Biomedical subjects

N Labropoulos

Publications and source records attributed to N Labropoulos.

At least 19 recordsLinked to original sources

PubMed2006

Compression with or without early ambulation in the prevention of post-thrombotic syndrome: a systematic review.

INTRODUCTION: The aim of this study was to assess whether there is enough evidence to suggest that compression with or without early ambulation after proximal DVT reduces the risk of post-thrombotic syndrome (PTS). METHODS: Systematic review based on electronic and hand searching of the relevant literature. RESULTS: Four randomized studies were identified and despite the fact that there was lack of uniformity in reporting standards all but one showed significant risk reduction of PTS using compression. No difference in recurrent thromboembolic events (DVT or pulmonary embolism) was observed between the compression and control group. In one study the early outcome from the combination of early ambulation with compression was faster reduction of swelling with better well-being without increased risk of PE compared to the control group. Pooled analysis of all studies showed that PTS developed in 24% (61/254) in the compression group and in 46% (110/239) in the control group (chi2=25.36, p=0.0001; OR: 0.37, 95%CI: 0.25, 0.54; RR: 0.52, 95%CI: 0.40, 0.67; and RRR: 0.48, 95%CI: 0.33, 0.60) with a 48% risk reduction from the use of compression. CONCLUSION: Despite the fact that compression with or without early ambulation appears to be safe and it is more often associated with a decreased rate of PTS, the four existing studies do not permit meaningful data comparison due to lack of uniformity in reporting standards.

Bandages↗

PubMed2005

Duplex ultrasound investigation of the veins in chronic venous disease of the lower limbs--UIP consensus document. Part I. Basic principles.

OBJECTIVES: Duplex ultrasound investigation has become the reference standard in assessing the morphology and haemodynamics of the lower limb veins. The project described in this paper was an initiative of the Union Internationale de Phlébologie (UIP). The aim was to obtain a consensus of international experts on the methodology to be used for assessment of veins in the lower limb by ultrasound imaging. DESIGN: Consensus conference leading to a consensus document. METHODS: The authors invited a group of experts from a wide range of countries to participate in this project. Electronic submissions from the experts were made available to all participants via the UIP website. The authors prepared a draft document for discussion at a UIP Chapter meeting held in San Diego, USA in August 2003. Following this meeting a revised manuscript was circulated to all participants and further comments were received by the authors and included in subsequent versions of the manuscript. Eventually all participants agreed the final version of the paper. RESULTS: The experts have made detailed recommendations concerning the methods to be used for duplex ultrasound examination as well as the interpretation of images and measurements obtained. This document suggests a methodology for complete assessment of the superficial and perforating veins of the lower limbs, including recommendations on reporting results and training of personnel involved in these investigations. CONCLUSIONS: The authors and a large group of experts have agreed a methodology for the investigation of the lower limbs venous system by duplex ultrasonographpy.

Chronic Disease↗

PubMed2005

Duplex ultrasound investigation of the veins in chronic venous disease of the lower limbs--UIP consensus document. Part II. Anatomy.

OBJECTIVES: Duplex ultrasound investigation has become the reference standard in assessing the morphology and haemodynamics of the lower limb veins. The project described in this paper was an initiative of the Union Internationale de Phlébologie (UIP), The aim was to obtain a consensus of international experts on the methodology to be used for assessment of anatomy of superficial and perforating veins in the lower limb by ultrasound imaging. DESIGN: Consensus conference leading to a consensus document. METHODS: The authors performed a systematic review of the published literature on duplex anatomy of the superficial and perforating veins of the lower limbs; afterwards they invited a group of experts from a wide range of countries to participate in this project. Electronic submissions from the authors and the experts (text and images) were made available to all participants via the UIP website. The authors prepared a draft document for discussion at the UIP Chapter meeting held in San Diego, USA in August 2003. Following this meeting a revised manuscript was circulated to all participants and further comments were received by the authors and included in subsequent versions of the manuscript. Eventually, all participants agreed the final version of the paper. RESULTS: The experts have made detailed recommendations concerning the methods to be used for duplex ultrasound examination as well as the interpretation of images and measurements obtained. This document provides a detailed methodology for complete ultrasound assessment of the anatomy of the superficial and perforating veins in the lower limbs. CONCLUSIONS: The authors and a large group of experts have agreed a methodology for the investigation of the lower limbs venous system by duplex ultrasonography, with specific reference to the anatomy of the main superficial veins and perforators of the lower limbs in healthy and varicose subjects.

