支架影像增强技术StentBoost对支架后扩张的指导意义与血管内超声的比较分析

目的探讨支架影像增强技术StentBoost显影及判定支架后扩张的可行性及准确性。方法选择同时行血管内超声(IVUS)和StentBoost检查的心内科住院患者1 7例,其中无钙化患者3例,浅表钙化患者11例,深层钙化患者3例。其中14例因支架膨胀不均匀给予后扩张,分别对支架后扩张前后冠状动脉定量分析(QCA)、IVUS和StentBoost检测数据进行相关性分析。结果后扩张前支架内最小直径IVUS与StentBoost的相关性(r=0.9856,P0.01)优于QCA与StentBoost的相关性(r=0.9754,P0.01),也优于QCA与IVUS的相关性(r=0.9611,P0.01);后扩张后支架内最小直径QCA与StentBoost的相关性(r=0.8774,P0.01)最好。QCA、IVUS和StentBoost三者的相关性在深层钙化患者明显优于浅表钙化患者。结论支架后扩张前IVUS和StentBoost数据的相关性较好,而后扩张后两者相关性下降。     

支架影像增强显影技术及其对球囊后扩张的指导作用

目的:探讨支架影像增强显影技术(StentBoost,SB)增强冠状动脉(冠脉)支架显影以及对球囊后扩张的指导作用。方法:收集2009-03至2010-07经皮冠脉介入治疗(PCI)术后在SB指导下给予球囊后扩张的184例患者资料,平均年龄(64.5±10.9)岁(42～83岁),对其后扩张前后SB测量数据进行比较。其中52例(28.26%)患者给予血管内超声(IVUS)检查,并分别对冠脉狭窄程度定量分析(QCA)、IVUS和SB检测数据进行相关性分析。结果:后扩张后较后扩张前支架内最小直径[(2.72±0.35)mm vs.(2.42±0.39)mm]、支架内最大直径[(3.26±0.37)mm vs.(3.09±0.38)mm]及支架内平均直径[(2.99±0.36)mm vs.(2.76±0.43)mm]均明显增大,支架偏心指数(0.17±0.04 vs.0.22±0.06)明显减小,差异均有统计学意义(P<0.001)。支架内最小直径IVUS与SB的相关性r=0.979,P<0.0001;冠脉狭窄程度定量分析与SB的相关性r=0.973,P<0.0001;QCA与IVUS的相关性r=0.964,P<0.0001。结论:SB与IVUS具有良好的相关性,且在评价支架置入效果以及指导高压球囊后扩张方面具有临床实用价值。     

Safety and utility of intravascular ultrasound-guided carotid artery stenting.

Intravascular ultrasound (IVUS) is useful in evaluating coronary stent deployment. The aim of this study was to assess the safety and utility of IVUS in carotid artery stenting (CAS). Ninety-eight consecutive high-risk patients (107 arteries) underwent CAS. IVUS was performed prior to predilatation in 87 of the 107 vessels and in all 107 following stent deployment when an optimal angiographic appearance was obtained. Quantitative carotid angiography (QCA) and IVUS analysis were performed offline. Procedural success was 97%. Combined stroke or death at 30 days was 5.6%. IVUS measurements of the minimum lumen diameter (MLD) of the distal internal carotid artery (ICA) reference segment were similar to QCA (4.60 +/- 0.74 vs. 4.74 +/- 0.71 mm; P = 0.21). The ICA stent MLD was significantly smaller by IVUS compared to QCA (3.65 +/- 0.68 vs. 4.31 +/- 0.76 mm; P < 0.001). IVUS detected stent malapposition in 11%. IVUS findings, after an optimal angiographic result, necessitated additional treatment in 9% of procedures. Calcium was detected in more arteries with IVUS than angiography (61% vs. 46%; P < 0.05). Arteries with superficial lesion calcification subtending three or four quadrants by IVUS had a 31% incidence of stroke compared with a 1% incidence in arteries without severe superficial calcium (P < 0.001). We found IVUS imaging in CAS to be safe even prior to plaque dilatation. IVUS provides a more accurate assessment of stent dimensions, expansion, and apposition than angiography. Severe calcification by IVUS was associated with a higher risk of stroke.     

