Impact of intravascular ultrasound guidance on directional coronary atherectomy

In contrast to the luminogram of coronary angiography, intravascular ultrasound (IVUS) has proven to accurately assess both coronary lumen and vessel morphology due to its 360 degrees imaging capacity. Directional coronary atherectomy (DCA) improves the coronary lumen by removing plaque mass rather than stretching the vessel and compressing the plaque as with conventional percutaneous transluminal coronary angioplasty. In an attempt to optimize the procedural result of DCA we prospectively investigated the impact of IVUS guidance in a head to head comparison to on-line quantitative coronary angiography (QCA) on the result of DCA. In 16 consecutive patients IVUS demonstrated significant residual plaque mass after DCA irrespective of a satisfactory angiographic result. After a mean of 9 +/- 2 cuts luminal improvement was obtained with an area stenosis by angiography of 39 +/- 17% and by IVUS of 50 +/- 10% (p < 0.05), a diameter stenosis by angiography of 23 +/- 10% and IVUS of 35 +/- 14% (p < 0.05) and finally a minimal lumen diameter (MLD) by angiography of 2.9 +/- 0.5 mm and by IVUS of 2.3 +/- 0.5 mm (p < 0.005). After both on-line QCA and IVUS measurements a second series of 7 +/- 2 cuts were initiated to debulk more atheroma and improve stenosis dimensions. After additional cuts IVUS revealed further luminal improvement with an area stenosis by angiography of 25 +/- 16% and IVUS of 21 +/- 18% (n.s.), a diameter stenosis by angiography of 16 +/- 11% and by IVUS of 13 +/- 19% (n.s.) and finally a MLD by angiography of 3.1 +/- 0.5 mm and by IVUS of 2.8 +/- 0.3 mm (p < 0.05). Intraprocedural use of IVUS is superior to on-line QCA to assess the immediate result of DCA. IVUS-guided DCA results in more effective atheroma debulking than luminographic evaluation. Results of larger follow-up studies are needed to substantiate the intraprocedural advantage of IVUS with DCA.     

Intravascular Ultrasound Predictors of Angiographic Restenosis in Lesions Treated With Palmaz-Schatz Stents

Objectives. This study sought to evaluate the clinical, procedural, preinterventional and postinterventional quantitative coronary angiographic (QCA) and intravascular ultrasound (IVUS) predictors of restenosis after Palmaz-Schatz stent placement.Background. Although Palmaz-Schatz stent placement reduces restenosis compared with balloon angioplasty, in-stent restenosis remains a major clinical problem.Methods. QCA and IVUS studies were performed before and after intervention (after stent placement and high pressure adjunct balloon angioplasty) in 382 lesions in 291 patients treated with 476 Palmaz-Schatz stents for whom follow-up QCA data were available 5.5 ± 4.8 months (mean ± SD) later. Univariate and multivariate predictors of QCA restenosis (≥50% diameter stenosis at follow-up, follow-up percent diameter stenosis [DS] and follow-up minimal lumen diameter [MLD]) were determined.Results. Three variables were the most consistent predictors of the follow-up angiographic findings: ostial lesion location, IVUS preinterventional lesion site plaque burden (plaque/total arterial area) and IVUS assessment of final lumen dimensions (whether final lumen area or final MLD). All three variables predicted both the primary (binary restenosis) and secondary (follow-up MLD and follow-up DS) end points. In addition, a number of variables predicted one or more but not all the end points: 1) restenosis (IVUS preinterventional lumen and arterial area); 2) follow-up DS (QCA lesion length); and 3) follow-up MLD (QCA lesion length and preinterventional MLD and DS and IVUS preinterventional lumen and arterial area).Conclusions. Ostial lesion location and IVUS preinterventional plaque burden and postinterventional lumen dimensions were the most consistent predictors of angiographic in-stent restenosis.     

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。     

A contemporary re-evaluation of culprit lesion severity in patients presenting with STEMI

Background: Historical data report fatal myocardial infarction occurring when mildly-stenotic coronary plaques rupture; however, recent data suggest haemodynamically-significant coronary stenoses with fractional flow reserve (FFR) ≤ 0.8 and vessels with high plaque burden and minimum luminal area (MLA) < 4 mm² by intravascular ultrasound (IVUS) may be prognostically important. Therefore, we sought to re-evaluate culprit stenosis severity in patients presenting with ST-segment elevation myocardial infarction (STEMI).

