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The aim of this study was to investigate the possibility of 64-slice multislice computed tomography (MSCT) to detect vulnerable plaque derived by optical coherence tomography. From September 2007 through December 2009, 122 lesions in 81 patients were evaluated by 64-slice MSCT and optical coherence tomography. Based on optical coherence tomographic findings, lesions were classified as thin-capped fibroatheroma (TCFA; n=37) and non-TCFA (n=85). Mean computed tomographic density value of the lesion was lower and remodeling index was larger in the TCFA group (44.9 ± 19.2 vs 78.7 ± 25.0 HU, p <0.0001; 1.14 ± 0.20 vs 0.95 ± 0.16, p<0.0001, respectively). Mean computed tomographic density value was correlated and remodeling index was inversely correlated with fibrous cap thickness (r=0.605, p<0.0001; r=-0.591, p<0.0001, respectively). Optimal threshold of mean computed tomographic value and remodeling index identified by receiver operating characteristic curve were 62.4 HU and 1.08 (area under the curve 0.859 and 0.781). Signet ringlike appearance was observed more frequently in the TCFA group (65% vs 16%, p<0.0001). In multivariate analysis, independent predictors of TCFA were mean computed tomographic density value ≤62.4 HU (odds ratio 8.20, 95% confidential interval 2.49 to 27.0, p=0.0005), remodeling index ≥1.08 (odds ratio 6.10, 95% confidential interval 2.04 to 18.2, p=0.0012), and signet ringlike appearance (odds ratio 6.33, 95% confidential interval 2.03 to 19.7, p=0.0014). In conclusion, based on comparisons with optical coherence tomographic findings, 64-slice MSCT may have the potential to detect vulnerable plaque., (Copyright © 2011 Elsevier Inc. All rights reserved.)

New imaging techniques have been used as surrogate markers of atherosclerotic burden to determine the effects of pharmacologic intervention. The aim of this study was to better determine potential utility and limitations of intravascular ultrasound (IVUS) imaging for assessing regression and progression in coronary artery disease. Medline was searched for randomized trials using IVUS for assessing regression and progression in coronary artery disease (through September 2009). A comparison of IVUS studies with large trials evaluating the same issue with clinical end points was performed. A total of 26 relevant reports (8,631 patients randomized [median 207.5], 5,794 patients analyzed [median 152], duration 2 weeks to 3.4 years [median 12 months]) were identified. Three frequently used IVUS variables were the focus of the analysis: (1) nominal change in plaque volume, (2) percentage change in plaque volume, and (3) nominal change in percentage plaque volume. These variables were presented in 21, 12, and 11 studies, respectively. The variables were the primary end points in 4, 5, and 4 studies, respectively. Large variance with a relatively small difference was noticed in all 3 variables. Fewer than half of the variables showed statistically significant differences in comparing groups. Comparison of IVUS studies with large trials evaluating the same issue with clinical end points showed consistent and inconsistent results. In conclusion, the current method of calculating plaque volume using IVUS seems logical, and some clinical outcomes trials have yielded some evidence. Future studies are needed to determine which IVUS variable is the best surrogate to determine the effects of pharmacologic intervention in patients with coronary artery disease., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Whether gender affects long-term outcomes after bare metal stent implantation remains controversial. The aim of this study was to examine the impact of gender on neointimal hyperplasia in a large cohort of patients after stent implantation using 3-dimensional intravascular ultrasound. Lumen and stent areas were manually traced at 0.5-mm intervals throughout the stented segment. Using Simpson's method, lumen, stent, and neointimal (stent - lumen) volumes were calculated and standardized by stent length. Women were older, presented more often with hyperlipidemia or hypertension, and had smaller reference vessel diameter and mean stent area, compared with men. Although neointimal hyperplasia and neointimal thickness in women were similar to that in men, the percentage of neointimal hyperplasia (neointimal area divided by stent area) was higher in women due to the smaller stent area. After adjusting for stent area, the percentage of neointimal hyperplasia did not differ by gender. In conclusion, the results of this study indicate that neointimal hyperplasia after bare metal stent implantation in women is similar to that seen in men. Despite the similarity in outcome, there are several gender-specific differences in baseline characteristics.

