自制新型血管内超声双腔微导管引导下行慢性完全闭塞病变介入治疗

处理入口不明的慢性完全闭塞病变(CTO)可借助血管内超声,但反复交换微导管和超声导管可能增加操作相关并发症。解放军白求恩国际和平医院自主研发的新型血管内超声双腔微导管,由血管内超声导管以及与其并联为一体的治疗微导管构成,超声导管和工作导丝同步进入病变部位,相当于在血管内超声实时探查下进行直接定位操作,有助于正确把握穿刺方向,为介入医师进行慢性闭塞病变的治疗增添了新工具。在此基础上,本文通过结合1例应用此新型血管内超声双腔微导管成功治疗入口闭塞的CTO病变经验,为读者提供更为直观的认识。     

Comparison of intravascular ultrasound, external ultrasound and digital angiography for evaluation of peripheral artery dimensions and morphology

Validation of catheter-based intravascular ultrasound imaging has been based on comparisons with histology and digital angiography, each of which may have limitations in the assessment of arterial size and morphology. External, high-frequency ultrasound can accurately determine vessel dimensions and morphology and because, like ultravascular ultrasound, it also provides cross-sectional arterial ultrasound images, it may be a more appropriate technique for the in vivo comparison of arterial dimensions and morphology determined by intravascular ultrasound. Thus, intravascular ultrasound, external 2-dimensional ultrasound, Doppler color-flow imaging and digital angiography were compared for assessment of arterial dimensions and wall morphology at 29 femoral artery sites in 15 patients. Intravascular ultrasound and the other 3 imaging modalities correlated well in determination of lumen diameter (2-dimensional, r = 0.98, standard error of the estimate [SEE] = 0.14; Doppler color flow, r = 0.91, SEE = 1.11; angiography, r = 0.95, SEE = 0.91) and cross-sectional area (2-dimensional, r = 0.97, SEE = 0.04; Doppler color flow, r = 0.92, SEE = 0.14; angiography, r = 0.96, SEE = 0.08). However, lumen size measured by Doppler color flow was consistently smaller than that measured by the other 3 imaging modalities. Intravascular ultrasound detected arterial plaque at 15 sites, 5 of which were hypoechoic (soft) and 10 hyperechoic with distal shadowing (hard). Plaque was identified at 12 of 15 sites by Z-dimensional imaging (p = 0.30 vs intravascular ultrasound), but at only 6 of 15 sites by angiography (p = 0.003 vs intravascular ultrasound), only 1 of which was thought to be calcified plaque.(ABSTRACT TRUNCATED AT 250 WORDS)     

In-vitro validation, with histology, of intravascular ultrasound in renal arteries

OBJECTIVE: To investigate the feasibility of using intravascular ultrasound to characterize normal and diseased renal arteries. MATERIALS AND METHODS: Forty-four renal artery specimens from 21 humans, removed at autopsy, were studied with intravascular ultrasound in vitro. From each vascular specimen, two to four sets of corresponding intravascular ultrasound images and histologic sections were subjected to qualitative analysis. The renal arterial wall was considered normal by intravascular ultrasound when the wall thickness (intima and media) was 0.5 mm or less. On intravascular ultrasound imaging, a distinction was made between bright lesions with or without peripheral shadowing (i.e. calcification). Histological sections were examined and fibromuscular lesions were scored with or without calcifications. Quantitative analysis of a multitude of intravascular ultrasound cross-sections (interval 5 mm) included assessment of the lumen area, vessel area, plaque area and percentage area obstructed. The target site (smallest lumen area) was compared with a reference site (largest lumen area before the first major side branch). RESULTS: Of the 130 corresponding intravascular ultrasound images and histologic sections analysed, 55 were normal and 75 presented a bright lesion on ultrasound; in 31 lesions, peripheral shadowing was involved. The sensitivity of the intravascular ultrasound in detecting calcifications was 87%, and the specificity was 89%. Lumen area reduction at the target site was associated with vessel and plaque area enlargement in eight specimens, with plaque area enlargement in 12 specimens and with a vessel area reduction in 21 specimens. CONCLUSIONS: Intravascular ultrasound is a reliable technique for distinguishing renal arteries with or without a lesion. Both plaque development and local vessel narrowing may result in renal artery stenosis.     

