Arterial remodeling patterns before intervention predict diffuse in-stent restenosis: an intravascular ultrasound study

OBJECTIVES: The aim of this retrospective study was to determine the predictors of diffuse in-stent restenosis (ISR) among the lesions causing the first ISR by intravascular ultrasound (IVUS) studies. BACKGROUND: Although some predictors of diffuse ISR have been reported, parameters on IVUS relating to diffuse ISR are not well characterized.METHODS: We classified 52 ISR lesions that had undergone successful stent implantation and led to restenosis into two types--focal and diffuse ISR--using quantitative coronary angiography. Restenosis was defined as > or =50% diameter stenosis, and diffuse ISR as lesion length > or =10 mm at follow-up. The remodeling index (RI) was defined as the vessel area at the target lesion divided by that of averaged reference segments. RESULTS: There were no significant differences in patient, angiographic, and procedural characteristics between the focal (n = 25) and diffuse (n = 27) ISR groups. Baseline RI was significantly greater in the diffuse ISR group (1.03 +/- 0.18 vs. 0.88 +/- 0.24, p = 0.0159). Negative remodeling, defined as RI <0.9, was detected in 60% of the focal ISR group and in only 26% of the diffuse ISR group. By logistic regression analysis, baseline RI was the only independent predictor of diffuse ISR (p = 0.0341). Moreover, volumetric analyses revealed that lesions developing into diffuse ISR had less capacity to compensate for further plaque growth. CONCLUSIONS: Among the first ISR lesions, baseline positive remodeling was the most powerful predictor of diffuse ISR. Measuring pre-interventional arterial remodeling patterns by IVUS may be helpful to stratify lesions at higher risk.     

The natural course of atherosclerosis. Part I: incidence and progression.

The natural course of early atherogenesis is not well established. The current prospective survey was designed to monitor 5-year changes in carotid atherosclerosis in a large, stratified random sample of the general population using high-resolution duplex ultrasound (Bruneck Study). Incidence rates of carotid atherosclerosis ranged from near zero to 184 per 1000 person-years. Most atherosclerotic lesions developed at sites with enhanced wall thickness. Incidence of atherosclerosis in premenopausal women was less than half of that observed in men of equal age. The sex difference disappeared within 5 years after menopause and may possibly be attributed to sex variations in body iron stores. Preexisting atherosclerotic lesions may experience 1 of 2 different types of disease progression. 1) The first main type of plaque growth causing nonstenotic or diffuse dilative atherosclerosis was characterized by slow and continuous plaque extension, which usually affected several lesions simultaneously and did not primarily focus on the carotid bifurcation. This step-by-step process relied on a cumulative exposure to well-known risk factors such as hyper-lipidemia. Compensatory enlargement of the artery at the site of active atherosclerosis effectively preserved a (near) normal lumen. 2) The second main type of plaque growth was characterized by occasional prominent increases in lesion size. This process primarily occurred in the internal carotid artery and was mediated by procoagulant risk factors in a way that peak levels were relevant rather than cumulative exposure. As the main underlying pathomechanism, atherothrombosis may be hypothesized. Marked increases in plaque size and insufficient vascular remodeling acted synergistically in producing a significant compromise of the lumen. The current study provides novel insights into the natural course of early carotid atherosclerosis, thereby focusing on disease incidence and various types of spontaneous disease progression. Nonstenotic or diffuse dilating atherosclerosis and focal stenotic disease were found to constitute epidemiologically and etiologically distinct disease entities that develop and proceed independently of each other.     

Association of plaque characterization by intravascular ultrasound virtual histology and arterial remodeling

Positive remodeling is more often observed in lesions of patients who have acute coronary syndromes or vulnerable (rupture-prone) plaques. However, there are few data that correlate plaque morphology, composition, and arterial remodeling in vivo. We evaluated coronary plaque characterization of lesions with positive remodeling using intravascular ultrasound (IVUS) radiofrequency data analysis. Seventy-seven nonbifurcation native coronary lesions (in 50 patients) were imaged in vivo using 30-MHz IVUS transducers. Lesions were classified into 4 plaque types, fibrous, fibrofatty, dense calcium, and necrotic core, by using processing of the radiofrequency signal validated in vitro. The remodeling index was calculated as the lesion external elastic membrane area divided by the proximal reference external elastic membrane area. Lesions were divided into 2 groups: positive remodeling (remodeling index>1.0, 26 lesions) and intermediate/negative remodeling (remodeling index相似文献   

Location of focal vasospasm provoked by ergonovine maleate within coronary arteries in patients with vasospastic angina pectoris

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.     

