Neovalve construction in postthrombotic syndrome1 1Additional material for this article may be found online at www.jvascsurg.org

Systematic review and meta-analysis of deep venous reflux correction in chronic venous insufficiency

OBJECTIVE

The aim of this study was to investigate the technical feasibility, operative techniques, safety, and efficacy outcomes of procedures aimed at correcting deep venous reflux, in patients with chronic venous insufficiency.

METHODS

We performed systematic literature searches in PubMed, Embase, and Web of Science from databases' inception to February 2022. We included systematic reviews, randomized controlled trials, and observational studies describing surgical procedures to treat patients with deep reflux due to primary and secondary incompetence, post-thrombotic syndrome (PTS). Proportion meta-analyses were performed for all the efficacy and safety outcomes.

RESULTS

We included 57 studies in the quantitative synthesis: three randomized controlled trials including 252 patients and 54 case series including 4004 patients. Studies included a median of 38 patients, with a mean age of 51 years; 52% of them were males. Forty percent of studies included 2291 patients with primary incompetence, 29% of studies included 595 patients with PTS, and 31% of studies included 1118 patients with both diseases. As for primary incompetence, pooled estimates for all procedures showed an 89% (95% confidence interval [CI], 82%-94%) of ulcer healing, 10% (95% CI, 4%-18%) ulcer recurrence, 98% (95% CI, 93%-100%) valve patency, 84% (95% CI, 78%-90%) valve competence, 0.05% (1/1904 patients) pulmonary embolism, 1% (95% CI, 0%-3%) wound infections, 5% (95% CI, 1%-9%) hematoma, 2% (95% CI, 0%-6%) lymphocele, 2% (95% CI, 1%-4%) thrombosis, 85% (95% CI, 74%-94%) pain improvement, 89% (95% CI, 65%-100%) edema improvement, and 85% (95% CI, 73%-93%) lipodermatosclerosis improvement. Patients with PTS showed less favorable outcomes: 82% (95% CI, 71%-91%) of ulcer healing, 18% (95% CI, 5%-36%) ulcer recurrence, 88% (95% CI, 78%-96%) valve patency, 78% (95% CI, 66%-88%) valve competence, no pulmonary embolism, 6% (95% CI, 0%-22%) wound infections, 6% (95% CI, 3%-10%) hematoma, 5% (95% CI, 1%-12%) lymphocele, 7% (95% CI, 1%-16%) thrombosis, 79% (95% CI, 59%-94%) pain improvement, 75% (95% CI, 61%-88%) edema improvement, and 64% (95% CI, 9%-100%) lipodermatosclerosis improvement.

CONCLUSIONS

The number of studies included in each meta-analysis are limited, and knowing how this element can affect the statistical power, as well as the absence of comparative control groups, it is not possible to draw definitive conclusions. Nevertheless, deep venous reconstructive surgery for reflux may increase the probability of clinical improvement in patients affected by chronic venous insufficiency. Outcomes appear to be satisfactory even if possible adjunctive procedures may be required over the course of the patient's lifetime. Consequently, a strict follow-up protocol is required to maintain outcomes. Further studies are required to evaluate deep venous reconstructive surgery for reflux particularly as to how it compares with the more recently introduced endovenous approaches.

Chronic venous insufficiency: Part 2 Diagnosis and treatment

Chronic venous insufficiency (CVI) is a common medical condition that results from venous hypertension of the extremities, leading to significant morbidity. The diagnosis of CVI is quite straightforward from patient history and obvious clinical manifestations. In the recent past, availability of various invasive and non-invasive modalities have assisted in evaluation of such cases. Although compression therapy is the mainstay of management, newer surgical and other interventional techniques are now being considered for patients who do not respond to conventional medical management. This review article will outline a diagnostic approach in cases of CVI and discuss the management principles encompassing conservative, pharmacological, and interventional options.

Safety and feasibility report on nonimplantable endovenous valve formation for the treatment of deep vein reflux

OBJECTIVE

Definitive treatment techniques for symptomatic deep venous reflux have been relegated to complex and invasive open surgery which is rarely performed today. The BlueLeaf System provides an endovenous method for the formation of deep venous valves without an implant, avoiding the complications associated with permanent foreign materials. The system has the adaptability to form valves within the femoral and popliteal veins at multiple levels in a single procedure. The aim was to determine the midterm safety and efficacy of this novel device in an early feasibility study.