Chronic Disease↗

PubMed2005

Clinical significance of ostial great saphenous vein reflux.

PURPOSE: To evaluate anatomical and haemodynamic differences in patients with great saphenous vein (GSV) insufficiency by duplex scanning and air plethysmography. MATERIAL AND METHODS: Duplex scanning and air plethysmography examination were undertaken. One hundred and twenty-one limbs in 91 patients were selected prospectively and divided into three groups: group A consisted of 27 controls; group B consisted of 25 limbs with GSV reflux and normal saphenous femoral junction (SFJ) and group C consisted of 69 limbs of patients with GSV and SFJ reflux. The presence of reflux and GSV diameter (SFJ, proximal and medial thirds of the thigh, the knee and medial and distal thirds of the calf) were assessed by duplex scanning. Air plethysmography was used to evaluate haemodynamic parameters: total venous volume (VV), venous filling index (VFI), residual volume fraction (RVF) and ejection fraction (EF). RESULTS: There was a significant difference in GSV diameter among the three groups in almost all segments evaluated (e.g. medial thigh group A = 2.4 SD 0.3 mm; B = 3.2 SD 0.7 mm; C = 5.9 SD 2.2mm p<0.001, Anova). A significant difference in VFI was found among the groups (group A = 1.2 SD 0.5; B = 2.0 SD 1.4; C = 4.0 SD 2.5 p<0.05, Anova). VV was statistical different between groups A and C (p = 0.004) and B and C(p = 0.03). EF and RVF were comparable in all groups. The VFI was normal in 68% in group B comparing with only 14.5% in group C patients, finding a reflux more than 5ml/s (determined by VFI) in 26.1% of the group C patients, comparing with only 4% of group B patients (p<0.05). CONCLUSION: We have shown that in patients with GSV reflux those with incompetence of the ostial valve of the GSV show greater venous reflux and dilatation of the saphenous trunk than those in whom the ostial valve is competent.

Adult↗

PubMed2005

Neovascularization after great saphenous vein ablation.

OBJECTIVE: To determine the prevalence, distribution, and flow characteristics of intraluminal neovascularization in patients undergoing great saphenous vein (GSV) endovenous laser (EVLT) or radiofrequency ablation (RFA). METHODS: Duplex ultrasound (DU) was performed in patients undergoing EVLT or RFA before, during, and after their procedures. Follow-up included assessment for deep venous thrombosis and obliteration. When new vessels were identified, the source, extent, direction, and location of flow were noted. Flow channel diameters were measured and the resistivity index (RI) was used to characterize the flow patterns. RESULTS: A total of 102 venous ablations were performed of which 46 were RFA, and 56 EVLT. Arterio-venous fistulae (AVF) were found in five patients that were not identified by DU prior to intervention. Involved segments had variable length and multiple channels (mean diameter 2.2mm). No patient had local or systemic symptoms related to the AVF. The mean RI was 0.42, consistent with an AVF. The perivenous arteries feeding the AVF had enhanced flow but a significantly higher RI (0.63, p<0.001). CONCLUSION: Multiple small vessels were found directly adjacent to the involved vein segments forming small AVF within the obliterated vein. The prevalence of AVF in the ablated GSV was 5%. This process may be responsible for recanalization or recurrence after endovenous ablation procedures.

Adult↗

PubMed2005

Are your arteries older than your age?

