Saphenous vein wall thickness in age and venous reflux-associated remodeling in adults

Transfer Learning-Based Approach for Thickness Estimation on Optical Coherence Tomography of Varicose Veins

In-depth mechanical characterization of veins is required for promising innovations of venous substitutes and for better understanding of venous diseases. Two important physical parameters of veins are shape and thickness, which are quite challenging in soft tissues. Here, we propose the method TREE (TransfeR learning-based approach for thicknEss Estimation) to predict both the segmentation map and thickness value of the veins. This model incorporates one encoder and two decoders which are trained in a special manner to facilitate transfer learning. First, an encoder-decoder pair is trained to predict segmentation maps, then this pre-trained encoder with frozen weights is paired with a second decoder that is specifically trained to predict thickness maps. This leverages the global information gained from the segmentation model to facilitate the precise learning of the thickness model. Additionally, to improve the performance we introduce a sensitive pattern detector (SPD) module which further guides the network by extracting semantic details. The swept-source optical coherence tomography (SS-OCT) is the imaging modality for saphenous varicose vein extracted from the diseased patients. To demonstrate the performance of the model, we calculated the segmentation accuracy-0.993, mean square error in thickness (pixels) estimation-2.409 and both these metrics stand out when compared with the state-of-art methods.

Common femoral vein wall thickness measurement by Doppler ultrasonography is an accurate diagnostic test for Behçet's Disease both in supine and standing positions

OBJECTIVES

We recently reported the first controlled Doppler ultrasonography (US) study demonstrating increased common femoral vein (CFV) thickness in Behçet's Disease (BD). Standard lower extremity venous Doppler US is performed in erect position. In order to confirm accuracy and applicability of method, we measured CFV thickness in both supine and standing positions in this study.

METHOD

We included sex and age-matched 42 BD patients and 41 healthy controls (HCs). After routine visits, bilateral CFV thickness was measured with Doppler US both in supine and standing positions.

RESULTS

Bilateral CFV thickness was significantly higher in BD than in HC. There were no statistically significant differences in measurements of CFV wall thickness between standing and supine positions in both groups.

CONCLUSIONS

CFV measurement by Doppler US is a new and non-invasive diagnostic tool for the diagnosis of BD. Our study confirmed that patient position does not affect CFV wall thickness measurement for diagnosis of BD.

Vicious Circle With Venous Hypertension, Irregular Flow, Pathological Venous Wall Remodeling, and Valve Destruction in Chronic Venous Disease: A Review

Substantial advances occurred in phlebological practice in the last two decades. With the use of modern diagnostic equipment, the patients' venous hemodynamics can be examined in detail in everyday practice. Application of venous segments for arterial bypasses motivated studies on the effect of hemodynamic load on the venous wall. New animal models have been developed to study hemodynamic effects on the venous system. In vivo and in vitro studies revealed cellular phase transitions of venous endothelial, smooth muscle, and fibroblastic cells and changes in connective tissue composition, under hemodynamic load and at different locations of the chronically diseased venous system. This review is an attempt to integrate our knowledge from epidemiology, paleoanthropology and anthropology, clinical and experimental hemodynamic studies, histology, cell physiology, cell pathology, and molecular biology on the complex pathomechanism of this frequent disease. Our conclusion is that the disease is initiated by limited genetic adaptation of mankind not to bipedalism but to bipedalism in the unmoving standing or sitting position. In the course of the disease several pathologic vicious circles emerge, sustained venous hypertension inducing cellular phase transitions, chronic wall inflammation, apoptosis of cells, pathologic dilation, and valvular damage which, in turn, further aggravate the venous hypertension.

Relevance of vein wall thickness in Behcet's disease: A systematic review and meta-analysis

OBJECTIVES

To perform a meta-analysis on articles evaluating the common femoral vein wall thickness (VWT) in Behcet's disease and its possible clinical, laboratory and treatment correlates (BD).

METHODS

Systematic search of EMBASE and PubMed databases from inception to October 2023; we employed random effect meta-analyses for continuous outcomes.

