Iliofemoral venous stenoses: effectiveness of treatment with metallic endovascular stents

Iliocaval and iliofemoral venous stenting for obstruction secondary to tumor compression

BACKGROUND

Cancer patients with pelviabdominal masses can suffer from lower extremity symptoms due to venous compression. The effectiveness of venous stenting has been established in extrinsic venous compression in benign conditions like May-Thurner syndrome. In this retrospective study we evaluate the efficacy and safety of caval, iliocaval and iliofemoral venous stenting for cases of extrinsic venous compression caused by malignant masses in cancer patients.

METHODS

IRB-approved retrospective review of patients who underwent iliofemoral venography with venoplasty and stenting between January 2018 and February 2022 was performed. Patients with extrinsic venous compression caused by malignant masses were included. Data on patient demographics, pre-procedure symptoms, procedural technique, stent characteristics, outcomes and follow-up were collected. Descriptive statistics were used to assess technical success, clinical success, primary stent patency and adverse events of the procedure.

RESULTS

Thirty-seven patients (19 males, 18 females) who underwent 45 procedures were included. Deep venous thrombosis (DVT) was present in 21 (57%) patients. Twenty-nine patients (78%, 95% CI 62-90%) reported clinical improvement of the presenting symptoms. The median overall survival after the procedure was 4.7 months (95% CI 3.58-5.99). Eight (22%) patients were alive at last follow up with median follow up of 10.33 months (Range 2-25 months). Twenty-six patients had patent stents on their last follow up imaging (70%, 95% CI 61%-91%). Two patients had a small access site hematoma which resolved spontaneously. Two patients developed moderate, and 1 patient developed severe adverse events related to post procedure therapeutic anticoagulation.

CONCLUSION

Venous stenting is a safe procedure and should be considered as part of the palliative care for patients with debilitating lower extremity symptoms related to iliocaval and iliofemoral venous compression.

Iliocaval and Iliofemoral Venous Stenting for Obstruction Secondary to Tumor Compression: Single Center Experience

Background

Cancer patients with pelviabdominal masses can suffer from lower extremity symptoms due to venous compression. The effectiveness of venous stenting has been established in extrinsic venous compression in benign conditions like May-Thurner syndrome. In this retrospective study we evaluate the efficacy and safety of caval, iliocaval and iliofemoral venous stenting for cases of extrinsic venous compression caused by malignant masses in cancer patients.

Methods

IRB-approved retrospective review of patients who underwent iliofemoral venography with venoplasty and stenting between January 2018 and February 2022 was performed. Patients with extrinsic venous compression caused by malignant masses were included. Data on patient demographics, pre-procedure symptoms, procedural technique, stent characteristics, outcomes and follow-up were collected. Descriptive statistics were used to assess technical success, clinical success, primary stent patency and adverse events of the procedure.

Results

Thirty-seven patients (19 males, 18 females) who underwent 45 procedures were included. Deep venous thrombosis (DVT) was present in 21 (57%) patients. Twenty-nine patients (78%, 95% CI 62-90%) reported clinical improvement of the presenting symptoms. The median overall survival after the procedure was 4.7 months (95% CI 3.58-5.99). Eight (22%) patients were alive at last follow up with median follow up of 10.33 months (Range 2-25 months). Twenty-six patients had patent stents on their last follow up imaging (70%, 95% CI 61%-91%). Two patients had a small access site hematoma which resolved spontaneously. Two patients developed moderate, and 1 patient developed severe adverse events related to post procedure therapeutic anticoagulation.

Conclusion

Venous stenting is a safe procedure and should be considered as part of the palliative care for patients with debilitating lower extremity symptoms related to iliocaval and iliofemoral venous compression.

Society of Interventional Radiology Position Statement on the Management of Chronic Iliofemoral Venous Obstruction with Endovascular Placement of Metallic Stents

PURPOSE

To state the position of the Society of Interventional Radiology (SIR) on the endovascular management of chronic iliofemoral venous obstruction with metallic stents.

MATERIALS AND METHODS

A multidisciplinary writing group with expertise in treating venous disease was convened by SIR. A comprehensive literature search was conducted to identify studies on the topic of interest. Recommendations were drafted and graded according to the updated SIR evidence grading system. A modified Delphi technique was used to achieve consensus agreement on the recommendation statements.

RESULTS

A total of 41 studies, including randomized trials, systematic reviews and meta-analyses, prospective single-arm studies, and retrospective studies were identified. The expert writing group developed 15 recommendations on the use of endovascular stent placement.

CONCLUSIONS

SIR considers the use of endovascular stent placement for chronic iliofemoral venous obstruction to be likely to help selected patients, but the risks and benefits have not been fully quantified in well-designed randomized studies. SIR recommends urgent completion of such studies. In the meantime, careful patient selection and optimization of conservative therapy are recommended prior to stent placement, with attention to appropriate stent sizing and quality procedural technique. The use of multiplanar venography with intravascular ultrasound is suggested in diagnosing and characterizing obstructive iliac vein lesions and in guiding stent therapy. After stent placement, SIR recommends close patient follow-up to ensure optimal antithrombotic therapy, durable symptom response, and early identification of adverse events.