METHODS

Feasibility of endovenous deep venous valve formation was assessed in patients with chronic venous insufficiency (Clinical, Etiologic, Anatomic, Pathophysiologic [CEAP] 4-6). Follow-up was completed through 1 year, assessing vein patency and reflux time (RT) with duplex ultrasound examination. Venous clinical improvement was evaluated using the revised Venous Clinical Severity Scale.

RESULTS

Of the 14 patients, 13 (93%) had successful formation of at least one monocuspid valve, with a mean number of 1.4 valves (range, 0-3 valves) per patient. There were no device-related serious adverse events during the index procedure. There were no deep venous thromboses reported at any time point, including 10 patients through the 1-year follow-up. In patients with at least one valve formed, site reported duplex ultrasound examination measured the average RT in the popliteal vein below valve formations, was 3.0 ± 1.0 seconds at baseline, 3.9 ± 3.1 seconds at 30 days, and 3.6 ± 2.1 seconds at 360 days. The revised Venous Clinical Severity Scale improved in all 13 successfully treated patients, decreasing from 15.0 ± 6.0 at baseline to 11.6 ± 5.5 at 30 days, 10.7 ± 5.3 at 210 days, and 9.4 ± 5.0 at 360 days (P = .0002; baseline to 360 days). Among the five patients with an ulcer who reached the 360-day follow-up visit, all (100%) healed at least one ulcer. Two patients (40%) healed all ulcers and three patients (60%) had a decrease in ulcers number but remained at C6 at 360 days. The five patients with a total of nine active ulcers at baseline had four active ulcers at 360 days.

CONCLUSIONS

The BlueLeaf System holds promise as a minimally invasive means to safely form fully autogenous deep venous valves. Reconstructed deep veins remained patent, without deep venous thrombosis and symptomatic improvement was consistently observed; however, a decrease in the RT was not. Incremental device design improvements have been undertaken to improve valve function. The results of these iterations await further clinical evaluation.

Human trial using the novel bioprosthetic VenoValve in patients with chronic venous insufficiency

BACKGROUND

Chronic venous insufficiency (CVI) is a disease characterized by failure of the venous valves that allow blood from the lower limbs to return to the heart. The more severe types of CVI (C4b-C6 disease) significantly influence patients' quality of life (QOL). The treatment options for CVI of the deep system are limited. The present study is the first-in-human study using a prosthetic venous valve, VenoValve, to initially evaluate patient outcomes. We evaluated the feasibility, initial safety, and performance outcomes of the VenoValve.

METHODS

Ten patients with C5-C6 CVI of the deep venous system secondary to postthrombotic syndrome had had a VenoValve surgically implanted into the femoral vein in Bogota, Colombia, under approval of the local ethics committee and Colombian National Food and Drug Surveillance Institute, national health care regulatory body, or the Colombian National Food and Drug Surveillance Agency. Follow-up examinations were conducted postoperatively at 2 and 14 days and then every 30 days for 6 months. The results of the assessments for adverse events, reflux time, disease severity (venous clinical severity scores), pain scores (visual analog scale), and QOL (VEINES-QOL/Sym [venous insufficiency epidemiological and economic study-QOL/symptoms] questionnaire) were documented.

RESULTS

Ten patients underwent successful implantation of the VenoValve into the femoral vein as outpatients (100% technical success rate). Of the 10 patients, 9 had undergone VenoValve placement under regional anesthesia and 1 under local anesthesia. Six patients had required bovine patch angioplasty of the vein. Four adverse events occurred, including one case of hematoma at the incision site that was aspirated, 2 cases of superficial wound infection in C6 patients treated with antibiotics, and 1 case of a bleeding complication due to warfarin anticoagulation. One patient's VenoValve had thrombosed at 5 months due to nontherapeutic anticoagulation. Improvements in all 5 patients who had reached the 6-month follow-up mark with the VenoValve were demonstrated during the study period by decreases in the venous clinical severity scores (61% decrease from baseline), visual analog scale for pain scores (57% decrease), and reflux time (40% decrease) and a statistically significant improvement in the VEINES-QOL/Sym questionnaire. The patient with the occluded VenoValve had experienced improvements in all areas except for the reflux time. The latter patient had shown improvement because her ulcer had nearly healed before the occurrence of the thrombosis.