血管内超声分析斑块组成与冠状动脉重构之间的关系

目的 本研究的目的旨在应用血管内超声显像(IVUS)技术探讨斑块组成与冠状动脉重构之间的关系.方法 对77例冠心病患者(男性53例,平均年龄58±10岁)的罪犯血管采用ClearView或Galaxy2 (美国波士顿科学公司)血管内超声显像仪进行IVUS检查,其中31例为稳定性心绞痛,46例为急性冠状动脉综合征.对病变进行定性和定量测定.根据斑块组成回声的不同,分为软斑块、纤维斑块、钙化斑块和混合斑块,后三者统称为硬斑块.重构指数(RI)=病变处血管横截面积/平均参考血管面积.若RI＞1.0为正性重构;RI＜1.0为负性重构.比较不同重构形式病变的特性.结果 77处病变中,45处(58%)发生正性重构,32处(42%)发生负性重构.比较两组患者的临床表现,正性重构的患者更多的表现为急性冠状动脉综合征(74%比43%, P=0.006).与负性重构相比,正性重构病变部位的斑块面积和血管面积较大,斑块组成更多为软斑块(71%比34%, P＝0.001),发生钙化的较少(21%比54%, P＝0.003),钙化范围也较小[(18±37)°比(40±50)°, P＝0.027].进行多因素回归分析后,斑块组成和临床表现在两组患者中的差别仍具有统计学意义.结论冠状动脉重构与临床表现及斑块组成有关,正性重构病变软斑块较多见且钙化较少.     

Technology Insight: optical coherence tomography--current status and future development

The understanding of concepts in coronary artery disease, such as the vulnerable or high-risk plaque, which accounts for many acute coronary events arising from non-flow-limiting coronary lesions, has advanced remarkably. Although coronary angiography is an established imaging technique for visualizing atherosclerotic disease, it is limited by its two-dimensional imaging aspect and a low sensitivity for identifying lesions in the presence of positive remodeling and diffuse disease. Moreover, coronary atherosclerotic plaques cannot be characterized. Although intravascular ultrasound is currently the most commonly employed adjunctive method to better define lesions, it is limited by low resolution. The development of new technologies for improved coronary plaque characterization has, thus, been desired. Optical coherence tomography is a developing technique that uses near-infrared light for the cross-sectional visualization of the vessel wall at the microscopic level. It enables excellent resolution of coronary architecture and precise characterization of plaque architecture. Quantification of macrophages within the plaque is also possible. These capabilities allow precise identification of the most common type of vulnerable plaque, the thin-cap fibroatheroma. Here, we discuss results from clinical studies which indicate that optical coherence tomography is a promising imaging technique for improved characterization of the coronary atherosclerotic plaque.     

Spectrum of remodeling behavior observed with serial long-term (>/=12 months) follow-up intravascular ultrasound studies in left main coronary arteries

Most intravascular ultrasound (IVUS) studies of arterial remodeling in native coronary arteries reported a remodeling index obtained at a single time point. We analyzed serial IVUS examinations, including the vessel cross-sectional area changes (remodeling behavior), of 60 hemodynamically nonstenotic left main lesions (baseline vs 18.4 +/- 9.4 months follow-up). Lumen reduction resulted from vessel reduction (sometimes despite plaque + media decrease), plaque + media increase (with or without vessel increase), or both. The percent annual changes in lumen area correlated strongly with changes in vessel (r = 0.84), but not with changes in plaque + media area. Plaques were classified as group A lesions, reflecting positive remodeling behavior (vessel changes >0), or group B lesions, reflecting negative (or intermediate) remodeling behavior (vessel changes <==0). Both groups did not differ significantly in demographics, laboratory data, and medications. Group A lesions (n = 40) more often showed plaque + media increase than group B lesions (32 of 40 [80%] vs 9 of 20 [45%]; p = 0.02). Group A lesions had, on average, mild annual lumen increase despite mild plaque + media increase, i.e, overcompensation of remodeling for plaque + media increase (vessel increase greater than plaque + media area increase, 19 of 40 [47%]). Conversely, group B lesions (n = 20) showed a significant lumen area reduction (-2.8 +/- 2.6 mm(2)/year) as a result of a decrease in vessel area only. Thus, serial long-term reduction of lumen size may result from vessel shrinkage (sometimes despite plaque decrease), plaque increase (with or without vessel increase), or both; overall, only the remodeling behavior has a significant relation to lumen changes. More than 30% of lesions show a negative remodeling behavior, which shows no relation to patient characteristics or initial plaque burden.     