Assessment of optimum stent deployment by stent boost imaging: comparison with intravascular ultrasound

Stent boost (SB) imaging is an enhancement of the radiologic edge of the stent by digital management of regular X-ray images. The purpose of the present study was to validate SB imaging by comparison with the anatomical standard using intravascular ultrasound (IVUS). We investigated SB and IVUS after stent implantation in 68 arteries in 60 patients. Based on those findings, we added high-pressure dilatation in four patients and another stent implantation in four patients. We defined the SB criteria for adequate stent deployment as: complete stent expansion, stent minimum diameter ≥70% of reference diameter, and stent minimum diameter ≥2.0 mm; and IVUS criteria for adequate stent deployment as: minimal stent area ≥5.0 mm². If the reference vessel was <2.8 mm, adequate stent deployment was defined as minimum stent area ≥4.5 mm². IVUS findings indicated inadequate stent deployment in 21/72 observations (29%). Seven SB images showed inadequate stent expansion. SB predicted inadequate findings of IVUS with 100% specificity, 33% sensitivity, and 81% agreement. Although the sensitivity of SB image for adequate stent deployment is low, the specificity is sufficiently high for it to be the first-line for monitoring just after stent implantation in centers where IVUS is not used routinely.     

支架影像增强显影技术在冠脉支架植入术中的应用效果观察

目的：评价支架增强显影（ SB）技术在冠脉支架植入术中的应用效果。方法将204例行冠状动脉支架植入术的患者随机分为观察组和对照组,各102例。两组均采用常规冠状动脉造影方法行冠状动脉造影,并在其指导下进行冠状动脉支架植入术。对照组支架植入后采用QCA自动分析系统测量支架直径的相关参数（包括支架直径的最小值、最大值、均值）并计算支架偏心指数。同时进行支架可视性和球囊内扩张必要性评分。观察组在支架植入后行SB,测量上述指标并进行上述评分。观察组26例支架植入后行血管内超声（ IVUS）检查,测量上述指标并进行上述评分。结果对照组支架植入后支架可视性得分低于观察组, P＜0．05。对照组发现30处、观察组发现48处有球囊内扩张必要性而行支架球囊内扩张术。两组QCA、SB、IVUS测得植入支架最小直径、最大直径、直径均值和支架偏心指数差异无统计学意义。 Pearson相关性分析显示QCA与SB、QCA与IVUS、SB与IVUS测得支架最小直径均有良好的相关性,r分别为0．772、0．775、0．782,P均＜0．05。结论 SB可明显提高支架的可视性,有效指导支架的球囊内扩张,在测量支架直径方面甚至可以替代冠脉内超声。     

Stent boost enhancement compared to intravascular ultrasound in the evaluation of stent expansion in elective percutaneous coronary interventions

Background

Stent underexpansion is a major risk factor for in-stent restenosis and acute in-stent thrombosis¹Intravascular ultrasound (IVUS) is one of the standards for detection of stent underexpansion (de Feyter et al. 1999; Mintz et al., 2001). StentBoost (SB) enhancement allows an improved angiographic visualization of the stent (Koolen et al., 2005).

Assessment of coronary stent deployment using computer enhanced x‐ray images‐validation against intravascular ultrasound and best practice recommendations

