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Vein Diameter (vein + diameter)
Selected AbstractsEffect of intermittent compression of upper arm veins on forearm vessels in patients with end-stage renal diseaseHEMODIALYSIS INTERNATIONAL, Issue 3 2005Rina R. Rus Abstract Native arteriovenous fistula is the best vascular access for chronic hemodialysis. Primary and long-term success depends, in part, on the state of arteries and veins at the time of the operation. The aim of our study was to investigate the effects of intermittent compression of upper arm veins on forearm vessels in patients with terminal renal disease. The study group was composed of 16 chronic hemodialysis patients who performed daily intermittent compression of the upper arm without vascular access by elastic band (Eschmarch). Ten chronic hemodialysis patients were included in the control group, which performed no specific activity. Forearm measurements were obtained at the beginning of the study and 4 and 8 weeks later during the course of intermittent compression of the upper arm veins. The forearm circumference and maximal handgrip strength were measured. The artery measures, including endothelium-dependent vasodilatation and forearm vein variables, were obtained by ultrasonography measurements. The forearm circumference, maximal handgrip strength, and artery variables, including endothelium-dependent vasodilatation, remained unchanged. The basal venous diameters (2.29 ± 0.19 mm at the beginning, 2.46 ± 0.19 mm after 4 weeks, and 2.53 ± 0.18 mm after 8 weeks) were significantly increased in the study group. The distensibility of veins was preserved in the study group. There were no significant changes in the control group. Our study demonstrated that daily intermittent compression of the upper arm veins increases the forearm vein diameter and preserves the distensibility of veins in patients with end-stage renal failure. [source] Risk factors for portal venous thrombosis after splenectomy in patients with cirrhosis and portal hypertensionBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 6 2010N. Kinjo Background: Portal venous thrombosis (PVT) is a potentially fatal complication following splenectomy. Its mechanisms and risk factors are poorly understood, especially in patients with cirrhosis and portal hypertension. This study investigated risk factors for PVT following splenectomy in such patients. Methods: All consecutive patients with cirrhosis who underwent splenectomy in Kyushu University Hospital between 1998 and 2004 were included in this retrospective study. They were divided into two groups based on the presence or absence of postoperative PVT. Preoperative and operative factors were compared, and the relationships between formation of PVT and its independent variables were analysed. In some cases, portal venous flow was measured before and after splenectomy using duplex Doppler ultrasonography. Results: PVT developed after surgery in 17 (24 per cent) of 70 patients studied. Multivariable analysis showed that increased splenic vein diameter and low white cell count were significant independent risk factors for PVT. Portal venous flow after splenectomy was greatly reduced in the PVT group, but not in patients without PVT. Conclusion: Large splenic vein diameter and low white cell count are independent risk factors for PVT after splenectomy in patients with cirrhosis and portal hypertension. Copyright © 2010 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source] Comparison of liver hemodynamics according to doppler ultrasonography in alcoholic patients subtyped by Cloninger classification and non-alcoholic healthy subjectsACTA NEUROPSYCHIATRICA, Issue 1 2006Z. Sumru Cosar Background:, The aim of this study was to search for morphological and hemodynamic changes in hepatic and splanchnic vasculature in alcoholic patients without the signs of hepatic damage and subtyped by Cloninger classification by means of sonography, and compare the subtypes among themselves and with nonalcoholic healthy subjects. Methods:, Thirty alcohol dependent patients and 30 healthy subjects with no alcohol problem or hepatic impairment were included in the study. Patients were subtyped by Cloninger classification and all patients were evaluated by gray-scale and spectral Doppler ultrasound. The diameter of the portal vein, portal venous velocity, peak systolic and end diastolic velocities of hepatic and superior mesenteric arteries were assessed. RI, PI and systolic/diastolic velocity ratios were also calculated. Results:, Portal vein diameter (PV diameter), portal vein cross sectional area (PV area), portal vein velocity (PV PSV), hepatic artery peak systolic velocity (HA PSV), hepatic artery end diastolic velocity (HA EDV), hepatic artery resistive index (HA RI), hepatic artery pulsatility index (HA PI), and systolic/diastolic velocity ratios (HA S/D), superior mesenteric artery peak systolic velocity (SMA PSV), superior mesenteric artery end diastolic velocity (SMA EDV), superior mesenteric artery resistive indices (SMA RI), pulsatility index (SMA PI), and systolic/diastolic velocity rates (SMA S/D) showed no significant difference among the groups (P > 0.01). Although there is no significant difference in PV PSV, HA PSV, SMA PSV, SMA EDV values between the groups, mean values of Type II alcoholics is greater than other groups. Portal vein cross-sectional area was greater in alcoholic patients (Type I, II and III) compared to the control group (P = 0.000). Portal vein velocity, hepatic artery peak systolic and end diastolic velocity, superior