血管内影像技术的新进展

近年来血管内影像技术,特别是血管内超声领域的研究进展,主要包括:(1)对易损斑块认识的不断深入和检测率的逐步提高;(2)更有效地指导冠状动脉介入治疗,特别是指导药物洗脱支架的置入和随访。多种新型血管内影像技术日趋成熟,包括虚拟组织学血管内超声、整合背向散射血管内超声、光学相干断层成像术、近红外光谱仪、血管镜及血管内磁共振与传统的灰阶血管内超声一起,推动着血管内影像技术进入崭新的阶段。     

Optimized ultrasound imaging catheters for use in the vascular system

Clinical experience with 6 and 9 Fr ultrasound imaging catheters (UICs) reveals that several transducer and catheter tip varieties are needed for optimum imaging of diseased intravascular sites. Our UIC design has combined established catheter design and very high frequency ultrasound imaging technology to create a versatile, user configured system for intravascular ultrasound imaging. Optimum use requires proper strategic selection of transducer and catheter sizes, frequencies of operation, and interventional accessories.     

In vitro analysis of coronary atheromatous lesions by intravascular ultrasound; reproducibility and histological correlation of lesion morphology.

AIM: To determine the reproducibility and histological correlation of qualitative intravascular ultrasound imaging of atheromatous coronary arteries using the recently proposed European Society of Cardiology classification of plaque composition in conditions approximating the clinical setting. METHODS: Atheromatous lesions (n=21), identified from 30 post-mortem human coronary arteries, were imaged using intravascular ultrasound in a pulsatile flow system which simulates coronary flow. Fifty sites (21 x minimum lumen area and 29 x distal reference sites) were selected independently by two observers from continuous video recordings. Atheromatous plaque was classified as echodense, echolucent, heterogeneous or calcified by each observer and by one observer on separate occasions. Arterial specimens were histologically sectioned at these sites and similarly analysed by a third observer blinded to the intravascular ultrasound appearances. RESULTS: Overall inter- and intra-observer reproducibility for plaque-type (Kappa 0.87[0.80-0.94] and 0.89[0. 85-0.93 respectively]) and focal calcification (0.78[0.74-0.82] and 0.88[0.84-0.92]) was high. Differences in site selection significantly influenced reproducibility particularly at reference sites. Agreement for overall plaque type between intravascular ultrasound and histology occurred in 89% of sites (Kappa 0.73[0.69-0. 77]). Specificity and positive predictive values for individual plaque types were greater than 90%. CONCLUSION: Using modern intravascular ultrasound technology in an in vitro system which approximates the clinical setting the proposed ESC classification of plaque composition by intravascular ultrasound is reproducible and correlates well with histology. It should therefore perform reliably in diagnostic intravascular ultrasound examinations and in the guidance of percutaneous coronary interventions.     

Usefulness of computed tomographic angiography guided percutaneous coronary intervention

The intravascular ultrasound qualities of coronary computed tomographic angiography provide the rationale for a new approach to the selection of patients for percutaneous coronary intervention and to guide the performance of the procedure. Minimum luminal diameter and minimum luminal area derived from computed tomographic angiography are readily measured and are used to triage patients to medical therapy or angiographic evaluation, with subsequent decisions based on the severity of disease and intravascular ultrasound findings. Technical decisions related to percutaneous coronary intervention are guided by lesion length and plaque characteristics. In conclusion, computed tomographic angiography has the requisite intravascular ultrasound characteristics to greatly impact percutaneous coronary intervention.     

