Increase in Echogenicity of Echolucent Carotid Plaques after Treatment with Total Triterpenic Fraction of Centella asiatica: A Prospective, Placebo-Controlled, Randomized Trial

The aim of this study was to evaluate whether total triterpenic fraction of Centella asiatica (TTFCA), was effective in modulating collagen production over 12 months, by producing an increase in echogenicity in echolucent carotid plaques. Part I was a pilot study aimed at evaluating the effects of TTFCA on different types of plaques. Part II was a prospective, randomized, placebo-controlled trial aimed at evaluating the effects of TTFCA on hypoechoic-echolucent plaques. The sonographic examination of carotid plaques was made with high-resolution ultrasound. Capturing, digital image processing, and normalization were standardized, interobserver, intrascanner, gain-level variability were standardized using as reference blood (black) for the most echolucent parts of the plaque and the adventitia (white) as the most echogenic part. Normalization of echo texture was obtained and plaque characterization differentiated echo-texture of plaque associated with events and those that did not cause embolization, thrombosis, or cardiovascular events. After identifying plaques at higher risk, patients were treated with TTFCA (oral tablets, 60 mg, thrice daily for 12 months) to evaluate whether this compound, by modulating collagen synthesis, could increase the echogenicity and therefore the stability of echolucent plaques. Part II was aimed at evaluating the effects of TTFCA on hypoechoic-echolucent plaques. Asymptomatic patients with echolucent plaques (GSM < 18) were treated with TTFCA (60 mg, oral tablets three times daily for 12 months) or with comparable placebo after informed consent. All patients were also treated with antiplatelet agents. In part I, at inclusion the GSC in the hypoechoic group was 15 (range, 12–18) while in the hyperechoic group it was 26 (range, 24–31); at 6 months it was increased in the hypoechoic group and at 12 months the increase was significant (19.5; p<0.05). There was a minor increase in GSM in the hyperechoic group (30; ns). In part II in the treatment group there was a significant difference in GSM (increase) at 12 months (p<0.05), improvement in texture (p<0.05) and a nonsignificant decrease in stenosis. No changes were observed in the placebo group. Events were observed in 6.5% of patients in the TTFCA group and in 11% in the control group (p<0.05). In conclusion these observations suggest a positive action of TTFCA on the stabilization of hypoechoic, low-density carotid plaques.

Modification of the Echogenicity of Femoral Plaques after Treatment with Total Triterpenic Fraction of Centella aslatica: A Prospective, Randomized, Placebo-Controlled Trial

The aim of this study was to evaluate whether TTFCA (total triterpenic fraction of Centella asiatica), was effective, by modulating collagen production, in a period of 12 months, increasing the echogenicity of echolucent plaques at the femoral bifurcation. Hypoechoic atherosclerotic plaques have been found to be associated with an increased evidence of cerebrovascular events. In this type of plaques stromal composition is limited as the collagen component is generally very low; the plaque composition is mainly due to lipid accumulation or thrombosis. The aim of this study was the evaluation of echogenicity of hyperechoic plaques and how it could be modified by a drug acting on the modulation of collagen synthesis. Antiplatelet agents were used in all patients; cholesterol-lowering agents were used in 34% of patients in the treatment group and in 36% in the placebo group. TTFCA was used at the dose of 60 mg thrice daily (oral tablets). Of the 60 included subjects 26 completed the study in the treatment group and 24 in the placebo group. At inclusion the average GSM in the treatment group was 14 (SD 3) and 14.3 (SD 3) in controls. At 12 months GSM was increased up to 22.8 (SD 4) in the treatment group and it was 15 (SD 3) in controls. Considering texture no significant changes were observed in controls while a qualitative increase in homogenicity was observed in the TTFCA group. Plaque size measured at the beginning and at the end of the study showed a median increase in size, in controls (23%; range 0%–44%); it was unchanged in the TTFCA group (variation 7%; 4%–26%). In conclusion in the treatment group plaques increased in echogenicity and in homogenicity; size and stenosis remained unchanged. Modulating the scarring process within echolucent plaques (low echogenicity, high echolucency, with a very low collagen/stromal component), possibly by collagen modulation, makes plaques more stable. This has been achieved and documented in the present study by an increase in the gray-scale median (plaques become more echogenic, more ‘white’). The variation in GSM is generally associated with a lower risk of wall thrombosis, rupture and embolization. These observations indicate a positive action of TTFCA on the stabilization of hypoechoic, low-density femoral plaques

Incidence, Natural History and Risk Factors of Deep Vein Thrombosis in Elective Knee Arthroscopy

Aims: to determine the incidence, anatomical distribution and extent of deep vein thrombosis (DVT) in limbs undergoing elective unilateral knee arthroscopy without active prophylaxis, to evaluate its effect on venous function following early diagnosis, and to quantify the impact of risk factors on its incidence. Methods: 102 consecutive patients undergoing unilateral knee arthroscopy without prophylaxis were studied. A history was obtained with emphasis on the risk factors for thromboembolism, and physical examination and colour duplex were performed prior to and within a week after surgery. Patients who developed calf DVT were given aspirin (150 mg) and compression stockings; those with proximal DVT were admitted for anticoagulation (heparin followed by warfarin). Follow-up (mean 118 [range 84-168] days) entailed weekly physical and duplex examinations during the first month and monthly thereafter. Results: 8 patients developed calf DVT in the operated leg (incidence 7.84% [95% Cl: 2.7%-13.2%]); thrombosis was asymptomatic in 4 of those (50%), caused calf tenderness in 4 (50%) and a positive Homan’s sign in one (12.5%). DVT occurred in the following veins: peroneal 4 subjects (50%), soleal 4 (50%), gastrocnemial 2 (25%) and tibial 2 (25%). Propagation of a calf DVT to the popliteal vein was identified in 1 patient (12.5%). After a median period of 118 days, total clot lysis was found in 50% of DVTs, with partial thrombus resorption in the rest; reflux in the thrombosed veins was present in 75% of limbs with DVT. 43% of patients had 1 risk factor for DVT and 20% had ≥2. The incidence of DVT was higher amongst those with two or more risk factors for thromboembolism (p <.05) or those with previous thrombosis alone (p <.005). Symptoms or signs of pulmonary embolism were not documented. Conclusions: Elective unilateral knee arthroscopy performed without prophylaxis is complicated by ipsilateral calf DVT in 7.8% (95% CI: 2.7%-13.2%) of cases. The risk is higher in the presence of previous thrombosis (relative risk: 8.2) and two or more risk factors for DVT (relative risk: 2.94). Thrombosis may propagate to the proximal veins, despite early diagnosis. 50% of calf clots totally lyse in 4 months, yet reflux develops in at least 75% of limbs with DVT. Further studies to determine optimal prophylaxis are warranted.

