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Objectives: We sought to evaluate the accuracy of standardized total plaque volume (TPV) measurement and low-density non-calcified plaque (LDNCP) assessment from coronary CT angiography (CTA) in comparison with intravascular ultrasound (IVUS)., Methods: We analyzed 118 plaques without extensive calcifications from 77 consecutive patients who underwent CTA prior to IVUS. CTA TPV was measured with semi-automated software comparing both scan-specific (automatically derived from scan) and fixed attenuation thresholds. From CTA, %LDNCP was calculated voxels below multiple LDNCP thresholds (30, 45, 60, 75, and 90 Hounsfield units [HU]) within the plaque. On IVUS, the lipid-rich component was identified by echo attenuation, and its size was measured using attenuation score (summed score ∕ analysis length) based on attenuation arc (1 = < 90°; 2 = 90-180°; 3 = 180-270°; 4 = 270-360°) every 1 mm., Results: TPV was highly correlated between CTA using scan-specific thresholds and IVUS (r = 0.943, p < 0.001), with no significant difference (2.6 mm 3 , p = 0.270). These relationships persisted for calcification patterns (maximal IVUS calcium arc of 0°, < 90°, or ≥ 90°). The fixed thresholds underestimated TPV (- 22.0 mm 3 , p < 0.001) and had an inferior correlation with IVUS (p < 0.001) compared with scan-specific thresholds. A 45-HU cutoff yielded the best diagnostic performance for identification of lipid-rich component, with an area under the curve of 0.878 vs. 0.840 for < 30 HU (p = 0.023), and corresponding %LDNCP resulted in the strongest correlation with the lipid-rich component size (r = 0.691, p < 0.001)., Conclusions: Standardized noninvasive plaque quantification from CTA using scan-specific thresholds correlates highly with IVUS. Use of a < 45-HU threshold for LDNCP quantification improves lipid-rich plaque assessment from CTA., Key Points: • Standardized scan-specific threshold-based plaque quantification from coronary CT angiography provides an accurate total plaque volume measurement compared with intravascular ultrasound. • Attenuation histogram-based low-density non-calcified plaque quantification can improve lipid-rich plaque assessment from coronary CT angiography.

Background: It has been shown that CT attenuation of noncalcified plaques depends on luminal contrast attenuation (LCA). Although tube potential (kilovolt [kV]) has been shown to exert influence on plaque attenuation through LCA as well as its direct effects, in-vivo studies have not investigated plaque attenuation at lower tube potentials less than 120 kV. We sought to evaluate the effect of kV and LCA on thresholds for lipid-rich and fibrous plaques as defined by intravascular ultrasound (IVUS)., Methods: CT attenuation of IVUS-defined plaque components (lipid-rich, fibrous, and calcified plaques) were quantified in 52 consecutive patients with unstable angina, who had coronary CT angiography performed at 100 kV (n = 25) or 120 kV (n = 27) using kV-adjusted contrast protocol prior to IVUS. CT attenuation of plaque components was compared between the two groups., Results: LCA was similar in the 100-kV and 120-kV groups (417.6 ± 83.7 Hounsfield Units [HU] vs 421.3 ± 54.9 HU, p = 0.77). LCA correlated with CT attenuation of lipid-rich (r = 0.49, p = 0.001) and fibrous plaques (r = 0.32, p < 0.05), but not with that of calcified plaques (r = 0.04, p = 0.81). When plaque attenuation was normalized to LCA, lipid-rich (0.087 ± 0.036, range -0.012-0.147) and fibrous plaque attenuation (0.234 ± 0.056, range 0.153-0.394) were distinct (p < 0.001) with no overlap for both kV groups. CT attenuation was not significantly different between 100-kV and 120-kV groups for lipid-rich (34.0 ± 21.5 vs 39.3 ± 12.9, p = 0.33) or fibrous plaques (95.4 ± 19.1 vs 97.6 ± 22.0, p = 0.75)., Conclusion: Plaque attenuation thresholds for non-calcified plaque components should be adjusted based on LCA. Further adjustment may not be required for different tube potentials., (Copyright © 2019 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.)

When patients who have previously undergone coronary artery bypass graft surgery develop ischemia symptoms that cannot be controlled by optimal medical therapy, repeat revascularization is indicated. The revascularization strategy should be based on individual clinical and anatomical characteristics. We report here a challenging patient who presented with recurrent stable angina due to worsening of a proximal right coronary artery (RCA) stenosis to chronic total occlusion (CTO) after anastomosis of the right gastroepiploic artery (GEA) to the posterior descending artery. A soft guidewire was advanced through the right GEA collateral channel to the distal end of the CTO, but the dedicated CTO guidewires could not be advanced across the severely calcified CTO using the retrograde wire crossing or kissing wire techniques. The RCA was eventually revascularized by implantation of drug-eluting stents using the intravascular ultrasound-guided reverse controlled antegrade and retrograde subintimal tracking technique.

