Clinical feasibility of resting full-cycle ratio as a unique non-hyperemic index of invasive functional lesion assessment.

The resting full-cycle ratio (RFR) is a new physiologic index to assess myocardial ischemia. RFR and fractional flow reserve (FFR), the conventionally used index, have not been directly compared in evaluating the entire cardiac cycle. Accordingly, we aimed to compare the diagnostic performance of RFR directly with FFR and clarify the clinical feasibility of RFR as a unique non-hyperemic index in evaluating the cardiac cycle. The diagnostic performance of RFR was compared with FFR using an automated online calculation software. A total of 156 consecutive patients with 220 intermediate lesions were enrolled. RFR showed significant correlation with FFR (r = 0.774, p < 0.001). RFR systole and RFR diastole did also with FFR (r = 0.918, p < 0.001, and r = 0.733, p < 0.001, respectively). With FFR < 0.80 as a reference standard, RFR showed good diagnostic accuracy (DA: 80.5%), similar DA between RFR systole and RFR diastole (79.6% and 87.5%, p = 0.58, respectively), and good DA in any lesion locations, especially in non-left anterior descending coronary artery (LAD) lesions (73.7% and 87.6% for LAD vs. non-LAD, p < 0.05, respectively). RFR is a feasible and reliable non-hyperemic index regardless of the difference in cardiac cycle in evaluating physiological lesion severity in daily practice.

Safety and efficacy of intracoronary nicorandil as hyperaemic agent for invasive physiological assessment: a patient-level pooled analysis.

AIMS: Our aim was to evaluate the safety and efficacy of intracoronary (IC) nicorandil as an alternative choice of hyperaemic agent for invasive physiologic studies. METHODS AND RESULTS: A total of 480 intermediate coronary lesions from 429 patients enrolled from six Japanese and Korean centres were analysed. IC nicorandil showed earlier achievement of hyperaemia (time to the lowest FFR: 18.0 s [1st and 3rd quartile value 15.6-21.5] vs. 44.0 s [36.0-60.0], p<0.001) with similar hyperaemic efficacy, compared with intravenous (IV) adenosine/ATP (FFR 0.82 [0.75-0.87] vs. 0.82 [0.74-0.88], p=0.207). FFR measurements with both agents showed excellent correlation and classification agreement (CA) for FFR ≤0.80 (r=0.941, ICC 0.980, CA 90.8%, kappa=0.814, AUC of nicorandil 0.980, all p<0.001). Only three patients (0.7%) showed changes in classification across the grey zone (0.75-0.80). IC nicorandil produced fewer changes in blood pressure (BP) and heart rate (HR) and showed less chest pain than IV adenosine/ATP (all p<0.001). When comparing ΔFFR according to ΔBP or ΔHR between IV adenosine/ATP and IC nicorandil, there were no correlations, either between ΔFFR and ΔBP (r=-0.114, p=0.091), or between ΔFFR and ΔHR (r=1.000, p=0.151). CONCLUSIONS: Nicorandil IC bolus injection is a simple, safe and effective hyperaemic method for FFR measurement and can be used as a substitute for adenosine.

Intravascular ultrasound assessment of postprocedural incomplete stent apposition.

BACKGROUND: There has been no detailed intravascular ultrasound (IVUS) analysis to evaluate the degree to which stent underexpansion or reference vessel/stent size mismatch contributes to the occurrence of post-procedural incomplete stent apposition (post-ISA). METHODS: We evaluated 238 lesions treated with everolimus-eluting stents (n = 110) or paclitaxel-eluting stents (n = 128). Reference lumen/stent area ratio was defined as the ratio of lumen area adjacent to the stent edge in the reference segment to stent area at the stent edge or at stent body ISA site. RESULTS: Post-ISA was observed in 36 of the 238 cases (15%) at the proximal stent edge, 15 of the 238 cases (6%) at the distal stent edge and 14 of the 238 cases (6%) at stent body. Reference lumen/stent area ratio was significantly greater in the ISA group compared with non-ISA in proximal edge (127 ± 20 vs. 99 ± 10%; P<.001), and greater reference lumen/stent area ratio (118 ± 18 vs. 94 ± 11%; P<.001) and higher presence of calcification (60 vs. 29%; P<0.001) were observed in distal edge ISA group compared with non-ISA. At the stent body, presence of calcification was more frequently observed in the ISA compared with the non-ISA group (86 vs. 42%; P=.002). CONCLUSIONS: Post-ISA at the stent edge was significantly associated with vessel/stent mismatch rather than stent underexpansion. IVUS-guided appropriate stent or balloon sizing might be useful to prevent post-ISA and optimize initial stent deployment.