Intravascular ultrasound assessment of longitudinal plaque distribution patterns in patients with angiographically silent coronary artery disease after heart transplantation

AIMS: The purpose of this three-dimensional intracoronary ultrasound (ICUS) study was to assess longitudinal plaque distribution patterns in patients with angiographically silent coronary artery disease (CAD) after heart transplantation (HTX). METHODS AND RESULTS: Out of 334 patients without diameter stenosis >/=25% determined by coronary angiography, 321 underwent successful three-dimensional ICUS (30 MHz) of the left main coronary artery (LMCA) and all segments of the left anterior descending coronary artery (LAD). Early plaque formation was found in 296 patients (92.2%). Single (focal CAD, n = 65) or multiple (polyfocal CAD, n = 77), discrete coronary lesions were found in 142 patients and continuous plaque formation of at least one entire coronary segment (diffuse CAD) in 154 patients. Using multivariate regression analysis, male sex (P = 0.01), increasing post-transplantation time (P = 0.003) and increasing donor age (P = 0.001) were independent clinical predictors for diffuse CAD. Both focal and diffuse CAD most frequently affected the proximal LAD (88% compared with 89.6%, NS). The mean intimal index of each LAD segment was significantly higher in patients with diffuse CAD (P < 0.001) and showed a proximal-to-distal decline in patients with focal/polyfocal (LMCA, 10.1 +/- 14.3, LAD-6, 30.1 +/- 17.4%, LAD-7, 16.3 +/- 14.1%, LAD-8, 4.6 +/- 11.1%; P < 0.001) and diffuse (LMCA, 27.0 +/- 16.0, LAD-6, 47.8 +/- 16.1%, LAD-7, 41.9 +/- 14.5%, LAD-8, 24.9 +/- 23.3%; P < 0.01) CAD. CONCLUSION: Evaluation of longitudinal plaque distribution after HTX by three-dimensional ICUS revealed a time-dependent increase in the incidence of diffuse CAD and a proximal-to-distal decline in frequency and magnitude of early plaque formation.     

Positive remodeling on coronary computed tomography as a marker for plaque vulnerability on virtual histology intravascular ultrasound

Coronary computed tomographic angiography allows direct evaluation of the vessel wall and thus positive remodeling, which is a marker of vulnerability. The purpose of this study was to assess the association between positive remodeling on computed tomography angiogram (CTA) and vulnerable plaque characteristics on virtual histologic intravascular ultrasound (VH IVUS) images. Forty-five patients (78% men, 58 ± 11 years old) underwent computed tomographic angiography followed by VH IVUS. On CTA, the remodeling index was determined for each lesion by a blinded observer using quantitative analysis. Positive remodeling was defined based on a remodeling index ≥1.0. Percent necrotic core and presence of thin-capped fibroatheroma (TCFA) were used as markers for plaque vulnerability on VH IVUS images. Ninety-nine atherosclerotic plaques were evaluated, of which 37 lesions (37.4%) were identified as having positive remodeling on CTA. Higher levels of plaque vulnerability were identified in lesions with positive remodeling compared to lesions without positive remodeling. Percent necrotic core was significantly higher in lesions with positive remodeling (15.7 ± 7.8%) compared to lesions without this characteristic (10.2 ± 7.2%, p <0.001). Furthermore, significantly more TCFA lesions were identified in positively remodeled lesions (n = 16, 43.2%) than in lesions without positive remodeling (n = 3, 4.8%, p <0.001). In conclusion, lesions with positive remodeling on CTA are associated with increased levels of plaque vulnerability on VH IVUS images including a higher percent necrotic core and a higher prevalence of TCFA. Thus evaluation of remodeling on CTA may provide a valuable marker for plaque vulnerability.     

