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  • 1
    ISSN: 1573-7241
    Keywords: intravascular ultrasound ; atherosclerosis ; progression/regression ; statin ; peripheral arteries
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The purpose of this study was to compare the vascular response seen with intravascular ultrasound (IVUS) at 1-year follow-up between statin-treated and non–statin-treated patients. Patients (n=10) undergoing percutaneous transluminal angioplasty (PTA) of the femoropopliteal artery were studied with IVUS immediately after PTA and at 1-year follow-up. In nondilated matched vascular segments, the change in lumen, vessel, and plaque volume was assessed. In balloon-dilated matched vascular segments, the change in lumen, vessel, and plaque area was assessed. A comparison was made between statin-treated (n=5) and non–statin-treated patients (n=5) in lumen, vessel, and plaque changes. At follow-up, both statin-treated and non–statin-treated patients showed a similar increase in plaque volume at the nondilated segment (+4% and +2%, respectively). In statin-treated patients the plaque volume increase was compensated by an increase in vessel volume (+2%), resulting in an increase in lumen volume (+1%). In non–statin-treated patients, on the other hand, the increase in plaque volume was associated with a decrease in vessel volume (−2%), resulting in a decrease in lumen volume (−4%). At the balloon-dilated segment a similar trend in changes of lumen, vessel, and plaque was encountered. Differences between both groups of patients were not statistically significant. Despite the nonsignificant nature of the observation, this small retrospective IVUS study may generate the hypothesis that statin therapy may contribute to superior long-term lumen dimensions by inducing positive vascular remodeling both in nondilated and balloon-dilated vascular segments.
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  • 2
    ISSN: 1615-5947
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: n = 2); a true aneurysm of the popliteal artery (n= 4); an aneurysmal dilatation of a Biograft bypass (n= 2); a false aneurysm of the superficial femoral aneurysm (n= 1); and a false aneurysm of a composite bypass (n= 1). In 8 of the 10 patients the stent-graft was composed of one or more Palmaz stents sutured to an ePTFE tube graft; in the other 2 patients a venous covering was used in combination with Palmaz stents. The procedure was guided by angiography and intravascular ultrasound. The results of our investigation showed that endovascular stent-grafting of aneurysms of the femoropopliteal artery is a feasible but experimental technique that should be restricted to a selected group of patients.
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  • 3
    ISSN: 1573-0743
    Keywords: polymer ; PETP ; stent ; angiography ; intravascular ultrasound ; morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A polyethylene-terephthalate (PETP, polyester), self-expanding, braided mesh stent has been developed for percutaneous (coronary) arterial implantation.In vitro measurements showed that the radial pressure delivered by this device was similar to a self-expanding, stainless steel stent. Due to hysteresis-like behaviour, it proved necessary to mount the polymer stent on the delivery system immediately before the placement procedure, and to select a diameter in the unconstrained condition, which was 60% larger than the diameter of the target vessel. Eight polyester stents were implanted in peripheral arteries of four pigs. Except for heparin during the implantation procedure, antithrombotic or antiplatelet drugs were not administered. After four weeks repeat angiography revealed that one of the stents was subtotally occluded. At autopsy, two other stents proved to be located in the aortic bifurcation, probably due to failure of the delivery system. Quantitative angiographic assessment showed that the mean luminal diameters at the site of stent placement were 3.3±0.2 mm before, 3.2±0.2 mm immediately after, and 2.7±0.5 mm at four weeks after implantation. Intravascular ultrasound (IVUS) examination after 4 weeks could identify the individual struts of the stents, as well as their length. In addition, a description of the extent of neointimal hyperplasia was feasible. The IVUS assessment was validated by histological examination. In conclusion, polyester stents can be constructed with mechanical properties similar to stainless steel stents. After implantation in porcine peripheral arteries, five of six correctly placed stents were patent at four weeks. Imaging of stents by angiography and IVUS provided complementary information.