Objective : To investigate the accuracy of stent measurements using coronary x‐ray angiograms with a computer based stent enhancement algorithm applied (StentBoost, SB). To derive recommendations for best practice when using such systems. Background : Computer enhancement algorithms allow better visualization of intracoronary stents to assist in ensuring adequate stent deployment. Factors that affect the accuracy of measurements taken on such systems are yet to be fully understood. Methods : We analysed stent deployment of 43 stents in 33 patients measuring minimum stent diameter and cross sectional area (CSA) using intravascular ultrasound (IVUS), SB enhanced x‐ray images, and quantitative coronary angiography (QCA). We investigated if the use of two projections and method of calibration influenced correlation between IVUS and SB measurements. Results : Using two views and performing calibration via the guide catheter improved agreement between SB and IVUS measurements. For example, minimum stent diameter assessed with SB using one view and balloon markers for calibration produced a correlation coefficient, r, of 0.21, whereas using two views and the guide catheter for calibration increased agreement to r = 0.62. Relative measures of stent deployment, such as the ratio of minimum to maximum CSA, produced good correlation between IVUS and SB (r = 0.74). Conclusions : When using the SB system, two projection angles should be used to image the stent. For absolute measurements, the guide catheter should be used for calibration purposes. Relative measures of stent size, which are probably sufficient for assessment of deployment, also give good agreement with similar measures on IVUS, and require no calibration. © 2012 Wiley Periodicals, Inc.     

Original studies: Comparison of angiography and intravascular ultrasound for the assessment of lumen size after coronary stent placement: Impact of dilation pressures

This study was designed to assess the extent of potential discrepancies between intravascular ultrasound (IVUS) and quantitative coronary angiography (QCA) measurement of intrastent minimal luminal diameter and to evaluate the impact of dilation pressures and the balloon:artery ratio on the assessment of the minimal lumen diameter (MLD) by these imaging modalities. IVUS is recommended as an adjunct to angiography to assess stent expansion; however, the extent of potential discrepancies between the two imaging modalities is not well defined. Included were 225 patients in whom coronary Palmaz-Schatz stents were successfully placed after PTCA. IVUS and QCA were performed at the end of the intervention. We compared the MLD assessed by QCA and IVUS in the instent and reference site. The MLD assessed by IVUS and QCA were 2.68 ± 0.41 mm and 3.08 ± 0.47 mm (P < 0.001), respectively, at the tightest intrastent site and 3.19 ± 0.50 mm and 3.17 ± 0.52 ns at the reference site. There was a correlation between the dilation pressure and the difference between QCA- and IVUS-based intrastent MLD measurement (y = −0.05x + 1.11; r = −0.53; P < 0.0001). At low dilation pressures, a significant difference beween the image modalities was found, but after high dilation pressures no discrepancies were detected. No relation was found with the balloon:artery ratio. These data provide clear evidence that in the case of low-pressure dilation, the exclusive reliance on data obtained by QCA will not yield sufficiently accurate information on intrastent MLD, whereas after high dilation pressure, the differences between the imaging modalities are minimized. Cathet. Cardiovasc. Diagn. 42:113–119, 1997. © 1997 Wiley-Liss, Inc.     

One-year follow-up after intravascular ultrasound assessment of moderate left main coronary artery disease in patients with ambiguous angiograms.

OBJECTIVES: The purpose of this study was to correlate angiographic and intravascular ultrasound (IVUS) findings in left main coronary artery (LMCA) disease and identify the predictors of coronary events at one year in patients with LMCA stenoses. BACKGROUND: Significant (> or =50% diameter stenosis [DS]) LMCA disease has a poor long-term prognosis. METHODS: One hundred twenty-two patients who underwent angiographic and IVUS assessment of the severity of LMCA disease and who did not have subsequent catheter or surgical intervention were followed for one year. Standard clinical, angiographic and IVUS parameters were collected. RESULTS: The quantitative coronary angiography (QCA) reference diameter (3.91 +/- 0.76 mm, mean +/- 1 SD) correlated moderately with IVUS (4.25 +/- 0.78 mm, r = 0.492, p = 0.0001). The lesion site minimum lumen diameter (MLD) (2.26 +/- 0.82 mm) by QCA correlated less well with IVUS (2.8 +/- 0.82 mm, r = 0.364, p = 0.0005). The QCA DS measured 42 +/- 16%. During the follow-up period, 4 patients died, none had a myocardial infarction, 3 underwent catheter-based LMCA intervention and 11 underwent bypass surgery. Univariate predictors of events (p < 0.05) were diabetes, presence of another lesion whether treated with catheter-based intervention or untreated with DS > 50% and IVUS reference plaque burden and lesion lumen area, maximum lumen diameter, MLD, plaque area and area stenosis. Using logistic regression analysis diabetes mellitus, an untreated vessel (with a DS > 50%) and IVUS MLD were independent predictors of cardiac events. CONCLUSIONS: In selected patients assessed by IVUS, moderate LMCA disease had a one-year event rate of only 14%. Intravascular ultrasound MLD was the most important quantitative predictor of cardiac events. For any given MLD, the event rate was exaggerated in the presence of diabetes or another untreated lesion (>50% DS).     

