Assessment of coronary compensatory enlargement by three-dimensional intravascular ultrasound

Several techniques have been used to demonstrate that human arteries respond to atherosclerosis by increasing their total arterial area to prevent a decrease in blood flow. Three-dimensional reconstructions of coronary arteries can document this compensatory response accurately and specifically. Seven human coronary arteries were reconstructed using intravascular ultrasound and biplane angiography, and vessel geometries were quantified. In all seven vessels, as plaque area increased, overall vessel area increased (R = 0.986, 0.933, 0.984, 0.678, 0.763, 0.963, and 0.830), but luminal cross-sectional area did not significantly decrease. Focal compensatory enlargement was identified in each vessel, and in some cases this response appeared to occur until the vessel was 65% occluded. Luminal enlargement near the proximal ends was attributed to the natural taper of the vessel. The semi-automated, three-dimensional segmentation technique used in this study allows reproducible quantification, as there is no subjective manual tracing involved. Following the intravascular ultrasound transducer in time and space with biplane angiography allows for accurate reconstruction with or without automated pullback devices. Information on the rate of change of vessel measurements is also presented, which, when combined with visualization of accurate 3D geometry, provides a unique assessment of coronary compensatory enlargement. This reconstruction technique can be applied in a clinical environment with no major modification.     

Effect of coronary risk factors on arterial compensatory enlargement in japanese middle-aged patients with de novo single-vessel disease--an intravascular ultrasound study

BACKGROUND: Compensatory enlargement (CE) of atherosclerotic human arteries has been reported; however, the pattern of arterial remodeling in response to plaque formation is not unique. HYPOTHESIS: The study was undertaken to determine the extent of coronary artery compensatory enlargement at stenotic lesions and to correlate the arterial compensatory enlargement with risk factors. METHODS: We studied 62 patients with stable angina and de novo single-vessel disease using intravascular ultrasound and obtained good images in 42 patients (68%). The vessel cross-sectional area (VA), lumen cross-sectional area (LA), and plaque cross-sectional area (PA) were measured at the lesion site and at proximal and distal reference sites. Positive CE was defined as increase in VA of lesion site > 10% compared with that of proximal reference site (CE group, n = 15); shrinkage was defined as reduction in VA of lesion site > 10% compared with that of proximal reference site (S group, n = 14); inadequate CE was defined as intermediate between CE and S (IE group, n = 13). All subjects had coronary risk factors measured before this study. RESULTS: There was no difference in VA, LA, or PA among the three groups at the proximal and distal reference sites, nor in LA at the lesion site; however, VA and PA were significantly smaller in the S group than in the other groups (p < 0.01). Of coronary risk factors, increased systolic blood pressure (SBP), increased diastolic blood pressure (DBP), and decreased high-density lipoprotein cholesterol (HDL-c) levels had the strongest association with shrinkage (p < 0.05). CONCLUSION: Hypertension and decreased HDL level may contribute to the shrinkage response in middle-aged patients with stable angina.     

Intravascular ultrasound catheter entrapment after coronary artery stenting.

Intracoronary ultrasound (IVUS) facilitates optimal stent deployment in the treatment of coronary artery disease, which may favorably improve long-term outcome after stenting. Complications associated with IVUS include coronary vasospasm and rarely more serious adverse events such as vessel perforation or stent deformation. We report an IVUS catheter tip entrapment within a self-deploying nitinol stent.     

Intravascular ultrasound findings in patients with abnormal coronary flow reserve after stenting.

A coronary flow reserve (CFR) of 2.0 has been advocated as the endpoint for coronary intervention therapy. Experience shows, however, that CFR does indeed exceed 2.0 in many cases poststenting, while remaining below 2.0 in others. In this study, we assessed the clinical characteristics and IVUS findings of patients whose CFR remained below 2.0 after stent implantation, specifically 16 patients with CFR below 2.0 (22 lesions, 64 +/- 9 years, 4 female), and 102 patients with CFR above 2.0 (112 lesions, mean age 66 +/- 11 years, 22 female). Patient population comprised patients selected for retrospective study, but participants were selected on the basis of matching patient and lesion characteristics. The IVUS findings showed that incidence of calcified lesions and post-PTCA dissection of hard plaque were higher among patients with CFR < 2.0. Further, IVUS-obtained vascular measurements showed post-PTCA area stenosis to be 58.7 +/- 15.2% in the CFR < 2.0 group, and 45.3 +/- 12.5% among CFR > or = 2.0 patients (P < 0.05). These findings indicate that patients with diffuse calcified lesions or high post-PTCA % area stenosis, as determined by IVUS, are more likely to have lower CFR after stenting.     