Delphi Consensus on Reporting Standards in Clinical Studies for Endovascular Treatment of Acute Iliofemoral Venous Thrombosis and Chronic Iliofemoral Venous Obstruction

Acute iliofemoral deep vein thrombosis and chronic iliofemoral venous obstruction cause substantial patient harm and are increasingly managed with endovascular venous interventions, including percutaneous mechanical thrombectomy and stent placement. However, studies of these treatment elements have not been designed and reported with sufficient rigor to support confident conclusions about their clinical utility. In this project, the Trustworthy consensus-based statement approach was utilized to develop, via a structured process, consensus-based statements to guide future investigators of venous interventions. Thirty statements were drafted to encompass major topics relevant to venous study description and design, safety outcome assessment, efficacy outcome assessment, and topics specific to evaluating percutaneous venous thrombectomy and stent placement. Using modified Delphi techniques for consensus achievement, a panel of physician experts in vascular disease voted on the statements and succeeded in reaching the predefined threshold of >80% consensus (agreement or strong agreement) on all 30 statements. It is hoped that the guidance from these statements will improve standardization, objectivity, and patient-centered relevance in the reporting of clinical outcomes of endovascular interventions for acute iliofemoral deep venous thrombosis and chronic iliofemoral venous obstruction in clinical studies and thereby enhance venous patient care.

A Clinical Trial of Venous Stent Placement for Post-thrombotic Syndrome: Current Status and Pandemic-related Changes

Patients with post-thrombotic syndrome (PTS) and iliac vein obstruction have lower extremity symptoms, activity limitation and impairment of health-related quality of life. Preliminary studies suggest that iliac vein stent placement, which eliminates venous outflow obstruction, may reduce the clinical severity of PTS. However, stent placement is associated with patient risk, inconvenience and cost. Therefore, the Chronic Venous Thrombosis – Relief with Adjunctive Catheter-directed Therapy (C-TRACT) trial was launched to rigorously assess the risk–benefit ratio of stent placement for the treatment of moderate or severe PTS. In the trial, patients in both treatment groups receive a high quality of multi-modality PTS care that includes medical, compressive, and ulcer therapies. Due to the COVID-19 pandemic, the trial protocol and practices were modified to enhance the study feasibility while preserving its ability to answer its primary question. This review summarises the current status of the trial and the potential impact of the pandemic-related adaptations to future venous clinical practice and research.

Three-Year Results from the Venovo Venous Stent Study for the Treatment of Iliac and Femoral Vein Obstruction

Purpose

To assess safety and patency of the Venovo venous stent for the treatment of iliofemoral vein obstruction.

Materials and Methods

Twenty-two international centers enrolled 170 patients in the VERNACULAR study (93 post-thrombotic syndrome; 77 non-thrombotic iliac vein lesions). Primary outcome measures were major adverse events at 30 days and 12-month primary patency (freedom from target vessel revascularization, thrombotic occlusion, or stenosis > 50%). Secondary outcomes included the Venous Clinical Severity Score Pain Assessment and Chronic Venous Quality-of-Life Questionnaire assessments (hypothesis tested). Secondary observations included primary patency, target vessel and lesion revascularization (TVR/TLR), and assessment of stent integrity through 36 months.

Results

Freedom from major adverse events through 30 days was 93.5%, statistically higher than a pre-specified performance goal of 89% (p = 0.032) while primary patency at 12 months was 88.6%, also statistically higher than a performance goal of 74% (p < 0.0001). Mean quality-of-life measures were statistically improved compared to baseline values at 12 months (p < 0.0001). Primary patency at 36 months was 84% (Kaplan–Meier analysis) while freedom from TVR/TLR was 88.1%. There was no stent embolization/migration, and no core laboratory assessed stent fractures reported through 36 months. Six deaths were reported; none adjudicated as device or procedure related.

Conclusion

The Venovo venous stent was successfully deployed in obstructive iliofemoral vein lesions and met the pre-specified primary outcome measures through 12 months. At 3 years, primary patency was 84%, reintervention rates were low, standardized quality-of-life and pain measures improved from baseline, and there was no stent migration or fractures.

Level of Evidence

Level 2—prospective, multicenter, controlled clinical study without a concurrent control or randomization. Pre-specified endpoints were hypothesis-tested to performance goals derived from peer-reviewed clinical literature.

Registration clinicaltrials.gov

Unique Identifier NCT02655887.

Effect of Stent Strut Interval on Neointima Formation After Venous Stenting in an Ovine Model

OBJECTIVE

The impact of stent design on venous patency is not well studied. The purpose of this study was to investigate the effect of stent material burden on endothelial coverage of stented venous segments, which may contribute to vessel healing and patency.

METHODS

Segmented self expanding bare nitinol stents (18 × 50 mm) comprising 5 mm long attached metallic rings separated by 2, 5, or 8 mm gaps were implanted in the inferior vena cava (IVC) of 10 sheep. These stents were designed and manufactured for the purposes of this study. At six, 12, and 24 weeks after implantation the animals were euthanised and the stented vessels harvested for histomorphometric analysis. Three sections from the metallic part as well as the gaps between the struts were reviewed for quantification of endothelialisation after six, 12, and 24 weeks. The intimal thickness over and between the stent struts was measured. The endothelialisation score (graded from 1 for complete luminal endothelialisation to 5 for absence of endothelial cells) was determined.