Preintervention arterial remodeling affects vessel stretch and plaque extrusion during coronary stent deployment as demonstrated by three-dimensional intravascular ultrasound

The mechanisms of lumen enlargement during stent implantation may be significantly affected by arterial remodeling. To assess effects of lesion remodeling, we performed 3-dimensional intravascular ultrasound (IVUS) analyses in 55 coronary lesions before and after deployment of balloon-expandable stents. Standard quantitative analysis was performed, and arterial remodeling was assessed by the remodeling index (target site divided by mean of proximal and distal reference segment vessel areas), which classified lesions into group A (remodeling index < or =1, negative or intermediate remodeling, n = 40) or group B (remodeling index >1, positive remodeling, n = 15) lesions. Characteristics of the 55 patients and the interventional procedures were similar in the 2 groups. IVUS demonstrated that stenting resulted in increased lumen and vessel dimensions and in a reduced plaque size (p < or =0.001 each) in both group A and group B lesions. The extent of lumen increase inside the stents was almost identical, but resulted from different mechanisms: (1) vessel stretch was greater in group A (p <0.002 at minimum lumen site); (2) plaque compression (or embolization) tended to be greater in group B (p = 0.05, along entire stented segment); (3) plaque redistribution within the stent was observed in both groups (p <0.005 both); and (4) significant (p <0.01) plaque extrusion into the distal reference segment was found in group B only. Thus, the remodeling pattern of coronary lesions has a significant impact on the mechanisms of lumen enlargement during stent deployment. Lesions with positive remodeling show more plaque extrusion into the distal reference and less stent-induced vessel stretch than those with negative remodeling.     

Intravascular ultrasonic analysis of plaque characteristics associated with coronary artery remodeling.

We sought to determine the patient and plaque characteristics associated with the different forms of arterial remodeling as seen by intravascular ultrasound (IVUS) before coronary intervention. Remodeling in response to plaque accumulation may occur in the form of compensatory enlargement and/or focal vessel contraction. Previous studies report variation in the frequency and form of arterial remodeling. We performed preintervention IVUS imaging on 169 patients. Vessels were categorized as exhibiting compensatory enlargement or focal contraction if the arterial area at the lesion was larger or smaller, respectively, than both proximal and distal reference arterial areas; otherwise the artery was considered not to have undergone significant remodeling. Calcification was assessed and noncalcified plaque density was measured by videodensitometry. Sixty-one of 169 patients (66 narrowings) (46 men and 15 women, age 56+/-11 years) had adequate reference segments. Remodeling occurred in 43 of 66 patients (65%): compensatory enlargement in 27 of 66 (41%) and focal contraction in 16 of 66 (24%). Lesions with focal contraction had significantly smaller arterial area (13.3+/-3.3 vs. 18.1+/-7.0 mm2, p = 0.02) and plaque area (9.5+/-2.8 vs 13.7+/-5.5 mm2, p<0.01). Cross-sectional stenosis was similar (71+/-9% vs. 75+/-10%, p = NS), as was plaque density (p = 0.20), eccentricity, and calcium. Patient age, gender, and lesion location were not related to the form of remodeling. Similarly, history of diabetes, hypercholesterolemia, or hypertension was not predictive. Smoking was the only risk factor associated with focal contraction (p<0.01). Thus, whereas compensatory enlargement appears to be the most common form of coronary artery remodeling, focal contraction occurs more often in smokers.     

Coronary arterial remodeling: From bench to bedside

Coronary arterial remodeling describes changes of vessel size at the site of atherosclerotic lesions. Positive remodeling (expansion) of early lesions maintains lumen size despite plaque accumulation. In contrast, negative remodeling (shrinkage) contributes to luminal stenosis independent of plaque accumulation. Because of these adaptive changes, plaque progression/regression is not closely reflected in luminal size. Histologic studies have demonstrated that the pathophysiologic role of arterial remodeling is more complex than a mere compensatory process. Surprisingly, there is a consistent association between positive arterial remodeling, local inflammatory response, and plaque vulnerability. In vivo tomographic imaging techniques, in particular intravascular ultrasound, and potentially computed tomography and magnetic resonance imaging, allow the observation of remodeling in clinical settings. The integration of basic knowledge about arterial remodeling with clinical observations from in vivo imaging could lead to a better understanding of plaque progression, regression, and vulnerability and may eventually have implications for disease prevention.     