Extramural vessel wall hematoma causing a reduced vessel diameter after coronary stenting: Diagnosis by intravascular ultrasound and treatment by stent implantation

An extramural vessel wall hematoma occured immediately after implanting a coronary stent in an in-stent-restenosis of the intermedius branch. Angiography showed a significant luminal reduction distal to the intervention site. Intravascular ultrasound revealed an extramural echolucent zone compressing the vessel lumen. Stent implantation compressed the hematoma and allowed adequate myocardial perfusion. This demonstrates the value of intravascular ultrasound (IVUS) in cases of unusual angiographic results which can help to manage complications after coronary intervention. Cathet. Cardiovasc. Diagn. 43:438–443, 1998. © 1998 Wiley-Liss, Inc.     

Use of intravascular ultrasound in evaluating repeated balloon rupture during coronary stenting

Balloon rupture during coronary angioplasty is a well-recognized complication of PTCA. Coronary angiography commonly fails to elicit the cause of balloon perforation. We present a case with multiple balloon rupture during additional high-pressure inflations of a Palmaz-Schatz stent where intravascular ultrasound was useful in revealing a calcified lesion protruding through the struts of the stent. Cathet Cardiovasc Diagn 40:52–54, 1997. © 1997 Wiley-Liss, Inc.     

血管内超声表现不同的冠状动脉斑块临床特点比较

目的 采用血管内超声（IVUS）分析冠心病患者冠状动脉内斑块的临床特点。方法 入选2010年1月至2013年12月在沈阳军区总医院心内科住院并经冠状动脉造影证实的冠心病患者220例,根据IVUS斑块回声强弱分为3组：衰减斑块组（n＝42）,钙化斑块组（n＝63）和纤维斑块组（n＝115）。对此220例患者的基线资料和斑块特点进行比较分析。根据IVUS检查结果,确定需行经皮冠状动脉介入治疗（PCI）术的患者有140例（全部成功）,其中衰减斑块组26例（PCI比率62%）,钙化斑块组41例（PCI比率65%）、纤维斑块组73例（PCI比率63%）。对此140例患者的斑块特点、PCI术特点以及随访情况进行比较分析。结果 钙化斑块组患者年龄较其余两组大（P＜0.05）,总胆固醇（TC）和低密度脂蛋白胆固醇（LDL-C）均显著低于其余两组（P＜0.05）;衰减斑块组患者的既往心肌梗死或冠状动脉搭桥术（CABG）以及吸烟史均显著高于其余两组（P＜0.05）。钙化斑块组的最小管腔面积和病变血管直径显著低于其余两组（P＜0.05);与其他两组患者相比,衰减斑块组患者的斑块负荷较重、病变血管面积较大（P＜0.05）。在行PCI术的患者中：与其他两组患者相比,衰减斑块组患者的斑块负荷较重（P＜0.05）。行PCI术的各组患者在1年内发生死亡、心肌梗死和再次血运重建的概率间无统计学差异（P＞0.05）。结论 吸烟、既往心肌梗死或CABG史与衰减斑块的发生有关;与钙化斑块组及纤维斑块组相比,衰减斑块组具有较大的斑块负荷;PCI对IVUS证实的不稳定斑块具有较好的治疗效果。     

Subintimal guidewire tracking during successful percutaneous therapy for chronic coronary total occlusions: Insights from an intravascular ultrasound analysis