RESULTS

All stents were successfully deployed and all 10 sheep survived until the time of harvesting. Macroscopic inspection after 24 weeks showed only partial endothelialisation over stents with 2 mm and 5 mm skipped segments, whereas the stents with 8 mm skipped segments were totally incorporated into the vein wall. After 24 weeks, the mean (SD) neointimal thicknesses over stent struts with 2 mm, 5 mm, and 8 mm skipped segments were 254.0 (51.6), 182.2 (98.1), and 194.6 (101.1) μm, respectively. Comparison of endothelialisation scores of stents over time showed statistically significantly better endothelialisation over stents with 8 mm gaps after 12 and 24 weeks.

CONCLUSION

Stent designs providing structural support to veins with larger gaps between the scaffold material appear to lead to faster and more complete endothelialisation as well as a thinner intimal layer.

A clinical guide to Deep venous stenting for chronic iliofemoral venous obstruction

INTRODUCTION

An increase in endovenous interventions for deep venous pathologies has been observed. This article aims to provide an overview of the role of venous stenting in the management of chronic conditions affecting the deep venous system of the lower limbs, with a focus on intervention relating to the vena cava and iliofemoral venous segments.

METHOD

An overview of the literature on the minimally invasive venous stenting procedures that are being increasingly used in the management of chronic conditions affecting the deep venous system of the lower limbs.

RESULTS

We discuss key areas of interest to a venous specialist practicing in this area, including diagnostic imaging in chronic deep venous disease, with a focus on the use of intravascular ultrasound in this context; treatment of chronic venous outflow obstruction, including the rationale and structural indications for stenting, current guidance regarding stent placement, and fundamental points to consider during decision-making (endophlebectomy and stenting, stenting across the inguinal ligament, optimal sizing of venous stents, extension of venous stenting to beyond the common femoral vein confluence, the role of thrombolysis useful in chronic venous disease, and arteriovenous fistulae); outcomes and initial reports of stenting; and the future of venous stents.

CONCLUSION

Deep venous stenting has become a key treatment option for chronic (thrombotic or non-thrombotic) obstructive venous disease. Dedicated venous stents and intravascular ultrasound represent important technological advances in the minimally invasive treatment of symptomatic chronic deep venous obstruction, which previously required open surgical reconstruction.

Iliac vein stenting in a patient with lower extremity swelling resulting from diffuse pelvic mass: A case report

We report a 66-year-old male patient with severe right lower extremity swelling resulting from diffuse pelvic mass with compression on right external iliac vein. The patient had papillary urothelial carcinoma of bladder seven years ago and radical cystectomy and ureterostomy was performed. Recurrence of malignancy had occurred five years after the operation. The patient had also bilateral diffuse lung metastasis. The external iliac vein had severe stenosis and invasion of pelvic mass into the vein was evident on venography. Venoplasty of external iliac vein was performed throughout the stenosis. A venous stent of 80 mm length and 12 mm diameter was introduced over the guidewire and deployed in the external iliac vein. Dramatic clinical response was evident since postoperative day two. Swelling of right lower extremity was resolved dramatically on three-month and six-month follow-up visits. We believe that endovascular venous recanalization of iliac veins is feasible and safe in patients with unresectable and diffuse pelvic masses.

Analysis of patent, unstented lower extremity vein segment diameters in 266 patients with venous disease

OBJECTIVE

The objective of this study was to characterize the average maximum diameters of widely patent lower extremity vein segments in patients with underlying venous disease and the demographic factors that affect these diameters.

METHODS

Maximum axial diameters of each deep vein segment from the diaphragm to the knee were measured from computed tomography venography studies for all patients who underwent venous stent placement during a 20-year period at a single quaternary venous referral institution. Limbs containing only widely patent, unstented vein segments without variant anatomy were identified for inclusion. The final analysis involved diameter measurements from 870 imaging studies of 266 patients. Multivariate linear regression was used to identify factors associated with vein segment diameters.

RESULTS

Average vein segment diameters ranged from 7.8 mm for the left and right femoral veins to 27.9 mm for the long axis of the suprarenal inferior vena cava. Multivariate linear regression demonstrated that women had larger IVC, common iliac vein, and external iliac vein diameters, whereas men had larger common femoral veins. Laterality, height, weight, and sex also had statistically significant associations with the diameters of select vein segments.

CONCLUSIONS

This study provides an estimate of the average diameters of widely patent deep vein segments in the lower extremities from the diaphragm to the knees in patients with underlying venous disease and characterizes covariates that significantly affect vein diameter. These findings may help interventionalists better select devices for endovascular intervention.

Guidance of Venous Stent Implantation after Catheter-directed Thrombosis in Patients with Acute Left Lower Extremity Deep Venous Thrombosis based on Pressure Gradient Differences between the Iliac Vein and Inferior Vena Cava: A Single-center Retrospective Study

BACKGROUND

Iliac vein compression syndrome (IVCS) can lead to acute deep venous thrombosis (DVT) and post-thrombotic syndrome (PTS). Endovascular venous stenting has become a preferred treatment for IVCS. In this article, we guide stent implantation by the pressure gradient of iliac vein and inferior vena cava. To evaluate the feasibility of guidance of venous stent implantation based on venous pressure gradient difference.

METHODS

A retrospective analysis was performed on patients with acute left lower extremity DVT who were treated in our center from March 2012 to December 2017. The patients were divided into 2 groups: group 1: from January 2015 to December 2017, patients were treated with catheter-directed thrombolysis (CDT) and stent implantation was guided by the pressure gradient of iliac vein and inferior vena cava after thrombectomy; group 2: from May 2012 to December 2014, patients underwent CDT treatment without stent implantation. In group 1, the patients were divided into 2 groups according to the difference in pressure gradient after CDT: the stent group (>2 mm Hg) and the control group (≤2 mm Hg). All patients were evaluated by color Doppler ultrasound at 1, 3, and 6 months after the operation to evaluate the patency of the iliofemoral vein. The Villalta score was used to evaluate the incidence of PTS.