Methods: Patients undergoing primary percutaneous coronary intervention (PPCI) for STEMI with adjunctive thrombectomy between October 2008 and February 2010 (n = 336/572; 59%) underwent quantitative coronary angiography (QCA) after thrombus aspiration to determine vessel reference area (RA), MLA and percentage area stenosis (AS). To validate findings, QCA and FFR were measured in 50 patients with stable angina and an angiographically-intermediate lesion.

Results: STEMI patients had anatomically-severe underlying culprit disease similar to that of the stable cohort (AS: 91.6 ± 9.5% versus 90.1 ± 8.1%; P = 0.11). Additionally, anatomically-severe lesions defined by QCA were more likely to be functionally-significant by FFR and vice-versa (P = 0.02 and 0.002 respectively).

Conclusion: These contemporary data suggest that STEMI culprit lesions, defined by luminal stenosis after thrombus aspiration, are angiographically significant, with similar stenosis severity to stable, ischaemia-inducing lesions.     

Quantitative angiographic and intravascular ultrasound study >5 years after directional coronary atherectomy

Aggressive and optimal directional coronary atherectomy (DCA) using intravascular ultrasound (IVUS) guidance provides favorable outcomes within 1 year. However, no previous data are available on the changes that occur in target lesions for the long term after stand-alone DCA. This study's aim evaluates, using quantitative angiography and intravascular ultrasonography, the natural history of changes that occur in target lesions between short- (about 6 months) and long-term (>5 years) follow-up angiography after stand-alone DCA. Of 186 patients (221 lesions) with successful stand-alone DCA, 48 patients (53 lesions) underwent revascularization within 6 months, and 14 patients subsequently died, leaving a study population of 124 patients (154 lesions). Complete quantitative coronary angiography (QCA) was obtained in 91 patients (101 lesions) and complete serial IVUS assessment was obtained for 38 lesions before and after intervention and during follow-up. From short- to long-term follow-up angiography, the minimal luminal diameter significantly increased (from 2.12 to 2.56 mm; p <0.0001); lesion subgroups with >30% diameter stenosis at short-term follow-up angiography showed significant late regression as assessed by QCA. Serial IVUS assessment revealed that the vessel cross-sectional area did not change (from 17.3 to 17.4 mm(2); p = NS); however the lumen cross-sectional area significantly increased (from 7.3 to 9.5 mm(2); p <0.0001) due to the reduction of plaque plus media cross-sectional area (from 10.0 to 7.9 mm(2); p <0.0001). The change in lumen cross-sectional area correlated with the change in plaque plus media cross-sectional area (r = -0.686, p <0.0001). Target lesions show late regression due to plaque reduction at >5 years after stand-alone DCA.     

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。     

血管内超声、64层螺旋CT及定量冠状动脉造影对不稳定性心绞痛患者冠状动脉病变的评价

目的 应用血管内超声(rvos)探讨不稳定性心绞痛(UAP)低、中及高危组患者动脉粥样硬化斑块的特点,评价定量冠状动脉造影(QCA)和64层螺旋CT(MDCT)的诊断价值.方法 采用IVUS、MDCT和QCA分析61例UAP患者(低危组17例,中危组33例,高危组11例)71支病变血管.分析比较3组患者斑块的形态学特点.根据IVUS斑块回声的强度,将斑块分为软斑块、纤维斑块、钙化斑块、混合斑块,计算最小面积处斑块负荷,并分为≤50%、51%～74%及≥75%3类病变.以IVUS结果为标准,评价QCA计算血管狭窄程度的可信性,MDCT诊断3类病变的敏感性和特异性,及对斑块成分诊断的可靠性.结果 QCA可估计低危组和中危组患者的斑块负荷(低危组r=0.768,P<0.01;中危组r=0.721,P<0.01).高危组患者血管重构明显(冠状动脉重构指数=1.21±0.31),QCA低估了IVUS的斑块负荷[分别为(67±14)%、(75±16)%,r=0.551,P<0.01].MDCT对冠状动脉病变有较高的阴性预测值(87.8%-96.3%),但无法区分典型粥样硬化斑块内的纤维帽(kappa=0.245)及脂质核(kappa=0.235).3组患者IVUS斑块特点分析结果表明,随着危险度程度的增加,软斑块比例、血管正性重构程度、血管外弹力膜面积、最小管腔面积、斑块负荷、斑块破裂及血栓发生率逐渐增加.结论 QCA可以相对准确地评价UAP低危和中危组患者的冠状动脉狭窄程度,同时会低估高危组患者的病变程度.MDCT对于冠心病的诊断有非常高的阴性预测值可用于排除冠心病,但是无法可靠地区分粥样硬化斑块内的纤维帽及脂质核.IVUS检查显示软斑块、正性血管重构和最小管腔面积<4mm~2者可能为UAP高危组患者.     