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  • 4
    ISSN: 1573-0743
    Keywords: oesophageal echocardiography ; color Doppler ; infective endocarditis ; thoracic aorta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The diagnostic value of oesophageal echocardiography is most striking in patients in whom precordial studies are of inadequate quality or fail to establish a definitive diagnosis. Oesophageal studies have excellent image quality, can be completed within 10 minutes without complications and, in most instances, enables the clinical question to be answered. In 50 patients referred for suspected thoracic aorta pathology, oesophageal echocardiography correctly excluded or diagnosed the type of aortic dissection, aortic aneurysm or the site of coarctation. Of 35 patients referred with suspected infective endocarditis, oesophageal echocardiography revealed complications in 18 patients, including vegetation, mycotic aneurysm, abscess or chordal rupture. Oesophageal echocardiography is extremely helpful to visualize intracardiac mass lesions. In 27 patients with a history of systemic or pulmonary embolism, the technique confirmed the presence, size and position of a mass lesion in 11 patients. Oesophageal color Doppler flow imaging further expands the diagnostic capabilities, particularly in patients with mitral valve prosthesis. Our experience indicates that oesophageal echocardiography significantly extends the diagnostic potential of echocardiography. Detailed knowledge of cardiothoracic anatomy and its pathologic sequelae is, however, a prerequisite for the efficient and safe application of this method.
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  • 5
    ISSN: 1432-086X
    Keywords: Key words: Iliac artery—Balloon angioplasty—Histology—Intravascular ultrasound
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Purpose: Intravascular ultrasound (IVUS) was used to assess in vitro the morphologic and quantitative effects of balloon angioplasty (PTA) of the iliac artery. Methods: Forty human iliac arteries (≥ 30% area stenosis) were studied with IVUS in vitro before and after PTA and the findings were validated with histology. Results: The sensitivity of IVUS for dissection was 74% and for media rupture 59%. The incidence of vascular damage was higher when the whole segment was analyzed rather than the target site alone. Dissections occurred at the thinnest region of the plaque, unrelated to plaque calcification. Following PTA, quantitative changes at the target site were greater compared with the overall data derived from all cross-sections. The increase in lumen area was caused solely by an increase in vessel area. Conclusions: IVUS is sensitive in detecting dissections, which occurred irrespective of calcification at the thinnest region of the plaque. The increase in lumen area after PTA was caused by stretching of the vessel.
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  • 6
    ISSN: 1432-1971
    Keywords: Ebstein's anomaly ; Echocardiography ; Overriding tricuspid valve ; Ventricular septal defect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The M-mode echocardiographic diagnosis of overriding tricuspid valve rests on the ability to demonstrate simultaneously two atrioventricular valves with no intervening septal echo [6, 13]. When scanning inferiorly toward the body of the ventricles, a distinct septal echo at the level of the midportion of the tricuspid valve can be detected. Here we report a case of Ebstein's anomaly, pulmonary stenosis, and ventricular septal defect (VSD), in which the echogram falsely indicated an overriding tricuspid valve.
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  • 7
    ISSN: 1432-1971
    Keywords: Two-chambered right ventricle ; Unguarded tricuspid orifice ; Ebstein's anomaly
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Catheterization and anatomical data are presented of an infant with cyanosis due to a most unusual variant of unguarded tricuspid valve orifice in association with a two-chambered right ventricle. The inlet portion of the right ventricle ended blindly and was completely separated from the outlet portion by a muscular wall. The outlet chamber, which supported the pulmonary trunk, received its blood from the left ventricle through an outlet foramen. The condition is considered to be related to imperforate Ebstein's anomaly.