RESULTS

The meta-analysis included 9 case-control and 1 cohort study: the VWT was greater in BD (n = 650) than in controls (n = 396) (p < 0.0001) with wide heterogeneity (I2 = 94.4%); a sensitivity analysis that included mean age of BD participants, gender, disease duration and activity, C-reactive protein, smoking status, immune-suppressive and anti-inflammatory medication, revealed that the heterogeneity variance was partly explained by age (p < 0.0001), male gender (p = 0.03), disease duration (p < 0.0001) and smoking (p = 0.06). The VWT was greater in BD with thrombotic/vascular (n = 189) than in non-thrombotic/vascular BD (n = 140) (p = 0.006) with no heterogeneity.

CONCLUSION

VWT is greater in BD than controls: age, male gender, disease duration and smoking relate to VWT that was greater in BD patients with a history of thrombotic/vascular disease. Prospective studies are required to assess whether VWT may be considered a vascular marker of disease activity.

Measuring the Whole Wall Thickness of the Common Femoral Vein as a Distinctive Diagnostic Tool to Distinguish Behçet's Disease Presenting with Oral Ulcers from Recurrent Aphthous Stomatitis

Recurrent oral ulcers, which are the first and most common manifestation of Behçet's disease (BD), have several etiological causes but are often idiopathic and known as recurrent aphthous stomatitis (RAS). In recent years, publications have drawn attention to the fact that whole-wall thickness (WWT) and intima-media thickness (IMT) measurements of the common femoral vein (CFV) may be useful in the diagnosis of BD, which are independent of organ involvement. In this study, the usefulness of the WWT and IMT of the CFV measured by venous Doppler ultrasound (US) was investigated in differentiating BD presenting with oral ulcers from RAS. Patients with BD (n = 84), patients with RAS (n = 85), and healthy controls (HCs) (n = 70) were the three groups included. Both the right and left WWT of the CFV were significantly higher in the BD compared with the HCs and RAS groups (p < 0.001). The diagnostic cutoff values of ≥0.58 mm for the WWT of the CFV performed well against both the patients with RAS and HCs for the discrimination of BD (sensitivity = 79.8%, specificity = 64.7%). In patients with recurrent oral ulcers, the WWT of the CFV measurement may be a distinctive new diagnostic tool for the differential diagnosis of BD and RAS.

Intima-media thickness of common femoral vein is increased in Behçet's disease

The histopathological data about vascular inflammation in Behçet's disease(BD) mainly comprises patients with arterial involvement. Inflammatory cell infiltration was mainly observed around the vasa vasorum and adventitial layer of the aneurysmatic vessels, and only a few cells were seen in the intimal layer during active arteritis. There is limited data for the histopathology of venous inflammation. We recently showed that increased common femoral vein(CFV) wall thickness is a specific sign of vein wall inflammation in BD. We aimed to investigate the different vein subsections measuring the whole wall and the intima-media thickness(IMT) of CFV with ultrasonography in BD. We found increased IMT of CFV compared to controls as well as CFV wall thickness. This study shows that there is a full layer venous wall inflammation in BD independent of vascular involvement. Our results suggest that venous endothelial inflammation may trigger the thickening of the vein wall and cause thrombotic tendency in BD.

Impact of statin treatment on patients diagnosed with chronic venous disease. Morphological analysis of the venous wall and clinical implications

OBJECTIVES

The study evaluates the potential morphological changes that may occur in the venous wall in the case of the patients with chronic venous disease which associates treatment with statins for at least 2 years.

METHODS

Operated patients with chronic venous disease in the CEAP C2-C3 stage were included in the study. 215 venous fragments, collected from 50 patients within the study group and 179 venous fragments collected from 52 patients within the control group were microscopically analysed, evaluating a series of morpho-anatomical parameters.

RESULTS

In the study group, it was found that, venous reflux predominantly affects small veins, and also, a significant increase in collagen deposits in the adventitia and media tunics, proportional to the thickening of the venous wall.

CONCLUSION

Our results indicate possible effects of statins upon the venous morphology. Further studies are needed to determine the impact of these results on daily practice.