Mechanism of cutting balloon angioplasty for in-stent restenosis: an intravascular ultrasound study.

We investigated by intravascular ultrasound (IVUS) the mechanism of action of cutting balloon (CB) angioplasty in patients with in-stent restenosis. Seventy-one consecutive restenotic lesions of 66 patients were studied by quantitative coronary angiography (QCA) and IVUS before, immediately after, and, in 20 cases, at 24-hr time interval after CB. CB was selected according to 1:1 CB-to-stent ratio and inflated at 8 atm for 60-90 sec. Both IVUS planar and volumetric (Simpson's rule, 25 patients) analysis were carried out. IVUS measurements included external elastic membrane area (EEMA), stent area (SA), minimal lumen area (MLA), and restenosis area (RA). Following CB, QCA analysis showed increase of minimal lumen diameter (1.17 +/- 0.46 vs. 2.45 +/- 0.51 mm; P < 0.0001) and decrease of diameter stenosis (64% +/- 13% vs. 21% +/- 9%; P < 0.0001). IVUS measurements showed a significant increase of MLA (2.18 +/- 0.80 vs. 7.31 +/- 1.8 mm(2); P < 0.0001), SA (9.62 +/- 2.6 vs. 10.7 +/- 2.75 mm(2); P < 0.0001), and EEMA (17.27 +/- 5 vs. 18.1 +/- 5 mm(2); P < 0.0001) and a decrease of RA (7.43 +/- 2.63 vs. 3.45 +/- 1.39 mm(2); P < 0.0001). No significant change was observed in the original plaque + media area (7.65 +/- 3 vs. 7.38 +/- 2.9 mm(2); P = NS). Thus, of the total lumen enlargement (5.13 +/- 1.85 mm(2)), 23% was the result of increase in mean SA, whereas 77% was the result of a decrease in mean RA. These changes were associated with a 5% increase in EEMA. IVUS volumetric changes paralleled planar variations. Angiographic and IVUS changes were well maintained at 24 hr. CB enlarges coronary lumen mainly by in-stent tissue reduction associated with a moderate degree of additional stent expansion. Favorable QCA and IVUS acute results are maintained at 24 hr.     

Comparison of two- and three-dimensional quantitative coronary angiography to intravascular ultrasound in the assessment of intermediate left main stenosis

Angiographic evaluation of intermediate left main coronary artery stenosis (LMS) is often limited. Three-dimensional (3D) quantitative coronary angiography has recently developed to overcome 2-dimensional (2D) quantitative coronary angiographic (QCA) limitations. In patients with angiographically intermediate LMS, we investigated whether 3D quantitative coronary angiography was superior to 2D quantitative coronary angiography in predicting the presence of a significant LMS, defined as a minimum luminal area <6 mm(2) at intravascular ultrasound (IVUS). 2D and 3D quantitative coronary angiography were compared in their measurements of minimum luminal area, percent area stenosis, minimum luminal diameter, and percent diameter stenosis and in their prediction of an IVUS minimum luminal area <6 mm(2). In total 58 target lesions were interrogated, 25 (43%) of which had an IVUS minimum luminal area <6 mm(2). Correlation between 3D-QCA minimum luminal area and IVUS minimum luminal area was stronger than the correlation between 2D-QCA minimum luminal area (or minimum luminal diameter) and IVUS minimum luminal area (R = 0.67, p = 0.0001, and R = 0.40, p = 0.001, respectively, p = 0.04 for comparison). To predict IVUS minimum luminal area <6 mm(2), the most accurate 2D-QCA measurement was minimum luminal diameter (area under curve 0.81, cutoff 2.2 mm, p = 0.0001), and the most accurate 3D-QCA measurement was minimum luminal area (area under curve 0.86, cutoff 5.6 mm(2), p = 0.0001). 2D-QCA percent diameter stenosis did not significantly predict IVUS minimum luminal area <6 mm(2) (area under curve 0.56, cutoff 38%, p = 0.45). In conclusion, the accuracy of quantitative coronary angiography in predicting LM IVUS minimum luminal area <6 mm(2) is limited. When IVUS is not available or contraindicated, 3D quantitative coronary angiography may assist in the evaluation of intermediate LMS. Among 2D-QCA parameters, minimum luminal diameter is more accurate than percent diameter stenosis in predicting significant LMS.     