PURPOSE: To determine the effect of age and atherosclerotic risk factors on the carotid intima-media layer thickness and morphology characteristics. PATIENTS AND METHODS: Three groups of subjects were included in the study: Individuals with atherosclerotic risk factors including a family history of CHD, hypertension, hyperlipidemia, diabetes, and/or smoking (group A, n=180), age- and sex-matched healthy subjects without risk factors (group B, n=60) and a group of significantly younger volunteers (group C, n=25). The carotid artery was imaged longitudinally with B-mode ultrasound. Intima media thickness (IMT) was measured in the common (CCA) and internal carotid (ICA) arteries. Surface irregularity and continuity of the intima-media layer (IML) were assessed by high definition imaging. Echogenicity of the wall was quantified using Adobe Photoshop. The presence of calcium deposits was recorded. The double line wall pattern seen in young healthy people was used as a control to assess patterns and texture of the carotid IML. Fifteen subjects had their measurements repeated for intraobserver variability. RESULTS: IMT measurements were reproducible in both the CCA and ICA (coefficient of variation 6% and 9%). IMT increased linearly with age (adjusted R(2)=0.72, p<0.0001), which was also an independent risk factor for increased IMT. All the risk factors had a significant association with increased IMT. In the lowest (third) decade the wall/blood interface was smooth and the double line was visualized with an echolucent center. With increased age and number of risk factors present, the wall/blood interface became more irregular (p<0.01), the double line was distorted (p<0.01) and the IML was more echogenic (p<0.01). The increase in IMT and the changes in the echogenicity of the IML were more pronounced in the ICA. CONCLUSIONS: Age is an independent risk factor for increased IMT. Atherosclerotic risk factors are associated with the age-related changes seen in the IML. Such changes are also seen in younger asymptomatic volunteers with risk factors indicating that their arteries are older than their age.

Adult↗

PubMed2005

Clinical significance of superficial vein thrombosis.

OBJECTIVE: To evaluate the clinical implications of superficial thrombophlebitis (STP) including its demographic characteristics, distribution, risk factors, relationship with deep vein thrombosis (DVT), pulmonary embolism (PE), diagnosis and management. METHODS: Data were collected from relevant papers using a MEDLINE search and an extensive bibliography review. Studies were considered only when they contained pertinent material to STP. Thirty-seven papers were analysed. RESULTS: The diversity of patients and methods used in the different studies made the comparison among them difficult. STP is a common condition with an underestimated prevalence. There are many risk factors associated with STP but the strongest relation was seen with hypercoagulable states. Malignancy may be another important factor but the strength of this association remains unknown. Coexistence with DVT was found in 6-53%. PE occurred in 0-33.3%. Propagation to DVT ranged from 2.6 to 15%. Treatment has not been standardised and may include elastic compression, anti-inflammatory drugs, anticoagulation and surgery. CONCLUSION: The limited number of prospective randomised studies on STP does not allow strong recommendations to be given. Although STP most often is perceived as benign, it can coexist with or progress to DVT, and even give rise to PE. It is also associated with hypercoagulability and malignancy.

Humans↗

PubMed2005

Management of the near total internal carotid artery occlusion.

OBJECTIVES: The risk of stroke in patients with near total internal carotid artery (ICA) occlusion is perceived to be high as stroke risk increases with severity of the stenosis. The management of this entity has not been addressed specifically in the existing randomised trials and thus it remains controversial. METHODS: Systematic review of the relevant literature. RESULTS: The management of patients with near total ICA occlusion remains controversial: some favour intervention whereas others have condemned it as dangerous or of no benefit. A prospective multicentre randomised trial regarding intervention versus best medical treatment for patients with symptomatic near total ICA occlusion seems difficult because of the large number of patients required to power the study. Nevertheless, it appears hard to decline surgery based on the current evidence. CONCLUSIONS: Because of the current controversy over the best management of the near total ICA occlusion, prospective observational studies are needed to demonstrate its prevalence in the symptomatic and asymptomatic population and any associated excess stroke risk. Based on the current evidence, surgery is the treatment of choice in most centres but its validity over best medical treatment remains untested.