64层双源螺旋CT与血管内超声对冠状动脉粥样硬化斑块性质的对比研究

目的对比冠状动脉血管内超声(IVUS)与64层双源螺旋CT(64-sCT)检查对冠状动脉粥样硬化斑块特征判定的准确性。方法选择35例不稳定性心绞痛患者行64-sCT与IVUS检查,分别测定同一病变同一位置的血管横截面积、管腔横截面积、斑块负荷;采用IVUS判定斑块性质,64-sCT测定其CT值。结果 45支血管(左前降支23支;左回旋支15支;右冠状动脉7支)的72个不同截面行IVUS与64-sCT检查,在可用于评估的68个截面中,64-sCT对51个存在斑块的截面,正确显示49个存在斑块(敏感性96%),对提示17个无斑块的截面,正确显示16个无斑块存在(特异性94%)。脂质斑块(25±14)HU、纤维斑块(90±20)HU、钙化斑块(530±185)HU;混合斑块中,钙化-脂质斑块(540±175)HU、钙化-纤维斑块(540±195)HU、纤维-脂质斑块(91±22)HU。纤维-脂质斑块与纤维斑块差异无统计学意义;钙化-脂质斑块、钙化-纤维斑块与钙化斑块差异无统计学意义。靶血管外弹力膜截面积、管腔截面积、斑块负荷、狭窄程度之间差异无统计学意义。结论对比IVUS与64-sCT检查能够定性及定量分析冠状动脉粥样硬化斑块,但其精确度仍有一定的限制。     

Is imaging the left main able to rule out severe LAD stenosis?

The 5-year cardiac mortality rate has been reported to be more than 50% in patients with leftmain coronary artery (LMCA) stenosis.The purpose of this study was to visualize the LMCA using intravascularultrasound in patients who undergo interventions of the left anterior descending coronary artery (LAD).This wasdone in order to see the incidence and severity of plaque formation in the LMCA in patients with severe LADstenesis,and to address if scanning LMCA is able to rule out LAD significant stenosis or vice versa.Methods Atotal of 293 patients with intervention of the LAD stenosis were examined with intravascular ultrasound(IVUS).Theimages of 278 patients were suitable for analysis.Results Fifty-three (19%) were found to have angiographielumen reduction in the LMCA ranging from 11% to 35% (19±8%).Sixty-one patients were found to have nativecalcification in the LMCA.Atherosclerotic plaques in LMCA were detected in 211/278 (76%) patients,of which164/211 (78%) were eccentric,and 51/211 (24%) had calcium deposit.The cross-sectional plaque area rangedfrom 1.5 mm~2 to 21 mm~2 (8.4±4.7 mm~2).Area of stenusis was 34±14% (8-66%) and diameter of stenosis was21±8% (7-42%).A weak relationship concerning severity of stenosis between LAD stenosis and LMCA stenosiswas found in the 59 patients with pre-interventional IVUS examinations (r=0.47,P<0.05).ConclusionsLMCA is frequently involved with atherosclerotic lesions in patients with severe LAD stenosis.A weak relationshipdoes exist concerning the severity of stenosis between LAD and LMCA.However,IVUS for LMCA lesion is not ableto rule out lAD stenosis.(J Ceriatr Cardiol 2004;1:35-39.)     