Chronic Venous Disease and the Leukocyte-Endothelium Interaction: From Symptoms to Ulceration

The mechanisms regulating varicose vein development and the subsequent skin sequelae seen in chronic venous disease (CVD) have been investigated recently. Despite the diversity of signs and symptoms associated with the disease, it seems likely that they are related to venous hypertension. Valvular incompetence is the most important cause of venous hypertension. Recent findings suggest that inflammatory processes are involved in the structural remodeling in venous valves and in the vein wall, leading to valvular incompetence and the development of varicose veins. This has been shown by Ono and colleagues, who found infiltration of valve leaflets and the venous wall by leukocytes (monocytes and tissue macrophages) in all valve specimens from patients with CVD and in none from controls. Further work by Takase and colleagues confirmed this hypothesis. Vein wall remodeling is likely to involve the complex interplay of a range of factors, including an altered ratio between metalloproteinases (MMPs) and their tissue inhibitors (TIMPs), and elevated levels of cytokines and growth factors favor an alteration of the extracellular matrix. Neutrophils and mast cells and their interaction with the venous endothelium are believed to play an important role in the initiation of the inflammatory response in CVD. The transmission of high venous pressures to the dermal microcirculation results in the stimulation of an inflammatory process in which cytokine and growth factor release leads to leukocyte migration into the interstitium and the initiation of further inflammatory events. This process is associated with the intense dermal fibrosis and tissue remodeling seen in chronic venous insufficiency. The many manifestations of the disease are frequently associated with symptoms usually ascribed to CVD. The proportion of patients with symptoms increases with increasing CEAP clinical classes, but the mechanisms underlying symptom appearance have not been elucidated. It has been postulated that it is related to the inflammatory cascade of events seen at all stages of CVD and in which the leukocyte and its interaction with the endothelium play a key role. It is increasingly believed that the emerging twin themes of disturbed venous flow patterns and chronic inflammation underlie and link all the manifestations of the disease. Among the many pathophysiologic mechanisms at work, the leukocyte-endothelium interactions seem to be important in many aspects of the disease and have been identified as a possible target for pharmacologic intervention. Pharmacologic agents that could attenuate various elements of the inflammatory cascade and inhibit the inflammatory process might offer a greater opportunity to prevent future morbidity. It seems reasonable to speculate that such treatment could reduce the risk of CVD progression if applied as soon as the first symptoms appear.

Combined modalities in the prevention of venous thromboembolism: A review of the literature

Objective

Despite recent advances in the field of venous thromboembolism (VTE) prophylaxis and adherence to guideline recommendations, VTE remains a serious problem, especially in high-risk groups. The aim of the present review was to summarize the evidence supporting the use of combined modalities, both physical and pharmacological, in VTE prevention.

Methods

Using Medline, original studies on the value of combined modalities in VTE prevention were identified. Keywords used for physical methods included elastic stockings and intermittent pneumatic compression, and for pharmacological methods included unfractionated and low molecular weight heparin. Relevant articles from their bibliography were also retrieved.

Results

Combined pharmacological and physical modalities were more effective than each modality alone in a variety of specialties, including orthopaedic, general and cardiac surgery, as shown by 14 of the 18 randomized or case-control studies retrieved. Mean reduction in VTE incidence was 69% (range 16–100%).

Conclusion

Combined modalities are more effective than single modalities in VTE prophylaxis. These results endorse their use, especially in high-risk patients, and support this otherwise typical recommendation of the consensus documents on VTE prophylaxis.

Value of Color Flow Duplex Imaging in Detection of Subtotal and Total Internal Carotid Artery Occlusion

The aim of this retrospective study was to estimate the predictive value of color flow duplex imaging (CFDI) in the detection of near-total and total internal carotid artery (ICA) occlusion. The authors reviewed all diagnoses of 95-99% ICA stenosis and ICA occlusion made by CFDI from 1991 to 1994 at St. Mary's Hospital. One hundred thirtyseven patients with CFDI diagnosis of ICA occlusion and 42 with 95-99% stenosis had also been subjected to intraarterial digital substraction angiography during the same period and within one month from the CFDI. They compared the results of both methods to estimate the positive predictive value (PPV) of CDFI in the detection of ICA occlusion and 95-99% stenosis. Furthermore, they compared the PPV of CDFI diagnoses during 1991-1993 with that of 1994 for the same spectrum of ICA disease.

CFDI had 96% PPV in the diagnosis of carotid occlusion (95% confidence interval, 94-97.9%, false-positive rate 3.6%) and 83% in the diagnosis of 95-99% stenosis (95% confidence interval 63.4-88.9%, false-positive rate 17%). Although there was improvement of CFDI's ability in the diagnosis of occlusion during 1994 in comparison with the 1991-1993 period, this was not statistically significant (PPV 95.9% and 97.4% respectively).

CFDI may slightly underestimate or overestimate the degree of tight ICA stenosis. However, in the diagnosis of ICA occlusion CFDI is highly reliable.

Liquid Crystal Thermography and Duplex in the Preoperative Marking of Varicose Veins

Objective:

To determine the role of liquid crystal thermography (LCT) in preoperative marking of varicose veins and incompetent perforating veins.

Design:

Single patient group study comparing techniques.

Setting:

Teaching hospital vascular laboratory.

Patients:

Two hundred patients (265 legs) referred to St Mary's Hospital Vascular Laboratory for preoperative varicose vein marking.

Methods:

Patients were studied using LCT and duplex ultrasonography to identify calf perforating veins.

Results:

In part I of the study LCT identified 47 ‘areas at risk’, 42 of which were demonstrated to contain incompetent perforating veins on duplex examination (positive predictive value 89%). Thirty-eight of these 42 patients were explored at operation and 36 (95%) were confirmed as incompetent. The remaining two perforating veins could not be located. In part II of the study LCT identified 327 ‘areas at risk’, 299 of which were demonstrated to contain incompetent perforating veins on duplex examination (positive predictive value 91%).

Conclusion:

LCT is useful in the identification of incompetent perforating veins, it is easy to perform, less time consuming, cheaper and can replace duplex scanning.

Angiographic and Duplex Grading of Internal Carotid Stenosis: Can We Overcome the Confusion?

The stroke risk reduction benefit of surgical intervention in carotid occlusive disease has been validated in multicenter trials for various angiographically defined lesion severity categories. The two divergent angiographic grading methods used for internal carotid artery stenosis in these trials have caused confusion in the clinical application of their recommendations. Moreover, while today's highly accurate carotid duplex scanning can obviate the need for preoperative angiography in many cases, the duplex criteria must be tailored to achieve sufficiently reliable results on which therapeutic decisions can be made. This review offers a clarification of the discrepancies between the angiographic grading techniques and how their measurements of percent stenosis correlate to the duplex criteria needed to support the treatment decision-making process for carotid obliterative disease.

Make it Easy: Duplex Examination of the Venous System

Objective:

A methodological report of duplex ultrasound examination of the venous system, with Particular consideration of the best position for examining the patient.

Design:

Single patient group, comparison of duplex ultrasound imaging with phlebography.

getting:

Teaching hospital vascular laboratory.

Patients:

Patients referred for assessment of their venous system.

Main outcome measures:

Duplex ultrasound scanning of the lower limb, ascending phlebography.

Results:

Our results of duplex ultrasound scanning in the diagnosis of deep vein thrombosis as compared with Phlebography show a sensitivity of 94% and a specificity of 91%.

Conclusions:

We found it advantageous to examine the Patient standing during proximal vein imaging and sitting for distal venous examination. Veins dilated as a result of gravitational effects are visualized more easily. The examiner, by resting the elbow on his/her distal Thigh, has a more stable hand, facilitating the test. The Patient, by resting the heel on the edge of the examiner's chair, relaxes the calf muscles, thus simplifying the augmentation manoeuvre. The inflation of a tourniquet applied to the distal thigh dilates the calf veins.