Objectives : We sought to determine the frequency of subintimal guidewire tracking during successful percutaneous coronary intervention (PCI) for chronic coronary total occlusions (CTOs) and to better understand the procedural implications of this event. Background : Successful PCI for chronic CTO is associated with improved outcomes in patients with ischemia. While subintimal guidewire tracking resulting in failure to cross is recognized as the major mode of failure for CTO PCI, the implications of subintimal guidewire tracking during successful CTO PCI are unknown. Methods : Between March 2007 and October 2007, 26 consecutive patients, each with one de‐novo CTO lesion successfully crossed with a guidewire were included in the analysis. Intravascular ultrasound (IVUS) was performed in each CTO vessel after guidewire crossing. Cases were classified as having definite subintimal wire tracking or no clear evidence of subintimal wire tracking based on analysis of IVUS images. Results : Subintimal wire tracking occurred in 45% of cases. In cases where subintimal wire tracking was present, a previous attempt at CTO PCI was more common (42% vs. 7%, P ≤ 0.05). Subintimal wire tracking was also associated with significantly longer final mean stent length (71 vs. 50 mm), procedure time (122 vs. 69 min), fluoroscopy time (47 vs. 22 min), and contrast dose (300 vs. 199 mL, P ≤ 0.05 for all). There was one perforation in the subintimal group which was successfully treated with stent placement. Conclusions : Subintimal wire tracking occurs frequently during successful PCI for CTO and is associated with increased lesion and procedural complexity.© 2011 Wiley Periodicals, Inc     

Value of intravascular ultrasound in the assessment of coronary pseudostenosis during coronary interventions

Coronary pseudostenosis (PS) are increasingly visualized during coronary interventions. In many patients PS are readily recognized by a characteristic angiographic pattern, but in other cases the diagnosis remains difficult. The value of intravascular ultrasound (IVUS) in the study of PS remains unknown. In this study, IVUS was used to assess the morphologic appearance of the vessel wall in 10 consecutive patients showing images of PS during coronary interventions. Mean age of the group was 60 ± 12 years and two patients were female. IVUS was performed with a motorized pullback system to assess lumen, plaque, and total vessel cross-sectional areas. Measurements were performed both at the site of PS and at the distal reference segment. PS were always located on angled coronary segments. In one patient no lumen narrowing was detected with IVUS at the site of PS. In the remaining nine patients, however, a very localized elliptic-shaped lumen narrowing was demonstrated. As compared with the distal reference segment, coronary lumen (6.3 ± 2.2 vs. 12.7 ± 4.8 mm², P < 0.001) and total vessel area (11.9 ± 3.3 vs. 16.1 ± 6.1 mm², P < 0.05) were smaller at the site of PS. Severe lumen asymmetry was also documented at this site. In addition, a characteristic image of a flattened, three-layered wall, overlying a hypoechogenic space, was visualized in five patients. This unique pattern was considered the correlate of a partial coronary intussusception. PS induced some resistance to the advancement of catheters in two patients and temporary flow impairment in two additional patients. However, in every case, the image of PS disappeared once the guidewire was removed. Thus, at sites with PS, IVUS allows ruling out severe atherosclerosis and coronary dissections. In addition, IVUS also provides important diagnostic clues, including the image of intussusception, for making the correct diagnosis of this benign entity. Cathet. Cardiovasc. Intervent. 46:327–332, 1999. © 1999 Wiley-Liss, Inc.     

Spontaneous coronary artery dissection with pseudoaneurysm formation diagnosed by intravascular ultrasound: a case report

Spontaneous coronary artery dissection is a rare cause of myocardial ischemia. Coronary artery pseudoaneurysm may occur after percutaneous coronary interventions and rarely spontaneously. We present a patient who had spontaneous coronary artery dissection with formation of a pseudoaneurysm diagnosed by intravascular ultrasound.     

Ambiguous coronary angiography: Clinical utility of intravascular ultrasound

We report the use of intravascular ultrasound (IVUS) in situations where angiography was ambiguous or uncertain in assessing the significance of coronary stenoses. The indications for performing intravascular ultrasound were (1) angiographic findings did not correlate with the clinical presentation (n = 5) and (2) the lesion was not seen well by angiography because of overlapping vessels at the site of suspected stenosis (n=3). We studied eight lesions in seven patients. Six nonobstructive stenoses on angiography were shown by IVUS to be significant. In two patients, stenoses were thought to be significant on angiography, but, due to overlapping of the vessels, there was doubt regarding the severity of the narrowing. In these two patients, IVUS clearly showed that the lesions were nonobstructive. As seen from the above results, angiography underestimated 6/8 stenoses and overestimated in 2/8 stenoses when compared to IVUS. We conclude that IVUS can be used to clarify ambiguous angiographic findings which can have a major impact on the clinical decision making. © 1992 Wiley-Liss, Inc.     