冠状动脉分叉病变支架跨越分支技术对分支血管的影响及机制——血管内超声和冠状动脉造影对照研究

目的用血管内超声（IVUS）与冠状动脉造影（CAG）对照研究冠状动脉分叉病变主支支架跨越分支技术（Cross-over技术）对直径≥2mm的分支的影响,分析分支狭窄加重和急性闭塞的机制以及斑块和血管的形态学对分支转归的影响。方法对32例患者的35处分叉病变全部进行介入治疗前后IVUS检查,对比分析术后IVUS和量化冠状动脉造影（QCA）下分支受影响情况,利用IVUS目测术后分叉处斑块移位,多因素分析术前分叉处主支和分支开口的病变形态学特征对分支转归的影响。结果术前IVUS和QCA测得的分支开口直径狭窄率（D%）为18.67%±16.29%和29.06%±23.15%（P〈0.05）,面积狭窄率（A%）为31.17%±25.54%和42.22%±31.81%（P〉0.05）;术后IVUS和QCA测得的分支急性闭塞率均为2.86%,原有狭窄加重发生率分别为14.29%和48.57%（P=0.012）,新出现狭窄发生率分别为11.43%和14.29%（P=0.294）;IVUS测定术前、术后分支开口的管腔横截面积（L-CSA）分别为5.780±3.677 mm2和6.143±3.545 mm2,t=0.405,P=0.687。而QCA测得的D%和A%较术前明显加重（术前比术后,D%为29.06%±23.15%比42.24%±20.38%,t=2.482,P=0.016;A%为42.22%±31.81%比60.22%±27.33%,t=2.492,P=0.015）。IVUS分析分支开口狭窄加重的原因包括斑块移入、血管壁皱缩,其他可能的原因包括血管痉挛和血管变形（椭圆形趋势）。术前分叉处主支软斑块与术后分支狭窄有关。结论与IVUS相比,QCA高估冠状动脉分叉病变分支开口的狭窄程度。冠状动脉分叉病变Cross-over技术后,CAG高估分支受影响的程度;造成分支开口狭窄加重的可能原因包括斑块移入、血管壁皱缩、痉挛和血管变形。术前分叉处主支软斑块是预测分支狭窄受影响的因素。     

The impact of coronary artery disease risk factors on intravascular ultrasound-derived morphologic indices of human coronaries

OBJECTIVE: The relationship of intravascular ultrasound (IVUS)-derived measurements of atherosclerotic plaque to various coronary artery disease (CAD) risk factors is not well known. The purpose of this study was to examine the relationship of percent coronary luminal stenosis by IVUS to other IVUS measures of CAD, as well as the relationship of common IVUS measures of CAD to traditional CAD risk factors. We hypothesized that one or more IVUS measures of CAD might relate more strongly to CAD risk factors than does percent luminal coronary stenosis. METHODS: The records of 897 consecutive patients (57% men, mean age 62 years) who underwent IVUS investigation of their coronary arteries from 1996 through 2001 were retrospectively reviewed. IVUS was performed using a 20-MHz probe (Jomed, Rancho Cordoba, CA) and a manual pull-back technique to image the coronary arteries. Coronary artery remodeling ratio-i.e., the ratio of coronary lesion external elastic membrane cross-sectional area (EEM CSA) to proximal reference artery EEM CSA; plaque burden-i.e., plaque plus media CSA divided by EEM CSA; calcium arc; and percent stenosis of luminal cross-sectional area were measured by a single reader. RESULTS: Percent area stenosis, the most commonly used IVUS parameter, did not correlate with the other three IVUS-derived parameters, nor was it related to any of the CAD risk factors considered. In contrast, remodeling ratio was directly correlated with plaque burden (r=0.22, P<0.001), but inversely related to calcium arc (r=-0.13, P=0.01). IVUS plaque burden was significantly correlated with male gender (P<0.0001) and diabetes mellitus (DM) (P=0.003). In multivariate analyses including age, gender, and CAD risk factors, plaque burden was significantly associated with age, male gender, and DM, but not with chronic renal failure, hypertension, or hypercholesterolemia. The multivariate model also revealed that the calcium arc was significantly associated with male gender and age. These IVUS findings provide anatomic documentation that the traditional CAD risk factors relate more strongly to plaque burden than to percent coronary arterial luminal narrowing.     