Discrepancy in the assessment of jailed side branch lesions by visual estimation and quantitative coronary angiographic analysis: comparison with fractional flow reserve.

OBJECTIVE: We sought to evaluate the variability in the assessment of jailed side branch (SB) lesions by visual estimation and quantitative coronary angiography (QCA) and to compare those results with fractional flow reserve (FFR). METHODS: Twenty jailed SB lesions with available FFR (median 0.76; range, 0.39-0.94) were selected from the PRESSURE trial. Lesions were assessed by three independent QCA core laboratories with different QCA systems and by three different cardiologist groups (five European bifurcation club members, five Korean experts, and five trainees). Agreements of the continuous measurements were expressed as the intraclass correlation coefficient (ICC) and average coefficient of variance (CV), and those of the categorical values as kappa. RESULTS: Mean minimum lumen diameter (MLD) and % diameter stenosis differed among the three QCA systems up to 0.30 mm and 9.65%, respectively (P < 0.001). Three QCA systems showed fair agreement for the measurements of reference diameter, % diameter stenosis, MLD, and lesion length (ICC 0.346-0.686, CV 8.7-29.5%), and a poor agreement on stenosis of 75% or more (Fleiss κ 0.14 and mean κ 0.18). Agreements of visual estimation among the three groups were poor to fair (Fleiss κ 0.167-0.367). Sensitivity and specificity for predicting ischemia-inducible lesion (FFR < 0.75) were 64.7% and 48.0% for visual estimation and 56.6% and 56.6% by QCA, respectively. Visual estimation overestimated the % diameter stenosis and functional significance of the lesions compared with QCA (P < 0.001) and FFR (P = 0.036). CONCLUSIONS: Angiographic assessment of jailed SB lesions by both QCA and visual estimation showed variability. Visual estimation tended to overestimate the severity of jailed SB lesions compared to FFR and QCA.

Intraoperative fluorescence imaging system for on-site assessment of off-pump coronary artery bypass graft.

OBJECTIVES: The aim of this study was to evaluate the intraoperative fluorescence imaging (IFI) system in the real-time assessment of graft patency during off-pump coronary artery bypass graft. BACKGROUND: Intraoperative fluorescence imaging is an intraoperative angiography-like imaging modality using fluorescent indocyanine green excited with laser light. Recently, assessment of graft patency using the IFI system was introduced into clinical use. The feasibility and efficacy of IFI technology in off-pump coronary artery bypass graft has not been systematically compared with other conventional diagnostic modalities. METHODS: Patients undergoing off-pump coronary artery bypass graft received IFI analysis, intraoperative transit time flowmetry, and postoperative X-ray angiography. In off-line IFI analysis, the graft washout was classified based on the number of heartbeats required for indocyanine green washout: fast washout (15 beats). RESULTS: A total of 507 grafts in 137 patients received IFI analysis. Of all the IFI analyses, 379 (75%) grafts were visualized clearly up to the distal anastomosis. With regard to anastomosis location, anterior location was associated with a higher percentage of fully analyzable images (90%). More than 80% of images were analyzable, irrespective of graft type. Six grafts with acceptable transit time flowmetry results were diagnosed with graft failure by IFI, which required on-site graft revision. All revised grafts' patency was confirmed by post-operative X-ray angiography. Conversely, 21 grafts with unsatisfactory transit time flowmetry results demonstrated acceptable patency with IFI. Graft revision was considered unnecessary in these grafts, and 20 grafts (95%) were patent by post-operative X-ray angiography. Compared with slow washout, fast washout was associated with a higher preoperative ejection fraction, use of internal mammary artery grafts, and anterior anastomosis location. CONCLUSIONS: The IFI system enables on-site assessment of graft patency, providing both morphologic and functional information. This technique may help reduce procedure-related, early graft failures in off-pump bypass patients.