The aging venous system: from varicosities to vascular cognitive impairment

Aging-induced pathological alterations of the circulatory system play a critical role in morbidity and mortality of older adults. While the importance of cellular and molecular mechanisms of arterial aging for increased cardiovascular risk in older adults is increasingly appreciated, aging processes of veins are much less studied and understood than those of arteries. In this review, age-related cellular and morphological alterations in the venous system are presented. Similarities and dissimilarities between arterial and venous aging are highlighted, and shared molecular mechanisms of arterial and venous aging are considered. The pathogenesis of venous diseases affecting older adults, including varicose veins, chronic venous insufficiency, and deep vein thrombosis, is discussed, and the potential contribution of venous pathologies to the onset of vascular cognitive impairment and neurodegenerative diseases is emphasized. It is our hope that a greater appreciation of the cellular and molecular processes of vascular aging will stimulate further investigation into strategies aimed at preventing or retarding age-related venous pathologies.

Ultrasonographic measurement of the vascular wall thickness and intima-media thickness in patients with Behçet's disease with symptoms or signs of vascular involvement: A cross-sectional study

Objectives

This study aims to measure and compare bilateral carotid intima-media thickness (CIMT), bilateral jugular, common femoral, and main portal vein wall thicknesses (VWTs) in Behçet’s disease (BD) patients with and without vascular involvement to obtain a cut-off value for vascular complications and determine their relationship with disease activity.

Patients and methods

Sixty-three BD patients (41 males, 22 females; median age: 38.0 years; min 20 - max 71 years) and 30 healthy control subjects (14 males, 16 females; median age: 40.3 years; min 21 - max 60 years) were included in this cross-sectional study between February and March 2020. According to imaging findings, BD patients were divided into two groups as those with and without vascular complications. Disease duration, medical treatment and BD manifestations of patients were questioned. Disease activity was evaluated using the Behçet's Disease Current Activity Form (BDCAF) and the Behçet's Syndrome Activity Scale (BSAS). Two radiologists blinded to the diagnosis of BD used ultrasound to measure VWT and CIMT. Receiver operating characteristics were assessed to obtain sensitivity and specificity values for each VWT and CIMT.

Results

The groups were similar in terms of age, sex, and body mass index (p>0.05). There was a significant difference between the BD groups when the BDCAF and BSAS scores were compared, while there was no difference between them in terms of disease duration and medical treatment (p>0.05). All VWTs and CIMTs were significantly higher in patients with BD compared to healthy controls (p<0.05). There was no significant difference between the BD groups in terms of CIMT, jugular and common femoral VWTs (p>0.05). But portal VWT was significantly higher in patients with vascular involvement (p<0.05). A cut-off value of ≥1.35 mm yielded a sensitivity of 79.2% and a specificity of 82.4% for the diagnosis of vascular involvement with the highest Youden's index (area under the curve, 0.869; 95% confidence interval, 0.783 to 0.956).

Conclusion

Portal VWT has high sensitivity and specificity for the screening of vascular involvement in patients with BD.

Femoral vein wall thickness measurement: A new diagnostic tool for Behçet's disease

OBJECTIVES

Diagnosing Behçet's disease (BD) is a challenge, especially in countries with a low prevalence. Recently, venous wall thickness (VWT) in lower extremities has been shown to be increased in BD patients. In this study, we aimed to investigate the diagnostic performance of common femoral vein (CFV) thickness measurement in BD and whether it can be used as a diagnostic tool.

METHODS

. Patients with BD (n = 152), ankylosing spondylitis (n = 27), systemic vasculitides (n = 23), venous insufficiency (n = 29), antiphospholipid syndrome (APS; n = 43), deep vein thrombosis due to non-inflammatory causes (n = 25) and healthy controls (n = 51) were included in the study. Bilateral CFV thickness was measured with ultrasonography by a radiologist blinded to cases.

RESULTS

Bilateral CFV thickness was significantly increased in BD compared with all control groups (P < 0.001 for all). The area under the receiver operating characteristic curve for bilateral CFV thicknesses in all comparator groups was >0.95 for the cut-off value (0.5 mm). This cut-off value also performed well against all control groups with sensitivity rates >90%. The specificity rate was also >80% in all comparator groups except APS (positive predictive value: 79.2-76.5%, negative predictive value: 92-91.8% for right and left CFV, respectively).

