Thrombophilia testing has limited usefulness in clinical decision-making and should be used selectively.

Management of venous thromboembolism (VTE) includes evaluation for hypercoagulable state, especially if the VTE occurs in young patients, is recurrent, or is associated with a positive family history. These laboratory tests are costly, and surprisingly, there is little evidence showing that testing leads to improved clinical outcomes. Evidence based on observational prospective studies suggests that optimal duration of anticoagulation should be based on clinical risks resulting in VTE, such as transient, permanent, and idiopathic or unprovoked risks, and less on abnormal thrombophilia values. Thrombophilia screening is important in a subgroup of clinical scenarios, such as when there is clinical suspicion of antiphospholipid antibody syndrome, heparin resistance, or warfarin necrosis; with thrombosis occurring in unusual sites (such as mesenteric or cerebral deep venous thrombosis); and for pregnant women or those seeking pregnancy or considering estrogen-based agents. Thrombophilia screening is not likely to be helpful in most cases of first-time unprovoked VTE in the setting of transient risks, active malignant disease, deep venous thrombosis of upper extremity veins or from central lines, two or more VTEs, or arterial thrombosis with pre-existing atherosclerotic risk factors. The desire by both patient and physician for a scientific explanation of the clotting event may alone lead to testing, and if so, it should be with the understanding that an abnormal test result will likely not change management, and normal results do not accurately exclude a thrombophilic defect because there are likely factors yet to be discovered. Such false assumptions may lead to shorter durations of treatment than are optimal.

On the existence of helical flow in veins of the lower extremities.

PURPOSE: Helical flow has been shown to be present in the heart and arteries, but its existence in veins has not been demonstrated before. This study aimed to investigate if helical flow is present in the venous system and if the venous valves contribute to development of this flow pattern. METHODS: Color and spectral Doppler were used to calculate the true velocity vectors at five cross-sectional planes of the femoral and common femoral veins in 10 healthy individuals and eight patients with chronic venous disease. RESULTS: This study demonstrated that helical flow is a normal finding in the segments of veins that are in close proximity and downstream from a venous valve and a venous junction. This flow pattern is more prevalent when the calf muscle pump is active. Incompetence of the proximal great saphenous vein affects the outflow pattern, so that the helical flow is no longer present and is replaced by disorganized turbulent flow. CONCLUSIONS: These findings suggest that helical flow is detectable, may have a physiological role in venous circulation, and the absence of it may be a feature of venous disease.

Pretreatment elevated D-dimer levels without systemic inflammatory response are associated with thrombotic complications of thermal ablation of the great saphenous vein.

OBJECTIVE: To examine possible association of plasma levels of biomarkers of inflammation and hemostatic activation with the incidence of thrombotic complications after thermal ablation of the great saphenous vein (GSV). METHODS: This was a prospective cohort study of 120 patients with primary chronic venous disease and reflux limited to the GSV and its tributaries, who were to undergo treatment with radiofrequency ablation of the GSV. Plasma concentration of C-reactive protein (high-sensitivity CRP) and D-dimer were measured immediately prior to the ablation procedure, and in 64 patients, at 20 to 36 hours, 1 week, and 1 month after the treatment. A complete bilateral duplex ultrasound scan was performed prior to treatment, within the first 36 hours and at 1 month after treatment. Incidence of thrombotic complications was based on findings of duplex ultrasound scans. RESULTS: Sixteen patients developed thrombotic complications. These included seven endovenous heat-induced thromboses, seven thromboses of untreated superficial veins, one thrombosis of the posterior tibial vein, and one gastrocnemius vein thrombosis. In two patients, endovenous heat-induced thromboses coincided with superficial phlebitis. Multivariate analysis showed that patients who had a combination of normal baseline levels of CRP and elevated levels of D-dimer were more than seven times more likely to develop thrombotic complications compared with all other patients (odds ratio, 7.3; 95% confidence interval, 2.2-23.9; P = .002). Both CRP and D-dimer levels significantly increased at 24 to 36 hours and returned to the baseline values at 1 month after the treatment. The D-dimer levels were significantly higher in patients with thrombotic complications at the baseline, 24 to 36 hours and 1 week after the treatment but became not statistically significant a month after the treatment. CONCLUSIONS: These findings suggest that preoperative activation of the hemostatic system plays an important role in the development of thrombotic complications after thermal ablation of the GSV and that such activation can be detected by commonly used clinical practice laboratory tests.