Effect of stent design on reduction of elastic recoil: A comparison via quantitative intravascular ultrasound

The increase in minimum lumen diameter achieved by coronary stent placement can be further enhanced by reducing the immediate recoil that occurs after stent deployment. The effect of various stent designs—flexible coils, slotted tubes, and a locking stent—on minimization of postdilation stent recoil was evaluated using an in vitro model of circumferential compression. The stents were expanded to 7 atm (3.82 ± 0.02 mm); as pressure was reduced, lumen diameter and cross-sectional area (CSA) were determined by on-line intravascular ultrasound imaging (30 MHz) positioned inside the dilating balloon (n = 10–15 inflation-deflation cycles). Stent recoil was assessed by calculation of percent change in CSA from 7 atm to negative balloon pressure: −33.1 ± 5.6%(GR-II) and −22.4 ± 3.8%(Wiktor) in the coil stents; −20.0 ± 4.2%(JJIS coronary), −8.4 ± 2.6%(JJIS biliary), and −6.9 ± 1.5%(Multilink) in the slotted tube stents; and −1.9 ± 3.2%in the Navius ZR1 locking stent (P<0.05 vs. Multilink, P<0.0001 vs. others). A range of resistances to recoil is demonstrated by this model, with coil stent designs undergoing greater elastic recoil than slotted tube stent designs. The locking stent design demonstrated the greatest radial strength and the most reduction in elastic recoil. Cathet. Cardiovasc. Intervent. 47:251–257, 1999. Published 1999 Wiley-Liss, Inc.     

血管内超声在冠状动脉临界病变中的应用研究

目的:研究传统冠状动脉定量分析方法(QCA)与血管内超声(IVUS)在冠状动脉临界病变中的应用。方法:共入选经过冠状动脉造影(至少4体位造影)证实病变狭窄处于临界病变的患者150例。将入选者分为:常规冠状动脉造影组90例(QCA),血管内超声组60例(IVUS)。通过QCA和血管内超声定量分析方法分析2组最小管腔直径、参考血管直径、直径狭窄率及最小管腔面积等参数指标;将相关数据建立直线回归分析方程,分析二者之间是否具有线性关系;采用Cox回归模型分析2组免于心血管事件方面差异,观察2组术后住院期间、30d、3个月、6个月、9个月和12个月主要心血管事件。结果:血管内超声组分别采用QCA和IVUS分析,参考血管直径2者具有正相关性分别为(3.28±0.19)mmvs.(3.17±0.21)mm,R=0.627。最小管腔直径分别为(2.04±0.18)mmvs.(2.0±0.17)mm,R=0.782。比较2组之间的参数:QCA组通过计算得出直径狭窄率,与IVUS管腔面积狭窄率之间无相关性(R20.05,P=0.222),IVUS最小管腔面积(4.7±0.67)mm2。通过COX回归模型显示2组在免于心血管事件方面的差异,可见QCA组发生心血管事件率具有较高的趋势。结论:对于临界病变的患者,采用IVUS的方法能够检测出更严重狭窄的发生率,传统冠状动脉造影判定结果往往低估真正的病变情况。对于临界病变的患者,采用IVUS进行测量分析,具有减低心血管事件风险的趋势。     

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.     

Morphological effects on in-stent restenosis assessed by intravascular ultrasound imaging.

The purpose of this study was to evaluate the rupture and dissection of the vessel wall immediately after balloon dilatation by intravascular ultrasound (IVUS) imaging and to predict restenosis in patients who underwent subsequent coronary stent implantation. Stent implantation improves the long-term results of coronary angioplasty by reducing lesion elastic recoil and arterial remodeling. However, several studies have suggested that neointimal hyperplasia is the cause of instant restenosis. We recruited 60 patients in whom IVUS studies were performed immediately after successful balloon dilatation and just before stent implantation. We compared IVUS parameters with 6-month follow-up quantitative coronary angiography. This was performed in 51 lesions of 51 patients (85%). Qualitative analysis included assessment of plaque composition, plaque eccentricity, plaque fracture and the presence of dissection. In addition, minimal luminal diameter, percent diameter stenosis, percent area stenosis and plaque burden were quantitatively analyzed. Two morphological patterns after balloon dilatation were classified by IVUS. Type I was defined as absence or partial tear of the plaque without disclosure of the media to lumen (22 lesions). Type II was defined as a split in the plaque or dissection of the vessel wall with disclosure of the media to the lumen (29 lesions). At 6 months follow-up, angiographic restenosis occurred in 17 of the 51 lesions (33%). Restenosis was significantly (p < 0.05) more likely to occur in type II (13/29: 45% incidence) than in type I (4/22: 18% incidence). The assessment of plaque morphology immediately after balloon dilatation and before stent implantation provides important therapeutic and prognostic implications.     

