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Intravascular ultrasound (IVUS) provides precise anatomic information in coronary arteries including quantitative measurements and morphological assessment. To standardize the IVUS analysis in the current era, this updated expert consensus document summarizes the methods of measurements and assessment of IVUS images and the clinical evidence of IVUS use in percutaneous coronary intervention.

There are 3 main reasons to promote the practical application of IVUS during PCI. First reason is to understand the mechanism of vessel dilatation. Even if angiographic stenoses are similar, their pathophysiologies are different. It is important to understand what can happen by dilating coronary artery with balloon/stent, and to develop a strategy to achieve the maximum effect. Second reason is to anticipate possible complications and to reduce them in advance. In that case, we can deal with it as calmly as possible. Third reason is to validate the PCI performed. This should lead to further improvements of the procedures, which in turn will lead to improved short- and long-term prognosis. Then, high-quality PCI could be possible. This review summarizes the standard usage of IVUS in routine clinical practice and the use of IVUS in specific situations, especially complex lesions.

Background This study evaluated the mechanism of decline in coronary pressure from the proximal to the distal part of the coronary arteries in the left anterior descending (LAD) versus the right coronary artery (RCA) from the insight of coronary hemodynamics using wave intensity analysis (WIA). Methods Twelve patients with angiographically normal LAD and RCA were prospectively enrolled. Distal coronary pressure, mean aortic pressure, and average peak velocity were measured at 4 different positions: 9, 6, 3, and 0 cm distal from each coronary ostium. Results The distal-to-proximal coronary pressure ratio during maximum hyperemia gradually decreased in proportion to the distance from the ostium (0.92±0.03 and 0.98±0.03 at 9 cm distal to the LAD and RCA ostium). WIA showed the dominant forward-traveling compression wave gradually decreased and the backward-traveling suction wave gradually decreased in proportion to the decrease in coronary pressure through the length of the non-diseased LAD but not the RCA. Conclusions The pushing wave and suction wave intensities on WIA were diminished in proportion to the distance from the ostium of the LAD despite the wave intensity not changing across the length of the RCA, which may lead to gradual intracoronary pressure drop in the angiographically normal LAD.

Background and aims We developed a deep learning (DL) model for automated atherosclerotic plaque categorization using optical frequency domain imaging (OFDI) and performed quantitative and visual evaluations. Methods A total of 1103 histological cross-sections from 45 autopsy hearts were examined to compare the ex vivo OFDI scans. The images were segmented and annotated considering four histological categories: pathological intimal thickening (PIT), fibrous cap atheroma (FA), fibrocalcific plaque (FC), and healed erosion/rupture (HER). The DL model was developed based on pyramid scene parsing network (PSPNet). Given an input image, a convolutional neural network (ResNet50) was used as an encoder to generate feature maps of the last convolutional layer. Results For the quantitative evaluation, the mean F-score and IoU values, which are used to evaluate how close the predicted results are to the ground truth, were used. The validation and test dataset had F-score and IoU values of 0.63, 0.49, and 0.66, 0.52, respectively. For the section-level diagnostic accuracy, the areas under the receiver-operating characteristic curve produced by the DL model for FC, PIT, FA, and HER were 0.91, 0.85, 0.86, and 0.86, respectively, and were comparable to those of an expert observer. Conclusions DL semantic segmentation of coronary plaques in OFDI images was used as a tool to automatically categorize atherosclerotic plaques using histological findings as the gold standard. The proposed method can support interventional cardiologists in understanding histological properties of plaques.

The development of peri-stent contrast staining (PSS) after coronary intervention with implantation of a stent is observed in approximately 1–3% of patients treated with drug-eluting stent. Although the cumulative incidences of late in-stent restenosis and stent thrombosis are significantly higher in lesions with PSS than in those without the finding, the mechanisms for the development of PSS have not yet been fully elucidated. In this report, we describe a case of rapid development of PSS with ulcer formation caused by rupture of atherogenic neointima, which was observed by serial optical coherence tomography examinations over 6 months. Protrusion of the stent-jailed underlying necrotic core toward the lumen by the contracting force might have resulted in formation of atherogenic neointima within the stent. Subsequently, rupture of this necrotic core induced by iatrogenic neointimal injury due to balloon dilation and dissolution of the accumulated necrotic core may have resulted in PSS formation 6 months after the procedure. These findings may be helpful for consideration of etiology and therapeutic strategy for lesions with PSS.