Multicenter assessment of venous reflux by duplex ultrasound.

OBJECTIVE: This prospective multicenter investigation was conducted to define the repeatability of duplex-based identification of venous reflux and the relative effect of key parameters on the reproducibility of the test. METHODS: Repeatability was studied by having the same technologist perform duplicate tests, at the same time of the day, using the same reflux-provoking maneuver and with the patient in the same position. Reproducibility was examined by having two different technologists perform the test at the same time of the day, using the same reflux-provoking maneuver and with the patient in the same position. Facilitated reproducibility was studied by having two different technologists examine the same patients immediately after an educational intervention. Limits of agreement between two duplex scans were studied by changing three elements of the test: time of the day (morning vs afternoon), patient's position (standing vs supine), and reflux initiation (manual vs automatic compression-decompression). RESULTS: The study enrolled 17 healthy volunteers and 57 patients with primary chronic venous disease. Repeatability of reflux time measurements in deep veins did not significantly differ with the time of day, the patient's position, or the reflux-provoking maneuver. Reflux measurements in the superficial veins were more repeatable (P < .05) when performed in the morning with the patient standing. The agreement between the clinical interpretations significantly depended on a selected cut point (Spearman's ρ, -0.4; P < .01). Interpretations agreed in 93.4% of the replicated measurements when a 0.5-second cut point was selected. The training intervention improved the frequency of agreement to 94.4% (κ = 0.9). Alternations of the time of the duplex scan, the patient's position, and the reflux-provoking maneuver significantly decreased reliability. CONCLUSIONS: This study provides evidence to develop a new standard for duplex ultrasound detection of venous reflux. Reports should include information on the time of the test, the patient's position, and the provoking maneuver used. Adopting a uniform cut point of 0.5 second for pathologic reflux can significantly improve the reliability of reflux detection. Implementation of a standard protocol should elevate the minimal standard for agreement between repeated tests from the current 70% to at least 80% and with more rigid standardization, to 90%.

The controversy of managing calf vein thrombosis.

BACKGROUND: Controversy persists as to whether all calf vein thrombi should be treated with anticoagulation or observed with duplex surveillance. We performed a systematic review of the literature to assess whether data could support either approach, followed by examination of its natural history by stratifying results according to early clot propagation, pulmonary emboli (PE), recurrence, and postthrombotic syndrome (PTS). METHODS: A total of 1513 articles were reviewed that were published from January 1975 to August 2010 using computerized database searches of PubMed, Cochrane Controlled Trials Register, and extensive cross-references. English-language studies specifically examining calf deep vein thrombosis (C-DVT) defined as axial and/or muscular veins of the calf, not involving the popliteal vein, were included. Papers were independently reviewed by two investigators (E.M., F.L.) and quality graded based on nine methodologic standards reporting on four outcome parameters. RESULTS: Of the 1513 citations reviewed, 31 relevant papers meeting predefined criteria were found: six randomized controlled trials (RCT) and 25 observational cohort studies or case series. There was a single RCT directly comparing anticoagulation with no anticoagulation with compression and duplex surveillance, and they found no difference in propagation, PE, or bleeding in a low-risk population. Based on two studies of moderately strong methodology, C-DVT propagation was reduced with anticoagulation. When treatment was unassigned, moderately strong evidence suggested that about 15% propagate to the popliteal vein or higher. However, based on nonrandomized data but with moderate to high quality (level A and B studies), propagation to popliteal or higher was 8% in those with no anticoagulation treated with surveillance only. Propagation involving adjacent calf veins but remaining in the calf occured in up to one-half of all those who propagate. Major bleeding was an intended endpoint in three RCTs and was reported as 0% to 6%, with a trend toward lower bleeding risk in more recent studies. PE during surveillance in studies with unassigned treatment was strikingly lower than the historical reports of PE recorded at presentation, emphasizing the distinction that must be made between the two entities. Recurrence in C-DVT is lower than thigh DVT, and data suggest that in low-risk groups with transient risk factors, 6 weeks of anticoagulation may be sufficient, as opposed to 12 weeks. Studies of PTS reported that patients with C-DVT had fewer symptoms than their thigh DVT counterparts. Approximately one out of 10 showed symptoms of CEAP Class 4 to 6; however, C5 or C6 with healed or active ulceration were not commonly encountered. CONCLUSIONS: No study of strong methodology could be found to resolve the controversy of optimal treatment of C-DVT. Given the risks of propagation, PE, and recurrence, the option of doing nothing should be considered unacceptable. In the absence of strong evidence to support anticoagulation over imaging surveillance with selective anticoagulation, either method of managing calf DVT must remain as current acceptable standards.