Carotid Artery, Internal↗

PubMed2004

New insights into the development of popliteal cysts.

BACKGROUND: This prospective study was designed to investigate the aetiology of popliteal (Baker's) cysts. METHODS: Some 426 legs in 312 individuals were investigated with ultrasonography for the presence of a popliteal cyst. Participants included healthy volunteers, patients with a painful knee, and a group of patients with signs and symptoms of deep vein thrombosis (DVT). The location, thickness and content of all cysts were recorded. In addition, the popliteal fossa was dissected in four cadaver knees. RESULTS: The prevalence of popliteal cyst increased with age and was significantly higher in those aged over 50 years (P < 0.001). Compared with controls (incidence 3.0 per cent), cysts were more common in patients with DVT symptoms (9.5 per cent; P = 0.141) and those with painful knees (19.8 per cent; P < 0.001). All cysts were located in the posteromedial aspect of the popliteal fossa; the majority extended between the deep fascia and the medial head of the gastrocnemius muscle. At this level an area without external support of the posterior capsule was identified between the two expansions of the semimembranosus muscle from the medial side (the oblique popliteal ligament and the expansion over the popliteus muscle) and the posterior cruciate ligament from the lateral side. This area was also located in the knee dissections. No association was found between popliteal cyst and acute DVT. CONCLUSION: Popliteal cysts are relatively common in patients over 50 years old with a painful knee or with signs and symptoms of DVT. They form in the posteromedial popliteal fossa because the synovial capsule does not provide anatomical support in this region.

Adolescent↗

PubMed2004

Sapheno-femoral junction reflux in patients with a normal saphenous trunk.

OBJECTIVE: To determine the patterns and clinical importance of saphenofemoral junction (SFJ) reflux in patients with chronic venous disease (CVD) and a normal great saphenous vein (GSV) trunk. METHODS: Fifteen hundred consecutive patients were examined using duplex ultrasound (DU) in three centres. Patients with reflux involving the SFJ and/or its tributaries only were included and its prevalence and patterns were studied. Patients with GSV trunk reflux or in any other veins were excluded. The SFJ diameter was categorised as normal, dilated or varicose. The results of surgery were evaluated by DU in 42 patients 1 year after the procedure. RESULTS: SFJ area incompetence with a competent GSV trunk occurred in 8.8% of limbs. It was significantly more common in CEAP class 2, 13.6% compared to class 3, 8.2% (p=0.03), class 1, 2.7%, class 4, 4.4% and classes 5 and 6 together, 1.5% (p<0.001 for all). The SFJ had a normal diameter in 21%, dilated in 62% and varicose in 17%. Reflux was seen in 39% of limbs with a normal SFJ diameter, in 85% of those with a dilated SFJ and in all varicose SFJs. Of the 42 operated limbs, 27 had ligation and division of the SFJ and tributary phlebectomies. Fifteen had tributary phlebectomies only, leaving the SFJ intact. At one-year follow-up, SFJ area reflux was found in six limbs (14.3%), involving the SFJ alone in 1, a main tributary in 1 and 4 small tributaries. No reflux was found in the GSV trunk. All but two of the 42 patients were satisfied with the results. CONCLUSIONS: SFJ reflux with tributary involvement and sparing of the GSV trunk occurs in 8.8% of CVD patients. Such reflux is found in the entire spectrum of CVD, but it is more common in class 2. Local surgery with or without SFJ ligation has very good results at 1 year. DU scanning prior to treatment is important in all patients so that the intact GSV can be spared.

Dilatation, Pathologic↗

PubMed2003

Improved venous return by elliptical, sequential and seamless air-cell compression.