CONCLUSION

Increased CFV thickness is a distinctive feature of BD and is rarely present in healthy and diseased controls, except APS. Our results suggest that CFV thickness measurement with ultrasonography, a non-invasive radiological modality, can be a diagnostic tool for BD with sensitivity and the specificity rates higher than 80% for the cut-off value ≥0.5 mm.

Evaluation of the efficacy of foam sclerosant after addition of glycerine on human great saphenous vein: histological and immunohistochemical study

INTRODUCTION

Several treatment modalities have been postulated to improve the efficacy of varicose vein treatment. Addition of glycerine to the sclerosing material has been documented to increase its viscosity and subsequently prolong the duration of stability, in addition to the direct sclerosing effect of glycerine. This histological and immunohistochemical study investigated the efficacy of addition of glycerine 72% to sclerotherapy on the human varicose vein.

METHODS

After surgical stripping of great saphenous veins, three equal segments were resected between two clamps. Specimen 1 was injected with saline only, specimen 2 was exposed to foam sclerosant 2%, and specimen 3 was exposed to a mixture of foam sclerosant 2% and glycerine 72%. All segments were left for 5min. Vein segments were then processed for histological and immunohistochemical study.

RESULTS

Microscopically, haematoxylin and eosin-stained specimen 1 showed endothelial swelling, cytoplasmic eosinophilia and pyknotic nuclei. The media showed sarcoplasm vacuolisation and necrosis. Specimen 3 showed hypereosinophilic sarcoplasm of the smooth muscle fibres. Oedema was less evident, with a relative decrease in the thickness of the wall compared with specimen 2. Immunohistochemically, the expression of smooth muscle actin was weak in specimen 3 compared with specimens 1 and 2. Expression of CD31 antibody was much reduced in specimen 2 which showed conserved islands of endothelial cells. By contrast, there was a complete loss of endothelial cells in specimen 3.

CONCLUSION

Addition of glycerine 72% to foam sclerosant has a more damaging effect on human vein wall.

Predictors for the risk and severity of post-thrombotic syndrome in vascular Behçet's disease

OBJECTIVE

Deep vein thrombosis (DVT) of the lower extremities is the most common form of vascular involvement in Behçet disease (BD), frequently leading to post-thrombotic syndrome (PTS) as a disabling complication. We have described the clinical characteristics and predictors of PTS presence among patients with BD and lower extremity DVT. We also used venous Doppler ultrasound (US) examinations in our assessment.

METHODS

Patients with BD (n = 205; 166 men, 39 women; age 39 ± 9.5 years) and a history of DVT were investigated. The Villalta scale was used to assess the presence and severity of PTS. Doppler US examinations were performed within 1 week of the clinical evaluation. The total number of vessels with reflux, thrombi, recanalization, and collateral vessels were calculated.

RESULTS

Of the 205 patients with BD, 62% had had PTS and 18% had had severe PTS. Patients with PTS had had greater reflux (P = .054) and thrombosis (P = .02) scores compared with patients without PTS. Treatment with anticoagulation (AC), immunosuppressive (IS) therapy, or AC combined with IS drugs did not affect the occurrence of PTS. However, patients treated with IS therapy, with or without AC drugs, had a decreased incidence of severe PTS compared with the AC-only group (P = .017). Patients treated with AC plus IS agents also had increased collateral scores compared with patients treated with only IS drugs. Interferon-α use seemed to provide better recanalization scores compared with azathioprine only (1.0 [range, 0-14] vs 2.5 [range, 0-10]; P = .010).

CONCLUSION

Patients with BD and DVT have a high risk of developing severe PTS. IS treatment decreases the development of severe PTS. AC therapy might influence the course of PTS by increasing the collateral scores, and the use of interferon-α also increased recanalization scores. Routine assessment with Doppler US examinations could be helpful in the prediction of severe PTS.