Atherosclerotic coronary lesions with inadequate compensatory enlargement have smaller plaque and vessel volumes: observations with three dimensional intravascular ultrasound in vivo

Objective—To compare vessel, lumen, and plaque volumes in atherosclerotic coronary lesions with inadequate compensatory enlargement versus lesions with adequate compensatory enlargement.
Design—35 angiographically significant coronary lesions were examined by intravascular ultrasound (IVUS) during motorised transducer pullback. Segments 20 mm in length were analysed using a validated automated three dimensional analysis system. IVUS was used to classify lesions as having inadequate (group I) or adequate (group II) compensatory enlargement.
Results—There was no significant difference in quantitative angiographic measurements and the IVUS minimum lumen cross sectional area between groups I (n = 15) and II (n = 20). In group I, the vessel cross sectional area was 13.3 (3.0) mm² at the lesion site and 14.4 (3.6) mm² at the distal reference (p < 0.01), whereas in group II it was 17.5 (5.6) mm² at the lesion site and 14.0 (6.0) mm² at the distal reference (p < 0.001). Vessel and plaque cross sectional areas were significantly smaller in group I than in group II (13.3 (3.0) v 17.5 (5.6) mm², p < 0.01; and 10.9 (2.8) v 15.2 (4.9) mm², p < 0.005). Similarly, vessel and plaque volume were smaller in group I (291.0 (61.0) v 353.7 (110.0) mm³, and 177.5 (48.4) v 228.0 (92.8) mm³, p < 0.05 for both). Lumen areas and volumes were similar.
Conclusions—In lesions with inadequate compensatory enlargement, both vessel and plaque volume appear to be smaller than in lesions with adequate compensatory enlargement.

     

Imaging of post-mortem coronary arteries by 30 MHz intravascular ultrasound

Intravascular ultrasound cross-sectional imaging of the atherosclerotic artery may be employed to guide plaque ablation by spark erosion, atherectomy, laser irradiation or other means. To assess whether in the coronary artery the echolucent zone of the three-layered ultrasound appearance of muscular arteries might be a reliable boundary to halt transluminal ablative angioplasty, epicardial coronary arteries were scanned under pressure over a distance of 4–8 cm at 1 mm intervals. A 5.2F catheter with a 30 MHz transducer rotating at 600 RPM was used. In 419 images from four post-mortem hearts, aged at death 22, 31, 56 and 82 years, the presence of a distinct echolucent zone was scored as percentage of the wall circumference. The median scores were 0%, 0%, 10% and 75%, respectively. In the three youngest hearts, the three-layered appearance was largely absent. In the 82 year old heart, in contrast, the three-layered appearance could generally be identified. Within subjects, the presence of an echolucent zone was variable in location. Qualitatively, neither abundant medial elastin tissue nor a reduced medial thickness could explain the absence of an echolucent zone when the ultrasound image was compared to the corresponding microscopic section.The results show that in the 82 year old heart, 30 MHz intravascular ultrasound discrimination of coronary wall layers would be adequate to guide transluminal plaque ablation. In the younger hearts, guided ablation would fail due to the limited presence of a distinct echolucent zone as an ultrasound landmark of the media. Whether the presence or absence of an echolucent zone is related to age remains to be determined.     

Plaque characterization of atherosclerotic coronary arteries by intravascular ultrasound

Intravascular ultrasound provides cross-sectional images of arteries and enables accurate delineation of lumen dimensions and wall structure. Moreover, ultrasound characterization of atherosclerotic plaque subtypes may have important implications in determining the natural history and the clinical outcome of patients with coronary artery disease. The reliability of intravascular ultrasound to differentiate plaque morphology subtypes was studied in 60 coronary segments excised from 33 coronary arteries obtained from 17 patients at necropsy. Ultrasound was performed with a 25-MHz transducer mounted on the distal end of a rigid probe that was rotated manually inside the lumen artery. Plane film radiography was also performed to establish the presence of calcific deposits. A total of 82 histologic transverse sections corresponding to 82 ultrasound imaging sites were studied from the 60 coronary segments. Of the first 54 images, 36 were fibrous plaques and yielded dense homogenous echo reflections, 6 had discrete areas of lipid that were less echogenic and 12 had calcific deposits that cast echo-free shadows beyond areas of intense echo reflections. The predictive accuracy of evaluating plaque composition in the remaining 28 ultrasound imaging sites was 96%. Thus, anatomical structure of coronary arteries and composition of atherosclerotic lesions can be assessed accurately with intravascular ultrasound and may have potential for better understanding of the atherosclerotic process and provide guidance to interventional procedures.     