AIM: The risk of deep vein thrombosis (DVT) in the peri-operative period is significant, but can be reduced with the use of mechanical intermittent pneumatic compression (IPC). These devices have reached widespread use in hospitals and have been found to be effective prophylactic measures against DVT. This study evaluates the latest design features of one particular IPC device in comparison to current models. METHODS: Duplex ultrasound scanning was performed on 40 lower extremities of 20 healthy volunteers before and during the application of the IPC device (VenaFlow System, Aircas, NJ, USA. Two hemodynamic parameters were measured, acceleration time from spontaneous baseline venous flow and peak vein velocity. All measurements were obtained by scanning proximal to the saphenofemoral junction in the common femoral vein in both extremities for each subject. Data were obtained from 3 compression cycles and averaged for each extremity. Results were compared with a recent prospective study form our center using a slow-filling and a rapid-filling sequential IPC devices. RESULTS: The medians for spontaneous average peak velocities at rest of the right and left lower extremities were 26 cm/s and 24.1 cm/s. The median augmented peak velocities during the compression cycle of the device in the right and left side were 79.6 cm/s and 79.0 cm/s. This represented a 306.2% increase in average peak velocity on the right side and a 327.8% increase on the left side. The median acceleration time was 305 ms +/- 40 in the left and 310 ms +/- 50 in the right limb. There was no statistically significant difference in the spontaneous and augmented velocities between the right and left lower extremities in each subject. In comparison to existing slow- and rapid-filling IPC devices the VenaFlow System had superior peak velocities and shorter acceleration times. CONCLUSION: The use of elliptical, sequential and rapid-filling compression of the leg with overlapping air-cells produces significant hemodynamic changes in the common femoral vein, which are superior to other sequential slow- or rapid-filling IPC devices. Randomized studies should be performed to determine the efficacy of this new device in DVT prevention.

Adult↗

PubMed2002

Early thrombus remodelling of isolated calf deep vein thrombosis.

OBJECTIVE: this prospective study was designed to evaluate the evolution of thrombus propagation and lysis in relation to patterns and distribution of isolated calf DVT. METHODS: fifty-two limbs in 48 patients mean age 59+/-15, range 24-78 years, with isolated calf DVT that had at least one exam within 10 days of DVT detection were included in the study. Patients with a documented episode of prior DVT or evidence of post-thrombotic changes during the initial ultrasound exam were excluded. The initial thrombus length, patterns and location of the thrombi were recorded. On follow-up the propagation and lysis patterns of the clot were studied. RESULTS: remodelling of the thrombus, excluding echotexture and vein diameter changes on ultrasound, occurred in 23 limbs, (44%). Ascending propagation only was seen in seven limbs (13%) descending propagation only in two (4%) and in both directions in five (10%). Propagation at least to popliteal vein was detected in seven limbs (13%). Thrombus developed or extended to initially uninvolved veins in six limbs (12%). Pulmonary embolism developed only in one patient (2%; 95% CI: 0-11%). The site and the size of thrombus or the number of veins involved in the baseline exam did not correlate with the remodeling of thrombus. Soleal and gastrocnemial veins were comparable with the posterior tibial and peroneal veins in terms of thrombus propagation and lysis. CONCLUSIONS: early thrombus remodelling occurs in 44% of limbs with isolated calf DVT. This includes ascending and descending thrombus propagation and lysis. Thrombus development or propagation to initially uninvolved calf veins is found in 12%. Thrombus remodelling does not appear to be related to size, site and patterns of thrombosis.

Adult↗

PubMed2001

Nonsaphenous superficial vein reflux.