Intravascular ultrasound: potential tool to assess coronary anastomosis quality

Coronary angiography and Doppler flow measurements are most commonly used to assess the patency of anastomoses in the operating theater. Intravascular ultrasound might be another means of monitoring the surgical procedure during coronary artery bypass. Five sheep underwent off-pump bypass of the left anterior descending coronary artery using the left internal mammary artery. The running suture was evaluated by intraoperative fluoroscopy and a coronary intravascular ultrasound probe inserted into the target artery proximal to the anastomosis. Macroscopic examination of the anastomosis was performed to validate the angiographic and intravascular ultrasound images. The diameter, cross-sectional area, and compliance of each anastomosis were calculated in systole and diastole. All anastomoses were patent without signs of stenosis. In one case, intravascular ultrasound showed an intimal flap, which was confirmed by macroscopic examination. The mean major anastomotic diameter was 4.5 +/- 0.5 mm on angiography and 4.0 +/- 0.5 mm on intravascular ultrasound. From the ultrasound data, the mean cross-sectional anastomotic area was calculated as 6.21 +/- 0.1 mm(2) in systole and 5.49 +/- 0.1 mm(2) in diastole, and these data were used to calculate the cross-sectional anastomosis compliance. Coronary intravascular ultrasound can visualize intima-to-intima apposition and provide reliable calculations of anastomosis compliance.     

有关血管内超声对易损斑块评估研究的进展

易损斑块（VP）已被广泛认为是引起急性冠状动脉综合征（ACS）和心脏猝死的主要原因。近年来，侵入性或非侵入性血管内超声成像技术已经成为检测VP的主要手段之一。本文就血管内超声对易损斑块评估的优缺点进行以下综述。     

Tissue characterization with intra-arterial ultrasound: Special promise and problems

Although we are able to identify many tissue types based on the screen image in intravascular ultrasound, there is additional information in the ultrasound signal which could be of assistance in characterization and identification of tissue. Intravascular ultrasound has several special characteristics which affect tissue characterization. These include the high transducer frequency, small transducers, short and relatively uniform path to the tissue, and limited tissue types to identify. These characteristics influence the results obtained by absolute backscatter, local statistics, frequency dependent backscatter, and angle dependency of backscatter. These effects are both positive and negative, and in many cases can be observed in clinical imaging. Another area of tissue characterization which can be performed with ultrasound is measurement of arterial wall elasticity. This can be of importance in the evaluation of mechanisms of dilatation, and the potential for complications.     

Interventional applications of intravascular ultrasound imaging: initial experience and future perspectives

Intravascular ultrasound imaging offers the potential to provide more detailed information about vessel and lesion morphology and physiology than is currently available from angiography. The greatest impact of intravascular ultrasound upon clinical decisions may be in the area of cardiac and vascular interventions. To evaluate the utility of intravascular ultrasound, we prospectively studied 45 patients, 11 of whom underwent interventional procedures. Intravascular ultrasound imaging was performed before and after interventions using a 20 MHz, mechanically rotating transducer on either 6.5 Fr or 8.0 Fr catheter systems. Interventions included seven peripheral vessel balloon angioplasties (Femoral artery-two, Renal artery-two, Arteriovenous fistula-two, Aortic coarctation-one), two Femoral artery rotational atherectomies, and two balloon valvuloplasties (Pulmonic valve-1, Mitral valve-1). Intravascular ultrasound and digital angiography provided similar information about vessel size. However, morphological information about the vessel wall, plaque composition, plaque topography, luminal thrombus, and vessel dissections was better appreciated by intravascular ultrasound. Intravascular ultrasound was determined to have provided unique and clinically useful information in 10/11 (91%) interventions. These preliminary data illustrate the potential value of intravascular ultrasound for the evaluation of the vascular system and in particular its value in interventional procedures.     