CONCLUSIONS

The early results of the first-in-human trial using the VenoValve appear promising, with improvements in clinical outcomes and QOL. The VenoValve is the first prosthetic valve that has shown success at 6 months of follow-up. These findings offer insight for creating better outcomes for these highly disabled patients.

Performance changes of venous valves following tissue treatment with novel in vitro system

OBJECTIVES

The purpose of this study is to test venous valve performance and identify differences between native tissue and replacement devices developed with traditional tissue treatment methods using a new in vitro model with synchronized hemodynamic parameters and high-speed valve image acquisition.

METHODS

An in vitro model mimicking the venous circulation to test valve performance was developed using hydrostatic pressure driven flow. Fresh and glutaraldehyde-treated vein segments were placed in the setup and opening/closing of the valves was captured by a high-speed camera. Hemodynamic data were obtained using synchronized hardware and virtual instrumentation.

RESULTS

Geometric orifice area and opening/closing time of the valves was evaluated at the same hemodynamic conditions. A reduction in geometric orifice area of 27.2  ± 14.8% (p < 0.05) was observed following glutaraldehyde fixation. No significant difference in opening/closing time following chemical fixation was observed.

CONCLUSIONS

The developed in vitro model was shown to be an effective method for measuring the performance of venous valves. The observed decrease in geometric orifice area following glutaraldehyde treatment indicates a decrease in flow through the valve, demonstrating the consequences of traditional tissue treatment methods.

Systematic Review and Meta-Analysis of Iliofemoral Stenting for Post-thrombotic Syndrome

OBJECTIVE

Stent placements are considered as a treatment for post-thrombotic syndrome (PTS) with iliofemoral obstruction, but the application of these iliofemoral venous stents has also caused a lot of controversy. The purpose of this systematic review and meta-analysis was to summarise the efficacy and safety of venous stents in PTS with obstruction in iliofemoral venous segments.

METHODS

MEDLINE, EMBASE, and the Cochrane Central Register for Controlled Trials databases and key references were searched up to 15 January 2018. The main relevant outcomes included technical success, peri-operative complications, symptom resolution, a change of symptom scores, and long-term patency of the stents.

RESULTS

Overall, 504 limbs of 489 patients from seven studies were included in this study. A GRADE assessment showed the quality of the evidence was "very low" for 11 relevant outcomes. The technical success rate was 95%. The pooled rate of complications including 30 day thrombotic event, per-operative venous injury, and back pain was 3.4%, 18.14%, and 52%, respectively. The rates of ulcer healing, pain and oedema relief were 75.66%, 52%, and 42%, respectively. The primary, assisted primary and secondary patency rates were 83.36%, 90.59%, and 94.32%, respectively, at 12 months and 67.98%, 82.26%, and 86.10%, respectively, at 36 months.

CONCLUSIONS

Endovenous stenting has the potential to be effective and has a low risk of peri-operative complications. The quality of evidence to support this treatment is very low. Endovenous iliofemoral stenting should be considered a treatment option for PTS with iliofemoral obstruction.

Present and future options for treatment of infrainguinal deep vein disease

OBJECTIVE

Management of chronic deep vein disease focuses on the alleviation of reflux and obstruction. For the suprainguinal veins, the main underlying pathologic process is obstruction, which has been recognized as a significant contributor to chronic venous insufficiency. This is currently being addressed with venous stenting and the development of dedicated stents designed for this segment of the venous system. Treatment of the femoropopliteal vein (FPV) is far more challenging because of the idiosyncratic anatomy, the hemodynamic physiology, and the technical aspects of size mismatch and valve flow dynamics in managing deep venous reflux. This review article discusses traditional and emerging technologies to treat infrainguinal disease.

METHODS

Previous and current articles addressing this issue were reviewed. Emphasis was placed on emerging techniques and technologies.

RESULTS

Significant bench work, in vitro and in vivo studies, have been conducted over the last 40 years addressing the issue of infrainguinal reflux and obstruction. Historically, open procedures to address FPV reflux and obstruction have had variable success in a few centers around the world. The significant increase of emerging endovascular therapies may allow more appropriate, reproducible, widespread treatment of infrainguinal deep venous disease.