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  • 8
    ISSN: 1432-086X
    Keywords: Key words: Atherectomy—Intravascular ultrasound—Arteriosclerosis—Arteries, extremities—Femoral artery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Purpose: To evaluate the role of intravascular ultrasound (IVUS) before and after directional atherectomy (DA) in the treatment of femoropopliteal artery stenosis. Methods: In 12 patients with 16 stenoses IVUS was performed before and immediately after an angiographically successful DA. This was defined as a diameter reduction (DR) ≤ 50%, which was calculated using the minimal lumen diameter compared with the diameter of a nearby ``normal'' segment. In the presence of residual plaque on IVUS an additional DA was performed. Endpoints studied were DR ≤ 30% on IVUS compared with the IVUS findings of the angiographically normal reference segment, or when no additional atherosclerotic material could be removed by further DA passages. Results: Additional DA (mean 1.6 per lesion) had to be performed in all patients. Initial DA increased the cross-sectional free lumen area (FLA) from 3.8 ± 2.0 mm2 to 8.1 ± 2.7 mm2 (p= 0.0004). Additional DA increased FLA to 9.3 ± 2.3 mm2 (p= 0.002) after the second passage and to 9.8 ± 2.4 mm2 (p= 0.09) after the final DA run. The plaque area (PLA) before DA decreased from 18.1 ± 4.2 mm2 to 15.4 ± 4.8 mm2 (p= 0.002) after the first passage, and to 13.5 ± 5.0 mm2 (p= 0.004) and 12.8 ± 4.4 mm2 (p= 0.07) after the second and final DA runs, respectively. PLA of the reference segment (9.5 ± 5.7 mm2) was significantly smaller (p= 0.006) than the final PLA of the treated lesion, indicating a large amount of retained plaque. As a result of DA there was an increase in the area bordered by the medial layer, i.e., the total vessel area (from 21.9 ± 4.7 mm2 to 23.0 ± 4.7 mm2), significantly in eccentric and soft lesions. On IVUS, dissection and plaque rupture after the final passage was seen in 12 of 16 stenoses; two dissections were seen on the completion angiogram. After the final passage in all stenoses except three, the DR with IVUS was ≤ 30%. Conclusion: Lumen enlargement following DA is predominantly due to plaque excision. Vessel expansion combined with plaque excision varies in different stenoses and is an important factor in eccentric and soft lesions. Despite additional DA considerable plaque remains.
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  • 9
    ISSN: 1432-086X
    Keywords: Key words: Angiography—Intravascular ultrasound—Femoropoliteal artery—Balloon angioplasty
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Purpose: To compare angiographic and intravascular ultrasound (IVUS) data before and after balloon angioplasty (PTA) of the femoropopliteal artery. Methods: Qualitative and quantitative analyses were performed on corresponding angiographic and IVUS levels obtained from 135 patients. Results: IVUS detected more lesions, calcified lesions, and vascular damage than angiography. Sensitivity of angiography was good for the presence of a lesion (84%), moderate for eccentric lesions (53%) and for vascular damage (52%), and poor for calcified lesions (30%). The increase in angiographic diameter stenosis was associated with a decrease in lumen area and increase in percentage area stenosis on IVUS. Conclusions: Angiography is less sensitive than IVUS for detecting lesion eccentricity, calcified lesions, and vascular damage. Presence of a lesion and amount of plaque were underestimated angiographically. Only before PTA was good agreement found between angiographic diameter stenosis and lumen size on IVUS.
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  • 10
    ISSN: 1540-8183
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: An intravascular ultrasonic imaging device (40 MHz) was used to obtain in vitro ultrasonic images and matching histologic cross-sections, derived from human vascular specimens. The feasibility of assessing vessel wall morphology as well as the ability to accurately document plaque thickness was determined. Based on the echogenicity of the arterial media, intravascular ultrasound could distinguish muscular arteries from elastic arteries, veins, and bypass grafts. The hypoechoic media only present in the muscular type of artery proved to be an essential landmark to document superimposed atherosclerosis. Plaque thickness calculated in these arteries showed close relationship with the corresponding histologic cross-section. Using real-time in vivo intravascular imaging (30 MHz), the morphology of the vessels interrogated was studied. The dynamic change of the arterial wall, as well as the outcome after intervention, is discussed.
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