Trends in patient reported outcomes of conservative and surgical treatment of primary chronic venous disease contradict current practices.

OBJECTIVE: To analyze patient-reported quality of life (QOL) and symptoms in a prospective cohort of CVD patients who was managed within the framework of existing policies. STUDY DESIGN: Prospective cohort study of 150 patients with C2-C4 clinical class of primary chronic venous disease (CVD). Management consisted of initial conservative measures, following which, the patients were given a choice of continuing conservative therapy, or surgical treatment. Patients completed Specific Quality of Life and Outcome Response--Venous (SQOR-V) tool before initial visit, after completion of conservative treatment, and at 1 and 12 month follow up visits after surgical treatment. Management consisted of initial conservative measures. QOL score and symptom score (SS) part of this instrument was analyzed separately. RESULTS: Conservative treatment resulted in improvement of symptom score in 85(57%) patients, and the QOL in 111(74%) patients. Despite this improvement, the majority of patients (121) chose surgical option. At the 1-month follow up after surgical treatment 97 (80%) patients reported significant improvement of their symptoms and 114 (94%) in the QOL compare to their status after conservative therapy. The QOL improvement was due mainly to improvement in symptom score. Patients who improved after conservative therapy were more than 15 times more likely to have symptoms relief at 1 month (RR = 15.6, 95% CI 4.3-56.5), and 21 times higher at 1 year after surgery (RR = 21.3, 95% CI 4.7-96.9) compared with those who did not change the SS. CONCLUSIONS: Surgical treatment resulted in a better relief of symptoms compare to conservative therapy. The relief of symptoms after conservative therapy predicts better outcomes of surgical treatment. These findings suggest that success of conservative therapy should be considered as an indication, and the failure of conservative therapy should not be an indication to surgical treatment.

On the mechanism of action of pneumatic compression devices: Combined magnetic resonance imaging and duplex ultrasound investigation.

OBJECTIVE: This study investigated the relationships between the interface pressure produced by intermittent pneumatic compression (IPC) devices, the deformation of extremity tissues produced by this pressure, and changes in venous blood flow associated with this deformation by use of magnetic resonance imaging (MRI) and duplex ultrasound (DUS) imaging in addition to the pressure measurement. METHODS: The calf garments of two IPC devices (WizAir, Medical Compression Systems, Inc, Ltd, Or-Akiva, Israel; VenaFlow, AirCast Inc, Summit, NJ) were tested in five healthy volunteers. The interface pressure was measured with Tactilus Human Body Interface sensor system (Sensor Products Inc, Madison, NJ). Changes in tissue volumes were assessed with MRI. Velocity and flow changes in the great saphenous vein (GSV) and femoral veins (FV) were evaluated by DUS scans. RESULTS: The spatial distribution of interface pressure differed substantially between the two devices. These differences were in the location and percentage of calf surface area to which different pressure was applied. Both devices produced the tissue compression consistent with each device's unique pattern of the interface pressure distribution. Compression by the IPC devices was associated with a measurable decrease in the volume of subcutaneous tissue under the garment, the total volume of superficial veins, and the volume of the GSV. No measurable changes occurred in subfascial volume of the calf. Compression was associated with significant increase in flow velocities in the GSV and FV. The increase of volume flow was significant in FV, but not in GSV. Comparing hemodynamic data with MRI data showed that the flow velocity increase in FV and GSV caused by IPC highly correlated with decrease in volume of superficial veins and subcutaneous tissue measured by MRI, but not with changes in subfascial volume. A single strongest predictor of venous flow increase was the change in subcutaneous veins volume. CONCLUSIONS: This methodology provides means for the investigation of relationships between the pressure in the garment, interface pressure, tissue deformation, and hemodynamic respond to IPC. The clinical efficacy of IPC should not be explicitly attributed to the magnitude of the pressure in the garment. Similar hemodynamic responses to IPC can be produced by different spatial distributions of pressure resulting in different patterns of tissue compression. Further investigation of biomechanical mechanisms of IPC is needed to guide the development of better engineering solutions for mechanical devices aimed at prevention of venous thrombosis.