Relation between preintervention remodeling and late arterial responses to coronary angioplasty or atherectomy

We used the serial intravascular ultrasound (IVUS) data from the Serial Ultrasound REstenosis trial to explain why positive remodeling lesions have a higher rate of clinical restenosis after non-stent interventions. Serial IVUS was performed before intervention and immediately and 1 and 6 months after percutaneous transluminal coronary angioplasty (n = 35) or directional coronary atherectomy (n = 26). External elastic membrane, lumen, and plaque + media (external elastic membrane minus lumen) areas were measured at the reference and stenosis. Stenoses were divided into 3 groups: positive remodeling (lesion greater than proximal reference external elastic membrane), intermediate remodeling (lesion external elastic membrane smaller than proximal reference but larger than distal reference), and negative remodeling (lesion equal to or less than distal reference external elastic membrane). The early (postintervention to 1 month) and late (1- to 6-month) changes in lesion external elastic membrane and plaque + media areas were compared. An early increase in plaque + media area was associated with an equal or greater increase in external elastic membrane area in positive (r = 0.78, p < 0.0001), intermediate (r = 0.69, p < 0.0001), and negative (r = 0.59, p = 0.0003) remodeling lesions. A late (1- to 6-month) decrease in external elastic membrane area correlated inversely with the early increase in plaque + media area in positive (r = 0.77, p = 0.0002) and intermediate (r = 0.45, p = 0.0003), but not in negative (r = 0.02, p = 0.9) remodeling lesions. In positive remodeling lesions, the early increase in plaque + media area was associated with both an exaggerated early increase and late decrease in external elastic membrane area. Positive remodeling lesions have an exaggerated early increase in external elastic membrane area and, especially, an exaggerated late decrease in external elastic membrane area after percutaneous transluminal coronary angioplasty and directional coronary atherectomy. This may explain that the increased clinical restenosis after positive remodeling lesions is treated with non-stent interventions.     

Intravascular ultrasound assessment of the association between spatial orientation of ruptured coronary plaques and remodeling morphology of culprit plaques in ST-elevation acute myocardial infarction

The aim of this study was to assess the association between the spatial location of plaque rupture and remodeling pattern of culprit lesions in acute anterior myocardial infarction (MI). Positive remodeling suggests a potential surrogate marker of plaque vulnerability, whereas plaque rupture causes thrombus formation followed by coronary occlusion and MI. Intravascular ultrasound (IVUS) can determine the precise spatial orientation of coronary plaque formation. We studied 52 consecutive patients with acute anterior MI caused by plaque rupture of the culprit lesion as assessed by preintervention IVUS. The plaques were divided into those with and without positive remodeling. We divided the plaques into three categories according to the spatial orientation of plaque rupture site: myocardial (inner curve), epicardial (outer curve), and lateral quadrants (2 intermediate quadrants). Among 52 plaque ruptures in 52 lesions, 27 ruptures were oriented toward the epicardial side (52%), 18 toward the myocardial side (35%), and 7 in the 2 lateral quadrants (13%). Among 35 plaques with positive remodeling, plaque rupture was observed in 21 (52%) on the epicardial side, 12 (34%) on the myocardial side, and 2 (6%) on the lateral side. However, among 17 plaques without positive remodeling, plaque rupture was observed in 6 (35%), 6 (35%), and 5 (30%), respectively (p?=?0.047). Atherosclerotic plaques with positive remodeling showed more frequent plaque rupture on the epicardial side of the coronary vessel wall in anterior MI than those without positive remodeling.     

A novel quantitative method for evaluating diffuse in-stent narrowing at follow-up angiography.

A new quantitative parameter, diffuse index (DI), was proposed to evaluate objectively whether in-stent restenosis is diffuse or focal in nature. A total of 343 patients (346 lesions) with Wiktor-GX, AVE MS-II, or JOMED stents were evaluated at follow-up angiography. According to the QCA-CMS definition, lesion length is derived from the 100% reference diameter function (RDF). By moving the RDF downward, the lesion length, LL(x), at each percentage x of the RDF can be calculated. We have defined the DI by the ratio of this calculated length LL(x) and the total stent length, SL, in other words, DI = [LL(x)/SL]. The percentage plaque area (% PA) was calculated by dividing the plaque area by the sum of the plaque area and luminal area within the stent. An excellent correlation was found between the DI at 88% RDF and the % PA in all three stents (r > 0.88). The individual correlation curves were nearly identical, independent of the type of stent. Furthermore, based on the overall data, the combination of a DI > 0.8 and % PA > 30% correlated with a high incidence of subsequent major adverse cardiac events (13/25 = 52%). From these data, it can be concluded that the diffuse index is a new objective quantitative parameter to describe whether in-stent restenosis is of focal or diffuse nature.     