Phlebosclerosis in lower extremities veins - a systematic review

Phlebosclerosis is a venous wall degenerative disease which has gained little popularity in the literature due to its uncertain clinical significance. The objective of this review is to evaluate the epidemiology, etiology and clinical significance of phlebosclerosis in lower extremities veins, particularly the effect of preexisting phlebosclerosis of the great saphenous vein on vein graft patency. Medline was searched from inception until November 1, 2019. Reference lists of included studies were scanned. Only articles published after 1949 were included. Two reviewers independently screened titles/abstracts and full-text papers for any study design in relation to phlebosclerosis in lower extremities veins and abstracted data. A total of 16 Cohort studies and one case-control study (3708 participants, mean age 61.8 years, 59.3 % men, and 40.7 % women) were included after screening 317 titles and abstracts, and 80 full-text articles. The incidence of phlebosclerosis ranged from 1.5-9.7 % depending on the radiological features. On the contrary, the incidence of the phlebosclerotic great saphenous vein prior to its use as a vein graft was 26.9-91 % on histological examination. The small saphenous vein was the most common location of phlebosclerosis followed by the great saphenous vein. There is a link between phlebosclerosis and age, venous insufficiency and haemodialysis. As for the vein graft patency seven studies demonstrated a correlation between preexisting phlebosclerosis and vein graft stenosis, whereas three studies failed to prove any association. In conclusion, the radiological incidence of phlebosclerosis depended on the ultrasound findings. Its presence in the great saphenous vein prior to its use as a vein graft is established on histological examination. The small saphenous vein is mainly affected. Risk factors included age, haemodialysis, and venous insufficiency. Preexisting wall thickness of the great saphenous vein graft seemed to affect negatively its patency in bypass surgery.

Venous Compliance in Great Saphenous Vein Incompetence: Pre- and Post-interventional Changes

Objective

Methods

Results

Conclusions

•

Venous compliance reflects the mechanical properties of the vessel wall.

•

Calf venous compliance is reduced in patients with great saphenous vein insufficiency.

•

Venous reflux parameters markedly improve after surgical intervention.

•

Venous compliance is further reduced in the post-operative state.

Ultrasonographic assessment of normal jugular veins in Standardbred horses

Background

Ultrasonography (US) is the recommended imaging technique to evaluate jugular veins. This prospective randomized clinical study was designed to collect a series of B-mode US measurements of manually distended jugular veins in healthy Italian Standardbreds and to find possible correlations between ultrasound measurements and animal morphometric characteristics. Forty-two horses, eight males and 34 females (range 3–22 years; bodyweight 494.4 ± 41.7 kg), were included in the study. The diameters and wall thicknesses of both jugular veins were measured at three different sites of the neck. The differences in ultrasound measurements based on scans, age, gender, side, and site of the neck were evaluated by ANOVA or by the Kruskal-Wallis test. The effects of the morphometric measures on each ultrasound parameter were evaluated by MANOVA (P < 0.05).

Results

The ultrasound measurements did not differ significantly between the three different sites or between genders; hence, they were pooled together in the results. On the transverse scan, the mean dorsoventral and lateromedial diameters were 1.58 ± 0.23 and 2.20 ± 0.25 cm, respectively; the mean superficial and deep wall thicknesses (SWT and DWT) were 0.07 ± 0.01 and 0.08 ± 0.01 cm, respectively. On the longitudinal scan, the mean dorsoventral diameter was 1.59 ± 0.26 cm, and the SWT and DWT were both 0.08 ± 0.01 cm. Neck length, from the caudal edge of the mandible to the thoracic inlet, was related to the dorsoventral diameter in both longitudinal and transverse scan and to the SWT and DWT in transverse scan, whereas height at the withers (measured with tape) and estimated weight were related to the wall thickness. Dividing the subjects into groups by age in years (“young” 3–7, “mature” 8–14, “old” > 14), differences were found for the lateromedial diameter in the transverse scan and the SWT on the longitudinal scan. The main limitation of this study was that only one operator performed the measurements.

Conclusion

The US measurements of the jugular veins and their relationship with morphometric measures reported in this manuscript might be considered as guidelines both for early diagnosis and monitoring jugular vein abnormalities in healthy Italian Standardbred horses.