Primary chronic venous disorders.

Primary chronic venous disorders, which according to the CEAP classification are those not associated with an identifiable mechanism of venous dysfunction, are among the most common in Western populations. Varicose veins without skin changes are present in about 20% of the population while active ulcers may be present in as many as 0.5%. Primary venous disorders are thought to arise from intrinsic structural and biochemical abnormalities of the vein wall. Advanced cases may be associated with skin changes and ulceration arising from extravasation of macromolecules and red blood cells leading to endothelial cell activation, leukocyte diapedesis, and altered tissue remodeling with intense collagen deposition. Laboratory evaluation of patients with primary venous disorders includes venous duplex ultrasonography performed in the upright position, occasionally supplemented with plethysmography and, when deep venous reconstruction is contemplated, ascending and descending venography. Primary venous disease is most often associated with truncal saphenous insufficiency. Although historically treated with stripping of the saphenous vein and interruption and removal of major tributary and perforating veins, a variety of endovenous techniques are now available to ablate the saphenous veins and have generally been demonstrated to be safe and less morbid than traditional procedures. Sclerotherapy also has an important role in the management of telangiectasias; primary, residual, or recurrent varicosities without connection to incompetent venous trunks; and congenital venous malformations. The introduction of ultrasound guided foam sclerotherapy has broadened potential indications to include treatment of the main saphenous trunks, varicose tributaries, and perforating veins. Surgical repair of incompetent deep venous valves has been reported to be an effective procedure in nonrandomized series, but appropriate case selection is critical to successful outcomes.

Prevention of air travel-related deep venous thrombosis with mechanical devices: active foot movements produce similar hemodynamic effects.

OBJECTIVE: We compared the hemodynamic effects of different mechanical devices aimed for prevention of travel-related deep venous thrombosis with active foot movements. METHODS: Two battery-operated intermittent pneumatic compression (IPC) devices and three foot and calf muscle pump facilitating devices (PFD) that claimed to prevent travel-related deep venous thrombosis were tested in 17 healthy volunteers on the ground and in 8 of same volunteers during flight. Flow changes during active foot movements were compared with the effects of each of the tested devices. RESULTS: There was no significant difference in hemodynamic effect between PFDs and active foot movements. The hemodynamic effects of IPC devices were significantly less compared with active foot movements. Values obtained during air flights were not significantly different from those obtained on the ground. CONCLUSIONS: Whereas IPC use for prevention of venous stasis during flight can be justified for immobile patients or during sleep, PFDs do not provide additional hemodynamic benefits compared with simple movements of the foot.

The effect of ultrasound-guided sclerotherapy of incompetent perforator veins on venous clinical severity and disability scores.

PURPOSE: Current techniques to treat venous ulcerations and patients with severe lipodermatosclerosis include the elimination of incompetent perforator veins by open surgical ligation and division or by subfascial endoscopic perforator surgery. An alternative and less invasive means to obliterate perforator veins is ultrasound-guided sclerotherapy (UGS). We hypothesize that UGS is a clinically effective means of eliminating perforator veins and results in improvement of the clinical state (scores) without the complications associated with other more invasive methods. METHODS: Between January 2000 and March 2004, UGS was used to treat chronic venous insufficiency in 80 limbs of 68 patients. This was a clinical series of patients who had perforator incompetence and no previous surgery for venous disease < or = 2 years of their UGS procedure. Most had perforator disease without coexisting axial reflux of the saphenous or deep venous systems. Color flow duplex scanning was used to identify incompetent perforator veins in the calf, and duplex guidance was used to inject each perforator with the liquid sclerosant sodium morrhuate (5%). Patients were restudied by duplex scanning up to 5 years after treatment. Clinical results were determined by Venous Clinical Severity Score (VCSS) and Venous Disability Score (VDS) before and after treatment. RESULTS: Of the 80 limbs treated with UGS, 98% of incompetent perforators were successfully obliterated at the time of treatment, and 75% of limbs showed persistent occlusion of perforators and remained clinically improved with a mean follow-up of 20.1 months. According to the CEAP classification, there were 46.2% with limb ulceration or C6, 1.2% C5, 28.7% C4, 17.5% C3, and 6.2% C2 with pain isolated to the site of the perforator(s). Of those who returned for follow-up, the VCSSs changed from a median of 8 before treatment (95% confidence interval [CI], 3 to 15) to a median of 2 after treatment (95% CI, 0 to 7) (P < .01). Likewise, VDSs dropped from a median of 4 before treatment (95% CI, 1 to 3) to 1 after treatment (95% CI, 0 to 2) (P < .01). There were no cases of deep vein thrombosis involving the deep vein adjacent to the perforator injected. One patient had skin complications with skin necrosis. Perforator recurrence was found more frequently in those with ulcerations than those without. CONCLUSION: UGS is an effective and durable method of eliminating incompetent perforator veins and results in significant reduction of symptoms and signs as determined by venous clinical scores. As an alternative to open interruption or subfascial endoscopic perforator surgery, UGS may lead to fewer skin and wound healing complications. Perforator recurrence occurs particularly in those with ulcerations, and therefore, surveillance duplex scanning after UGS and repeat injections may be needed.