RESULTS

The primary and secondary patency rate of group 1 at 1, 3, and 6 months after operation were higher than that in group 2 (P < 0.05). In group 1, there was no significant difference in the primary and secondary patency rate between the stent group and the control group at 1, 3, and 6 months after the operation. The incidence of PTS in group 1 at 6 months after the operation was lower than that in group 2 (P < 0.05). In group 1, there was no significant difference in the incidence of PTS between the stent group and the control group at 6 months after the operation.

CONCLUSIONS

Practice proves that it is simple and effective to guide stent implantation according to differences in pressure gradients. Two millimeter of mercury is the traditional standard for venous pressure interference in the pelvic area, and the effectiveness of this method was proved.

Long-term outcome and quality of life in patients with iliac vein compression syndrome after endovascular treatment

Purpose

Deep venous thrombosis induced by iliac vein compression syndrome often interferes with patients’ work or daily living. This study aims to investigate the long-term outcome and quality of life in patients with iliac vein compression syndrome after endovascular treatment.

Methods

From October 2011 until June 2016, 28 patients with acute deep venous thrombosis diagnosed as iliac vein compression syndrome by ultrasonography were enrolled in this perspective study. Fifteen patients underwent balloon dilation and stent insertion (group A); 13 patients received anticoagulation treatment, thrombolysis, or balloon dilation without stenting (group B). The Medical Outcomes Study-Short Form-36 was used to assess the quality of life preoperatively and after endovascular treatment. The follow-up of Short Form-36 questionnaire was obtained within 12.13 ± 12.04 months after repair.

Results

There was no operative mortality in two groups, and technical success was achieved in 14 (93.3%) patients in group A. Thirteen (86.7%) patients were cured in group A, which was significantly higher than that of group B (46.2%, p = 0.042). Only one patient showed occlusion of stent in group A, with a secondary patency rate of 93.3%. Except for ‘Role emotion’, all remaining domains were significantly improved in group A when compared with preoperative score ( p < 0.01). The scores of ‘Physical functioning’, ‘Role physical’, and ‘General health’ in group A were significantly higher than those of group B ( p < 0.05).

Conclusions

Endovascular stenting to treat iliac vein compression syndrome shows beneficial clinical outcome, cumulative patency rate, and quality of life, with high technical success and low complications.

Treatment of venous stenosis in oncologic patients

Symptomatic obstruction related to malignant involvement of large veins may occur in central veins both in the thoracic and pelvic regions, and in the abdominal region of the body. Both cases represent a therapeutic challenge, and endovascular revascularization, consisting of angioplasty and stent placement, is safe and effective. Superior vena cava stenting has become widespread in the management of occlusive venous disease. The percutaneous placement of large expandable metal stents allows rapid restoration of normal blood flow in the majority of patients, thus improving symptoms. Published data on the diagnosis and treatment of symptomatic cancer-related iliocaval obstructions are limited and mainly consist of case reports and small case series. The present review reports the current state of endovascular treatment for both superior vena cava occlusion and iliac compression syndrome in cancer patients.

The Treatment of Post-Thrombotic Syndrome

BACKGROUND

Post-thrombotic syndrome (PTS) arises in 20-50% of patients who have sustained a deep vein thrombosis and markedly impairs their quality of life.

METHODS

This review is based on pertinent publications retrieved by a selective literature search in PubMed and the Cochrane Library, and on the guidelines of the German Societies of Phlebology and Vascular Surgery (Deutsche Gesellschaft für Phlebologie, Deutsche Gesellschaft für Gefässchirurgie).

RESULTS

The treatment options are conservative treatment with compression and patient exercises, endovascular recanalization with stent angioplasty, and open bypass surgery of the iliac obstructions. The endovascular techniques yield patency rates of 73 to 100%, with thrombotic stent occlusion and hematoma as potential complications. The open operations have only been documented in studies with small case numbers (3 to 85 cases per study, patency rates 58 to 100%). The complications of these invasive procedures can include thrombotic bypass occlusion, hematoma, and wound infection. There have been randomized trials of conservative treatment, but not of surgical treatment. The American Heart Association, in its guidelines, gives the same weak recommendation for all surgical methods (IIb).

CONCLUSION

All conservative options should be exhausted as the first line of treatment. If PTS symptoms persist and markedly impair the patient's quality of life, the possible indication for surgery should be considered. As PTS hardly ever leads to death or limb loss, its treatment should be as uninvasive as possible. Endovascular recanalization is an attractive option in this respect. A conclusive evaluation of the role of endovascular procedures in PTS must await randomized trials of this form of treatment and of the optimal stent configuration.

