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Artery Proximal (artery + proximal)

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Medical Sciences	100%

Selected Abstracts

Diagnostic criteria for locating acquired arteriovenous fistulas with color doppler sonography

JOURNAL OF CLINICAL ULTRASOUND, Issue 6 2002
Jian-Chu Li MD
Abstract Purpose. The purpose of this prospective study was to evaluate and determine criteria for locating acquired arteriovenous fistulas using color Doppler sonography. Methods. We performed color Doppler sonography on 12 consecutive patients with acquired arteriovenous fistulas. We evaluated the morphologic and hemodynamic changes in the involved vessels to help locate the fistulas (10 in the extremities, 1 in the neck, and 1 in the abdomen). Results. In all cases, turbulent high-velocity flow spectrum and flow signals were present at the fistula sites, and arterialized waveforms from the draining veins were detected. In the 10 cases of acquired arteriovenous fistulas in the extremities, the resistance indices in the arteries proximal to the fistulas were all less than 1.00 (mean, 0.65), whereas the resistance indices in the arteries distal to the fistulas were all 1.00 or greater (mean, 1.17). In 70% of the cases, the diameter of the artery proximal to the fistula was at least 1.2 mm larger than that distal to the fistula. The fistula site was inferred by the point of maximal venous dilatation in 70% of the cases and by the focal perivascular color artifact in 82% of the cases. The fistula site was identified on gray-scale sonography and color flow imaging in 33% and 75% of the cases, respectively. Conclusions. Fistula sites can be located effectively and quickly by a combination of major and minor diagnostic criteria. The major diagnostic criteria are (1) junction of low- and high-resistance flow in the supplying artery, (2) a high-velocity arterialized waveform in the draining vein, and (3) a turbulent, high-velocity flow spectrum at the junction of the artery and the vein. The minor diagnostic criteria are (1) direct communication between the involved artery and vein, (2) significant change in the diameter of the supplying artery, (3) a focal point of venous dilatation, and (4) a focal perivascular color artifact. © 2002 Wiley Periodicals, Inc. J Clin Ultrasound 30:336,342, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/jcu.10084 [source]

Arteriographic evaluation of vascular changes of the extremities in patients with systemic sclerosis

BRITISH JOURNAL OF DERMATOLOGY, Issue 6 2006
M. Hasegawa
Summary Background, Although digital ulcerations frequently occur in patients with systemic sclerosis (SSc), there have been few reports on the macrovascular involvement. Objectives, To evaluate the macrovascular involvement in patients with SSc exhibiting digital ulceration or gangrene. Methods, Transfemoral catheter arteriography of the upper and/or lower extremities was performed in eight patients (one man and seven women, age range 42,71 years) with SSc exhibiting digital ulceration or gangrene. The background of the patients, such as autoantibody profiles and vascular risk factors including smoking habits, was also investigated. Results, Macrovascular involvement was detected in seven of eight patients. In three of seven patients who underwent arteriography of the upper extremity, occlusion was limited to the digital arteries. Obliteration of the ulnar artery and superficial palmar arch was detected in three of seven patients, and the radial artery in one patient. Only one of five patients who underwent arteriography of the lower extremity showed the occlusion limited to digital arteries of the foot. Occlusion of the posterior tibial artery, dorsalis pedis artery and arcuate artery was detected, each in one patient. Two patients showed occlusion of the plantar arch. Overall, the occlusion of arteries proximal to the digits was demonstrated in four of eight patients. Three of the four patients were positive for antitopoisomerase-1 antibody and had diffuse cutaneous SSc (dcSSc) with multiple skin ulcers or gangrene. Conclusions, Macrovascular involvement as detected with arteriography is not rare in SSc patients with digital ulceration or gangrene. Moreover, the vascular occlusion proximal to the digits seemed to be frequent in antitopoisomerase-1 antibody-positive dcSSc patients with multiple skin ulcers or gangrene. [source]

Diagnostic criteria for locating acquired arteriovenous fistulas with color doppler sonography

Magnetic resonance angiography of collateral vessels in a murine femoral artery ligation model

NMR IN BIOMEDICINE, Issue 1 2004
Shawn Wagner
Abstract The in vivo detection of growing collateral vessels following arterial occlusion is difficult in small animals. We have addressed the feasibility of performing high resolution time-of-flight angiograms to monitor the growth of collateral vessels after femoral artery occlusion in mice. We will also present a low-pass quadrature birdcage coil construction with a sufficient signal-to-noise ratio to produce high resolution. After a 4-month recovery period a C57BL/6 mouse with a surgical occlusion of the right femoral artery was used to assess the image quality and time requirements to produce magnetic resonance angiograms sufficient to assess collateral artery development using a two-dimensional gradient echo sequence. At a resolution of 100,×,100,×,100,,m and a matrix size of 256,×,128,×,256 for a 2.56,cm isometric volume, three scans were performed with one, two and four repetitions resulting in signal-to-noise ratios for the femoral artery proximal to the ligation site of 58, 126 and 194, respectively. Five C57BL/6 mice were additionally measured 4 weeks after occlusion using two repetitions and the visual collateral vessels were assessed for number and location: 2.0,±,1.2 in quadriceps muscle, 0.6,±,0.5 in adductor (deep adductor vessel), 0.0,±,0.0 in adductor (surface adductor vessels). The results showed a significant difference, two-sided t -test, p,<,0.05, in number of vessels in all the locations. We have shown that this method can be utilized to elucidate the contribution of collateral vessels to arterial flow. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Electrophysiological effects of endothelin-1 and their relationship to contraction in rat renal arterial smooth muscle

BRITISH JOURNAL OF PHARMACOLOGY, Issue 4 2000
Luisa C Betts
The electophysiological effects of endothelin-1 (ET-1) and their relationship to contraction remain unclear in the renal circulation. Using endotheliumdenuded arteries from the main branch of the renal artery proximal to the kidney of the rat, we have examined its effects on tension and conducted parallel patch-clamp measurements using freshly isolated smooth muscle cells from this tissue. Pharmacological experiments revealed that ET-1 produced constriction of renal arteries dependent on the influx of extracellular Ca2+, mediated solely through ETA receptor stimulation. Current-clamp experiments revealed that renal arterial myocytes had a resting membrane potential of ,32 mV, with the majority of cells exhibiting spontaneous transient hyperpolarizations (STHPs). Application of ET-1 produced depolarization and in those cells exhibiting STHPs, either caused their inhibition or made them occur regularly. Under voltage-clamp conditions cells were observed to exhibit spontaneous transient outward currents (STOCs) inhibited by iberiotoxin. Application of voltage-ramps revealed an outward current activated at ,,30 mV, sensitive to both 4-AP and TEA. Taken together these results suggest that renal arterial myocytes possess both delayed rectifying K+ (KV) and Ca2+ -activated K+ (BKCa) channels. Under voltage-clamp, ET-1 attenuated the outward current and reduced the magnitude and incidence of STOCs: effects mediated solely as a consequence of ETA receptor stimulation. Thus, in conclusion, activation of ETA receptors by ET-1 causes inhibition of KV and BKCa channel activity, which could promote and/or maintain membrane depolarization. This effect is likely to favour L-type Ca2+ channel activity providing an influx pathway for extracellular Ca2+ essential for contraction. British Journal of Pharmacology (2000) 130, 787,796; doi:10.1038/sj.bjp.0703377 [source]