Revision of the CEAP classification for chronic venous disorders: consensus statement.

The CEAP classification for chronic venous disorders (CVD) was developed in 1994 by an international ad hoc committee of the American Venous Forum, endorsed by the Society for Vascular Surgery, and incorporated into "Reporting Standards in Venous Disease" in 1995. Today most published clinical papers on CVD use all or portions of CEAP. Rather than have it stand as a static classification system, an ad hoc committee of the American Venous Forum, working with an international liaison committee, has recommended a number of practical changes, detailed in this consensus report. These include refinement of several definitions used in describing CVD; refinement of the C classes of CEAP; addition of the descriptor n (no venous abnormality identified); elaboration of the date of classification and level of investigation; and as a simpler alternative to the full (advanced) CEAP classification, introduction of a basic CEAP version. It is important to stress that CEAP is a descriptive classification, whereas venous severity scoring and quality of life scores are instruments for longitudinal research to assess outcomes.

Reflux from thigh to calf, the major pathology in chronic venous ulcer disease: surgery indicated in the majority of patients.

The aim of this study was to define the underlying anatomical and pathophysiological conditions in limbs with venous ulcers in order to get information for the most appropriate treatment selection. Ninety-eight limbs (83 patients, 59 men), with active chronic venous ulcers, were analyzed retrospectively and classified according to the CEAP (clinical, etiological, anatomical, and pathophysiological) classification. Duplex-ultrasound was performed in all patients, while air-plethysmography and venography were performed selectively on potential candidates for deep venous reconstruction. Sixty-six ulcers were primary in origin and 32 were secondary. Reflux was present in all limbs except 1. Isolated reflux in 1 system (superficial = 3, deep = 4, perforator = 3) was seen in 10 legs (10%), while incompetence in all 3 systems was seen in 51 legs (52%). Superficial reflux with or without involvement of other systems was seen in 84 legs (86%), 72 legs (73%) had deep reflux with or without involvement of other systems, and incompetent perforator veins were identified in 79 limbs (81%). Axial reflux (continuous reverse flow from the groin region to below knee) was found in 77 limbs (79%). The femoral vein was the single most common deep venous segment in which either reflux or obstruction was found. Axial distribution of disease was found in the majority of cases and no patient had isolated deep venous incompetence below knee. Primary disease was the predominant etiologic cause and reflux was the main pathophysiological finding. Practically all patients were found to have 1 or more sites of reflux or obstruction that could benefit from operative treatment.

Effect of ethnicity on access and device complications during endovascular aneurysm repair.