mesenteric artery peak systolic and end diastolic velocity were significantly greater in alcoholic patients than in the control group (P < 0.001). No statistical difference was detected between other parameters evaluated. Conclusion:, In alcohol dependent patients, some hemodynamic and morphologic changes occur in hepatic and splanchnic circulation, even before the signs of hepatic damage develop, which can be detected by means of Doppler and gray-scale sonography. But as there is no significant difference between the Doppler ultrasonographic findings among alcoholics subtyped by a Cloninger classification, which is a clinical classification, it suggests that psychiatric classification doesn't show any correlation with biological parameters, and because of this Cloninger classification a psychiatric classification cannot be considered as a characteristic determinative factor in the prognosis of hepatic disorder due to alcohol use. However, higher values of Type II alcoholics can be attributed to the longer alcohol intake of this subtype. [source] Mathematical modeling of 980-nm and 1320-nm endovenous laser treatmentLASERS IN SURGERY AND MEDICINE, Issue 3 2007Serge R. Mordon PhD Abstract Background and Objectives Endovenous laser treatment (ELT) has been proposed as an alternative in the treatment of reflux of the great saphenous vein (GSV) and small saphenous vein (SSV). Numerous studies have since demonstrated that this technique is both safe and efficacious. ELT was presented initially using diode lasers of 810 nm, 940 nm, and 980 nm. Recently, a 1,320-nm Nd:YAG laser was introduced for ELT. This study aims to provide mathematical modeling of ELT in order to compare 980 nm and 1,320 nm laser-induced damage of saphenous veins. Study Design/Materials and Methods The model is based on calculations describing light distribution using the diffusion approximation of the transport theory, the temperature rise using the bioheat equation, and the laser-induced injury using the Arrhenius damage model. The geometry to simulate ELT was based on a 2D model consisting of a cylindrically symmetric blood vessel including a vessel wall and surrounded by an infinite homogenous tissue. The mathematical model was implemented using the Macsyma-Pdease2D software (Macsyma, Inc., Arlington, MA). Calculations were performed so as to determine the damage induced in the intima tunica, the externa tunica and inside the peri-venous tissue for 3 mm and 5 mm vessels (considered after tumescent anesthesia) and different linear endovenous energy densities (LEED) usually reported in the literature. Results Calculations were performed for two different vein diameters: 3 mm and 5 mm and with LEED typically reported in the literature. For 980 nm, LEED: 50 to 160 J/cm (CW mode, 2 mm/second pullback speed, power: 10 W to 32 W) and for 1,320 nm, LEED: 50 to 80 J/cm (pulsed mode, pulse duration 1.2 milliseconds, peak power: 135 W, repetition rate 30 Hz to 50 Hz). Discussion and Conclusion Numerical simulations are in agreement with LEED reported in clinical studies. Mathematical modeling shows clearly that 1,320 nm, with a better absorption by the vessel wall, requires less energy to achieve wall damage. In the 810,1,320-nm range, blood plays only a minor role. Consequently, the classification of these lasers into hemoglobin-specific laser wavelengths (810, 940, 980 nm) and water-specific laser wavelengths (1,320 nm) is inappropriate. In terms of closure rate, 980 nm and 1,320 nm can lead to similar results and, as reported by the literature, to similar side effects. This model should serve as a useful tool to simulate and better understand the mechanism of action of the ELT. Lasers Surg. Med. 39:256,265, 2007. © 2007 Wiley-Liss, Inc. [source] Effect of acute postural variation on diabetic macular oedemaACTA OPHTHALMOLOGICA, Issue 2 2010Martin Vinten Abstract. Purpose:, This study aimed to study the pathophysiology of diabetic macular oedema (DMO) by analysis of concomitant changes in macular volume (MV), mean arterial blood pressure (MABP), intraocular pressure (IOP), and retinal artery and vein diameters in response to acute postural changes in patients with DMO and healthy subjects. Methods:, Thirteen patients with DMO (13 eyes) and five healthy subjects (five eyes) were examined after resting in a chair for 15 mins using optical coherence tomography to measure MV and fundus photography to assess retinal vessel diameters. The patients then lay down for 60 mins, during which they were examined repeatedly before they were reseated and examined again. Intraocular pressure was measured using pulse-air tonometry, arterial blood pressure by sphygomanometry and fluid columns using rulers and a spirit level. Results:, In healthy subjects, retinal artery (p = 0.02) and vein (p = 0.001) diameters decreased when subjects lay down, whereas MV remained stable. In patients with DMO, no orthostatic variation in retinal vessel diameters could be demonstrated, whereas MV had increased by 2.4 ± 0.6% (mean ± standard error of the mean; p = 0.006) 50 mins after assuming a recumbent position. In both healthy subjects and DMO patients, MABP decreased and IOP increased in a recumbent position, with no significant difference between the groups. Conclusions: The increase in MV that occurs in DMO when changing from a seated to a recumbent position is associated with a failure of retinal artery contraction, a response seen in healthy subjects that appears to counter-regulate the increase in ocular perfusion pressure caused by assuming a recumbent position. [source] | ||||||||||