血管内超声与定量冠脉造影应用于冠脉临界病变诊治的比较

目的 研究血管内超声（intravascular ultrasound,IVUS）在优化民航飞行员冠脉临界病变诊断和治疗中的应用。 方法 通过定量冠脉造影（quantitative coronary angiography,QCA）和IVUS对120例飞行员患者165处冠脉临界病的最小管腔直径（minimal lumen diameter,MLD）、直径狭窄率（diamter stenosis,DS）与最小管腔面积（minimal lumen area,MLA）、面积狭窄率（area stenosis,AS）等参数进行对比分析;对IVUS提示管腔MLA<4 mm2飞行员患者的冠脉临界病变行支架植入术。 结果 ①同一临界病变处QCA显示的MLD,DS及MLA,AS值均小于IVUS相应的测量值,且差异有统计学意义（P<0.01）,表明IVUS对冠脉病变狭窄定量测量方面准确性更高;②IVUS提高血栓病变（15.0% vs. 2.5%,P<0.05）和心肌桥（42.5% vs. 2.5%,P<0.01）的诊断率;③与QCA相比,IVUS直接显示介入治疗中支架的贴壁情况,指导支架扩张完全。 结论 IVUS较QCA能更准确地检测冠脉临界病变范围,更灵敏地诊断血栓和心肌桥,利于全面优化临界病变的诊疗。     

Revisiting late loss and neointimal volumetric measurements in a drug-eluting stent trial: analysis from the SPIRIT FIRST trial.

This study was conducted to reevaluate the significance of angiographic late loss and to assess the agreement between new proposed neointimal volumetric measurements derived from quantitative coronary angiography (QCA) and standard intravascular ultrasound (IVUS)-based parameters. Neointimal volumetric measurements may better estimate the magnitude of neointimal growth after stenting than late loss. In 56 in-stent segments (27, everolimus; 29, bare metal) in the SPIRIT FIRST study, we compared QCA measures with the corresponding IVUS parameters. Two IVUS-late loss models were derived from minimal luminal diameter (MLD) using either a circular model or a so-called projected MLD. QCA-neointimal volume was calculated as follows: stent volume (mean area of the stented segment x stent length) at post procedure - lumen volume (mean area of the stented segment x stent length) at follow-up (the stent length either from nominal stent length or the length measured by QCA). Videodensitometric neointimal volume was also evaluated. Each of the three neointimal volume and percentage volume obstruction by QCA showed significant correlation with the corresponding IVUS parameters (r = 0.557-0.594, P < 0.0001), albeit with a broad range of limits of agreement. Late loss and volumetric measurements by QCA had a broader range of standard deviation than those by IVUS. QCA-volumetric measurements successfully confirmed the efficacy of everolimus-eluting stents over bare metal stents (P < 0.05). Our proposed QCA volumetric measurements may be a practical surrogate for IVUS measurements and a discriminant methodological approach for assessment of treatment effects of drug-eluting stents.     

A new intracoronary measurement catheter, MetriCath, compared to intravascular ultrasound and quantitative coronary angiography in a stented porcine coronary model.

