0.64, 1.00]). Despite advanced training, ICs underscored the number of lesions, bifurcations, and small-vessel disease (P<0.001), resulting in a lower score than ACL technicians (mean difference=7.5, P<0.001). CONCLUSIONS: Highly reproducible SYNTAX score measurements were quickly achieved by experienced ACL technicians. In contrast, agreement among ICs after the basic tutorial was initially poor but improved considerably after further training with the ACL, although differences still remained in interpretation of several lesion types. These findings have important implications for adoption of SYNTAX score methodology in routine practice and future clinical trials.