BACKGROUND: Information on nonsaphenous superficial venous reflux is lacking. This study was designed to determine the prevalence of reflux in nonsaphenous veins, their association and correlation with risk factors, and signs and symptoms of chronic venous disease (CVD). METHODS: Information on 835 limbs in patients with signs and symptoms of CVD were prospectively entered into a customized database. These patients had been referred from the venous clinic to the vascular laboratory for color-flow duplex scanning evaluation of the lower-limb veins. All patients were examined for reflux in the standing and sitting positions. Nonsaphenous reflux was defined as that in superficial veins that are not part of the greater or lesser saphenous systems. Particular attention was paid to the patterns of reflux and anatomy of the nonsaphenous veins from the proximal to the distal ends, including their connections with the saphenous and deep veins. RESULTS: Nonsaphenous venous reflux was found in 84 limbs (10%) of 72 patients, 67 of whom were women. The mean number of pregnancies in these patients was higher than that of 100 randomly selected women with saphenous reflux (3.2 vs 2.2). According to CEAP classification, 90% of the limbs were in CVD classes 1 through 3 and only 10% had skin damage (classes 4-6). Symptoms were present in 67 limbs (80%). Forty-two limbs (50%) had reflux in tributaries of lateral, posterior, and medial thigh. These veins were connected with perforators uniting with the deep femoral, femoral, and muscular veins of the thigh in 36 limbs. Reflux in these perforators was detected in 19 limbs. Reflux arising from the pelvic veins was found in 29 limbs (34%), 18 of which were from vulvar veins medial to saphenofemoral junction and 11 of which were from veins in the gluteal area. Incompetent veins from the sciatic nerve were found in nine limbs (10%). Reflux in the vein of the popliteal fossa was found in seven limbs (8%). Reflux in knee tributaries was detected in three limbs (4%), two of which were connected with posterolateral knee perforators and one with the posterior tibial nerve veins. CONCLUSIONS: The prevalence of nonsaphenous reflux in our practice was 10%. The vast majority of these patients (93%) were women with a mean of 3.2 pregnancies. Ninety percent of these limbs have signs and symptoms assigned to CVD classes 1 to 3. These data may simply reflect the referral pattern, but also a possible association with female sex and number of pregnancies. The unusual anatomy of these veins stresses the importance of color-flow duplex scanning before surgery.

Chronic Disease↗

PubMed2001

Decreased recurrent carotid stenosis by routine patching and intraoperative scanning.

Our objective was to review the results of carotid endarterectomies (CEAs) with Dacron patch angioplasty and intraoperative color-flow duplex scanning (CFS). In a 3-year period, patients who underwent CEA with Dacron patch angioplasty and intraoperative CFS were studied. We excluded patients who had primary closure, vein patch, and redo endarterectomy. Serial CFS was obtained first in the early postoperative period (one day to 3 weeks), then at 6 months, and then yearly. Intraoperative CFS abnormalities were classified as major, requiring immediate revision, or minor, which were observed. The diagnosis of recurrent stenosis by US was based on the detection of an increased peak systolic frequency (>8000 MHz) or velocity (>250 cm/second) in the internal carotid artery. There were 212 CEAs performed in 200 patients (128 men and 84 women) included in this study. Three patients (1.4%) awoke with a stroke, two (0.94%) had transient ischemic attacks, and three (1.4%) developed transient hypoglossal nerve paresis. Intraoperative CFS showed a major defect that required an immediate revision in six patients (2.8%). Minor abnormalities were detected in another 41 patients (19.3%), but no revision was necessary. In follow-up three patients were identified with a severe recurrent carotid stenosis (>80%) and they underwent redo CEA. This rate of recurrence (1.4%) is significantly lower than the rate we had previously reported in a larger study (82 of 1209, 6.8%; P = 0.003). We conclude that the combined use of Dacron patch angioplasty and intraoperative CFS after CEA is associated with a low perioperative morbidity and a low incidence of recurrent stenosis in the first 2 years after operation.

Aged↗

PubMed2000

Expanded indications for ultrasound-guided thrombin injection of pseudoaneurysms.