The purpose of this study was to compare measurements by MetriCath to intravascular ultrasound (IVUS) and quantitative coronary angiography (QCA). The MetriCath system consists of a low-pressure (200 mm Hg) balloon catheter connected to a pressure transducer and infusion pump linked to a computer that records pressure-volume curves. Cross-sectional area of blood vessels is obtained directly from the unrestrained and in-stent pressure-volume measurements. We compared stent cross-sectional area measurements by MetriCath, IVUS, and QCA in a porcine stented coronary artery model. Comparison of area measurements in 14 stents showed no significant differences between the three methods (P = 0.66). On average, values differed 0.37 +/- 0.60 mm(2) between MetriCath and QCA, 0.13 +/- 0.55 mm(2) between MetriCath and IVUS, and 0.22 +/- 0.80 mm(2) between IVUS and QCA. This corresponds to 6.2% +/- 10%, 3.0% +/- 9.0%, and 3.1% +/- 12.9% relative difference from the average of two corresponding measurements. Linear regression analysis showed excellent correlation between measurements (r = 0.99 for all comparisons). The differences in in-stent area measurements between MetriCath and both QCA and IVUS were small. Considering the ease and rapidity of obtaining MetriCath results, this technique may form an alternative to the others in evaluating stent expansion. Based on these findings, clinical evaluation seems warranted.     

A novel three‐dimensional quantitative coronary angiography system: In‐vivo comparison with intravascular ultrasound for assessing arterial segment length

Background : Accurate on‐line assessments of vessel dimensions are of utmost importance for selecting the appropriate stent size in coronary interventions. Recently a new three‐dimensional quantitative coronary angiography (3D QCA) analytical software package was developed to accurately assess the vessel dimensions for the planning and guidance of such coronary interventions. This study aimed to validate the 3D QCA software package for assessing arterial segment length by comparing with intravascular ultrasound (IVUS). In addition, the difference in the two measurements from 3D QCA and IVUS for curved segments was studied. Methods : A retrospective study including 20 patients undergoing both coronary angiography and IVUS examinations of the left coronary artery was set up for the validation. The same vessel segments of interest between proximal and distal markers were identified and measured on both angiographic and IVUS images, by the 3D QCA software and by a quantitative IVUS software package, respectively. In addition, the curvature of each of the segments of interest was assessed and the correlation between the accumulated curvature of the segment and the difference in segment lengths measured from the two imaging modalities was analyzed. Results : 37 vessel segments of interest were identified from both angiographic and IVUS images. The 3D QCA segment length was slightly longer than the IVUS segment length (15.42 ± 6.02 mm vs. 15.12 ± 5.81 mm, P = 0.040). The linear correlation of the two measurements was: 3D QCA Length = ?0.09 + 1.03 × IVUS Length (r² = 0.98, P < 0.001). Bland‐Altman plot showed that the difference in the two measurements was not correlated with the average of the two measurements (P = 0.141), but with the accumulated curvature of the segment (P = 0.015). After refining the difference by the correlation, the average difference of the two measurements decreased from 0.30 ± 0.86 mm (P = 0.040) to 0.00 ± 0.78 mm (P = 0.977). Conclusions : The 3D QCA software package can accurately assess the actual arterial segment length. The difference in segment lengths measured from 3D QCA and IVUS was correlated with the accumulated curvature of the segment. © 2010 Wiley‐Liss, Inc.     

Intravascular ultrasound and quantitative coronary angiography assessment of late in-stent restenosis: in vivo human correlation and methodological implications.