CONCLUSIONS

Adequate and durable therapies for infrainguinal venous disease represent one of the greatest challenges for a vein specialist. Recently, a cluster of interest and techniques/technologies have been developed. The endovascular management of arterial disease is mature. The endovenous management of infrainguinal disease is on the cusp of meaningful innovation. The purpose of this evidence summary is to describe the options for the management of chronic FPV disease, with emphasis on emerging technologies and techniques.

Latest Innovations in the Treatment of Venous Disease

Venous disease is more common than peripheral arterial disease. Pathophysiologically, venous disease can be associated with obstruction, reflux, or both. A common feature in chronic venous disease is ambulatory venous hypertension. Inflammatory and pro-thrombotic mechanisms can be activated. The current therapies, including compression, ablation, and recanalization are discussed.

Time taken to the maximum increase in the oxygenated hemoglobin level in calf muscle as a predictor of mild and moderate post-thrombotic syndrome

BACKGROUND

Near-infrared spectroscopy (NIRS) allows continuous noninvasive monitoring of changes in the tissue levels of oxygenated hemoglobin (O2Hb) and deoxygenated hemoglobin (HHb) and can identify the severity of chronic venous diseases. Here we investigated the predictors of post-thrombotic syndrome (PTS) using NIRS in patients with a first episode of deep venous thrombosis (DVT).

METHODS

The study enrolled 129 patients with DVT. Risk factors in each patient were assessed at presentation. Venous abnormalities confirmed by ultrasound and parameters derived from NIRS were evaluated at 6 months after DVT. On standing, increases in O2Hb and HHb (ΔO2Hbst and ΔHHbst) and the times taken for each concentration to become maximal (TO2Hbst, and THHbst) were measured. During 10 tiptoe movements, O2Hb showed a continuous decrease (ΔO2Hbex), whereas venous expulsion (ΔHHbEex) and subsequent retention (ΔHHbRex) were observed. The oxygenation index (HbD; HbD = O2Hb - HHb) was also calculated at the end of standing and at the end of 10 tiptoe movements (ΔHbDst and ΔHbDex). Final clinical manifestations were evaluated at 6 years, and PTS was considered to be present if the Villalta score was ≥5.

RESULTS

Thirteen patients were excluded and 116 patients were finally included. Of these, 19 (16%) developed PTS. Among various NIRS-derived parameters, TO2Hbst had the highest area under the curve (0.88; 95% confidence interval [CI], 0.80-0.93; P < .01) with the best cutoff value (TO2Hbst ≤48 seconds). On univariate analysis, variables associated with greater risk for development of PTS were stroke (odds ratio [OR], 5.59; 95% CI, 0.74-42.41; P = .06), idiopathic DVT (OR, 4.13; 95% CI, 1.36-12.55; P < .01) and iliofemoral DVT (OR, 4.31; 95% CI, 1.48-12.60; P < .01) at initial presentation, venous occlusion combined with reflux (OR, 4.24; 95% CI, 1.50-12.00; P < .01), and NIRS-derived TO2Hbst ≤48 seconds (OR, 43.03; 95% CI, 9.04-204.81; P < .01) at 6 months. Multivariate logistic regression analysis finally revealed venous occlusion combined with reflux (OR, 4.80; 95% CI, 1.03-22.36; P < .05) and NIRS-derived TO2Hbst ≤48 seconds (OR, 53.73; 95% CI, 8.43-342.41; P < .01) to be independently associated with PTS progression.

CONCLUSIONS

NIRS-derived TO2Hbst ≤48 seconds is a promising time-course predictor of PTS progression.

Valve reconstructions

The history of venous valve reconstruction extends back to 1968 when Robert L Kistner performed the first internal valve plasty to treat deep venous axial reflux. Throughout the past 50 years other techniques of reconstructive deep venous surgery (RDVS) were developed, not only to repair but also to replace venous valves. And the fact that several surgeons and centers have undertaken RDVS in the treatment of chronic venous insufficiency (CVI) reporting outcomes, has added knowledge to define more clearly the role of this kind of specialized surgery. Patients who may benefit from RDVS are among those where conventional treatment with compression stockings combined with superficial surgery has failed. Ulcer-healing rates of up to 70% have been reported after RDVS and ulcer-free periods of up to 36 months have been generated. But during five-year follow-up, freedom from ulceration period and clinical improvement rates were reduced significantly. This raises then the issue and challenge of durability of RDVS since the average age of patients who can benefit from it is about 50 years.