PURPOSE: We previously reported preliminary data on a new procedure that we developed for the treatment of femoral pseudoaneurysms after catheterization. This study presents our current results of percutaneous ultrasound-guided thrombin injection for treating pseudoaneurysms that arise from various locations and causes. METHODS: Between February 1996 and May 1999, we performed thrombin injection of 83 pseudoaneurysms in 82 patients. There were 74 femoral pseudoaneurysms: 60 from cardiac catheterization (36 interventional), seven from peripheral arteriography (four interventional), five from intra-aortic balloon pumps, and two from dialysis catheters. There were nine other pseudoaneurysms: five brachial (two cardiac catheterization, two gunshot wounds, one after removal of an infected arteriovenous graft), one subclavian (central venous catheter insertion), one radial (arterial line), and one distal superficial femoral and one posterior tibial (both after blunt trauma). Twenty-nine pseudo-aneurysms were injected while on therapeutic anticoagulation. Patients underwent repeat ultrasound examination within 5 days and after 4 weeks. RESULTS: Eighty-two of 83 pseudoaneurysms had initial successful treatment by this technique, including 28 of 29 in patients who were undergoing anticoagulation therapy. The only complication was thrombosis of a distal brachial artery, which resolved spontaneously. There were early recurrences in seven patients: four patients underwent successful reinjection; reinjection failed in two patients, who underwent surgical repair; and one patient had spontaneous thrombosis on follow-up. After 4 weeks, ultrasound examinations were completely normal or showed some residual hematoma, and there were no recurrent pseudoaneurysms. CONCLUSION: Ultrasound-guided thrombin injection of pseudoaneurysms has excellent results, which support its widespread use as the primary treatment for this common problem.

Adult↗

PubMed2000

Viscoelastic properties of normal and atherosclerotic carotid arteries.

BACKGROUND: remodelling of the arterial wall occurs with ageing, even in the absence of atherosclerotic risk factors. With increasing age, arteries dilate, thicken, and get stiffer. The aim of this study was to correlate carotid artery stiffness with wall thickness and plaque presence between healthy individuals and patients with early and advanced atherosclerosis. METHODS: twenty healthy volunteers, 40 carotid segments and 90 patients, 174 carotid segments, with vascular disease were included in the study. The carotid artery was imaged longitudinally and measurements of the intimal-medial thickness (IMT) and plaque were obtained. Systolic and diastolic blood pressures were taken from each arm. The carotid artery stiffness (pressure-strain elastic modulus, Ep) was calculated in all sites from the changes in pressure and diameter. M-mode was used to detect the diameter change (systolic to diastolic) over five cardiac cycles. RESULTS: in the healthy volunteers there was no evidence of plaque or increased IMT. The mean IMT was significantly higher in the patients compared to control (0.83+/-0.27 mm vs. 0.54+/-0.08 mm, p <0.0001). The IMT had a poor correlation with Ep at lower thickness (r=0.24, p=0.08) but this association became stronger with increasing thickness (r=0.62, p<0.001). Arterial segments with an IMT 5 0.88 mm became significantly stiffer compared to the controls (p<0.001) and to patients with an IMT<0.88 mm (p <0.01). Carotid Ep was markedly greater in arterial segments with plaques than in those with increased IMT (p <0.001) and the controls (p<0.0001). CONCLUSIONS: carotid wall areas with small increase in IMT have a poor correlation with carotid artery stiffness. The carotid stiffness increases in areas with marked wall thickening and particularly in segments with plaque. The simultaneous study of vessel-wall elastic behaviour with IMT and plaque changes may increase our understanding of atherosclerotic progression and wall remodelling.

Adult↗

PubMed2000

Effect of intermittent pneumatic foot compression on popliteal artery haemodynamics.