May-Thurner: diagnosis and endovascular management

Common left iliac vein compression, otherwise known as May-Thurner (MT), is an anatomical risk factor for lower extremity deep vein thrombosis (DVT). MT refers to chronic compression of the left iliac vein against the lumbar spine by the overlying right common iliac artery. The compression may be asymptomatic. The syndrome is a clinical spectrum of physical findings and history plus the lesion. It is characterized by the varying degrees of venous hypertension. This can be non-thrombotic, combined with acute DVT or post-thrombotic. Traditionally, acute DVT was treated with standard anticoagulation and sometimes, thrombectomy. However these measures do not address the underlying culprit lesion of mechanical compression. Furthermore, if managed only with anticoagulation, patients with residual thrombus are at risk for developing recurrent DVT or post-thrombotic syndrome (PTS). Both retrospective and prospective studies have shown that endovascular management should be the preferred approach to dissolve proximal thrombus and to also treat the underlying compression with endovascular stent placement.

Venous Compression Syndromes

Venous compression syndromes occur due to extrinsic compression causing complications of venous hypertension or venous thrombosis. This review focuses on 4 venous compression syndromes involving the left common iliac vein, subclavian vein, left renal vein, and popliteal vein. Clinical presentation, diagnostic methods, and management options are reviewed. When properly diagnosed and treated, long-term consequences can be avoided.

Minimally invasive treatments for venous compression syndromes

The management of venous compression syndromes has historically been reliant on surgical treatment when conservative measures fail. There are, however, several settings in which endovascular therapy can play a significant role as an adjunct or even a replacement to more invasive surgical methods. We explore the role of minimally invasive treatment options for three of the most well-studied venous compression syndromes. The clinical aspects and pathophysiology of Paget-Schroetter syndrome (PSS), nutcracker syndrome, and May-Thurner syndrome are discussed in detail, with particular emphasis on the role that interventionalists can play in minimally invasive treatment.

Use of Cryopreserved Small Aortic Homografts for Large Vein Replacement

Total obstruction, stenosis, or ligation of any large vein is associated with significant morbidity. No synthetic grafts can adequately replace large veins, particularly in areas subjected to motion (flexion or extension). Artificial prosthetic materials usually occlude within a short period.

Since 1987, the author has used cryopreserved allografts of small aortas varying from 1 to 1.7 cm in diameter to replace large vein channels in the upper or lower body. These allografts provide a manageable, pliable conduit with normal endothelium. He implanted grafts bridging gaps from 4 to 30 cm in length, in 14 patients (10 women, 4 men). Veins replaced were five iliac, three iliofemoral, and six subclavian-innominate. The long-term patency rate (follow-up 3 months to 10 years) is 93%.

The use of small aortic cryopreserved homografts for large vein replacement, particularly in mobile areas (groin, thoracic inlet, pelvis) is recommended. These grafts appear superior to any previous grafts used for the same purpose.

Acute right lower extremity iliofemoral deep venous thrombosis secondary to an anomalous inferior vena cava: a report of two cases

A congenital anomaly of the inferior vena cava is an increasingly identified risk factor for iliocaval deep venous thrombosis in young patients. We present two cases of acute right lower extremity iliofemoral deep venous thrombosis in 16 and 18-year-old patients that were ultimately diagnosed with an underlying anomalous iliocaval venous system. In one patient, the inferior vena cava was congenitally absent and the right iliac vein was diffusely stenotic with a proximally located high-grade stricture. In the other subject, the infrarenal inferior vena cava and right iliac vein were diffusely hypoplastic. Compensatory venous flow in both subjects was via large perilumbar venous collateral veins and a prominent azygous system. Both patients were successfully treated with a combination of initial catheter-directed thrombolysis followed by balloon angioplasty and venous stent placement.

Palliative endovascular treatment of cancer-related iliocaval obstructive disease: technical and clinical outcomes

BACKGROUND

Cancer-related obstruction of large abdominal and pelvic veins might become symptomatic with clinical signs of lower limb venous congestion. Technical and clinical outcome after interventional treatment is not well studied yet.

PURPOSE

To retrospectively assess the technical and clinical outcome of endovascular management of symptomatic cancer-related iliocaval venous obstructive disease.

MATERIAL AND METHODS

From 1998 to 2013, 19 patients (15 men, 4 women; mean age, 63.6 years) referred for interventional treatment of cancer-related iliocaval obstructive disease were identified. Patients' symptoms included unilateral (n = 16; 84%) or bilateral (n = 3; 16%) painful swelling of the lower limbs. Patients' demographics as well as interventional and clinical outcome data were collected.

RESULTS

All 19 patients underwent, under local anesthesia, stenting of the iliac vein (n = 16; 84%) or inferior vena cava (n = 3; 16%). Immediate technical success (n = 19) was 100%; immediate clinical success (n = 18) was 94.7%. During follow-up, seven patients (36.8%) presented with recurrent symptoms of painful limb swelling. Estimated survival after 3 and 6 months was 68.4% (95% confidence interval [CI], 47.8-82.3%) and 19.8% (95% CI, 11.9-29.2%), respectively.

CONCLUSION

Endovascular stenting of cancer-related iliocaval venous obstructive disease is safe and results in immediate relief of symptoms. However, recurrent venous obstruction is common. At 3 months follow-up, the majority of patients with iliac vein stenting were still alive.

Interventional therapy for venous thromboembolism

Advances in image-guided, catheter-based interventions have shown great potential to improve outcomes in patients with venous thromboembolism. Catheter-directed thrombolysis has been shown in one randomized controlled trial to reduce the risk of post-thrombotic syndrome in patients with acute lower extremity deep vein thrombosis; data from a larger national institute of health trial are expected in early 2017. The use of catheter-directed thrombolysis is also being increasingly considered for patients with submassive or massive pulmonary embolism. Preliminary studies suggest that endovascular stent placement and ablative therapies may be used to reduce symptoms and improve quality of life in severely affected patients with established post-thrombotic syndrome. In this article, we summarize the risks and benefits of endovascular venous thromboembolism therapies as currently understood, highlight clinical situations where their benefit may outweigh risks, and describe ongoing and upcoming pivotal research initiatives with multidisciplinary participation.