Open surgical treatment for postthrombotic syndrome

The postthrombotic syndrome counts as a frequent long-term complication after deep vein thrombosis with approximately 20%–50% of affected patients after deep vein thrombosis. The earliest that diagnosis of postthrombotic syndrome can be made is 6 months after deep vein thrombosis. Most patients suffer from swelling and chronic pain. In all, 5%–10% of patients may even develop venous ulcers. The complex etiology consists of limited venous drainage because of chronic occlusions and secondary insufficiencies of venous valves inducing non-physiological venous reflux. Conservative management, first of all compression therapy, is of crucial importance in treatment of postthrombotic syndrome. Endovascular and open surgical techniques can additionally be used in a small subgroup of patients. Although rarely performed, this article illuminates the open surgical techniques in treatment of postthrombotic syndrome such as venous bypass surgery, valve repair and varicose vein surgery.

Overview of guidelines for the prevention and treatment of venous leg ulcers: a US perspective

Comprehensive care of chronic venous insufficiency and associated ulcers requires a multipronged and interprofessional approach to care. A comprehensive treatment approach includes exercise, nutritional assessment, compression therapy, vascular reconstruction, and advanced treatment modalities. National guidelines, meta-analyses, and original research studies provide evidence for the inclusion of these approaches in the patient plan of care. The purpose of this paper is to review present guidelines for prevention and treatment of venous leg ulcers as followed in the US. The paper further explores evidence-based yet pragmatic tools for the interprofessional team to use in the management of this complex disorder.

Reconstructive surgery for deep vein reflux

DVR is defined as a reflux affecting the deep venous system. DVR essentially arises from two etiologies, primary deep valve incompetence (PDVI) and posthrombotic syndrome (PTS), knowing that axial reflux is correlated with severe chronic venous insufficiency. DVR correction aims at reducing the increased ambulatory venous pressure, which results from reflux in deep veins in orthodynamic conditions.

The results of DVR surgery are not easy to assess, as it is mostly combined with surgery for superficial venous system and/or perforators insufficiency.

In cases of primary insufficiency, valvuloplasty, the operation of choice, is credited at 5 years follow-up with a 70 % success rate in terms of clinical outcome and improved hemodynamic performance. In PTS, a meta-analysis of transpositions and transplants at more than 5 years estimates successful clinical outcome and improved hemodynamic performance at approximately 50 %. The Maleti neovalve construction technique has achieved by far better results.

Indications for DVR surgery are based on clinical, hemodynamic and imaging data. Etiology is a decisive factor in the choice of the technique.

Post-thrombotic syndrome: a clinical review

Up to half of patients with proximal deep vein thrombosis (DVT) will develop post-thrombotic syndrome (PTS) despite optimal anticoagulant therapy. PTS significantly impacts upon quality of life and has major health-economic implications. This narrative review describes the pathophysiology, risk factors, and diagnosis, prevention and treatment of PTS, to improve our understanding of the disease and guide treatment. Relevant articles were identified through systematic searches of the PubMed, EMBASE and Cochrane databases between 1966 and November 2011. Studies were included for detailed assessment if they met the following criteria: published in English, human study participants, study population aged > 18 years, and lower limb post-thrombotic syndrome. All non-systematic reviews and single patient case reports were excluded. Recurrent thrombosis, thrombus location and obesity are major risk factors, whereas the importance of gender and age remain uncertain. The diagnosis of PTS is based on clinical findings in patients with a known history of DVT. Several clinical scales have been described, with the Villalta Score gaining increasing popularity. Adequate anticoagulation and use of elastic compression stockings (ECS) following DVT can reduce the incidence of PTS. Catheter-directed thrombolysis and mechanical thrombectomy of acute DVT may preserve valvular function. Studies to date of these techniques are encouraging, and have reported improved hemodynamics and a reduced incidence of PTS. The management of established PTS is challenging. Compression therapy, aimed at reducing the underling venous hypertension, remains the mainstay of treatment. This is despite a paucity of high-quality evidence to support its use. Pharmacologic and surgical treatments have also been described, with a number of studies citing symptomatic improvement.