血管内超声与冠状动脉造影在不稳定性心绞痛患者冠状动脉轻度狭窄中的显像特征

目的探讨血管内超声(IVUS)与冠状动脉造影(CAG)在不稳定性心绞痛患者冠状动脉轻度狭窄中的显像特征。方法对经CAG发现冠状动脉轻度狭窄的30例不稳定性心绞痛患者42处病变进行IVUS检查,观察病变斑块性质和血管最大狭窄程度,并对CAG和IVUS两种检查结果进行比较。结果 CAG发现,偏心性狭窄26处,向心性狭窄16处,病变最窄处血管直径狭窄率为(29.06±7.20)%;IVUS发现,偏心性斑块34处,向心性斑块8处,易损斑块28处,病变最窄处血管直径狭窄率为(37.37±6.50)%,面积狭窄率为(41.51±7.50)%。IVUS所测病变最窄处血管直径狭窄率明显高于CAG(P<0.05)。结论 CAG低估血管内病变情况,IVUS可准确地判定冠状动脉的病变性质和狭窄程度,更好地指导临床确定治疗策略。     

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.     

Randomized comparison of debulking followed by stenting versus stenting alone for ostial left anterior descending artery stenosis: intravascular ultrasound guidance

Background

Although directional coronary atherectomy (DCA) before stenting has the advantage of combining substantial removal of atheromatous plaque and prevention of elastic recoil, there has been no randomized study to investigate its efficacy in ostial left anterior descending artery (LAD) lesions. This study was aimed to evaluate the effect of DCA followed by stenting on ostial LAD stenosis under the guidance of intravascular ultrasound (IVUS).

Methods

Eighty-six patients with ostial LAD stenoses were randomly assigned to DCA followed by stenting (group I) or stenting alone (group II). Aggressive DCA or optimal stenting was performed in both groups under the guidance of IVUS. The primary end point was angiographic restenosis at 6 months.

Results

Baseline clinical and angiographic characteristics were similar between the 2 groups. The postprocedural minimal lumen diameter was larger in group I than group II (4.0 ± 0.4 mm vs. 3.5 ± 0.5 mm, P < .001). However, the angiographic restenosis rates were not significantly different between the 2 groups (9/32 [28.1%] in group I vs. 11/30 [36.7%] in group II, P = .472). The postprocedural IVUS stent area was the only independent determinant of restenosis by multivariate analysis (odds ratio .61, 95% CI 0.41-0.92, P = .018).

Conclusions

DCA followed by stenting achieved greater lumen gain than stenting alone for ostial LAD stenosis. However, DCA did not improve angiographic restenosis.     

Effects of adjunctive balloon angioplasty after intravascular ultrasound-guided optimal directional coronary atherectomy: the result of Adjunctive Balloon Angioplasty After Coronary Atherectomy Study (ABACAS).

OBJECTIVES: This study was conducted to evaluate: 1) the effect of adjunctive percutaneous transluminal coronary angioplasty (PTCA) after directional coronary atherectomy (DCA) compared with stand-alone DCA, and 2) the outcome of intravascular ultrasound (IVUS)-guided aggressive DCA. BACKGROUND: It has been shown that optimal angiographic results after coronary interventions are associated with a lower incidence ofrestenosis. Adjunctive PTCA after DCA improves the acute angiographic outcome; however, long-term benefits of adjunctive PTCA have not been established. METHODS: Out of 225 patients who underwent IVUS-guided DCA, angiographically optimal debulking was achieved in 214 patients, then theywere randomized to either no further treatment or to added PTCA. RESULTS: Postprocedural quantitative angiographic analysis demonstrated an improved minimum luminal diameter (2.88 +/- 0.48 vs. 2.6 +/- 0.51 mm; p = 0.006) and a less residual stenosis (10.8% vs.15%; p = 0.009) in the adjunctive PTCA group. Quantitative ultrasound analysis showed a larger minimum luminal diameter (3.26 +/- 0.48 vs. 3.04 +/- 0.5 mm; p < 0.001) and lower residual plaque mass in the adjunctive PTCA group (42.6% vs. 45.6%; p < 0.001). Despite the improved acute findings in the adjunctive PTCA group, six-month angiographic and clinical results were not different. The restenosis rate (adjunctive PTCA 23.6%, DCA alone 19.6%; p = ns) and target lesion revascularization rate (20.6% vs. 15.2%; p = ns) did not differ between the groups. CONCLUSIONS: With IVUS guidance, aggressive DCA can safely achieve optimal angiographic results with low residual plaque mass, and this was associated with a low restenosis rate. Although adjunctive PTCA after optimal DCA improved the acute quantitative coronary angiography and quantitative coronary ultrasonography outcomes, its benefit was not maintained at six months.     