Iliocaval Confluence Stenting for Chronic Venous Obstructions

PURPOSE

Different techniques have been described for stenting of venous obstructions. We report our experience with two different confluence stenting techniques to treat chronic bi-iliocaval obstructions.

MATERIALS AND METHODS

Between 11/2009 and 08/2014 we treated 40 patients for chronic total bi-iliocaval obstructions. Pre-operative magnetic resonance venography showed bilateral extensive post-thrombotic scarring in common and external iliac veins as well as obstruction of the inferior vena cava (IVC). Stenting of the IVC was performed with large self-expandable stents down to the level of the iliocaval confluence. To bridge the confluence, either self-expandable stents were placed inside the IVC stent (24 patients, SECS group) or high radial force balloon-expandable stents were placed at the same level (16 patients, BECS group). In both cases, bilateral iliac extensions were performed using nitinol stents.

RESULTS

Recanalization was achieved for all patients. In 15 (38 %) patients, a hybrid procedure with endophlebectomy and arteriovenous fistula creation needed to be performed because of significant involvement of inflow vessels below the inguinal ligament. Mean follow-up was 443 ± 438 days (range 7-1683 days). For all patients, primary, assisted-primary, and secondary patency rate at 36 months were 70, 73, and 78 %, respectively. Twelve-month patency rates in the SECS group were 85, 85, and 95 % for primary, assisted-primary, and secondary patency. In the BECS group, primary patency was 100 % during a mean follow-up period of 134 ± 118 (range 29-337) days.

CONCLUSION

Stenting of chronic bi-iliocaval obstruction shows relatively high patency rates at medium follow-up. Short-term patency seems to favor confluence stenting with balloon-expandable stents.

May-Thurner syndrome and other obstructive iliac vein lesions: meaning, myth, and mystery

Acute and chronic venous disorders of the lower extremities affect millions of people and cause substantial disability. Long ago, surgeons and pathologists identified the presence of 'spur-like' abnormalities of the left common iliac vein; these abnormalities were hypothesized to result from compression and/or irritation from the adjacent crossing right common iliac artery. In the 1990s, physicians, starting to perform catheter-directed thrombolysis to treat extensive deep vein thrombosis (DVT), observed that about 50% of patients had an iliac vein stenosis. Vascular physicians have become aware of the occasional patient with otherwise-unexplained extremity swelling and/or pain but without a DVT history who is subsequently found to have an iliac vein abnormality. These 'lesions' have been hypothesized to elevate ambulatory venous pressures and thereby produce lower-extremity symptoms, increase the risk of initial and recurrent DVT episodes, and increase the risk of treatment failure with medical and endovascular therapies for thrombotic and non-thrombotic venous conditions. As a result, many practitioners now actively seek iliac venous obstructive 'lesions' when evaluating patients with known or suspected venous disease. However, for many patients, it continues to be unclear what degree of obstruction to venous blood flow is being caused by such lesions, how clinically significant they are, how much emphasis should be placed on identifying them, and when they should be treated. This article seeks to improve the knowledge base of vascular practitioners who make clinical decisions about the diagnosis and treatment of obstructive iliac vein lesions.

Preliminary report on a new concept stent prototype designed for venous implant

Venous obstruction at iliocaval level in both forms, primary and secondary, is a significant cause of severe chronic venous insufficiency. A new therapeutic approach to this pathology emerged with the introduction of stenting procedures that proved effective, leading to good long-term results. However, at present, the majority of implanted stents have been designed for arterial implant and this can pose a limit in particular districts. The purpose of this preliminary acute study was to verify the deliverability and safety of a new stent specially designed for venous-vessel implant. We assess the safety and deliverability of two braided, self-expanding, nickel–titanium stents (Jotec GmbH, Hechingen, Germany) specially designed for endovascular implant in veins. The two stents, despite being based on the same concept, have a different design: stent A presents a proximal tapering shape specially designed to reduce migration, while stent B does not. Both of them are enlarged at their distal extremity and present variable radial force the length of the stent itself, the said force becoming very high in the intermediate segment. Stents were implanted in the internal jugular vein of a sheep, showing optimal deliverability. The completion venography showed the migration of stent B into the right atrium. Stent A maintained its location, confirmed by intravascular ultrasound examination. No scaffolding effect was detected and an adequate adherence and adaptability to the vein wall was obtained. In conclusions, the stent A design matches the characteristics required by vein implants. Stability is achieved even where difficult anatomical conditions apply, such as in the jugular vein. Deployment is easy and precise in a given landing zone. Radial resistive force is very high, as required in specific vein districts, but is also associated with good flexibility. Following this preliminary acute report, further studies are required.

Iliac vein stenting as a durable option for residual stenosis after catheter-directed thrombolysis and angioplasty of iliofemoral deep vein thrombosis secondary to May–Thurner syndrome

Introduction

This study aims to evaluate the primary patency and clinical outcomes after stenting for residual iliac venous stenosis during catheter-directed thrombolysis treatment of acute iliofemoral deep vein thrombosis arising from May–Thurner syndome.