In-vivo validation of spatially correct three-dimensional reconstruction of human coronary arteries by integrating intravascular ultrasound and biplane angiography

OBJECTIVES: The in-vivo validation of geometrically correct three-dimensional reconstruction of human coronary arteries by integrating intravascular ultrasound and biplane coronary angiography has not been adequately investigated. The purpose of this study was to describe the reconstruction method and investigate its in-vivo feasibility and accuracy. METHODS: In 17 coronary arteries (mean length, 85.7+/-17.1 mm) from nine patients, an intravascular ultrasound procedure along with a biplane coronary angiography was performed. From each angiographic projection, a single end-diastolic frame was selected in order to reconstruct the intravascular ultrasound catheter trajectory in space. In each end-diastolic intravascular ultrasound image, the lumen and media-adventitia contours were detected semi-automatically by an active contour algorithm. Each pair of contours was located on the catheter trajectory appropriately and interpolated with the adjacent pairs creating a three-dimensional volume of the arterial lumen and wall. The reconstructed lumen was back-projected onto both angiographic planes and the agreement between the back-projected and the angiographic luminal outlines was calculated. RESULTS: The angiogram-derived catheter length showed very high correlation (y=0.97 x + 1.8, P<0.001) and agreement with the corresponding pullback-derived values. Accordingly, the semi-automated segmentation of intravascular ultrasound images was also in significant correlation (r> or =0.96, P<0.001) and agreement with the reference manual tracing. The back-projected luminal borders showed good overall association with the corresponding angiographic ones (r=0.78, P<0.001) as well as remarkable agreement. CONCLUSIONS: Spatially correct three-dimensional reconstruction of human coronary arteries constitutes an imaging method with considerably high in-vivo feasibility and accuracy.     

血管内超声的新技术进展

血管内超声在冠心病诊断与治疗中发挥着非常重要的作用。近年来,出现许多血管内超声新技术,极大的丰富了其应用,现着重描述血管内超声的新技术进展。     

Clinical evaluation of acute and chronic pulmonary thromboembolism using intravascular ultrasound and angioscopy

Pulmonary artery thrombi and parietal lesions were observed in 13 patients (mean age 58 +/- 18 years) with acute pulmonary thromboembolism (n = 4) and chronic pulmonary thromboembolism (n = 9) using intravascular ultrasound and angioscopy at the time of right heart catheterization. Patients with acute pulmonary thromboembolism without underlying disease mainly had non-echogenic intraluminal mass, and good pulsatile vessel without intimal thickening. Angioscopy directly showed red thrombi with white fibrin coating, and no parietal lesions. Patients with chronic pulmonary thromboembolism could be classified into 3 groups: 1) Poor extensibility of the vessel wall and intimal thickening with non-echogenic thrombi on intravascular ultrasound, and relatively fresh parietal thrombi consisting of a mixture of red blood cell and fibrin, and spider web-like fibrin net on angioscopy (6 patients). 2) Crescent parietal thrombi and wall irregularity on intravascular ultrasound, and probably organized thrombi with a mixture of red and white surface on angioscopy (one patient). 3) Marked and echogenic intimal thickening and poor extensibility on intravascular ultrasound, and intimal surface irregularities and yellowish changes on angioscopy (one patient). All patients suffering acute deterioration in the chronic phase belonged to groups 1) or 2). Intravascular ultrasound and angioscopy are useful for characterizing the thrombi and related pulmonary artery lesions in patients with pulmonary thromboembolism. The pulmonary artery intima and thrombus differ between acute and chronic pulmonary thromboembolism.     