Background: Controlled antegrade and retrograde subintimal tracking (CART) or reverse CART techniques is the final step for percutaneous revascularization of coronary chronic total occlusion (CTO), but it still represents technical challenges and risk in interventional procedures., Objectives: Our purpose was to utilize intravascular ultrasound (IVUS)-guided reverse CART approach for percutaneous revascularization of CTO in our heart center, focusing on its safety, efficacy, and latest technical developments., Methods: From November 2006 to November 2012, 49 patients with CTO failed to antegrade and/or retrograde percutaneous revascularization of CTO from true lumen to true lumen were enrolled in and underwent IVUS guided reverse CART approach., Results: The mean J-CTO score of cases was 2.5. IVUS guidance was successfully implemented in 95.9%; IVUS identified that 61.7% of retrograde wires were located at intimal space, and 59.5% of antegrade wires were located at subintimal space. A Corsair channel dilator was used in 77.6% of cases. The success rates of technique and procedure were 95.9% and 93.9%, respectively; the technical minor complications were observed in 10.2% of cases, without significant clinic outcomes; 2.0% of cases occurred with a major adverse cardiac event of non-ST-elevation myocardial infarction; and no case occurred with target vessel revascularization or death. The mean length of stent implanted in a single CTO vessel was 51.3 mm. No patient appeared with radiation dermatitis and contrast-induced rise of creatinine., Conclusions: IVUS guided reverse CART approach is effective and safe for percutaneous revascularization of complex CTO, with a high success and a low complication rate. It is feasible to develop this approach for percutaneous revascularization of complex CTO. However, suitable case selection and lately device handling by experienced operators are the crucial points of success., (© 2013, Wiley Periodicals, Inc.)

We experienced a rare case in which a guidewire was advanced into a coronary vein through an arteriovenous fistula caused by wire perforation. The patient, who had chronic total occlusion (CTO) of the left circumflex coronary artery, was treated successfully with a procedure guided by intravascular ultrasound (IVUS). The IVUS-guided parallel-wire technique allowed recrossing of the guidewire into the distal true lumen of the CTO by identifying the anatomy of the occluded segment and the appropriate re-entry point. Angiography demonstrated that the fistula was completely sealed after stent deployment, and there was no extravasation.

Stent implantation in unprotected left main coronary artery (LMCA) bifurcation lesions may improve procedural and late clinical outcomes. However, concerns regarding stent-related complications, such as stent jail, subacute thrombosis, and in-stent restenosis remain. Optimal debulking by directional coronary atherectomy (DCA) with intravascular ultrasound (IVUS) guidance may be effective in this complex lesion subset, but this strategy has not yet been established. Our objective was to evaluate the safety and efficacy of IVUS-guided DCA for unprotected LMCA stenoses with distal bifurcation involvement. A total of 67 consecutive patients were included in this study and procedural success was achieved in all cases. Two cardiac deaths (2.9%) were noted and 3 patients (4.5%) underwent repeat angioplasty during hospitalization. There was no Q-wave myocardial infarction or emergency bypass surgery. Non-Q-wave myocardial infarction (creatine kinase-MB >3 times normal) occurred in 13.4% of patients. Stent implantation was necessary in 17 cases (25.4%) to achieve an optimal result. IVUS showed an improved lumen cross-sectional area and a low plaque burden in the LMCA after intervention. All-cause mortality, angiographic restenosis, and the target lesion revascularization rates at 6 months were 7.4%, 23.8%, and 20.0%, respectively. With IVUS guidance, aggressive DCA can be performed safely in unprotected LMCA bifurcation lesions, and optimal angiographic and IVUS results can be achieved with low residual plaque burden, which leads to a low restenosis rate. Optimal lesion debulking by DCA does not necessarily need adjunctive stenting in this specific anatomic subset.

It is not known whether any factors are related to tissue proliferation within and surrounding stents in humans. The authors used serial intravascular ultrasound (IVUS) to evaluate the relationship between IVUS parameters and tissue proliferation within and surrounding Multilink stents. They were able to analyze preinterventional and postinterventional and follow-up IVUS studies in 33 native vessel lesions in 33 patients with stable angina pectoris. Quantitative coronary angiography and IVUS measurements were performed before and after intervention and at follow-up. IVUS imaging using an automatic transducer pullback device allowed follow-up analysis of the same lesion site. The vessel area at the lesion site increased from 17.1 +/- 4.5 mm2 after intervention to 18.5 +/- 5.9 mm2 at follow-up (p<0.01). The in-stent tissue growth (after intervention to follow-up) in-stent plaque area (PA) was 1.6 +/- 1.1 mm2, and the peristent tissue growth (after intervention to follow-up) peristent PA was 0.8 +/- 2.3 mm2. In multivariate analysis, the preprocedural PA at the lesion site was the best predictor of the peristent tissue growth, whereas no factors predicted the in-stent tissue growth. Risk factors, clinical characteristics, and quantitative coronary angiographic parameters showed no relation to the peristent tissue growth or the in-stent tissue growth. The peristent tissue growth was closely related to the preprocedural plaque size, while the factors that affect the in-stent tissue growth were not identified.