Effects of Intermittent Sequential Compression in Venous Hypertensive Microangiopathy

Objective:

To investigate the acute effects of sequential compression on the microcirculation in limbs with chronic venous hypertension causing venous microangiopathy.

Design:

One group of patients with venous hypertension and a group of normal, comparable subjects were treated with intermittent sequential pneumatic compression applied for 30 min. Skin blood flow was measured by laser Doppler flowmetry at the perimalleolar region at rest (horizontal position) and on standing. The measurements were repeated at 0, 30 and 60 min after cessation of the compression. As criteria of inclusion, only limbs with high perimalleolar skin flux and decreased venoarteriolar response were included.

Setting:

St Mary's Hospital, London (teaching hospital).

Patients, participants:

Sixteen limbs in 16 patients with chronic venous hypertension and 12 limbs of comparable healthy volunteers were studied.

Results:

At rest, in the normal controls, the mean (SD) flux was 0.56 (0.3) units; it decreased on average by 35% on standing (venoarteriolar response). There was normal vasomotor activity. In patients, the mean flux was 1.45 (0.8) ( p < 0.025) and the median venoarticular response only 7%. There was very limited vasomotor activity. Vasomotor activity started 10 min after the commencement of compression. At the end of the compression period there was a marked change towards normality. Resting flux was 0.90 (0.5) (significantly decreased) and the venoarteriolar response had increased to 23% ( p < 0.025) with an improvement in vasomotor activity. These changes persisted at 30 and 60 min.

Conclusions:

The findings offer an explanation of the effect of sequential compression on the healing of leg ulcers in chronic venous insufficiency.

The Long-Term Effect of Elastic Compression on the Venous Haemodynamics of the Leg

The long-term haemodynamic effect of elastic compression has been evaluated in 16 patients (20 limbs) with superficial venous incompetence. Ambulatory venous pressure (AVP) and pressure recovery time (RT90) were measured with foot vein canulation. Air-plethysmography was used to measure venous volume, venous reflux and the ejecting capacity of the calf muscle pump, before and after the application of graduated elastic stockings, for 4 weeks. Limbs were tested without the stockings.

Elastic compression for 4 weeks produced a significant reduction in the venous volume ( P < 0.01), a significant decrease in venous reflux and an increase in the ejecting capacity of the calf muscle pump ( P < 0.01). The above changes explain the significant reduction in AVP and prolongation of RT90 ( P < 0.01) which was observed.

The results indicate that there is a considerable improvement in venous haemodynamics after 4 weeks support with graduated elastic compression.

The Effect of Elastic Compression on Calf Muscle Pump Function

The haemodynamic effect of elastic compression has been evaluated in 23 patients (26 limbs) with superficial venous incompetence. Ambulatory venous pressure (AVP) and pressure recovery time (RT90) were measured with foot vein canulation. Also the functional venous volume (VV) (venous capacitance), venous reflux and the ejecting capacity of the calf muscle pump were measured with air-plethysmography. The above measurements were made with and without a graduated compression elastic stocking.

Elastic compression produced a significant reduction in VV ( P < 0.01). Also a significant decrease in venous reflux and increase in the ejecting capacity of the calf muscle pump ( P < 0.01). The above alterations explain the significant reduction in AVP and prolongation of RT90 ( P < 0.01) which was observed as a result of elastic compression.

The measurements made in this study demonstrate in an objective and quantitative way the beneficial effect of elastic stockings in patients with superficial venous incompetence and how this effect is achieved.

A Rare Case of an Aneurysm of the External Iliac and the Common Femoral Vein

Objective:

To report a case of an external iliac – common femoral vein aneurysm and review the literature on the subject.

Design:

Case report.

Setting:

Academic Vascular Surgery and Radiology Units, St Mary's Hospital, London, UK.

Patients, Interventions and Results:

The aneurysm occurred in a 34-year-old woman and was diagnosed with venography, duplex scanning and magnetic resonance venography. It underwent acute thrombosis and, as the thrombus was well organized and extensive, thrombectomy was not possible. The patient was treated with standard heparin followed by oral anticoagulants for 5 months. Thirty months after the operation the right calf remains swollen but soft and non-tender and the patient is currently treated with grade II full-length compression stockings. Since there were no findings of vein compression or malignancy it seems that the formation of the aneurysm resulted from a congenital weakness of the venous wall.

Conclusions:

The most common presentation of these aneurysms is of a mass of the abdomen or the iliac fossa, while thromboembolism is not uncommon. The main causes are arteriovenous (AV) fistula formation and congenital weakness of the vein wall. For the first the preferred treatment is AV fistula ligation while for the rest ligation with or without vein reconstruction has been successfully used.

Microcirculatory changes parallel the clinical deterioration of chronic venous insufficiency

Objective: This study was designed to determine microcirculatory changes in patients belonging to different chronic venous insufficiency (CVI) classes.

Methods: A total of 80 patients from all CVI classes and 15 symptom-free volunteers were studied prospectively. Venous reflux was verified with duplex scanning. Patients with conditions that may have affected the local microcirculation were excluded. Skin blood flux (SBF) was measured using a laser Doppler flowmeter in the supine position in a constant room temperature of 22°C and after 10 minutes acclimatization. The veno-arteriolar response (VAR) was estimated from the SBF change from supine to dependent position. The vasomotor activity (VMA) was determined from the baseline SBF.The amplitude of cycles (AC) and SBF during heat stress at 45°C were also measured.

Results: Mean age, duration of disease and prevalence of deep vein thrombosis were greater in classes 4-6 compared with classes 1-3 ( P <0.02). Although there was an increase in SBF and AC in classes 2 and 3 compared with the controls this was not significant. Values for SBF and AC were higher in classes 4-6 than classes 1-3 ( P <0.01), and higher in class 6 than class 4 ( P <0.01). Upon heating, the SBF increased more in classes 1-3 than in classes 4-6 ( P <0.01), and in class 4 more than in class 6 ( P <0.01). Values for VAR and VMA decreased with worsening of CVI, but these changes were not significant.

Conclusions: Deterioration of the microcirculation is largely responsible for the clinical symptoms and signs seen in patients with CVI classes 4-6.

Comparison between insulin resistance indices and carotid and femoral atherosclerosis: a cross-sectional population study

AIM

The aim of this study was to investigate the association between commonly used insulin resistance (IR) indices and the presence and extent of carotid and femoral atherosclerosis in a general population setting.

METHODS

Cross-sectional analysis of 762 volunteers from the ongoing epidemiological Cyprus Study (46.6% male; mean age=60.5±10.2). 1) Carotid intima-media thickness (IMTcc), 2) carotid and femoral atherosclerotic plaque presence, 3) total plaque area in the carotid/femoral bifurcations (sum of the largest plaques in each carotid/femoral bifurcation-SPAcar/fem), and 4) total plaque area in both carotid and femoral bifurcations (sum of the areas of the largest plaques present in each of the four bifurcations-SPA) were measured using ultrasound at baseline. The HOMA-IR, QUICKI and McAuley indices as well as fasting insulin levels were estimated and their quartiles were used in linear and logistic regression analysis.

