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Intravascular imaging (IVI), including intravascular ultrasound (IVUS) and optical coherence tomography (OCT), is clinically useful for assessing the luminal size, lesion length, and plaque characteristics, as well as for evaluating stent deployment; however, it is not designed to estimate myocardial ischemia accurately. Thus, several types of IVI-derived fractional flow reserve (FFR) (IVI-derived FFR) have been developed and reported. In general, the algorithms of virtual FFR are based on basic fluid dynamics equations (mainly Poiseuille and Borda-Carnot equations) and original microvascular models (fixed velocity or calculating coronary flow reserve). Although the models and assumptions used in the past reports were mostly based on the standard population (not independent patient data), the developed software calculated FFR with high accuracy (88% to 94%) with strong correlations between IVI-derived FFR and wire-based FFR (0.69 to 0.89). Given several other less invasive virtual FFR methods currently available for clinical use, IVI-derived FFR would be limited for the sole use of pre-percutaneous coronary intervention (PCI) physiological evaluation; however, it may play a unique role at PCI guidance and optimization, potentially allowing comprehensive and time/cost-saving assessment of both anatomical and physiological lesion properties using a single diagnostic device., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Objectives: This study evaluated the relationship between platelet reactivity and plaque morphology using grayscale and radiofrequency intravascular ultrasound (IVUS) virtual histology (VH)., Background: Recent studies have reported that high on-treatment platelet reactivity (HPR) is associated with higher plaque volume and the presence of multivessel disease; however, the association between HPR and plaque morphology has not been evaluated., Methods: The ADAPT-DES (Dual AntiPlatelet Therapy With Drug Eluting Stents) intravascular ultrasound substudy was a prospective, multicenter, observational study of 8,582 patients undergoing percutaneous coronary intervention with drug-eluting stents in whom platelet reactivity on clopidogrel was assessed routinely. The current analysis included 909 culprit lesions from 773 patients with pre-intervention grayscale IVUS and IVUS-VH. HPR was defined as platelet reactivity >208 P2Y12 reaction unit in point-of-care P2Y12 testing by the VerifyNow assay, measured during steady-state platelet inhibition in patients receiving an antiplatelet agent., Results: HPR was associated with 3-vessel coronary artery disease (31.0% vs. 24.4%; p = 0.04). The incidence of fibroatheroma was higher in patients with HPR than those without HPR (77.1% vs. 68.9%; p = 0.01). The HPR group had larger percent plaque and media volume (plaque and media/external elastic membrane volume: 58.1% [95% confidence interval (CI): 57.1% to 59.0%] vs. 56.6% [95% CI: 55.8% to 57.5%]; p = 0.03) and plaque burden at the minimum lumen site (76.7% [95% CI: 75.7% to 77.8%] vs. 75.0% [95% CI: 74.0% to 76.0%]; p = 0.02). Despite a similar prevalence of attenuated plaque, patients with HPR had longer culprit lesion attenuated plaque length (8.0 [95% CI: 7.0 to 9.1] mm vs. 6.5 [95% CI: 5.9 to 7.1] mm; p = 0.01). On multivariate analysis, the presence of angiographic calcium (odds ratio [OR]: 1.85: 95% CI: 1.33 to 2.56; p = 0.0002) and HPR (OR: 1.45; 95% CI: 1.05 to 2.01; p = 0.02) were independent predictors for a culprit lesion fibroatheroma., Conclusions: HPR was associated with increased culprit lesion atherosclerotic burden and adverse plaque morphology among patients undergoing percutaneous coronary intervention. Platelet reactivity might be associated with not only blood clot formation, but also severity of atherosclerosis. (Assessment of Dual AntiPlatelet Therapy With Drug Eluting Stents [ADAPT-DES]; NCT00638794)., (Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study investigated coronary artery remodeling patterns associated with clinical outcomes., Background: In the prospective, multicenter PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree: An Imaging Study in Patients With Unstable Atherosclerotic Lesions) study, reported predictors of nonculprit lesion (NCL) major adverse cardiac events (MACE) were an intravascular ultrasound (IVUS) minimal lumen area (MLA) ≤4 mm(2), a plaque burden ≥70%, and a IVUS-virtual histology (VH) thin-cap fibroatheroma (TCFA), but not lesion site remodeling., Methods: Overall, 697 consecutive patients with an acute coronary syndrome were enrolled and underwent 3-vessel gray-scale and IVUS-VH; 3,223 NCLs were identified by IVUS. The remodeling index (RI) was calculated as the external elastic membrane area at the MLA site divided by the average of the proximal and distal reference external elastic membrane areas. First, one third of the patients were randomly selected to determine RI cutoffs related to NCL MACE (development cohort). Receiver-operating characteristic analysis showed that there were 2 separate cut points that predicted NCL MACE: RI = 0.8789 and RI = 1.0046 (area under the curve = 0.663). These cut points were used to define negative remodeling as an RI <0.88, intermediate remodeling as an RI of 0.88 to 1.00, and positive remodeling as an RI >1.00. Second, we used the remaining two-thirds of patients to validate these cut points with respect to lesion morphology and clinical outcomes (validation cohort)., Results: Kaplan-Meier curve analysis in the validation cohort showed that NCL MACE occurred more frequent (and equally) in negative and positive remodeling lesions compared with intermediate remodeling lesions. In this cohort, negative remodeling lesions had the smallest MLA, positive remodeling lesions had the largest plaque burden, and VH