This study examined whether coronary focal vasospasm occurs in a nonuniform distribution within the coronary tree and whether a longitudinal plaque distribution pattern is present in patients with vasospastic angina using 3-dimensional intravascular ultrasound analysis. Of 121 patients with clinically suspected angina without fixed stenosis in the coronary arteries, vasospasm was provoked in 82 patients with 92 lesions (42 focal, 50 diffuse) by intravenous ergonovine maleate injection. Most focal vasospasms occurred in the proximal third of the coronary arteries (proximal 28, mid 8, distal 6, p <0.01), corresponding to the historical high-risk zones for acute coronary occlusion. More plaque burden also existed in the proximal third of the coronary arteries in patients with focal vasospasm.

Diabetes mellitus is an independent predictor of restenosis after percutaneous coronary intervention. The pattern of restenosis after bare metal stent implantation in diabetic patients was examined with 3-dimensional intravascular ultrasound analysis. Lumen and stent were manually traced at every 0.5-mm interval in stented segments. Using Simpson's method, stent, luminal, and neointimal (stent minus lumen) volumes were calculated and average area was calculated as volume data divided by length. To measure the cross-sectional and longitudinal severities of luminal encroachment by the neointima, percent neointimal area (neointimal area divided by stent area) and neointimal hyperplasia 50 (IH50) (defined as percent stent length with percent neointimal area >50%) were calculated. In 278 patients (68 with diabetes and 210 without diabetes), there was a significantly higher percentage of maximal percent neointimal area with significantly longer percent stent length that was severely encroached by the neointima in diabetic patients. Diabetic patients showed a more heterogenous pattern of the neointima after bare metal stenting, resulting in longer high-grade obstruction segments. This may have important implications for stent design and pharmacokinetic properties of next-generation drug-eluting technology for this complex patient subset.

To assess whether asymmetric stent expansion affects suppression of neointimal hyperplasia after sirolimus-eluting stent implantation, 64 patients in the SIRolImUS-coated Bx Velocity stent trial who underwent single 18-mm stent implantation and 3-dimensional intravascular ultrasonography at 8-month follow-up were enrolled. To assess the longitudinal stent asymmetric expansion, 2 cross sections with a maximal/minimal stent area were chosen in each patient. To assess for tomographic stent asymmetric expansion, stent eccentricity was determined by dividing the minimum stent diameter by the maximum stent diameter. At the 2 cross sections with a maximal/minimal stent area, a sirolimus-eluting stent reduced neointimal hyperplasia significantly with no interaction between the treatment and stent areas. A sirolimus-eluting stent also significantly reduced neointimal hyperplasia in the concentric and eccentric stent groups.

To study the interaction of the sirolimus-eluting stent and vessel margins, we analyzed the intravascular ultrasound parameters in 317 edges of 167 stents having 18 edge stenoses at 8 months of follow-up from the SIRIUS trial. Of the baseline parameters, a larger reference percentage of plaque area and a larger edge stent area/reference minimum lumen area were associated with edge stenosis in the sirolimus-eluting stent cohort compared with the incidence of edge stenosis in the bare metal stent cohort. Thus, full lesion coverage and matching the stented segment properly to the adjacent segment using intravascular ultrasound guidance may improve sirolimus-eluting stent implantation efficacy further.

The effect of lesion characteristics on neointimal hyperplasia after sirolimus-eluting stent implantation was examined in 45 patients who underwent successful preinterventional intravascular ultrasound. There were no differences in neointimal hyperplasia between the moderate/severe calcified lesion group (calcium arc >120 degrees ) and the non/mild calcified lesion group or between the positive vessel remodeling group (external elastic membrane area at the minimal lumen area site larger than that at the proximal reference site) and negative vessel remodeling group. No correlation between preinterventional plaque burden and neointimal hyperplasia was found. In patients who have coronary artery disease, sirolimus-eluting stents continue to demonstrate striking suppression of neointimal proliferation, irrespective of lesion characteristics previously associated with greater restenotic risk.

Adjacent reference vessel response to smaller lumens at stented segments was examined with 3-dimensional intravascular ultrasound analysis. In 128 patients after bare metal stent implantation, minimal lumen area (MLA) within the stent and average lumen area at distal/proximal adjacent reference segments (5 mm) were obtained at baseline and follow-up. In the smaller in-stent MLA group (MLA <3 mm2), lumen area decreased significantly at the distal edge compared with the larger in-stent MLA group (MLA > or =3 mm2), although no significant difference was seen at the proximal edge. In-stent lumen patency may influence vascular responses at adjacent reference segments after bare metal stent implantation.