INTRODUCTION: There are no published reports on the association between ethnicity and outcome after aortoiliac stent grafting to treat aneurismal disease. Because Hawaii is a state with an ethnically diverse population, we conducted a retrospective study to examine this potential association. We hypothesized that individuals of Asian ancestry may have higher complication rates after endovascular repair compared with non-Asians. METHODS: All endovascular devices placed to treat aneurysm disease from 1996 to 2003 were evaluated in two institutions. The association between ethnicity and access-related and device-related complications, both periprocedural and delayed, was examined with logistic regression analysis. RESULTS: Ninety-two aortoiliac endografts were placed during the study period, including 87 in patients with abdominal aortic aneurysms with or without iliac aneurysm disease, and five patients with isolated iliac artery aneurysms. Forty-four percent of patients were categorized as Asian, 39% as white, 16% as Pacific Islander, and 1% as African American. Access-related and device-related complications (ADRCs) occurred in 11 of 92 (12%) of these patients. The following parameters were significantly associated with ADRCs: Asian ethnicity (P =.015), age greater than 80 years (P =.02), and external iliac diameter smaller than 7.5 mm (P =.01). Asian patients were more likely to have experienced ADRCs than were non-Asian patients (odds ratio, 7.3; 95% confidence interval, 1.5-35.8; P =.015). Asians also had smaller external iliac artery diameters (P =.0003) and more tortuous iliac arteries (P =.03) compared with non-Asians. After adjusting for iliac artery diameter and tortuosity, the association between Asian ethnicity and ARDCs became nonsignificant (P =.074), which suggests that the association between race and complications may be at least in part due to small and tortuous iliac arteries. There was no association between age, gender, or ethnicity and postoperative detection of endoleak. CONCLUSION: Our data indicate that individuals of Asian ancestry are far more likely to experience adverse access-related and device-related complications after aortoiliac stent grafting than are non-Asians. We found that this association is at least partly attributable to the smaller and more tortuous iliac arteries in persons of Asian ancestry.

Surgical disobliteration of postthrombotic deep veins--endophlebectomy--is feasible.

OBJECTIVE: Partial obstruction of postthrombotic veins is caused by endovenous scar tissue, which creates synechiae and septae that narrow and sometimes block the lumen. We have performed surgical disobliteration, or endophlebectomy, of chronically obstructed venous segments during various kinds of deep venous reconstructions to increase the flow through previously obstructed segments. In this article we describe the endophlebectomy technique, and report the availability of this procedure as an adjunct to deep venous reconstructions for the treatment of postthrombotic chronic venous insufficiency. Patients and methods Between July 1996 and February 2003, surgical disobstruction of 23 deep venous segments was performed in 13 patients in association with 14 deep venous reconstructions to treat advanced postthrombotic chronic venous insufficiency. Postthrombotic veins were surgically exposed, and a longitudinal venotomy was carried out at a variable length. The synechiae and masses attached to the intimal layer were carefully excised. Mean duplex scanning follow-up was 10.8 +/- 8.2 months (median, 8 months; range, 1-28 months). RESULTS: In 10 patients (77%) the treated segments remained primarily patent at median follow-up of 8 months (range, 1-28 months). Early thrombosis near the endophlebectomy site occurred in 3 patients, at 2, 5, and 12 days, respectively, after surgery. In 2 patients with early thrombosis further interventions were carried out with success. In a third patient with early postoperative thrombosis the final outcome was recanalization and reflux. These results yielded an overall secondary patency rate of 93%. No perioperative pulmonary embolism was observed. CONCLUSION: This series demonstrates that surgical disobliteration of postthrombotic deep veins is technically feasible, and led to patency of the segments for the duration of follow-up for up to 28 months (mean, 10.8 +/- 8.2 months). We used this technique with the objective of disobstructing postthrombotic veins, to increase flow through a previously narrowed lumen. Postoperative thrombosis at the site of endophlebectomy occurred in 23% of patients. Although this early experience is encouraging, further studies and longer follow-up are necessary to assess the durability of the procedure.

Deep axial reflux, an important contributor to skin changes or ulcer in chronic venous disease.