Increased vein wall thickness in Behçet disease

OBJECTIVE

Lower extremity (LE) deep venous thrombosis (DVT) is the main feature of vascular involvement in Behçet disease (BD). We thought that vein wall thickness (VWT) could be a surrogate marker for venous inflammation and hence predict future vascular involvement. We assessed VWT in proximal LE veins in BD patients without DVT, BD patients with DVT, and healthy controls in a formal, masked protocol.

METHODS

We studied 50 (43 male and 7 female) BD patients with LE DVT (group 1), 50 (43 male and 7 female) BD patients without any vascular involvement (group 2), and 50 (43 male and 7 female) age- and sex-matched apparently healthy controls (group 3). Two radiologists blinded to the diagnosis of BD used ultrasound to measure VWT of common femoral vein, femoral vein, and great saphenous vein in both legs. Interobserver reliability was assessed using the intraclass correlation coefficient and Bland-Altman plots.

RESULTS

There was good agreement between the two observers. The mean VWT was significantly increased in both BD patients with LE DVT and those without apparent vascular involvement compared with the healthy controls, whereas those with LE DVT had the highest VWT.

CONCLUSIONS

VWT of proximal deep and superficial LE veins is increased among the BD patients without any clinical and radiologic vascular involvement. This information, after prospective work, might be useful in management and elucidating disease mechanisms in vascular BD.

Great Saphenous Vein Diameters in Phlebological Practice in France: A Report of the DIAGRAVES Study by the French Society of Phlebology

OBJECTIVE

The aim was to evaluate the distribution of the diameter of the great saphenous vein (GSV) at mid-thigh level and to investigate its association with clinical class, symptoms, and proximal extent of reflux.

METHODS

Vascular physicians, members of the French Society of Phlebology, were invited to participate in a consecutive observational study in patients presenting with symptoms and/or signs of uni- or bilateral chronic venous disorders (CVDs) in previously untreated limbs (clinical class of the CEAP classification C0s - C6). Patients were included between January and March 2015. They completed a specially designed venous symptoms questionnaire. Duplex ultrasound of the included limbs was performed with the patient standing to detect reflux in the GSV and to measure the GSV inner diameter at mid-thigh.

RESULTS

Between January and March 2015, 35 physicians examined 1245 patients (2450 limbs after excluding 40 limbs): 77% were female, mean age 52 ± 14; 69% of the patients had venous symptoms in one or both legs. The most frequent symptoms were feeling of heaviness, feeling of swelling and aching. Predominant CEAP clinical classes were C2 (38% of limbs) and C1 (35%). In case of GSV reflux (40% of limbs), the average diameter was 5.6 ± 2 mm and the distribution was 62% < 6 mm, 30% between 6 and 8 mm, and 8% > 8 mm. The study showed a clear association between clinical class and GSV diameter (the higher the clinical class, the larger the diameter; p < .0001), between venous symptoms and diameter (the larger the diameter, the higher the intensity of symptoms, p < .0001 for overall discomfort) and between proximal extent of reflux and diameter (the more proximal the extent of reflux, the larger the diameter, p < .0001).

CONCLUSION

The DIAGRAVES study demonstrated that in France for patients consulting with CVDs, more than half of the incompetent GSVs had a diameter < 6 mm, while large diameters were relatively infrequent. This should be kept in mind when considering management strategies in patients with CVDs.

Vein wall remodeling in patients with acute deep vein thrombosis and chronic postthrombotic changes

Essentials This study examined vein wall remodeling in acute thrombosis and postthrombotic syndrome (PTS). Thrombus-wall interface was measured using ultrasound real-time high definition zoom. Experimental cohorts demonstrated increased vein wall thickness localized to affected segments. Presence of thrombus or PTS are the most important factors affecting wall thickening.