Quantitative coronary angiography (QCA) is routinely used for assessment of strategies aimed at reducing in-stent restenosis. Yet QCA enables only the measurement of luminal variation of stented segments and, unlike intravascular ultrasound (IVUS), provides only an indirect estimation of late in-stent neointimal formation, which has a key role in the process of in-stent restenosis. The aims of the present study were to correlate the IVUS measurement of in-stent intimal hyperplasia (IH) with QCA indexes of restenosis, to find out whether QCA is an adequate surrogate of IVUS, and, using either QCA and IVUS data, to define the sample sizes needed to demonstrate the effectiveness of strategies to reduce in-stent restenosis. The database of the European Imaging Laboratory was used to screen 154 stents implanted between 1997 and 2001 and studied by IVUS at 6 +/- 1 months of follow-up. All cases underwent serial QCA assessment (preintervention, postintervention, and follow-up). Only 131 cases with single stent implantation in native coronary arteries were included in the study. Stent restenosis, defined as percent diameter stenosis (DS) > 50%, was present at QCA in 69 out of 131 cases (53%). Linear regression analyses were performed to correlate the amount of IH, calculated by IVUS as the average of all cross-section areas (CSA; mean % IH CSA) and QCA indexes of restenosis (late loss and % DS). A positive significant correlation was found between IVUS mean % IH CSA and QCA % DS (r = 0.74; P < 0.0001) and between IVUS mean % IH CSA and QCA late loss (r = 0.72; P < 0.0001). Based on IVUS measurements of mean % IH CSA, a total sample size of 74 stents would be required in a two-arm comparison to have 0.80 power to detect at 0.05 significant level a 30% difference between two compared groups. Alternatively, adopting the QCA late loss, 230 stents would be required. QCA measurements of late in-stent restenosis are well correlated with IVUS calculation of in-stent neointimal formation. IVUS assessment of IH allows smaller sample sizes than QCA to document significant reductions of in-stent restenosis. Therefore, the use of IVUS should be encouraged in comparison studies aimed at revealing significant neointimal differences in small sample size populations.     

Quantitative measurements of in-stent restenosis: A comparison between quantitative coronary ultrasound and quantitative coronary angiography.

While quantitative coronary angiography (QCA) remains the standard used to assess new interventional therapies, intracoronary ultrasound (ICUS) is gaining interest. The aim of the study was to determine the relationship between QCA and quantitative coronary ultrasound (QCU) measurements after stenting. Sixty-two consecutive patients with both QCA and QCU analysis after stent implantation were included in the study. The mean luminal diameter (QCU vs. QCA) were 2.74 +/- 0.46 mm and 2.41 +/- 0.49 mm (P < 0.0001), the minimal luminal diameter (MLD) 2.08 +/- 0.44 mm and 1.62 +/- 0.42 mm (P < 0. 0001), and the projected QCU MLD 1.90 +/- 0.42 mm (P < 0.0001 with respect to QCA). Percentage obstruction diameter (QCU vs. QCA) were 41.53% +/- 10.78% and 43.15% +/- 12.72% (P = NS). The stent diameter (QCU vs. QCA) were 3.54 +/- 0.65 mm and 3.80 +/- 0.37 mm (P = 0. 0004). Stent length measured by QCU were longer at 31.11 +/- 13.54 mm against 28.63 +/- 12.75 mm, P < 0.0001 with respect to QCA. In conclusion, while QCA and QCU appear to be comparable tools for measuring corrected stent diameters and stent lengths, smaller luminal diameters were found using QCA. This is of particular relevance to quantitative studies addressing absolute changes in vascular or luminal diameters. Cathet. Cardiovasc. Intervent. 48:133-142, 1999.     

Bifurcation coronary lesions treated with the "crush" technique: an intravascular ultrasound analysis