Retention of an autologous endothelial layer on a bioprosthetic valve for the treatment of chronic deep venous insufficiency

PURPOSE

Percutaneous transcatheter implantation of porcine small intestinal submucosa (SIS) bioprosthetic valves has been reported as a treatment for chronic deep venous insufficiency (CDVI). Endothelial progenitor outgrowth cells (EOCs), isolated from whole ovine blood, were evaluated as a source of in vitro autologous seeding for SIS endothelialization. Retention of the EOC monolayer was evaluated to test the feasibility of delivering an endothelialized SIS valve.

MATERIALS AND METHODS

Twenty bioprosthetic venous valves were constructed from SIS sutured onto collapsible square stent frames and were seeded with ovine EOCs in vitro. Retention of the endothelial monolayer through valve loading and delivery (three valves), in vitro flow (three valves), and ex vivo flow (four valves) was evaluated with immunofluorescent staining and histologic analysis compared with paired unmanipulated control valves. In the ex vivo shunt loop, venous blood was pulled from an implanted dialysis catheter, through the valve, and returned to the sheep.

RESULTS

Immunofluorescent staining of EOCs on the valves after in vitro seeding revealed a confluent monolayer (95.6% ± 2.3% confluent) on each side of the valve. When examined by immunofluorescent staining, the endothelial monolayer remained intact after loading and delivery (97.1% ± 1.7%) and when subjected to flow in the in vitro loop (96.0% ± 3.0%). Histologic analysis of the valves subjected to the ex vivo shunt loop revealed retention of the endothelial monolayer.

CONCLUSIONS

Endothelial monolayers seeded on SIS were retained under loading and delivery, in vitro flow, and ex vivo flow. EOCs are a promising cell source for autologous endothelialization of bioprosthetic valves for the treatment of CDVI.

Postthrombotic syndrome: surgical possibilities

Postthrombotic syndrome (PTS) is a late outcome of deep vein thrombosis characterized by cramping pain, swelling, hyperpigmentation, eczema, lipodermatosclerosis, and ulceration in the leg due to increased venous outflow resistance and reflux venous flow. Newer surgical and endovascular interventions have a promising result in the management of postthrombotic syndrome. Early surgical or endovascular interventions in appropriately selected patients may decrease the incidence of recurrent ulceration and skin changes and provide a better quality of life. Duplex and IVUS (intravenous ultrasound) along with venography serve as cornerstone investigative tools for assessment of reflux and obstruction. Venous obstruction, if present, should be addressed earlier than reflux. It requires endovenous stenting, endophlebectomy, or open bypass procedures. Venous stripping, foam sclerotherapy, radiofrequency, or laser ablation are used to abolish superficial venous reflux. Valvuloplasty procedures are useful for incompetent but intact deep venous valves, while transposition or axillary vein autotransplantation is done for completely destroyed valves.

Evaluation of prosthetic venous valves, fabricated by electrospinning, for percutaneous treatment of chronic venous insufficiency

Chronic venous insufficiency (CVI) remains a major health problem worldwide. Direct venous valve surgical repair and venous segment transplantation are clinical options; however, they are highly invasive procedures. The objectives of this study were to fabricate prosthetic venous valves (PVVs) by electrospinning, for percutaneous treatment of CVI, and evaluate their hydrodynamic characteristics in vitro at the same locations and under the same flow conditions. The PVVs consisted of polyurethane fiber scaffolds attached to a cobalt-chromium stent. PVVs with two different valve-leaflet configurations were compared: biomimetic PVV (bPVV) and open PVV (oPVV). A balloon catheter was used to implant the devices in a poly(vinyl chloride) tube and the column outlet was set at a height of 100 cm above the test valve to simulate the elevation of the heart above a distal vein valve while standing; 50 wt% glycerin solution was used as the test fluid. The devices were evaluated for antegrade flow, effect of ankle flexion, and stagnation zones around the valve leaflets. During sudden hydrostatic backpressure, little leakage and constant peripheral pressure were observed for the devices; under forward pulsatile pressure of 0-4 mmHg, to simulate the effect of breathing, the oPVV had a higher flow rate than the bPVV. With regard to the effect of ankle flexion, the oPVV was functionless. Moreover, the stagnation zone around the oPVV valve leaflets was larger than that around the bPVV valve leaflets. These results suggest that the bPVV would be clinically suitable for percutaneous treatment of CVI.