SUMMARY

Introduction A few studies have investigated venous wall remodeling after venous thrombosis by using rodent models. Such information is lacking in humans. This study was designed to determine the acute and chronic effects of thrombus on the vein wall. Methods Patients aged > 16 years with deep vein thrombosis diagnosed by duplex ultrasound were assessed by the use of case-control methodology. Those with recurring thrombotic episodes, cardiorespiratory disease, terminal cancer, morbid obesity, penetrating trauma or significant inflammation were excluded. High-resolution ultrasound was employed to determine wall thickness, with strict quality criteria and inclusion of only technically adequate ultrasound images. Results Data were collected from patients with acute thrombosis (35), patients with chronic postthrombotic changes (15), and unaffected controls (32), with 853 total vein segments being analyzed. As compared with controls (mean 0.37 mm; 95% confidence interval [CI] 0.37-0.38 mm), venous wall thickness was increased in acute (mean 0.63 mm; 95% CI 0.61-0.64 mm) and postthrombotic (mean 0.85 mm; 95% CI 0.80-0.91 mm) venous segments. Ipsilateral, contralateral and unaffected control vein segments were not different. Ipsilateral segments were thicker than controls in postthrombotic syndrome (PTS) patients, but not in acute patients. Multiple regression analyses demonstrated small impacts of age and sex on vein wall thickness. Conclusions Wall thickness increases in all lower-tcglimb venous segments of patients with acute and postthrombotic disease. Age and sex may affect wall thickness, although further investigation is required to clarify their impact. The equivalence of ipsilateral and unaffected control segments suggests that acute vein wall remodeling is mediated through direct interaction with the thrombus, whereas remodeling in PTS patients may be affected by other factors.

Smooth muscle cells of human veins show an increased response to injury at valve sites

OBJECTIVE

Venous valves are essential but are prone to injury, thrombosis, and fibrosis. We compared the behavior and gene expression of smooth muscle cells (SMCs) in the valve sinus vs nonvalve sites to elucidate biologic differences associated with vein valves.

METHODS

Tissue explants of fresh human saphenous veins were prepared, and the migration of SMCs from explants of valve sinus vs nonvalve sinus areas was measured. Proliferation and death of SMCs were determined by staining for Ki67 and terminal deoxynucleotidyl transferase dUTP nick end labeling. Proliferation and migration of passaged valve vs nonvalve SMCs were determined by cell counts and using microchemotaxis chambers. Global gene expression in valve vs nonvalve intima-media was determined by RNA sequencing.

RESULTS

Valve SMCs demonstrated greater proliferation in tissue explants compared with nonvalve SMCs (19.3% ± 5.4% vs 6.8% ± 2.0% Ki67-positive nuclei at 4 days, respectively; mean ± standard error of the mean, five veins; P < .05). This was also true for migration (18.2 ± 2.7 vs 7.5 ± 3.0 migrated SMCs/explant at 6 days, respectively; 24 veins, 15 explants/vein; P < .0001). Cell death was not different (39.6% ± 16.1% vs 41.5% ± 16.0% terminal deoxynucleotidyl transferase dUTP nick end labeling-positive cells, respectively, at 4 days, five veins). Cultured valve SMCs also proliferated faster than nonvalve SMCs in response to platelet-derived growth factor subunit BB (2.9 ± 0.2-fold vs 2.1 ± 0.2-fold of control, respectively; P < .001; n = 5 pairs of cells). This was also true for migration (6.5 ± 1.2-fold vs 4.4 ± 0.8-fold of control, respectively; P < .001; n = 7 pairs of cells). Blockade of fibroblast growth factor 2 (FGF2) inhibited the increased responses of valve SMCs but had no effect on nonvalve SMCs. Exogenous FGF2 increased migration of valve but not of nonvalve SMCs. Unlike in the isolated, cultured cells, blockade of FGF2 in the tissue explants did not block migration of valve or nonvalve SMCs from the explants. Thirty-seven genes were differentially expressed by valve compared with nonvalve intimal-medial tissue (11 veins). Peptide-mediated inhibition of SEMA3A, one of the differentially expressed genes, increased the number of migrated SMCs of valve but not of nonvalve explants.

CONCLUSIONS

Valve compared with nonvalve SMCs have greater rates of migration and proliferation, which may in part explain the propensity for pathologic lesion formation in valves. Whereas FGF2 mediates these effects in cultured SMCs, the mediators of these stimulatory effects in the valve wall tissue remain unclear but may be among the differentially expressed genes discovered in this study. One of these genes, SEMA3A, mediates a valve-specific inhibitory effect on the injury response of valve SMCs.