Maximal hyperemia at the time of fractional flow reserve (FFR) measurement is generally induced by vasodilators, even when hyperemia at the onset of angina symptoms is caused by exercise stress. This study was designed to evaluate whether pharmacological hyperemia could be used as a substitute for exercise-induced hyperemia during FFR measurement. Twenty-two patients with angiographically intermediate stenosis in the left anterior descending artery (LAD) were prospectively enrolled. FFR measurements were repeated in the following two conditions while the pressure-wire was positioned in the same segment; (1) during pharmacological hyperemia induced by intracoronary administration of 2 mg nicorandil, (2) immediately after isotonic hand-grip exercise for 90 s (50% of maximum voluntary contraction) followed by intracoronary administration of 2 mg nicorandil. Isotonic hand-grip exercise increased systolic blood pressure (130 ± 19 versus 150 ± 22 mmHg, p

For the accurate measurement of small masses and forces, a voltage balance that uses electrostatic force between electrodes has been developed at the National Metrology Institute of Japan (NMIJ). This voltage balance enables traceable mass and force measurements based on the revised definition of the kilogram, as per electric standards. To confirm the reliability of the developed balance apparatus, the mass of a 2 mg wire weight was determined. The first complete uncertainty analyses were performed, following which the relative standard uncertainty of the mass measurement was estimated to be $5.3 \times 10^{-4}$ . The mass of the weight was measured via the submultiple method in a traceable manner with respect to the mass standard at NMIJ. The results obtained from the two different methods were observed to be in agreement within their uncertainties.

Aims Loss of skeletal muscle mass is an important determinant associated with poor long‐term prognosis in patients with acute decompensated heart failure (ADHF). However, limited evidence is available. This study investigated the prognostic value of the psoas muscle mass index (PMI) in patients with ADHF. Methods and results A total of 210 consecutive patients aged ≥60 years with ADHF were enrolled using a prospective database between 2015 and 2017. Primary endpoint was incidence of cardiac death. Cross‐sectional psoas muscle area at the L3 vertebral level was obtained by computed tomography, and PMI was calculated by height. Reduced PMI was defined as a PMI below the 25th sex‐specific percentile. Patients were also classified by their left ventricular ejection fraction (EF) as having either heart failure with a reduced ejection fraction (HFrEF, EF

This study evaluated whether intravascular ultrasound (IVUS) examination before rotational atherectomy (RA) can predict the optimal route of passage of the RA burr along the vessel. 30 patients with calcified lesions who underwent IVUS before and immediately after RA were enrolled. IVUS analyses were performed at the minimum lumen area (MLA) site and at 0.5 mm intervals. Each IVUS cross-section was divided into 4 quadrants around the center of the lumen, and pre- and post-RA IVUS cross-section images were merged. Of 1140 cross-sections, 498 (44%) contained debulked regions. When the guidewire and IVUS were located within the same quadrant, the debulked region were distributed within the same quadrant in 96% of cross-sections. The debulked region and the guidewire were distributed within the same quadrant in 81% and the debulked region and the IVUS in 72% of cross-sections, in case the guidewire and IVUS were located in different quadrants. When the guidewire and the IVUS was apart > 1.0 mm, the debulked regions were distributed within the same quadrant as the guidewire in 100% and the IVUS in 0% of cross-sections. The position of the guidewire rather than that of the IVUS catheter on pre-RA IVUS images could predict the course of the RA burr’s passage, especially when the guidewire and IVUS catheter were located apart from each other.