Catheter-based intravascular ultrasound discriminates bicuspid from tricuspid valves in adults with calcific aortic stenosis

A catheter-based intravascular ultrasound transducer was used to study aortic valve morphology in adults with calcific aortic stenosis. Examination of 14 postmortem specimens disclosed that intravascular ultrasound consistently identified the number of cusps or the presence of a calcified median raphe in the conjoined cusp, or both, and thereby distinguished a calcified bicuspid from a calcified tricuspid aortic valve. These postmortem findings were then employed to identify valvular morphology in 15 patients undergoing diagnostic cardiac catheterization or balloon aortic valvuloplasty, or both. Reproduction of criteria established in vitro allowed discrimination of congenital valvular morphology in all 15 patients, including 7 in whom assessment by intravascular ultrasound was confirmed by subsequent pathologic examination. Identification of aortic valvular morphology by intravascular ultrasound has potential therapeutic implications for patients considered to be candidates for operative or nonoperative aortic valvuloplasty.     

Multivariate predictors of intravascular ultrasound end points after directional coronary atherectomy

Objectives. This study attempted to identify the clinical, angiographic, procedural and intravascular ultrasound predictors of directional atherectomy results assessed by intravascular ultrasound.Background. Several angiographic and intravascular ultrasound variables have been associated with the outcome of directional coronary atherectomy. No study has incorporated both modalities into a predictive model.Methods. One hundred seventy patients were analyzed using preintervention and postintervention intravascular ultrasound and quantitative angiography. Clinical and procedural variables were collected by independent chart review. Quantitative and qualitative angiographic analysis was performed by a core laboratory in blinded manner. Intravascular ultrasound was performed using a transducer-tipped catheter, rotating within a stationary imaging sheath, and withdrawn automatically at 0.5 mm/s. Clinical, procedural, angiographic and ultrasound variables were tested iin a multivariate linear regression model. Dependent ultrasound variables included postatherectomy lumen cross-sectional area and percent cross-sectional narrowing (plaque plus media/external elastic membrane cross-sectional area) and, in a subgroup of 47 patients studied using volumetric analysis, percent plaque volume removal.Results. By multivariate stepwise linear regression analysis, predictors of residual lumen cross-sectional area (correcting for reference lumen area) included arc of calcium and preatherectomy plaque plus media cross-sectional area; predictors of residual cross-sectional narrowing were arc of calcium, preatherectomy plaque plus media cross-sectional area and lesion length; and predictors of percent plaque volume removal were arc of calcium and atherectomy device size.Conclusions. The preintervention lesion arc of calcium measured by intravascular ultrasound is the most consistent predictor of the effectiveness and results of directional coronary atherectomy.     

Diagnostic accuracy of optical coherence tomography and intravascular ultrasound for the detection and characterization of atherosclerotic plaque composition in ex-vivo coronary specimens: a comparison with histology

BACKGROUND: Both intravascular ultrasound and optical coherence tomography have been purported to accurately detect and characterize coronary atherosclerotic plaque composition. The aim of our study was to directly compare the reproducibility and diagnostic accuracy of optical coherence tomography and intravascular ultrasound for the detection and characterization of coronary plaque composition ex vivo as compared with histology. METHODS AND RESULTS: Intravascular ultrasound (20 MHz) and optical coherence tomography imaging was performed in eight heart specimens using motorized pullback. Standard histology using hematoxylin-eosin and van Gieson staining was performed on 4 mum thick slices. Each slice was divided into quadrants and accurately matched cross-sections were analyzed for the presence of fibrous, lipid-rich, and calcified coronary plaque using standard definitions for both intravascular ultrasound and optical coherence tomography and correlated with histology. After exclusion of 145/468 quadrants, we analyzed the remaining 323 quadrants with excellent image quality in each procedure. Optical coherence tomography demonstrated a sensitivity and specificity of 91/88% for normal wall, 64/88% for fibrous plaque, 77/94% for lipid-rich plaque, and 67/97% for calcified plaque as compared with histology. Intravascular ultrasound demonstrated a sensitivity and specificity of 55/79% for normal wall, 63/59% for fibrous plaque, 10/96% for lipid-rich plaque, and 76/98% for calcified plaque. Both intravascular ultrasound and optical coherence tomography demonstrated excellent intraobserver and interobserver agreement (optical coherence tomography: kappa=0.90, kappa=0.82; intravascular ultrasound: kappa=0.87, kappa=0.86). CONCLUSION: Optical coherence tomography is superior to intravascular ultrasound for the detection and characterization of coronary atherosclerotic plaque composition, specifically for the differentiation of noncalcified, lipid-rich, or fibrous plaque.     