Methods

A retrospective study was done for the all patients who underwent iliac vein stenting after catheter-directed thrombolysis treatment of acute iliofemoral deep vein thrombosis due to May–Thurner syndrome from January 2005 to April 2011 in Inha University Hospital. Patient information was assembled from the electronic medical records, imaging and interview. The patency of iliac vein stent was evaluated with serial computed tomography.

Results

Fifty-one patients were enrolled. The median age was 70 years (range 44–86). There were 37 females (72.5%). The duration of symptoms of acute deep vein thrombosis before catheter-directed thrombolysis treatment was 6 days (median, range 1–33). Self-expanding stent was used for iliac vein stenting. Initial technical success rate was 94.1%. There were two complications (3.9%): an arteriovenous fistula formation in left popliteal area and a right inguinal hematoma. Mean follow-up was 15.6 months (range 6 days–80.8 months). Primary patency rate after iliac vein stenting was 95.8% at 6 months, 87.5% at 12 months and 84.3% at 24 months. Four patients had recurrent thrombotic occlusion (7.8%) during the follow-up.

Conclusion

Iliac vein stenting showed good primary patency rate with few complications. Iliac vein stenting is a durable option for residual stenosis after catheter-directed thrombolysis treatment of acute deep vein thrombosis in May–Thurner syndrome.

Endovascular stent placement for malignant stenosis and occlusion of the bilateral iliac veins and inferior vena cava after failure of radiation therapy

A 70-year-old woman with advanced ureteral carcinoma was referred due to stenosis and occlusion of the bilateral iliac veins and inferior vena cava after failure of radiation therapy. We successfully placed endovascular stents in the bilateral iliac veins and the inferior vena cava. The stents remain patent after five months of follow-up without requiring secondary intervention. As far as we know, this is the first report of radioresistant malignant stenosis of the bilateral iliac veins and the inferior vena cava that was successfully treated with stent placement.

Endovascular treatment for post-thrombotic syndrome. Two case studies and a literature review

The recent application of endovascular treatment techniques to venous pathologies has meant that new therapeutic solutions can be offered to patients suffering from post-thrombotic syndrome. This often-underestimated condition frequently complicates cases of deep vein thrombosis, whether treated or not, leading to a chronic and disabling set of clinical symptoms (oedema, claudication, pain, venous ulcers, etc.) due to the combination of the pathophysiological phenomena of obstructions and reflux. These clinical signs see only minimal improvement when managed with the classic medical treatment, venotonic agents, and venous compression. We report the cases of two patients suffering with chronic post-thrombotic venous obstruction of the lower limbs in whom endovascular treatment brought clear and long-lasting clinical improvement.

Prophylactic Implantation of Inferior Vena Cava Filter during Endovascular Therapies for Deep Venous Thrombosis of the Lower Extremities

Patients with deep venous thrombosis (DVT) of the lower extremities have an increased risk of pulmonary emboli and post-thrombotic syndrome. Traditionally, they are treated medicinally, with anticoagulation therapy. Currently, endovascular therapies, with their higher efficiency, have replaced previously attempted systemic fibrinolytic therapies. There is a continuing controversy in the temporary use of filters in the inferior vena cava during these endovascular therapies, which may include catheter-directed thrombolysis, manual aspiration, mechanical thrombectomy, percutaneous transluminal angioplasty and placement of self-expandable metallic stents. Here, we present an overview of the literature and analysis on the application of prophylactic implantation of an inferior vena cava filter during endovascular therapy for DVT of the lower extremities.

Endovascular thrombolysis using monteplase for non-chronic deep venous thrombosis

This study was designed to evaluate the usefulness of endovascular thrombolysis using monteplase for deep venous thrombosis (DVT). Between December 2005 and October 2009, at our institution nine endovascular thrombolysis treatments with monteplase were performed for symptomatic DVT in eight patients (6 women, 2 men; mean age, 56 (range, 15-80) years). In all, systemic anticoagulation administered by the peripheral intravenous route with heparin and/or thrombolysis with urokinase followed by anticoagulation with orally administered warfarin had been performed, and subsequently six endovascular treatments without monteplase were administered. However, DVT persisted, and endovascular treatments with monteplase were tried. In six (67%) of the nine procedures, DVT completely or almost completely disappeared after endovascular thrombolysis with monteplase. Mean dose of monteplase used was 2,170,000 IU. There was only one procedure-related complication. In one patient, just after thrombolysis with monteplase, bleeding at the puncture site and gingival bleeding occurred. Bleeding was stopped by manual astriction only. Endovascular thrombolysis with monteplase may be an effective treatment for DVT, even in cases resistant to traditional systemic anticoagulation and thrombolysis and endovascular procedures without monteplase.

Symptomatic ileofemoral DVT after onset of oral contraceptive use in women with previously undiagnosed May-Thurner Syndrome

OBJECTIVE

May-Thurner syndrome is characterized by left common iliac obstruction secondary to compression of the left iliac vein by the right common iliac artery against the fifth-lumbar vertebra. This anatomic variant results in an increased incidence of left-sided deep venous thrombosis (DVT). Furthermore, while a preponderance of left-sided DVT has been demonstrated in women during pregnancy and oral contraceptive use, patients are not typically screened for this condition after developing a left-sided DVT. As anticoagulation alone is ineffective for DVT treatment in the setting of May-Thurner anatomy, more aggressive treatment is warranted. Failure to diagnosis this condition predisposes these women to the unnecessary risks of recurrent DVT and post-thrombotic syndrome.