PURPOSE: the aim was to investigate the effect of intermittent pneumatic foot compression (IPC(foot)) on popliteal artery haemodynamics in normal individuals and in patients with intermittent claudication due to peripheral vascular disease (PVD) (Fontaine stage II). MATERIAL AND METHODS: popliteal artery volume flow [vFl], pulsatility index [PI], mean velocity [mV], peak systolic [PSV] and end diastolic velocity [EDV], in 25 limbs of 20 normal subjects and 40 limbs of 32 stable claudicants were obtained in the sitting position before, during and within 30 seconds after the application of IPC(foot)(applied pressure: 120 mmHg; inflation time: 3 seconds; deflation time: 17 seconds) using colour-flow duplex imaging (CFDI). The reproducibility of flow velocity estimations using CFDI in the horizontal [hor] (recovery) and sitting [sit] positions was evaluated in 20 limbs of normal controls and 20 limbs of claudicants. RESULTS: popliteal artery vFl, mV, PSV and PI measurements were performed with a coefficient of variation (CV) of less than 14.6% among claudicants and of less than 13.3% in normal subjects. EDV is the least reproducible parameter with an overall CV range of 10.2-21.5% in normal controls and 9.1-18.6% in arteriopaths. On application of IPC(foot)popliteal artery vFl increased by 111% in the control group (p<0.001) and by 51% in the claudicants (p<0.001). Within 30 seconds of the cessation of pump action flow decreased significantly in both groups (p<0.001), but maintained a significantly higher level than that at baseline (p<0. 001, in both groups). The mV, PSV and EDV showed a similar pattern of significant changes. Both in normals and claudicants, the PI decreased with IPC(foot)(p<0.001) and increased post-compression; however, it was significantly lower than baseline (p<0.005) within 30 seconds of impulse delivery. CONCLUSIONS: current CFDI technology enables a reproducible estimation of popliteal artery flow velocities. IPC(foot)can significantly augment arterial calf inflow on an acute basis both in normals and claudicants. The increase of EDV and decrease of PI indicate that attenuation of peripheral resistance to flow is the main mechanism underlying the popliteal artery vFl enhancement on application of IPC(foot). Prospective trials on the long-term effect of IPC(foot)in the management of patients with PVD are indicated from the results of this study.

Adult↗

PubMed2000

Optimising the performance of intermittent pneumatic compression devices.

OBJECTIVES: this study was designed to determine whether an intermittent pneumatic compression device (IPC) with an increased maximal inflation pressure, a decreased time to maximal pressure and a longer duration of compression would improve venous return compared to a standard IPC device. METHODS: thirty limbs in 15 volunteers without evidence of venous disease were studied using duplex scanning at rest and during the application of two different IPC devices with different compression parameters. The first device IPC-1 (SCD 5325, Kendall) has a six-chambered cuff applying 45 mmHg after 12 s, sequentially from ankle to thigh followed by 60 s of non-compression. The second device IPC-2 (Vena-Assist(R), ACI Medical) has a foot, ankle and calf cuff, applies a pressure of 80 mmHg, has a pressure rise time of 0.3 s, maintains inflation for 5.5 s, and has a cycling time of 1 min. Peak venous velocity and acceleration time were measured at rest and during the IPC application. Measurements were obtained in supine position from the common femoral vein 1 cm above the saphenofemoral junction to include the entire venous outflow from the limb. RESULTS: peak venous velocity at rest was significantly higher in the right limb than in the left limb (26+/-7.2 vs. 22+/-5.7 cm/s, p<0.01). Peak venous velocity was significantly increased by both IPC devices (p <0.0001). IPC-2 achieved significantly higher peak venous velocity than IPC-1 (55.1+/-17.8 vs. 37.4+/-6.9 cm/s, p<0.0001). Acceleration time was also found to be significantly shorter (370+/-93.4 vs. 560+/-83.5 ms, p<0.0001) in IPC-2 than in IPC-1, respectively. CONCLUSIONS: we have demonstrated that progressive inflation at the foot, ankle and calf, increasing maximal inflation pressure and decreasing time to maximal pressure result in increased venous return. These changes may improve the efficacy of IPC devices in the prevention of deep-venous thrombosis (DVT) formation.

Adult↗