Intravascular ultrasound imaging following balloon angioplasty

Despite its long history and reliability, contrast angiography has several inherent limitations. Because it is a two-dimensional projection image of the lumen contour, the wall thickness cannot be measured and the plaque itself is not visualized. This results in an underestimation of the amount of atherosclerotic disease by angiography. An assessment of atherosclerosis could be improved by an imaging modality: (1) that has an inherent larger magnification than angiography and (2) that directly visualizes the plaque. Intravascular ultrasound fulfils these criteria. This presentation will provide evidence that intravascular ultrasound may prove complimentary or even superior to angiography as an imaging modality.Intravascular ultrasound demonstrates excellent representations of lumen and plaque morphology ofin vitro specimens compared with histology. There is very close intraobserver and interobserver variability of measurements made from intravascular ultrasound images. Phantom studies of stenoses in a tube model demonstrate that angiography can misrepresent the severity of stenosis when the lumen contour is irregular and not a typical ellipse, whereas intravascular ultrasound reproduces the cross-sectional morphology more accurately since it images the artery from within.In vitro studies of the atherosclerotic plaque tissue characteristics compare closely with the echo representation of fibrosis, calcification, and lipid material. In addition,in vitro studies of balloon angioplasty demonstrate that intravascular ultrasound accurately represents the changes in the structure of artery segments following balloon dilatation.     

A novel mechanism explaining early lumen loss following balloon angioplasty for the treatment of in-stent restenosis

We performed serial intravascular ultrasound analysis in patients who underwent balloon dilatation for in-stent restenosis. Early lumen loss was detected by intravascular ultrasound and was associated with minimal changes at the edges and at the external elastic membrane. These results on intravascular ultrasound suggest compression and decompression as the main mechanisms for early lumen loss after dilatation of in-stent restenotic lesions.     

Intravascular ultrasound imaging of the coronary arteries: an in vitro evaluation of measurement of area of the lumen and atheroma characterisation.

OBJECTIVE--To assess the accuracy of measurement of area of the lumen, and sensitivity, and specificity of detection of atheroma in coronary arteries in vitro with a commercially available 20 MHz intravascular ultrasound system. SETTING--A teaching hospital department of cardiology with the support of the department of cardiovascular pathology. PROCEDURE--10 segments of coronary artery were removed from cadaver hearts. Intravascular ultrasound imaging was performed at fixed levels and the vessels were then sectioned and photographed before histological preparation. An independent blinded observer measured luminal area and assessed the presence of atheroma on the intravascular ultrasound images of 76 vessel sections (304 quadrants). The sensitivity and specificity of detection of atheroma was assessed in comparison with the histologically prepared sections. Luminal areas from intravascular ultrasound, photographs of cross sections of the vessels and histological sections were compared with the technique of limits of agreement. RESULTS--Overall 36% of the 304 quadrants studied histologically had identifiable atheroma. Intravascular ultrasound sensitivity for atheroma was 0.593 and the specificity was 0.839. The positive predictive value was 0.674, and the relative risk 3.139. Values for area of the vessel lumen were on average 9.4 mm2 (confidence interval (CI) 8.6-10.2 mm2) larger than those measured from photographs and 10.7 (CI 9.8-11.6 mm2) larger than those measured from the histological sections. CONCLUSIONS--The intravascular ultrasound system assessed in this study significantly overestimated coronary vessel luminal area and had low sensitivity and specificity for detection of atheroma. Improvements in image resolution are required before this system can provide useful information on coronary artery size and morphology.