RESULTS

All IR indices studied were strongly associated with IMTcc (P<0.01for all) even after adjustment for age and sex and exclusion of diabetic subjects. However, when looking at plaque presence and size (i.e.area) only the HOMA-IR and especially the McAuley Index were associated with both carotid plaque presence (ORadj=1.17; 95%CI=1.01 to 1.36; P=0.03 and ORadj=0.86; 95%CI=0.74 to 0.99; P=0.04 respectively) and area (ORadj=0.10; 95%CI=0.008 to 0.20; P=0.03 and ORadj=-0.11; 95%CI=-0.20 to -0.009; P=0.03 respectively), after adjustment. The McAuley Index remained a significant predictor of both carotid plaque presence and area even after exclusion of diabetic subjects (P=0.04).

CONCLUSION

Our results show that while all indices were associated with carotid IMT, supporting a strong role for IR in intimal-medial thickening, only the HOMA-IR and especially the McAuley Index were associated with both carotid plaque presence and area, after adjustment. This highlights the importance of including triglyceride levels in estimating the risk for atherosclerotic plaque in the carotids as well as the possible differences in determinants for atherosclerosis between arterial sites.

Descending phlebography in patients with venous ulceration: hemodynamic implications

AIM

The aim of this paper is to report on the hemodynamic significance of the various degrees reflux as demonstrated on descending phlebography, by comparing the phlebographic findings with ambulatory venous pressure (AVP) measurements.

METHOD

Thirty-two patients (45 affected limbs) with active or healed venous ulceration were admitted to the study. Descending phlebography with grading of reflux (0-4 using Herman's grading), AVP and refilling time 90 (RT90) were performed in all patients. In addition, the presence of deep to superficial reflux into the great saphenous vein at the sapheno-femoral junction, thigh incompetent perforating veins, small saphenous vein at the saphenopopliteal junction and incompetent calf perforating veins was recorded using ascending functional phlebography. The examined limbs were separated into two groups according to the Grade of reflux. Group I consisted of limbs in which popliteal valve incompetence was not demonstrated on descending phlebography, i.e., Grades 0-2 (18 limbs). Group II consisted of limbs with popliteal reflux as demonstrated by descending venography, i.e., grades 3 and 4 (27 limbs).

RESULTS

In Group I the mean AVP ± SD was 47.2 ± 9.3 mmHg (range 31-67 mmHg). After the application of the ankle tourniquet to exclude the effects of the superficial venous incompetence on the pressure recordings, the mean AVP ± SD became 28.1 ± 9.9 mmHg (range 11-44) (paired t test: P < 0.001). In Group II (limbs with incompetent popliteal valves) the mean AVP ± SD was 71.6 ± 12.7 mmHg (range 49-95 mmHg) before the tourniquet. This was significantly higher than in Group I (t test: P < 0.001). The application of the ankle tourniquet in this group produced a small but significant decrease in the AVP (mean AVP ± SD: 66 ± 14.5 mmHg) (paired t test: P < 0.001).

CONCLUSION

Incompetence of the femoral valves in the presence of competent popliteal valves adds very little to the hemodynamic abnormality produced by superficial venous reflux. In the majority of these patients, there is co-existing reflux from deep to superficial veins with associated superficial valve incompetence which is responsible for the venous hypertension, skin changes and ulceration. The hemodynamic changes which in the past had been associated with deep venous insufficiency (AVP >45 mmHg and RT90 < 14 seconds despite the application of an ankle tourniquet) occur only when there is popliteal incompetence.

Consensus Document on Intermittent Claudication from the Central European Vascular Forum (C.E.V.F.)-3rd revision (2013) with the sharing of the Mediterranean League of Angiology and Vascular Surgery, and the North Africa and Middle East Chapter of International Union of Angiology

This paper is the review of the Consensus Document on Intermittent Claudication of the Central European Vascular Forum (CEVF), published in 2008, and and shared with the North Africa and Middle East Chapter of International Union of Angiology and the Mediterranean League of Angiology and Vascular Surgery. The Document presents suggestions for general practitioners and vascular specialists for more precise and appropriate management of PAD, particularly of intermittent claudication, and underlines the investigations that should be required by GPs and what the GP should expect from the vascular specialist (angiologist, vascular surgeon). The idea of the Faculty is to produce a short document, which is an easy reference in daily clinical practice, both for the GPs and vascular specialists.

Despeckle Filtering for Multiscale Amplitude-Modulation Frequency-Modulation (AM-FM) Texture Analysis of Ultrasound Images of the Intima-Media Complex

The intima-media thickness (IMT) of the common carotid artery (CCA) is widely used as an early indicator of cardiovascular disease (CVD). Typically, the IMT grows with age and this is used as a sign of increased risk of CVD. Beyond thickness, there is also clinical interest in identifying how the composition and texture of the intima-media complex (IMC) changed and how these textural changes grow into atherosclerotic plaques that can cause stroke. Clearly though texture analysis of ultrasound images can be greatly affected by speckle noise, our goal here is to develop effective despeckle noise methods that can recover image texture associated with increased rates of atherosclerosis disease. In this study, we perform a comparative evaluation of several despeckle filtering methods, on 100 ultrasound images of the CCA, based on the extracted multiscale Amplitude-Modulation Frequency-Modulation (AM-FM) texture features and visual image quality assessment by two clinical experts. Texture features were extracted from the automatically segmented IMC for three different age groups. The despeckle filters hybrid median and the homogeneous mask area filter showed the best performance by improving the class separation between the three age groups and also yielded significantly improved image quality.

Association of ultrasonic texture and echodensity features between sides in patients with bilateral carotid atherosclerosis

OBJECTIVES

Our objective was to estimate the correlation of echodensity and textural features, using ultrasound and digital image analysis, between plaques in patients with bilateral carotid stenosis.

DESIGN

Cross-sectional observational study.

METHODS

Patients undergoing carotid endarterectomy were recruited from Vascular Surgery at the Royal Victoria and Jewish General hospitals in Montreal, Canada. Bilateral pre-operative carotid ultrasound and digital image analysis was performed to extract echodensity and textural features using a commercially available Plaque Texture Analysis software (LifeQMedical Ltd). Principal component analysis (PCA) was performed. Partial correlation coefficients for PCA and individual imaging variables between surgical and contralateral plaques were calculated with adjustment for age, sex, contralateral stenosis, and statin use.

RESULTS

In the whole group (n = 104), the six identified PCA variables and 42/50 individual imaging variables were moderately correlated (r = .211-.641). Correlations between sides were increased in patients with ≥50% contralateral stenosis and symptomatic patients.

CONCLUSION

Textural and echodensity features of carotid plaques were similar between two sides in patients with bilateral stenosis, supporting the notion that plaque instability is determined by systemic factors. Patients with unstable features of one plaque should perhaps be monitored more closely or treated more aggressively for their contralateral stenosis, particularly if this is hemodynamically significant.

Prevention and treatment of venous thromboembolism--International Consensus Statement

The aim of this document is to provide a clear and concise account of the evidence regarding efficacy or harm for various methods available to prevent and manage venous thromboembolism (VTE).