OBJECTIVES: We report intravascular ultrasound (IVUS) findings after crush-stenting of bifurcation lesions. BACKGROUND: Preliminary results with the crush-stent technique are encouraging; however, isolated reports suggest that restenosis at the side branch (SB) ostium continues to be a problem. METHODS: Forty patients with bifurcation lesions underwent crush-stenting with the sirolimus-eluting stent. Postintervention IVUS was performed in both branches in 25 lesions and only the main vessel (MV) in 15 lesions; IVUS analysis included five distinct locations: MV proximal stent, crush area, distal stent, SB ostium, and SB distal stent. RESULTS: Overall, the MV minimum stent area was larger than the SB (6.7 +/- 1.7 mm2 vs. 4.4 +/- 1.4 mm2, p < 0.0001, respectively). When only the MV was considered, the minimum stent area was found in the crush area (rather than the proximal or MV distal stent) in 56%. When both the MV and the SB were considered, the minimum stent area was found at the SB ostium in 68%. The MV minimum stent area measured <4 mm2 in 8% of lesions and <5 mm2 in 20%. For the SB, a minimum stent area <4 mm2 was found in 44%, and a minimum stent area <5 mm2 in 76%, typically at the ostium. "Incomplete crushing"--incomplete apposition of SB or MV stent struts against the MV wall proximal to the carina--was seen in >60% of non-left main lesions. CONCLUSIONS: In the majority of bifurcation lesions treated with the crush technique, the smallest minimum stent area appeared at the SB ostium. This may contribute to a higher restenosis rate at this location.     

血管内超声在冠状动脉介入诊治中的运用

目的观察运用血管内超声(Intravascular ultrasound IVUS)测定冠脉病变血管的价值及安全性。方法30例冠心病患者,共46支冠状动脉血管在冠状动脉造影(Coronary angiography CAG)后行IVUS检查。IVUS测量狭窄段血管直径和截面积、斑块性质,与相应部位定量的冠状动脉造影(Quantitative coronary angiographyQCA)的结果比较。结果QCA检出偏心性狭窄25处(54.3%);IVUS检出偏心性狭窄32处(69.6%)(P<0.05)。IVUS发现30处(65.2%)靶血管病变钙化,而CAG检出18处(39.1%)血管病变钙化(P<0.01)。CAG和IVUS检出病变血管直径狭窄率分别为62.15%和74.35%(P<0.01)。46处(100%)靶血管完成IVUS检查,34处血管介入后复查,其中1处IVUS导管无法通过支架,IVUS检出不理想支架释放8处(24.2%)。所有患者随访1个月以上,未发现严重心脏缺血事件。结论IVUS可以准确地识别冠状动脉管腔形态、斑块性质,有助于冠脉介入手术策略的选择,是对CAG的有效补充,IVUS检查本身比较安全。     

Expansion of the Multilink-Tristar stent after direct implantation and predilatation: comparison of clinical,angiography and intravascular ultrasound parameters

Coronary stenting has become the primary therapeutic option for many coronary lesions. As opposed to conventional stenting the advantages of direct stenting are a reduction of procedural time, radiation exposure and costs. However, data about the incidence of in-stent restenosis are so far not available. It was the aim of this prospective study to compare the expansion of the Multilink stent after direct stenting and predilatation by quantitative coronary angiography (QCA) and intravascular ultrasound (IVUS). Between January 2000 and June 2001, 82 patients were assigned to direct stenting (46 lesions) or predilatation (40 lesions) in lesions of coronary arteries > 3 mm. The procedural success rate was 92% in patients undergoing direct stenting. The baseline clinical characteristics were similar in both groups. The comparison of the angiographic data shows that direct stenting was performed in lesions with a lower degree of stenosis (71 +/- 12% vs 79 +/- 11%, p = 0.01) and that significantly shorter stents were used (14.4 +/- 3.0 vs 17.8 +/- 4.1 mm, p = 0.0007). The mean stenosis length was not significantly different in either group (10.5 +/- 3.4 vs 11.7 +/- 4.3 mm, n.s.). The QCA data after stent implantation show no differences of either implantation technique. Stent expansion was assessed by IVUS estimation of the proximal, distal and minimal in stent area. The minimal in-stent area (9.53 +/- 3.23, mm2 vs 8.65 +/- 1.96 mm2, n.s.) and the stent symmetry index (0.88 vs 0.88 n.s.) were not different in either patient group. These results indicate that in this subset of selected coronary lesions > 3 mm, elective stent implantation with and without predilatation effectively can achieve comparable stent expansion as assessed by QCA and IVUS. In comparison to conventional stent implantation stents, which were implanted without predilatation, were significantly shorter to cover the same lesion length.