Vascular remodeling in atherosclerotic coronary arteries is affected by plaque composition

BACKGROUND: Narrowing of lumen in atherosclerotic lesions is determined not solely by accumulation of plaque but also by constrictive or expansive vascular remodeling. Underlying mechanisms and determinants of these bidirectional processes are not known. OBJECTIVES: To elucidate the response of vascular remodeling to progressive atherosclerosis by analyzing its potential association with composition of plaque. METHODS: Seventy patients with 77 de-novo coronary artery lesions underwent intravascular ultrasound imaging before coronary intervention. Target lesions were defined as soft, fibrous/mixed, and calcified plaques. Quantitative measurements of area of lumen (A(L)), total area of vessel (A(TV)) and area of plaque (A(P) = A(TV)-A(L)) were performed at the lesion site and at the proximal and distal reference sites. Remodeling was determined by using a remodeling index [I(R) = (stenosis of A(TV)/mean reference A(TV)) x 100]. RESULTS: Overall vascular remodeling was balanced with a mean remodeling index of 100.2+/-19.3% and a high interlesion range (60.2-152.4%). The remodeling index for soft lesions was significantly higher than those for fibrous/mixed and calcified lesions (110+/-18.8 versus 96.2+/-14.4 and 85.9+/-15.1%, P < 0.01). Calcified lesions exhibited lower remodeling indexes than did uncalcified lesions (85.9+/-15.1 versus 104.6+/-18.4%, P < 0.01). CONCLUSIONS: Processes involved in vascular remodeling are affected by composition of plaque insofar as there is a higher prevalence of constrictive remodeling among calcified plaques and a higher prevalence of expansive remodeling among soft lesions. These findings indicate that constrictive remodeling is a late manifestation in atherogenesis. Future studies are warranted in order to enhance the understanding of progression of atherosclerosis, and of mechanisms of vascular remodeling and their impacts on interventional therapy.     

Art und Ausma? des vaskul?ren Remodelings kritischer Koronarstenosen.?Eine Studie mit intravaskul?rem Ultraschall

The purpose of this study was to assess the dimension of regional vascular remodeling and its influence on lumen narrowing in vivo. Sixty-three patients with 68 coronary lesions were imaged by intravascular ultrasound before transcatheter therapy. Quantitative measurements of lumen area, vessel area, and plaque area were performed at the lesion site and at the proximal and distal reference site. Area stenosis was calculated as plaque area/vessel area. 100. The extent of remodeling was quantified by a remodeling index (RI = stenosis vessel area - mean reference vessel area/mean reference vessel area. 100). Additionally, three different groups of vascular remodeling were defined: 1) positive remodeling = stenosis vessel area > maximal reference vessel area; 2) intermediate remodeling = maximal reference vessel area >/= stenosis vessel area >/= minimal reference vessel area; 3) negative remodeling = stenosis vessel area < minimal reference vessel area. In 57% of lesions stenosis vessel area was not in between the proximal and distal reference area: 29% of lesions (20/68) had positive, 28% (19/68) negative, and 43% (29/68) intermediate remodeling. Overall remodeling index averaged -0.8+/-19.7%. In the negative remodeling group, reduction of vessel area contributed to 40+/-21% of lumen narrowing, in the positive remodeling group, stenosis vessel area was 21+/-12% enlarged (p<0.001). Lesions with negative remodeling exhibit a lesser plaque area, lesions with positive remodeling a larger than other vessels (8.2+/-2.4 mm(2), 13.8+/-3.7 mm(2), 10. 8+/-3.7 mm(2); p <0.001). Distinct vascular remodeling occurred in the majority of atherosclerotic lesions and is a bidirectional process. Overall, the extent and the frequency of positive and negative remodeling was almost balanced. In lesions with negative remodeling the plaque area was significantly lesser than in other lesions.     