Asian venous thromboembolism guidelines: prevention of venous thromboembolism

Venous thromboembolism (VTE) prophylaxis is under-utilized in Asia because of the misconception that its incidence is lower in Asians as compared to the Caucasians. The available data on VTE in Asia is limited due to the lack of well-designed multicenter randomized controlled trials as well as non-standardized research designs, making data comparison difficult. Emerging data indicates that the VTE incidence is not low in Asia, and is comparable to that reported in the Western literature in some instances. There is also a trend towards increasing incidence of VTE, as demonstrated by a number of hospital-based studies in Asia. This could be attributed to lifestyle changes, ageing population, increasing awareness of VTE and wider availability of Duplex ultrasound. The risk of VTE in hospitalized patients remain the same in Asians and Caucasians, even though there may be factors that are inherent to patients in Asia that influence the slight variation in incidence. The utilization rate of VTE prophylaxis remains suboptimal in Asia. The Asian Venous Thrombosis Forum (AVTF) comprises participants from various countries such as China, Hong Kong, India, Indonesia, Korea, Malaysia, Philippines, Singapore, Taiwan, Thailand and experts from Australia and Europe. The forum evaluated the available data on VTE from the Asian region and formulated guidelines tailored to meet the needs of the region. We recommend that serious considerations are given to VTE prophylaxis especially in the at-risk group and a formal hospital policy be established to facilitate the implementation. On admission to the hospital, we recommend assessing the patients for both VTE and bleeding risk. We recommend mechanical prophylaxis for patients at increased risk of bleeding and utilizing it as an adjunctive measure in combination with pharmacological prophylaxis in patients with high risk of VTE. For patients undergoing general or gynecological surgery and with moderate risk for VTE, we recommend prophylaxis with one of the following: low dose unfractionated heparin (LDUH), low molecular weight heparin (LMWH), fondaparinux or intermittent pneumatic compression (IPC). For the same group of patients at high risk of VTE, we recommend pharmacological or combination of pharmacological and mechanical prophylaxis. For patients undergoing major orthopedic surgeries like total hip replacement, total knee replacement and proximal hip fracture surgery, we recommend using one of the following: LMWH, fondaparinux, rivaroxaban, apixaban, edoxaban, dabigatran, warfarin or aspirin with IPC. For patients admitted to the hospital with acute medical illness and has moderate risk of VTE, we recommend prophylaxis with LDUH, LMWH or Fondaparinux. For the same group at high risk of VTE, we recommend combination of pharmacological and mechanical prophylaxis.

Combined (mechanical and pharmacological) modalities for the prevention of venous thromboembolism in joint replacement surgery

We performed a systematic review and meta-analysis to compare the efficacy of intermittent mechanical compression combined with pharmacological thromboprophylaxis, against either mechanical compression or pharmacological prophylaxis in preventing deep-vein thrombosis (DVT) and pulmonary embolism in patients undergoing hip or knee replacement. A total of six randomised controlled trials, evaluating a total of 1399 patients, were identified. In knee arthroplasty, the rate of DVT was reduced from 18.7% with anticoagulation alone to 3.7% with combined modalities (risk ratio (RR) 0.27, p = 0.03; number needed to treat: seven). There was moderate, albeit non-significant, heterogeneity (I2 = 42%). In hip replacement, there was a non-significant reduction in DVT from 8.7% with mechanical compression alone to 7.2% with additional pharmacological prophylaxis (RR 0.84) and a significant reduction in DVT from 9.7% with anticoagulation alone to 0.9% with additional mechanical compression (RR 0.17, p < 0.001; number needed to treat: 12), with no heterogeneity (I2 = 0%). The included studies had insufficient power to demonstrate an effect on pulmonary embolism.

We conclude that the addition of intermittent mechanical leg compression augments the efficacy of anticoagulation in preventing DVT in patients undergoing both knee and hip replacement. Further research on the role of combined modalities in thromboprophylaxis in joint replacement and in other high-risk situations, such as fracture of the hip, is warranted.

Screening for chronic cerebrospinal venous insufficiency (CCSVI) using ultrasound--recommendations for a protocol

Chronic cerebrospinal venous insufficiency (CCSVI) is a syndrome characterized by stenoses or obstructions of the internal jugular and/or azygos veins with disturbed flow and formation of collateral venous channels. Studies using ultrasound in patients with multiple sclerosis (MS) have demonstrated a high prevalence of CCSVI (mean 70%; range 0-100%; N.=1496), whereas, in normal controls and patients without MS the prevalence was much lower (mean 10%; range 0-36%; N.=635). Ultrasound uses a combination of physiological measurements as well as anatomical imaging and has been used for the detection of CCSVI by different centers with variable results. A high prevalence ranging from 62% to 100% of obstructive lesions has been found by some teams in patients with MS compared with a lower prevalence of 0-25% in controls. However, absence of such lesions or a lower prevalence (16-52%) has been reported by others. This variability could be the result of differences in technique, training, experience or criteria used. The current lack of a methodology shared among experts is a confounding element in epidemiologic studies, and does not permit further Bayesan or other kind of analysis. In order to ensure a high reproducibility of Duplex scanning with comparable accuracy between centers, a detailed protocol with standard methodology and criteria is proposed. This is also necessary for training. It has been shown that inter-rater variability increases post-training (from k=0.47 to k=0.80), while within-rater reproducibility in trained operators was k=0.75. Finally, the consensus document proposes a reporting standard of Duplex measurements, and future research to answer areas of uncertainty.

Can combined (mechanical and pharmacological) modalities prevent fatal VTE?

AIM

The aim of this paper was to perform a systemic review and meta-analysis of the efficacy of combined modalities (intermittent pneumatic leg compression and pharmacological prophylaxis, treatment group) against single modalities alone (control group) in preventing pulmonary embolism (PE), including fatal PE and deep-vein thrombosis (DVT) in high-risk patients.

METHODS

Databases searched included the Cochrane Central Register of Controlled Trials, the Specialized Register of the Peripheral Vascular Diseases Group, MEDLINE and EMBASE.

RESULTS

Seventeen studies, six of them randomized controlled trials (RCTs), which enrolled a total of 9998 patients in a variety of specialties were identified. Sixteen of the included studies evaluated the role of combined modalities on the incidence of symptomatic PE. These showed a reduction in symptomatic PE from 2.83% (122/4313) in the control group to 0.86% (33/3838) in the treatment group. Odds ratio was 0.34, 95% Confidence interval (CI) 0.23 to 0.50. Fatal PE was reduced from 0.56% (11/1972) in the control group to 0.07% (1/1377) in the treatment group (results were available in 10 studies). Odds ratio was 0.37 (95% CI; 0.09 to 1.48). Fourteen studies investigated the role of combined modalities on the incidence of DVT. These showed a reduction in DVT from 6.18% (200/3238) in the control group to 2.05% (63/3074) in the treatment group. Odds ratio was 0.31, 95% CI 0.23 to 0.43.

CONCLUSION

Combined prophylactic modalities decrease significantly the incidence of PE and DVT, compared to single modalities, but the reduction seen in fatal PE did not reach statistical significance. Further research on the role of combined modalities in reducing DVT and PE is necessary.

Introduction to the biomechanics of carotid plaque pathogenesis and rupture: review of the clinical evidence

The management of patients with asymptomatic carotid disease is currently under debate and new methods are warranted for better risk stratification. The role of the biomechanical properties of the atherosclerotic arterial wall together with the effect of different stress types in plaque destabilisation has only been recently investigated. PubMed and Scopus databases were reviewed. There is preliminary clinical evidence demonstrating that the analysis of the combined effect of the various types of biomechanical stress acting on the carotid plaque may help us to identify the vulnerable plaque. At present, MRI and two-dimensional ultrasound are combined with fluid-structure interaction techniques to produce maps of the stress variation within the carotid wall, with increased cost and complexity. Stress wall analysis can be a useful tool for carotid plaque evaluation; however, further research and a multidisciplinary approach are deemed as necessary for further development in this direction.