OBJECTIVE: We undertook this cross-sectional study to investigate the distribution of venous reflux and effect of axial reflux in superficial and deep veins and to determine the clinical value of quantifying peak reverse flow velocity and reflux time in limbs with chronic venous disease. PATIENTS AND METHODS: Four hundred one legs (127 with skin changes, 274 without skin changes) in 272 patients were examined with duplex ultrasound scanning, and peak reverse flow velocity and reflux time were measured. Both parameters were graded on a scale of 0 to 4. The sum of reverse flow scores was calculated from seven venous segments, three in superficial veins (great saphenous vein at saphenofemoral junction, great saphenous vein below knee, small saphenous vein) and four in deep veins (common femoral vein, femoral vein, deep femoral vein, popliteal vein). Axial reflux was defined as reflux in the great saphenous vein above and below the knee or in the femoral vein to the popliteal vein below the knee. Reflux parameters and presence or absence of axial reflux in superficial or deep veins were correlated with prevalence of skin changes or ulcer (CEAP class 4-6). RESULTS: The most common anatomic presentation was incompetence in all three systems (superficial, deep, perforator; 46%) or in superficial or perforator veins (28%). Isolated reflux in one system only was rare (15%; superficial, 28 legs; deep, 14 legs; perforator, 18 legs). Deep venous incompetence was present in 244 legs (61%). If common femoral vein reflux was excluded, prevalence of deep venous incompetence was 52%. The cause, according to findings at duplex ultrasound scanning, was primary in 302 legs (75%) and secondary in 99 legs (25%). Presence of axial deep venous reflux increased significantly with prevalence of skin changes or ulcer (C4-C6; odds ratio [OR], 2.7; 95% confidence interval [CI], 1.56-4.67). Of 110 extremities with incompetent popliteal vein, 81 legs had even femoral vein reflux, with significantly more skin changes or ulcer, compared with 29 legs with popliteal reflux alone (P =.025). Legs with skin changes or ulcer had significantly higher total peak reverse flow velocity (P =.006), but the difference for total reflux time did not reach significance (P =.084) compared with legs without skin changes. In contrast, presence of axial reflux in superficial veins did not increase prevalence of skin changes (OR, 0.73; 95% CI, 0.44-1.2). Incompetent perforator veins were observed as often in patients with no skin changes (C0-C3, 215 of 274, 78%) as in patients with skin changes (C4-C6, 106 of 127, 83%; P =.25). CONCLUSION: Continuous axial deep venous reflux is a major contributor to increased prevalence of skin changes or ulcer in patients with chronic venous disease compared with segmental deep venous reflux above or below the knee only. The total peak reverse flow velocity score is significantly higher in patients with skin changes or ulcer. It is questionable whether peak reverse flow velocity and reflux time can be used to quantify venous reflux; however, if they are used, peak reverse flow velocity seems to reflect venous malfunction more appropriately.

Mechanism of venous valve closure and role of the valve in circulation: a new concept.

PURPOSE: The purpose of this study was to investigate the blood flow changes and venous wall movements that occur in the perivalvular area during venous flow, to learn how these physiologic events influence the movements of the valve cusps, and to learn how the movements of the valve cusps influence the venous flow. MATERIALS AND METHODS: Twenty healthy volunteers (10 male, 10 female, age 18 to 52) were subjects of this study. Each volunteer was examined in semi-recumbent and standing positions at rest and during active foot movements. Ultrasound examinations were performed in the B-flow mode supplemented by B-mode and pulsed-wave Doppler scanning. RESULTS: Four phases of the valve cycle are described. During the opening phase (0.27 +/- 0.05 s), the cusps move from the closed position toward the sinus wall. After reaching a certain point, the valves cease opening and enter the equilibrium phase. During this phase (0.65 +/- 0.08 s), the leading edges remain suspended in the flowing stream and undergo self-excited oscillations with an amplitude of 0.01 to 0.16 cm. During the closing phase (0.41 +/- 0.07 sec), the leaflets move synchronously toward the center of the vein. The subsequent closed phase has a duration of 0.45 +/- 0.05 seconds when the cusps remain closed. During the equilibrium phase, flow separation occurs at the leading edge of the cusp with reattachment at the wall of sinus. At this point, flow splits into two streams at each valve cusp. Part of the flow is directed into the sinus pocket behind the valve cusp, forming a vortex along the valve cusp before re-emerging in the main stream in the vein. When the valve is maximally open, the two cusps create a narrowing of the lumen about 35% smaller than the vein distal to the valve. In this narrowed area flow accelerates, forming a proximally directed jet. CONCLUSIONS: The valve cusps undergo the four phases constituting the valve cycle. The local hemodynamic events, such as flow separation and reattachment, and vortical flow in the sinus play important roles in the valve operation. In addition to prevention of retrograde flow, the valve acts as a venous flow modulator. The vortical stream behind the valve cusps participates in the operation of the valve, and prevents stasis inside the valve pocket. The central jet possibly facilitates outflow.