High-speed rotational atherectomy and coronary stenting: QCA and QCU analysis.

To evaluate the acute effect of pretreatment with high-speed rotational atherectomy (HSRA) on stent deployment (rotastenting), we studied 33 patients with rotastenting of 40 segments, 34 patients with 40 coronary segments treated with Palmaz-Schatz stenting alone, and 34 patients with 40 segments treated with HSRA. The HSRA- and stent-alone patient groups were selected retrospectively by matching the quantitative coronary angiography (QCA) reference diameter (D ref). QCA revealed similar baseline percent of stenosis (85.3% +/- 12.4%), minimal luminal diameter (MLD), and D ref. The percent area expansion was calculated as a ratio between the minimal intrastent area and the reference area measured by intracoronary ultrasound. The rotastent group was characterized by more frequent calcification compared to HSRA and stent groups (67.5% vs. 20% and 12.5%; P < 0.01). Lesion length determined by QCA was longer both in the HSRA and the rotastent groups vs. the stent-alone group (21.1 +/- 12.3 and 20.9 +/- 4.3 vs. 17.0 +/- 7.7 mm; P < 0.05). In this small study, there was no difference demonstrated between final MLD in the rotastent and stent-alone groups. However, a smaller MLD was achieved in the HSRA group (3.0 +/- 0.7 vs. 3.1 +/- 0.5 vs. 2.5 +/- 0.7 mm, respectively; P < 0.01). The degree of stent expansion was higher in the rotastent group compared to the stent-alone group (91.9% +/- 4.4% vs. 79.7% +/- 3.4%; P < 0.03) and the % residual area of plaque was less for the rotastent group than for the stent-alone group (12.1% +/- 13.2% vs. 21.1% +/- 17.5%; P = 0.03). These data suggest that antecedent HSRA atheroma debulking using HSRA results in improved intravascular stent expansion and reduction in residual plaque, facilitating optimal stent deployment.     

Application of intravascular ultrasound for detection and quantitation of coronary atherosclerosis

Although angiography is widely utilized to assess the extent and severity of coronary artery disease (CAD), arteriography yields only a silhouette of the vessel lumen. Coronary intravascular ultrasound supplements angiography by providing a tomographic perspective of lumen geometry and vessel wall structure. Intracoronary ultrasound can now be performedin vivo utilizing small, flexible probes capable of negotiating tortuous vessles. We have performed coronary ultrasound in more than 100 patients, including a group of normal subjects, with no serious complications. Measurements of coronary lumen dimensions by angiography and ultrasound correlated closely for normal vessels (r=0.92) and for concentrically narrowed atherosclerotic vessels (r=0.90). However, the correlation between angiography and ultrasound was only fair for eccentrically narrowed arteries (r=0.79) and was poor following angioplasty (r=0.30). Coronary artery wall motion was measured by intravascular ultrasound and demonstrated significant differences between normal arteries (18% lumen area change) and atherosclerotic vessels (11% change). Coronary ultrasound demonstrated important differences in the structure of normal and altherosclerotic vessel walls. Arteries in normal subjects exhibited a thin intimal leading-edge echo (mean 0.20 mm) and subadjacent sonolucent zone (mean 0.12 mm). Atherosclerotic vessels typically demonstrated increased thickness of both structures and often exhibited dense fibrocalcific plaques that shadowed underlying anatomy. These ultrasound abnormalities were often present at angiographically normal sites. Several limitations of coronary intravascular ultrasound were apparent, including echo dropout, distortions produced by non-coaxial imaging, and inability to image small or severely narrowed vessels. Coronary intravascular ultrasound holds great promise for the detection and quantification of CAD in the clinical setting.     

Assessment of spontaneous coronary artery dissection by intravascular ultrasound in a patient with unstable angina

We describe a case of spontaneous coronary artery dissection that gave rise to post infarction unstable angina. An ambiguous angiographic appearance was shown by intracoronary ultrasound to arise from an extensive coronary dissection. The dissection membrane separating true and false lumina and features to suggest sluggish flow and early thrombosis in the false lumen were observed. No increase in lumen calibre was evident on ultrasound after PTCA (probably a consequence of the relatively large ultrasound catheter blank), but coronary flow reserve measured with intracoronary Doppler did improve and the patient remained stable and free of angina following the procedure.