The efficacy of a new stimulation technology to increase venous flow and prevent venous stasis

OBJECTIVES

Electrical stimulation of calf muscles has been shown to be effective in prevention of DVT. The aim was to determine: (a) dependence of venous blood velocity and ejected volume on the rates of stimulated calf contractions: (b) clinical factors affecting efficacy in healthy individuals.

METHODS

The maximum intensity stimulus tolerated was applied to calves of 24 volunteers. In popliteal veins, peak systolic velocities (PSV), ejected volume per individual stimulus (stroke volume SV) and ejected total volume flow per minute (TVF) of expelled blood were determined using ultrasound. Stimulation rates from 2 to 120 beats per minute (bpm) were applied.

RESULTS

Mean baseline popliteal PSV was 10 cm/s. For stimulation rates between 2 and 8 bpm, the PSV was 10 times higher and reached 96-105 cm/s. Stroke volume (SV) per individual stimulus decreased in a similar fashion. With increasing rates of stimulation the TVF increased by a factor of 12 times (from 20 ml/min to 240 ml/min).

CONCLUSION

Electrical stimulation is an effective method of activating the calf muscle pump. Enhancements of popliteal blood velocity and volume flow are key factors in the prevention of venous stasis and DVT. Further studies are justified to determine the stimulation rates in those with a compromised venous system.

Association of plaque echostructure and cardiovascular risk factors with symptomatic carotid artery disease

AIM

Severity of stenosis remains the main factor for assessing risk of stroke in patients with internal carotid artery (ICA) disease. This study was conducted to investigate the association of plaque echostructure and other established and emerging cardiovascular risk factors with symptomatic ICA disease.

METHODS

Cross-sectional study of consecutive patients with significant (>50%) ICA stenosis. Carotid plaque echostructure, smoking, hypertension, diabetes mellitus, serum lipoprotein (a), homocysteine, vitamin B12, folate, cholesterol to high-density lipoprotein ratio, triglycerides, C-reactive protein, and the Framingham risk score were assessed in 124 consecutive patients (70 asymptomatic; 54 symptomatic) with significant (>50%) ICA stenosis.

RESULTS

The asymptomatic and symptomatic groups did not differ in terms of gender distribution (P=0.76) and severity of stenosis (P=0.62). Echolucent plaques (type 1 and 2) were more predominant in patients with symptomatic disease (P=0.004, OR=2.13, 95% CI=1.26-3.6). Patients with plaques type 1 were relatively younger than those with type 4 (P=0.02). None of the other factors assessed had any significant association with symptomatic disease and any type of carotid plaque.

CONCLUSION

Besides the severity of carotid stenosis, the presence of an echolucent plaque appears as an important factor associated with symptomatic ICA disease. Also young patients are more likely to have an echolucent plaque suggesting an age-related association with plaque maturation.

Association of plaque echostructure and cardiovascular risk factors with symptomatic carotid artery disease

BACKGROUND

Severity of stenosis remains the main factor for assessing risk of stroke in patients with internal carotid artery (ICA) disease. This study was conducted to investigate the association of plaque echostructure and other established and emerging cardiovascular risk factors with symptomatic ICA disease.

DESIGN

Cross-sectional study of consecutive patients with significant (> 50%) ICA stenosis.

PATIENTS AND METHODS

Carotid plaque echostructure, smoking, hypertension, diabetes mellitus, serum lipoprotein (a), homocysteine, vitamin B12, folate, cholesterol to high-density lipoprotein ratio, triglycerides, C-reactive protein, and the Framingham risk score were assessed in 124 consecutive patients (70 asymptomatic; 54 symptomatic) with significant (> 50%) ICA stenosis.

RESULTS

The asymptomatic and symptomatic groups did not differ in terms of gender distribution (p = 0.76) and severity of stenosis (p = 0.62). Echolucent plaques (type 1 and 2) were more predominant in patients with symptomatic disease (p = 0.004, OR = 2.13, 95% CI = 1.26-3.6). Patients with plaques type 1 were relatively younger than those with type 4 (p = 0.02). None of the other factors assessed had any significant association with symptomatic disease and any type of carotid plaque.

CONCLUSIONS

Besides the severity of carotid stenosis, the presence of an echolucent plaque appears as an important factor associated with symptomatic ICA disease. Also, young patients are more likely to have an echolucent plaque suggesting an age-related association with plaque maturation.

Leukocyte telomere length is associated with measures of subclinical atherosclerosis

AIMS

Our aim was to test the association of mean leukocyte telomere length (LTL) with ultrasonic measures of subclinical atherosclerosis such as intima-media thickness in the common carotid (IMTcc) and sum of plaque areas (SPA) and with serological markers.

METHODS AND RESULTS

Carotid and femoral bifurcations were scanned in 762 general population volunteers (46% men) over 40. Four features were considered: (a) IMTcc, (b) sum plaque areas of carotid plaques (SPAcar), (c) sum plaque area of common femoral plaques (SPAfem) and (d) sum plaque area (SPA--sum of the plaque areas of the largest plaques present in each of both carotid and femoral bifurcations). Mean LTL was determined with a quantitative real-time PCR-based method. IMTcc was strongly associated with mean LTL both before and after correction for traditional risk factors (B=-0.002; 95% CI=-0.004 to -0.00; p=0.014). In sex-specific analysis, the association was stronger in men (p for sex interaction<0.001). SPAfem was associated with LTL in women before and after correction (B=-0.195; 95% CI=-0.38 to -0.01; p=0.037) (p for sex interaction<0.001). LTL was also associated with age and sex-adjusted levels of hsCRP (p=0.012), sCD40L (p=0.042), homocysteine (p=0.006), creatinine (p=0.02), ApoA1 (p=0.01), Lp(a) (p=0.04) and HOMA-IR (p=0.008).

CONCLUSIONS

Our results support the telomere hypothesis and highlight potential differences in the biological mechanisms leading to intima-media thickening and/or plaque formation between vascular beds. They may provide insights into a novel treatment of antisenescence to prevent atherosclerosis.

Common femoral artery intima-media thickness as marker for cardiovascular disease in asymptomatic adults

BACKGROUND

The common carotid intima-media thickness (IMT) is considered as a marker of cardiovascular disease, while the value of the common femoral IMT is not well defined. The aim of the present study was to investigate the value of common femoral IMT alone or in combination with the common carotid IMT as a marker of cardiovascular disease in asymptomatic adults.

PATIENTS AND METHODS

Eighty-three individuals with no history of cardiovascular disease were subjected to IMT measurement of both common carotid and common femoral arteries with high-resolution ultrasonography. The Framingham Heart Study (FHS) risk score was calculated for each subject (according to gender) and was correlated with the carotid IMT, femoral IMT, and the combined IMT measured at both arterial sites.

RESULTS

The carotid and femoral IMT separately and in combination were found to be correlated with the FHS risk score, calculated based on either the total cholesterol or low density lipoprotein plasma levels (carotid IMT: r = 0.28, p = 0.035, and r = 0.35, p = 0.007, respectively, femoral IMT: r = 0.38, p = 0.003, and r = 0.43, p = 0.001, respectively, carotid-femoral IMT: r = 0.37, p = 0.005, and r = 0.46, p = 0.0001, respectively). In addition, femoral IMT was found to be correlated with the carotid IMT (r = 0.41, p = 0.001).