Post-thrombotic syndrome: prevention is better than cure

Post-thrombotic syndrome (PTS) can be debilitating to patients and have a major economic impact on health-care services. It arises after deep venous thrombosis (DVT) due to residual venous obstruction or valvular reflux, leading to increased venous pressure in the microcirculation. While the inflammatory process at the time of DVT may aid thrombus resolution, it may also promote destruction of venous valves. The diagnosis of PTS is principally clinical and patients typically complain of leg heaviness, swelling, pain, itching, cramps, ulcer and signs of lipodermatosclerosis. Several clinical scales or classifications have been used but it is recommended that Villalta scale is the most suitable. Risk factors for PTS include a proximal DVT and recurrent thrombosis as well as obesity and prior varicose veins. Poor quality of anticoagulation control may also be a factor. Established PTS is usually managed along the same lines as chronic venous hypertension with compression therapy and leg elevation. Surgery has only a limited role but may benefit some patients. Further trials are desperately needed to define the role of acute thrombolysis and mechanical thrombectomy, which seem to be promising treatments in the studies to date. For patients who have had a DVT more attention should be given to prescribing and using compression hosiery.

Percutaneous management of chronic deep venous reflux: review of experimental work and early clinical experience with bioprosthetic valve

Lower extremity chronic deep venous insufficiency (CDVI) is common and remains a major health problem worldwide. Selected patients benefited from direct deep vein valve surgical repair or valve transplantation. A major limitation of this approach is that most of the patients are not candidates for these procedures due to obstructions or residual thrombus throughout the vein. The past 15 years have witnessed experimental efforts at catheter-based management of CDVI. This review describes the initial designs and experimental evolution of a mechanical and bioprosthetic venous valve that can be implanted by using a transcatheter technique. These valves consisted of single, double, or triple cusp leaflets made of synthetic or biological materials attached to a carrier or frame. All described devices for percutaneous transcatheter valve placement rely on some form of a vascular stent for valve attachment.

Percutaneous autologous venous valve transplantation: Short-term feasibility study in an ovine model

BACKGROUND

Limited experience with bioprosthetic venous valve percutaneously inserted into femoral veins in 15 patients has been promising in short-term results only to show disappointing long-term results. Percutaneous autogenous venous valve (PAVV) transplantation was explored in an ovine model as a possible alternative treatment.

METHODS

PAVV consisted of a vein segment containing a valve that was attached to a stent template. The stent templates (n = 9) were designed and hand made in our research laboratory. They consist of two stainless steel square stents 13 or 15 mm in diameter to fit the ovine jugular veins (JV), which ranges from 10 to 15 mm in diameter. A valve-containing segment of JV was harvested and attached with sutures and barbs inside the stent template (n = 9). The valve devices were then manually folded and front loaded inside the 4 cm chamber of the 13F delivery sheath and delivered into the contralateral JV by femoral vein approach. Transplanted PAVVs were studied by immediate and 3 months venograms. Animals were euthanized at 3 months, and jugular veins harvested to perform angioscopic evaluations in vitro.

RESULTS

PAVV transplantation was successful in all nine animals. Good valve function with no reflux was observed on immediate and 3 months venograms in eight valves. The transplanted maximal JV diameter ranged from 10.2 mm to 15.4 mm (mean 13.1 +/- 1.5 mm). Venoscopic examination revealed intact, flexible, nonthickened valve leaflets in eight specimens. One PAVV exhibited normal function of one leaflet only; the other cusp was accidentally cut during the transplantation procedure. All transplanted autologous valves were free of thrombus and incorporated into the vein wall of the host vessel.

CONCLUSION

This study demonstrated that autogenous valve transplants remained patent and competent without long-term anticoagulation for up to 3 months. The percutaneous autogenous venous valve may provide in future minimally invasive treatment for patients with chronic deep venous insufficiency, but long-term studies need to be done to document its continued patency and function.