冠心病患者冠状动脉重构的影响因素与病变特征

目的研究冠状动脉正性重构的影响因素与病变特征。方法测定124例冠心病患者的C反应蛋白、血脂、血常规、血沉等指标,并行冠状动脉造影,将患者分为有、无冠状动脉正性重构两组,比较两组患者实验室检查、临床表现和冠状动脉病变特点,单因素及多元logistic回归分析冠状动脉正性重构的影响因素。结果存在“罪犯”血管正性重构者占33.1%,不稳定性心绞痛的正性重构率高于稳定性心绞痛(分别43.0%和15.6%,P<0.01)。冠状动脉正性重构者不稳定性心绞痛比例、C反应蛋白水平和白细胞数明显高于无正性重构患者;而两组患者的年龄、性别、吸烟率、血脂、血沉、中性粒细胞及高血压、糖尿病、血脂异常患病率差异无显著性;正性重构者的多支病变、弥漫性病变、偏心病变、管壁不光滑比例及合并狭窄程度明显大于无正性重构者;多元logistic回归分析显示,与正性重构独立相关的因素是C反应蛋白水平和管壁不光滑。结论冠状动脉正性重构主要与炎症有关,并伴随不稳定斑块的继发病理改变。     

Mechanisms of acute gain and late lumen loss after atherectomy in different preintervention arterial remodeling patterns

The main mechanism of restenosis after directional coronary atherectomy (DCA) remains obscure. We investigated mechanisms of restenosis after DCA in different coronary artery remodeling patterns. DCA was performed in 51 de novo lesions. The lesions were evaluated by intravascular ultrasound (IVUS) before, immediately after, and 6 months after the procedure. According to the IVUS findings before DCA, we classified the lesions into the following 3 groups: (1) positive (n = 10), (2) intermediate (n = 25), and (3) negative (n = 16) remodeling. We measured lumen area, vessel area, and plaque area using IVUS before DCA, immediately after DCA, and at follow-up. Lumen area increase after DCA was mainly due to plaque area reduction in the positive and intermediate remodeling groups (90 plus minus 15% and 80 plus minus 25% increase in lumen area, respectively), whereas that in the negative remodeling group was due to both plaque area reduction (57 plus minus 22% increase in lumen area) and vessel area enlargement (43 plus minus 33% increase in lumen area). The plaque area increase correlated strongly with late lumen area loss in the positive and intermediate remodeling groups (r = 0.884, p <0.001; r = 0.626, p <0.001, respectively), but the decrease in vessel area was not correlated with lumen area loss. In contrast, both an increase in plaque area and a decrease in vessel area were correlated with late lumen area loss (r = 0.632, p = 0.009; r = 0.515, p = 0.041) in the negative remodeling group. Coronary artery restenosis after atherectomy was primarily due to an increase in plaque in the positive and/or intermediate remodeling groups. However, in the negative remodeling group, late lumen loss might have been caused by both an increase in plaque and vessel shrinkage.     

Intravascular ultrasonic analysis of atherosclerotic vessel remodeling and plaque distribution of stenotic left anterior descending coronary arterial bifurcation lesions upstream and downstream of the side branch

Bifurcation lesions remain a challenging lesion subset, even in the era of drug-eluting stents. The aim of this study was to investigate the longitudinal remodeling pattern and cross-sectional plaque location of bifurcation lesions. Seventy-four preintervention intravascular ultrasound studies of left anterior descending bifurcation lesions were analyzed, in which the lesion was located proximal (type A, n=32) or distal (type B, n=42) to the side branch. Vessel area and plaque area at the lesion (VAlesion and PAlesion) and at the reference site (VAreference and PAreference) were measured. The remodeling ratio was defined as VAlesion/VAreference, and the vessel compensation ratio was defined as (VAlesion-VAreference)/(PAlesion-PAreference). The geometric center of the lumen at the lesion site was identified, and the lesion site was divided into circumferential equal arcs to compare the cross-sectional distribution of percentage plaque area (100x[PAlesion/VAlesion]) between the 2 groups. The remodeling ratio (1.03+/-0.15 vs 0.94+/-0.14, p=0.01) and the vessel compensation ratio (0.0+/-0.36 vs -0.37+/-0.61, p<0.01) were significantly greater in type A than in type B lesions. The circumferential distribution pattern of percentage plaque area was significantly different between the groups (analysis of variance p<0.005), with greater percentage plaque area for the vessel wall opposite from the side branch in type B lesions (46.3+/-18.0% vs 54.6+/-15.4%, type A vs type B lesions, p<0.05). In conclusion, these results suggest that a major side branch may affect longitudinal lesion remodeling as well as the circumferential location of atherosclerotic plaque.