Aims Although tolvaptan has been reported to prevent worsening renal function (WRF) in patients with advanced acute heart failure (AHF), evidence regarding the effect of tolvaptan on renal function in patients with new‐onset AHF is not available. This study aimed to investigate the renoprotective effect of tolvaptan in patients hospitalized with new‐onset AHF. Methods and results A total of 122 consecutive patients hospitalized with new‐onset AHF between May 2015 and December 2018 were retrospectively evaluated. WRF was defined as an absolute increase in serum creatinine ≥0.3 mg/dL (≥26.4 μmol/L) within 48 h or a 1.5‐fold increase in serum creatinine after hospitalization. The furosemide group (n = 75) and the tolvaptan add‐on group (n = 47) were compared. The tolvaptan group consists of patients who received tolvaptan as an individual physicians' decision. The incidence of WRF was significantly lower in the tolvaptan add‐on group (8.5%) than in the furosemide group (24.0%, P = 0.03). Multivariate logistic regression analysis revealed that tolvaptan treatment was an independent variable related to the prevention of WRF [odds ratio (OR), 0.20; 95% confidence interval (CI), 0.05–0.85]. Furthermore, subgroup analysis revealed a more favourable effect of tolvaptan in patients with serum creatinine ≥1.1 mg/dL on admission (OR, 0.23; 95% CI, 0.06–0.98) and an ejection fraction

This study aimed to evaluate the vascular response to balloon angioplasty for drug-eluting stent (DES) in-stent restenosis (ISR) lesions based on our novel optical coherence tomography (OCT) classification to establish the optimal treatment strategy for ISR lesions after DES implantation. A total of 104 ISR lesions after DES implantation were imaged by OCT and categorized into the following six patterns: type I-homogeneous high-intensity tissue, type II-heterogeneous tissue with signal attenuation, type III-speckled heterogeneous tissue, type IV-mixed tissue containing poorly delineated region with invisible strut, type V-mixed tissue containing sharply delineated low-intensity region, and type VI-bright protruding tissue with an irregular surface. Serial volumetric OCT analysis was performed before and after balloon dilation to evaluate the vascular response to balloon angioplasty. After balloon dilation, the minimal decrease in neointimal volume was noted in type I lesions and maximal in type III lesions. In contrast, the increase in stent volume was significantly more in type I lesions than others. Neointimal tissue characterization by OCT allows us to provide useful information about the vascular response to balloon dilation, which can influence the therapeutic strategy for DES ISR lesions.

This study investigated the correlation between vascular flow reserve (VFR) values and wound healing rate in patients with critical limb ischemia.Peripheral VFR may be useful for predicting complete wound healing after endovascular therapy (EVT). However, published reports included small numbers of patients from single centers and long-term outcomes remain unknown.This was a prospective multicenter study that consecutively enrolled 104 patients (115 limbs) who received EVT for ischemic ulcerations. All lesions were treated with conventional balloon angioplasty. After EVT, VFR was measured using a pressure/temperature guidewire. The study endpoints were correlation between VFR values and wound healing rate at 3 months and 1 year.The median VFR was 2.9. A total of 110 and 104 limbs completed the 3-month and 1-year follow-up, respectively. The 3-month and 1-year wound healing rates were 49% and 76%, respectively. VFR was significantly associated with the 3-month and 1-year wound healing (p 0.001 for both). The crude hazard ratios of VFR (per 2-fold increase) for the 3-month and 1-year wound healing were 2.6 (1.7 to 3.9) and 2.9 (2.0 to 4.2), respectively. The estimated median time to wound healing was 5.0 (3.2 to 7.2) months, 3.3 (2.8 to 4.9) months, and 2.5 (2.0 to 3.0) months, when the VFR value was 2.4, 2.9, and 3.9, respectively.Post-procedure VFR is significantly associated with wound healing. VFR, measured in the catheterization laboratory, is useful in clinical risk stratification for patients with critical limb ischemia after EVT. (Predictor of Wound Healing in Patients with Critical Limb Ischemia-Multicenter Prospective Study; UMIN000012746).