大田 将也

Background: While the utilization of integrated backscatter intravascular ultrasound (IB-IVUS) for the quantitative in vivo assessment of coronary plaque continues to grow, the validity of IB-IVUS images obtained from newly developed and conventional systems remains uncertain. Methods and Results: To assess the accuracy and reliability of a newly developed IB-IVUS system (VISIWAVE) as compared to the conventional system (Clearview), we compared quantitative IB-IVUS plaque characteristics in the 2 systems using 125 post-mortem specimens from 26 coronary arteries in 11 cadavers, as well as using 200 clinical plaques in 32 patients undergoing coronary intervention. The overall agreement between the histological and IB-IVUS diagnoses using VISIWAVE (Cohen's kappa=0.82, 95%CI: 0.73-0.90) was similar to that using Clearview (Cohen's kappa=0.80, 95%Cl: 0.71-0.89). The 2 systems also demonstrated comparably high sensitivity and specificity. In the direct comparison, the overall agreement between IB-IVUS diagnoses using VISIWAVE and Clearview was also excellent (Cohen's kappa=0.87, 95%Cl: 0.78-0.95). In the clinical comparison, measured plaque dimensions were similar (VISIWAVE: 8.27 +/- 3.46 mm(2) vs. Clearview; 8.31 +/- 3.46 mm(2), P=0.44) and there was strong concordance between both greyscale and IB-IVUS parameters. Conclusions: There was close agreement of analyzed results in both systems when compared with the gold standard of histology. Both systems are able to reliably and accurately characterize coronary plaque and thereby make a valuable contribution to our understanding of atherosclerosis. (Circ J 2012; 76: 1678-1686)

OBJECTIVES The purpose of this study was to evaluate the effect of statin treatment on coronary plaque composition and morphology by optical coherence tomography (OCT), grayscale and integrated backscatter (IB) intravascular ultrasound (IVUS) imaging. BACKGROUND Although previous studies have demonstrated that statins substantially improve cardiac mortality, their precise effect on the lipid content and fibrous cap thickness of atherosclerotic coronary lesions is less clear. While IVUS lacks the spatial resolution to accurately assess fibrous cap thickness, OCT lacks the penetration of IVUS. We used a combination of OCT, grayscale and IB-IVUS to comprehensively assess the impact of pitavastatin on plaque characteristics. METHODS Prospective serial OCT, grayscale and IB-IVUS of nontarget lesions was performed in 42 stable angina patients undergoing elective coronary intervention. Of these, 26 received 4 mg pitavastatin after the baseline study; 16 subjects who refused statin treatment were followed with dietary modification alone. Follow-up imaging was performed after a median interval of 9 months. RESULTS Grayscale IVUS revealed that in the statin-treated patients, percent plaque volume index was significantly reduced over time (48.5 +/- 10.4%, 42.0 +/- 11.1%; p = 0.033), whereas no change was observed in the diet-only patients (48.7 +/- 10.4%, 50.4 +/- 11.8%; p = NS). IB-IVUS identified significant reductions in the percentage lipid volume index over time (34.9 +/- 12.2%, 28.2 +/- 7.5%; p = 0.020); no change was observed in the diet-treated group (31.0 +/- 10.7%, 33.8 +/- 12.4%; p = NS). While OCT demonstrated a significant increase in fibrous cap thickness (140 +/- 42 mu m, 189 +/- 46 mu m; p = 0.001), such changes were not observed in the diet-only group (140 +/- 35 mu m, 142 +/- 36 mu m; p = NS). Differences in the changes in the percentage lipid volume index (-6.8 +/- 8.0% vs. 2.8 +/- 9.9%, p = 0.031) and fibrous cap thickness (52 +/- 32 mu m vs. 2 +/- 22 mu m, p < 0.001) over time between the pitavastatin and diet groups were highly significant. CONCLUSIONS Statin treatment induces favorable plaque morphologic changes with an increase in fibrous cap thickness, and decreases in both percentage plaque and lipid volume indexes. (J Am Coll Cardiol Img 2012;5:169-77) (C) 2012 by the American College of Cardiology Foundation

Objectives Stent fracture (SF) of sirolimus-eluting stents (SES) has emerged recently in the literature and shown to be associated with an increased risk of restenosis; however, little is known regarding SF after bare-metal stent implantation. We sought to assess whether the use of SES was associated with an increased risk of SF compared with its bare-metal platform, the Bx-velocity stent (BX-BMS). Methods A total of 478 lesions in 416 patients undergoing SES implantation and subsequent angiography 6-9 months after the index procedure were compared with 152 lesions in 142 consecutive patients treated with BX-BMS. Stented lesions with total stent-length greater than 40 mm were excluded. Results There were no significant differences in overall baseline clinical and anatomic features between the SES and BX-BMS groups, or in SF frequencies at 6-9 month follow-up (4.4% for SES and 1.3% for BX-BMS, P = 0.078). In-stent restenosis was observed more often in SF lesions versus non-SF lesions (34.8 vs. 7.7%, P < 0.001) in association with a higher 3-year adverse events rate (27.3 vs. 13.6%, P = 0.076). The risk of SF at 6-9 months was independently associated with total stent length [odds ratio (OR), 2.13; 95% confidence interval (CI), 1.18-3.83; P = 0.012], angulated lesions (OR, 4.25; 95% CI, 1.80-10.00; P = 0.001), and right coronary artery lesions (OR, 3.55; 95% CI, 1.46-8.62; P = 0.005) but not with SES use. Conclusion Stent implantation in right coronary artery lesions, tortuous lesions, and/or longer lesions covered with longer stents, and not SES versus BX-BMS use, may be associated with increased likelihood of SF. Coron Artery Dis 21: 298-303 (C) 2010 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.