Quantitative Coronary Angiographic Analysis of Spasm and Elastic Recoil After High Speed Rotational Atherectomy

This study evaluates the short-term changes in coronary artery segments treated with high speed rotational atherectomy (HSRA). Quantitative coronary angiographic (QCA) analysis indices, such as degree of expected ablation, elastic recoil, and segmental spasm, were examined in 133 patients and restudied 24 hours after HSRA. The study was also designed to compare the early results of three different HSRA strategies: stand-alone (SA) HSRA; HSRA with adjunctive high (≥ 4 atm) pressure (HP BA) and low (≥ 2 atm) pressure balloon angioplasty (LP BA). Previous studies have suggested negligible elastic recoil after HSRA as well as demonstrated the possibility of further continuous improvement in vessel patency up to 24 hours postprocedure. From a total of 656 patients treated with HSRA, a cohort of 133 patients with successful HSRA of 167 lesions were restudied angiographically at 24 hours. Serial QCA evaluation of the treatment site was performed. Analysis of the relative gain in minimal luminal diameter (MLD) assessed at 24 hours postprocedure showed that the highest gain group (> 40%) had narrower initial lesions compared to moderate gain (1%–40%), or MLD loss groups (MLD 0.5 ± 0.4 mm vs 1.0 ± 0.3 and 1.5 ± 0.4, respectively, P < 0.01). The initial percent diameter stenosis was also higher in the high gain group (77.1 ± 16.0 vs 61.9 ± 11.8 and 53.0 ± 11.9, P < 0.01). Immediately postprocedure there was a significant increase in MLD and a decrease in percent diameter stenosis. There was no difference in residual lesion characteristics postprocedure. While progressive MLD decrease was observed in the loss group (MLD postprocedure 1.6 ± 0.5 and 1.2 ± 0.6 at 24 hours, P < 0.01), a continuous increase in MLD was noted in the high gain group (MLD postprocedure 1.7 ± 0.5 mm vs at 24 hours 2.0 ± 0.5 mm, P < 0.01). The high gain group was characterized by the most lesion debulking, the most pronounced segmental spasm, and the least elastic recoil. Adjunctive HP BA was associated with the largest size vessels (D ref. in SA HSRA group was 2.6 ± 0.8 mm vs 2.9 ± 0.6 mm in LP BA and 3.0 ± 0.7 mm in HP BA groups, P < 0.01), the lowest elastic recoil (SA HSRA 23.8%± 20.9% vs LP BA 15%± 16.8% and HP BA 5.7%± 14.4%, P < 0.05), and the highest incidence of vessel dissection (SA HSRA 8.1% vs LP BA 14.7% and HP BA 34.0%, P < 0.05). However, these larger vessels underwent the least amount of lesion debulking (SA HSRA 46.4%± 27.2% vs LP BA 38.6%± 24.0% and HP BA 30.5%± 19.5%, P _{SA HSRA vs. HP BA} < 0.001). There are measurable degrees of elastic recoil and local spasm observed after HSRA. HSRA of the most severe lesions yields the highest procedural gain, the lowest elastic recoil and the highest index of lesion ablation. In addition, some late increase in the MLD due to the resolution of spasm is observed at 24 hours postprocedure. SA HSRA is associated with higher degrees of expected lesion ablation. This is comparable to the degree of improvement in MLD, where adjunctive percutaneous transluminal coronary angioplasty is utilized as assessed at 24 hours postprocedure. HSRA with adjunctive HP BA yields immediate results showing the least elastic recoil and spasm at the expense of the highest incidence of dissection and side branch loss.