CONCLUSIONS

Common carotid and common femoral IMT showed similar correlation with the FHS risk score. Additionally, the combination of IMT from both arterial sites was found to have similar correlation with the FHS risk score to carotid IMT alone.

Combined intermittent pneumatic leg compression and pharmacological prophylaxis for prevention of venous thrombo-embolism in high-risk patients

BACKGROUND

It has been suggested that combined modalities (methods of treatment) are more effective than single modalities in preventing venous thrombo-embolism (defined as deep vein thrombosis and pulmonary embolism, or both) in high-risk patients.

OBJECTIVES

To assess the efficacy of intermittent pneumatic leg compression combined with pharmacological prophylaxis versus single modalities in preventing venous thrombo-embolism in high-risk patients.

SEARCH STRATEGY

The Cochrane Peripheral Vascular Diseases (PVD) Group searched the reference lists of their Specialised Register (last searched 17 July 2007) and the Cochrane Central Register of Controlled Trials (CENTRAL) (last searched The Cochrane Library 2008, issue 3) for relevant articles to identify additional trials.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or controlled clinical trials (CCTs) of combined intermittent pneumatic leg compression and pharmacological interventions used to prevent venous thrombo-embolism in high-risk patients.

DATA COLLECTION AND ANALYSIS

Data extraction was undertaken independently by two review authors using data extraction sheets.

Comparison of three intermittent pneumatic compression systems in patients with varicose veins: a hemodynamic study

AIM

Previous studies have demonstrated the hemodynamic impact of sequential leg compression, compared to uniform compression. The aim of this study was to compare the hemodynamic effectiveness of three compression devices: 1) circumferential sequential gradient compression (CSG); 2) a posterior uniform compression device (PU) and a posterior sequential rapid gradient inflation device (PSR).

METHODS

DESIGN OF THE STUDY

open, controlled trial. Thigh length sleeves were tested in 12 patients with primary bilateral varicose veins.

INTERVENTIONS

the three devices were tested in the semirecumbent position.

MAIN OUTCOME MEASURES

augmented flow velocity and volume flow, including the total and peak volume of blood expelled per hour during compression, were measured using duplex scanning. Refilling time was determined from velocity recordings of the common femoral vein. All values were expressed as median and interquartile range with P values obtained using the Mann-Whitney U-test.

RESULTS

Compared to the median baseline flow, all three devices increased flow during compression by 2.5-3 times (P<0.0001). The cycles per hour for the three devices CSG, PSR and PU were 78 (70-88), 60 and 60, respectively; the duplex effective compression time was 11, 12 and 6 s, respectively; single cycle volume expelled during compression was 105, 85 and 45 mL (P<0.005), respectively; the total volume expelled per hour was 7 800, 5 200 (P<0.028) and 3 300 (P<0.005) mL/hr, respectively; peak velocity increased (P<0.001) from baseline of 12 cm/s to 38 cm/s for the CSG, 33 cm/s for the PU and to 68 cm/s for the PSR.

CONCLUSION

The highest volume expelled per hour during compression was observed with the CSG and the lowest with the PSR. This was due to increased volume per cycle and more compression cycles over time, because of the CSG device's sensing of refill time. Although the peak velocity with the PSR was high, it was associated with reduced expelled volume, because of its short compression period. The PU occupied an intermediate position. The relative effectiveness of the three devices in deep vein thrombosis prevention should be tested in future studies.

Texture Analysis of Ultrasonic Images of Symptomatic Carotid Plaques can Identify Those Plaques Associated with Ipsilateral Embolic Brain Infarction

OBJECTIVES

The aim of our study was to determine the association between objective, computerised texture analysis of carotid plaque ultrasonic images and embolic CT-brain infarction in patients presenting with hemispheric neurological symptoms.

DESIGN

Cross-sectional study in patients with 50%-99% (ECST) carotid stenosis.

PATIENTS AND METHODS

Carotid plaque ultrasonic images (n=54, 26 with TIAs and 28 with stroke) obtained during carotid ultrasound were normalised and standardised for resolution and subsequently assessed visually for the presence of discrete echogenic or juxtaluminal echolucent components and overall echogenicity (plaque type). Using computer software, 51 histogram/textural features of the plaque outlines were calculated. Factor analysis was subsequently applied to eliminate redundant variables. Small cortical, large cortical and discrete subcortical infarcts on CT-brain scan were considered as being embolic.

RESULTS

Twenty-five cases (46%) had embolic infarcts. On logistic regression, grey-scale median (GSM), a measure of echolucency, spatial grey level dependence matrices (SGLDM) correlation and SGLDM information measure of correlation-1, measures of homogeneity were significant (p<0.05), but not grey level runlength statistics (RUNL) Run Percentage (RP), stenosis severity, type of symptoms or echolucent juxtaluminal components. Using ROC curves methodology, SGLDM information measure of correlation-1 improved the value of GSM in distinguishing embolic from non-embolic CT-brain infarction.

CONCLUSION

Computerised texture analysis of ultrasonic images of symptomatic carotid plaques can identify those that are associated with brain infarction, improving the results achieved by GSM alone. This methodology could be applied to prospective natural history studies of symptomatic patients not operated on or randomised trials of patients undergoing carotid angioplasty and stenting in order to identify high-risk subgroups for cerebral infarction.

Characterization of carotid atherosclerosis based on motion and texture features and clustering using fuzzy c-means

Analysis of B-mode ultrasound images of the carotid atheromatous plaque includes the estimation of texture from static images and the estimation of motion from image sequences. The combination of these two types of information may be valuable for accurate diagnosis of vascular disease. The purpose of this paper was to study texture and motion patterns of carotid atherosclerosis and select the optimal combination of features that can characterize plaque. B-mode ultrasound images of 10 symptomatic and 9 asymptomatic plaques were interrogated. A total of 99 texture features were estimated using first-order statistics, second-order statistics, Laws texture energy and the fractal dimension. Only five texture features were significantly different between the two groups. In the same subjects, the motion of selected plaque regions was estimated using region tracking and block-matching and expressed through: a/maximal surface velocity (MSV), and b/maximal relative surface velocity (MRSV). MSV and MRSV were significantly lower in asymptomatic plaques suggesting more homogeneous motion patterns. Clustering using fuzzy c-means correctly classified 74% of plaques based on texture features only, and 79% of plaques based on motion features only. Classification performance reached 84% when a combination of motion and texture features was used.

Haemodynamic and Clinical Impact of Superficial, Deep and Perforator Vein Incompetence

OBJECTIVE

The purpose of this study was to assess the effect of venous incompetence of the deep, superficial and perforator veins combined (i.e. multi-system incompetence) on the venous haemodynamics and clinical condition of limbs with chronic venous disease (CVD).