TCFA, especially VH TCFA with multiple necrotic cores, was most common in negatively remodeling lesions., Conclusions: The present study showed the novel concept that positive and negative lesion site remodeling was associated with unanticipated NCL MACE in the PROSPECT study. (, Prospect: An Imaging Study in Patients With Unstable Atherosclerotic Lesions [PROSPECT]; NCT00180466)., (Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Two-dimensional speckle tracking echocardiography (2D-STE) is a novel technology that directly measures regional left ventricular (LV) wall contraction. This study aimed to directly measure inner-layer thickening (radial strain) of the LV using 2D-STE, and to examine the relationship between radial strain and the degree of hypertrophy., Methods: The study enrolled 63 untreated hypertensive patients with normal geometry (N group, n=32) or concentric hypertrophy (CH group, n=31), classified according to LV mass index (LVMI) and relative wall thickness (RWT). Thirty normotensive subjects (C group, n=30) served as controls. Radial strain (ɛ) in the inner half (ɛi) and all layers of the LV wall (ɛa) were calculated from the LV short-axis view by 2D-STE., Results: LV ejection fraction did not differ significantly among the groups. However, ɛi and ɛa were significantly lower in the CH group compared with the C and N groups (p<0.01). A ratio of ɛi to ɛa was significantly lower in the CH group compared with the C and N groups (p<0.01). A multivariate regression model that included midwall fractional shortening, E/e', LVMI, RWT, and LV ejection fraction showed that LVMI (p=0.002) and RWT (p=0.014) were independent predictors (R(2)=0.59) of ɛi., Conclusion: Radial strain in the inner half layer of the LV wall decreases in parallel with the degrees of LV concentricity and hypertrophy in hypertensive patients. Radial strain in the inner half layer may identify subtle systolic dysfunction even in hypertensive patients with preserved LV chamber function., (Copyright © 2011 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.)

Slow/no-reflow phenomenon during emergent percutaneous coronary intervention in patients with ST-elevation myocardial infarction (STEMI) results in a poor prognosis. A high thrombus burden was an independent predictor of angiographic slow/no-reflow phenomenon. We experienced a case of a STEMI patient with massive intracoronary thrombus. In our case, a massive red thrombus was aspirated easily by adjunctive pulse infusion thrombolysis (PIT) after failed aspiration. Adjunctive pulse infusion thrombolysis after failed aspiration might be a useful strategy to prevent the slow/no-reflow phenomenon in STEMI patients with massive intracoronary thrombus., (Copyright © 2011 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Background: The aim of this study was to investigate the significance of the MOSAIC (measurement of stenosis by aliasing coronary flow) method for the detection of proximal left coronary stenosis in patients with unstable angina (UA) using transthoracic Doppler echocardiography (TTDE)., Methods: Patients (n=107) with UA were evaluated. Proximal left coronary flow was sought in the short axis (SAX) at the aortic root level using color Doppler guidance. When detected coronary flow showed color aliasing, the color velocity range was gradually increased until color aliasing nearly disappeared. Then, the color baseline was shifted until the color flow showed "isovelocity"., Results: Proximal coronary flow was detected in 86 (80.4%) of 107 patients. In these 86 patients, an optimal cutoff value of isovelocity ≥ 47.5 cm/s predicted significant coronary stenosis (percent diameter stenosis ≥ 70%) of the proximal left anterior descending (AHA segment 6) or left main coronary artery with a sensitivity of 88%, specificity of 97%, positive predictive value of 98%, and negative predictive value of 86%. In all 107 patients, the same cutoff value predicted significant coronary stenosis with a sensitivity of 78%, specificity of 98%, positive predictive value of 98%, and negative predictive value of 81%., Conclusions: The MOSAIC method may play a complementary role in expeditious risk stratification and decision making in patients with UA., (Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.)

Background: The aim of this study was to investigate the differences in left ventricular (LV) twisting behavior between patients with hypertrophic cardiomyopathy (HCM) and hypertensive heart disease (HHD)., Methods: Forty-four patients with HCM (mean age, 63±15 years), 35 patients with HHD (mean age, 63±13 years) and 20 age and sex-matched control subjects were evaluated. After a standard echocardiographic examination, LV twist and twisting velocity profiles from apical and basal short-axis images were analyzed using two-dimensional speckle tracking imaging., Results: LV diastolic and systolic dimensions, and ejection fraction were not significantly different among the groups. LV mass index and early diastolic mitral annular velocity were not significantly different between the HCM and HHD groups. The peak torsion in the HCM and HHD groups was significantly greater than that in the control group. The peak untwisting velocity in the HCM group was comparable with that in the control group. However, when the peak untwisting velocity was corrected by peak torsion, this ratio was significantly decreased in the HCM group compared with the values in the HHD and control groups. The time to peak untwisting velocity in the HCM group was significantly longer than the values in the HHD and control groups., Conclusions: These results suggest that enhanced peak torsion in HCM may improve untwisting behavior, but this mechanism fails to fully compensate for impaired untwisting behavior compared with HHD., (Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.)