METHODS

One hundred and thirty two limbs (16-C(1); 30-C(2); 20-C(3); 25-C(4); 21-C(5); 20-C(6)) of 121 patients were studied. We excluded those with previous venous surgery/sclerotherapy, peripheral arterial disease, recent deep vein thrombosis (< or =6 months), or inability to comply with the tests. The CEAP clinical class was assessed. Duplex ultrasonography (ultrasound) enabled classification according to: the presence of superficial([S]) (+/- perforator([P])) or deep([D]) (+/-S, +/-P) reflux (>.5s); the number of incompetent venous systems (single-system([S/P/D]), dual-system([S+P/S+D/P+D]), or triple-system([S+P+D])), and the number of incompetent perforators([0/1/2/> or =3]). The amount of reflux (Venous Filling Index([VFI])); calf pump Ejection Fraction([EF]), and Residual Volume Fraction([RVF]) were studied with air-plethysmography.

RESULTS

VFI in limbs with triple-system incompetence (VFI median 6.68 [IQR: 4.7-9.7]ml/s) was higher than in limbs with dual-system incompetence (4.5 [2.1-7.4]ml/s), and VFI in the latter was higher than in limbs with single-system incompetence (1.3 [0.69-2.3]ml/s)(p<0.01 Kruskal-Wallis). Although EF changes were small, RVF in limbs with triple-incompetence (39 [30-51] %) was higher than in single-system incompetence (26 [16-33] %)(p<0.01 Mann-Whitney). Limbs with superficial (+/-P) incompetence had a lower VFI (p<0.01) and RVF (p<0.02) than limbs with deep (+/-S+/-P) incompetence, and limbs with > or =2 incompetent perforator veins had a higher VFI (p<0.04) than those without perforators. All limbs with single-system incompetence were C(1-3,) whereas 78% of those with triple-incompetence were C(4-6) (p<0.01). The number of incompetent systems increased with clinical class (p<0.01).

CONCLUSIONS

The frequency of incompetence of more than one venous system increased with the clinical severity of venous disease and was accompanied by a 5-fold increase in the amount of reflux and a 50% rise in the RVF. The number of incompetent perforators per limb increased with the amount of reflux. The number of incompetent venous systems (superficial, deep, perforator) and perforator veins can be assessed by duplex ultrasound giving an objective indication of the functional severity of venous disease. In this way duplex ultrasound could be used to grade venous function in clinical practice as an alternative to APG measures which are less widely available.

Comparison of two intermittent pneumatic compression systems. A hemodynamic study

AIM

Sequential leg compression has been previously shown to be superior to uniform compression. The aim of our study was to compare the hemodynamic effectiveness of the portable sequential compression device (SCD Express Compression System, Tyco Healthcare Group LP, Mansfield, MA, USA) with a rapid inflation device (VenaFlow, Aircast, Inc, Summit, NJ, USA). The former, by sensing venous refill time, commences compression when the calf veins are refilled.

METHODS

The two devices were tested in 12 normal volunteers in the semirecumbent position using duplex ultrasound. Baseline and augmented flow velocity and volume flow were measured at the level of the common femoral vein, above the saphenofemoral junction. Refilling time was determined from velocity recordings of the common femoral vein. Total and peak volume of blood expelled per hour during compression were calculated using flow data and the individual cycling rate.

RESULTS

Both devices increased venous flow velocity, up to 3.8 times the baseline (all P<0.001). Refill time of the rapid inflation device was shorter in comparison with the sequential compression device (15+/-2.2 vs 25+/-4 s; P<0.001), suggesting incomplete vein evacuation. The sequential compression device, by augmenting flow throughout a significantly longer compression period per cycle (10.9 s vs 6.3 s), expelled significantly more venous blood (121+/-68 vs 81+/-63 mL; P<0.001). Similarly, the total volume of blood expelled per hour with the sequential compression device was 100% higher than the rapid inflation device (9685+/-5426 vs 4853+/-3658 mL; P<0.001). Although peak velocity enhancement was higher with the rapid inflation device, flow augmentation (a product of average blood flow velocity) was comparable (669+/-367 vs 771+/-574 cm/s; P=0.223) with the sequential compression device, mainly because the rapid inflation device failed to maintain flow enhancement beyond the initial flow surge.

CONCLUSIONS

Sequential compression showed hemodynamic superiority compared to a rapid inflation device. This was enhanced further by the sensing of refill time, which resulted in more compression cycles over time. The relative efficacy of the two devices in deep vein thrombosis prevention should be tested in future studies.

Severity of Asymptomatic Carotid Stenosis and Risk of Ipsilateral Hemispheric Ischaemic Events: Results from the ACSRS Study

OBJECTIVES

This study determines the risk of ipsilateral ischaemic neurological events in relation to the degree of asymptomatic carotid stenosis and other risk factors.

METHODS

Patients (n=1115) with asymptomatic internal carotid artery (ICA) stenosis greater than 50% in relation to the bulb diameter were followed up for a period of 6-84 (mean 37.1) months. Stenosis was graded using duplex, and clinical and biochemical risk factors were recorded.

RESULTS

The relationship between ICA stenosis and event rate is linear when stenosis is expressed by the ECST method, but S-shaped if expressed by the NASCET method. In addition to the ECST grade of stenosis (RR 1.6; 95% CI 1.21-2.15), history of contralateral TIAs (RR 3.0; 95% CI 1.90-4.73) and creatinine in excess of 85 micromol/L (RR 2.1; 95% CI 1.23-3.65) were independent risk predictors. The combination of these three risk factors can identify a high-risk group (7.3% annual event rate and 4.3% annual stroke rate) and a low risk group (2.3% annual event rate and 0.7% annual stroke rate).

CONCLUSIONS

Linearity between ECST per cent stenosis and risk makes this method for grading stenosis more amenable to risk prediction without any transformation not only in clinical practice but also when multivariable analysis is to be used. Identification of additional risk factors provides a new approach to risk stratification and should help refine the indications for carotid endarterectomy.

Improvement of the Walking Ability in Intermittent Claudication due to Superficial Femoral Artery Occlusion with Supervised Exercise and Pneumatic Foot and Calf Compression: A Randomised Controlled Trial

OBJECTIVES

To compare the effect of unsupervised exercise, supervised exercise and intermittent pneumatic foot and calf compression (IPC) on the claudication distance, lower limb arterial haemodynamics and quality of life of patients with intermittent claudication.

METHODS

Thirty-four eligible patients with stable intermittent claudication were randomised to IPC (n = 13, 3h/d for 6 months), supervised exercise (n = 12, three hourly sessions/week for 6 months) or unsupervised exercise (n = 9). In each patient, initial claudication distance (ICD), absolute claudication distance (ACD), resting ankle brachial pressure index (ABPI), and resting hyperaemic calf arterial inflow were measured before, 6 weeks, 6 months and 1 year after randomisation. Quality of life was assessed with the short form (SF)-36, walking impairment (WIQ) and intermittent claudication questionnaires (ICQ).

RESULTS

Compared with unsupervised exercise, both IPC and supervised exercise, increased ICD and ACD, up to 2.83 times. IPC increased arterial inflow (p < 0.05 at 6 weeks) and ABPI. Supervised exercise decreased arterial inflow and increased ABPI (p < 0.05 at 6 months). Unsupervised exercise had no effect on arterial inflow or ABPI. IPC improved significantly the ICQ score and the speed score of the WIQ, while supervised exercise improved the WIQ claudication severity score. At 1 year clinical effectiveness of supervised exercise and IPC was largely preserved.

CONCLUSIONS

IPC, by augmenting leg perfusion, achieved improvement in walking distance comparable with supervised exercise. Long-term results in a larger number of patients will provide valuable information on the optimal treatment modality of intermittent claudication.