METHODS

We present the occurrence of 7 adolescent patients with previously undiagnosed May-Thurner syndrome who presented with DVT after the initiation of oral contraceptive steroids (OCP) use. All 7 patients elected to proceed with mechanical thrombolysis/catheter based thrombolysis followed by endovascular stenting and were postoperatively treated with 6 months of warfarin.

RESULTS

Mean patient age was 18.3 +/- 3.3 years (range, 16-24 years). Mean time to presentation after initiation of OCP was 5 weeks (range, 2-10 weeks). Mean time to intervention was 16.8 days (range, 10-24 days). All patients were treated with mechanical thrombectomy. Our rate of intraoperative clot resolution was 100%. All 7 patients were treated with self expanding nitinol stents after angioplasty of the iliac vein stenosis with resolution of the stenotic segment. Primary stent patency is 100% (7/7). Mean follow-up time is 13 +/- 13.84 months (range, 6-42 months). There have been no long-term complications related to surgical treatment or anticoagulation. All 7 patients have experienced resolution of left leg swelling and pain and have no evidence of post-thrombotic syndrome or DVT recurrence to date.

CONCLUSIONS

Women on OCPs presenting with left-sided iliofemoral DVT should be screened for hypercoagulable disorders and underlying May-Thurner anatomy. Treatment of May-Thurner syndrome should include thrombolysis/thrombectomy and anticoagulation for current DVT in addition to angioplasty and stenting of the underlying obstruction.

Massage-induced delayed venous stent migration

Catheter-directed therapies in chronic deep vein thromboses can help improve leg function by mechanically addressing residual obstruction in lower extremity or pelvic veins, although the reported use of stents in leg veins is relatively unusual. The author reports a case of this type with long-term patency and clinical success, culminating in asymptomatic delayed venous migration of a stent to the right atrium after 3 years. Open heart surgery was required to remove the embedded stent fragments. The attributed mechanism was deep tissue massage of the thigh.

Successful iliac vein and inferior vena cava stenting ameliorates venous claudication and improves venous outflow, calf muscle pump function, and clinical status in post-thrombotic syndrome

OBJECTIVES

Stent therapy has been proposed as an effective treatment of chronic iliofemoral (I-F) and inferior vena cava (IVC) thrombosis. The purpose of this study was to determine the effects of technically successful stenting in consecutive patients with advanced CVD (CEAP3-6 +/- venous claudication) for chronic obliteration of the I-F (+/-IVC) trunks, on the venous hemodynamics of the limb, the walking capacity, and the clinical status of CVD. These patients had previously failed to improve with conservative treatment entailing compression and/or wound care for at least 12 months.

METHODS

The presence of venous claudication was assessed by > or =3 independent examiners. The CEAP clinical classification was used to determine the severity of CVD. Outflow obstruction [Outflow Fraction at 1- and 4-second (OF1 and OF4) in %], venous reflux [Venous Filling Index (VFI) in mL/100 mL/s], calf muscle pump function [Ejection Fraction (EF) in %] and hypertension [Residual Venous Fraction (RVF) in %], were examined before and after successful venous stenting in 16 patients (23 limbs), 6 females, 10 males, median age 42 years; range, 31-77 yearas, left/right limbs 14/9, using strain gauge plethysmography; 7/16 of these had thrombosis extending to the IVC. Contralateral limbs to those stented without prior I-F +/- IVC thrombosis, nor infrainguinal clots on duplex, were used as control limbs (n = 9). Excluded were patients with stent occlusion or stenoses, peripheral arterial disease (ABI <1.0), symptomatic cardiac disease, unrelated causes of walking impairment, and malignancy. Preinterventional data (< or =30 days) were compared with those after endovascular therapy (8.4 months; interquartile range [IQR], 3-11.8 months). Nonparametric analysis was applied.

RESULTS

Compared with the control group, limbs with I-F +/- IVC thrombosis before stenting had reduced venous outflow (OF4) and calf muscle pump function (EF), worse CEAP clinical class, and increased RVF (all, P < 0.05). At 8.4 months (IQR, 3-11.8 months) after successful I-F (+/-IVC) stenting, venous outflow (OF1, OF4) and calf muscle pump function (EF) had both improved (P < 0.001) and the RVF had decreased (P < 0.001), at the expense of venous reflux, which had increased further (increase of median VFI by 24%; P = 0.002); the CEAP status had also improved (P < 0.05) from a median class C3 (range, C3-C6; IQR, C3-C5) [distribution, C6: 6; C4: 4; C3: 13] before intervention to C2 (range, C2-C6; IQR, C2-C4.5) [distribution, C6: 1; C5: 5; C4: 4; C2: 13] after intervention. At this follow up (8.4 months median), venous outflow (OF1, OF4), calf muscle pump function (EF), and RVF of the stented limbs did not differ significantly from those of the control; significantly worse (P < 0.025) were the amount of venous reflux (VFI), and the CEAP clinical class, despite the improvement with stenting. Incapacitating venous claudication noted in 62.5% (10 of 16, 95% CI, 35.8%-89.1%) of patients (15 of 23 limbs; 65.2%, 95% CI, 44.2%-86.3%) before stenting was eliminated in all after stenting (P < 0.001).

CONCLUSIONS

Successful I-F (+/-IVC) stenting in limbs with venous outflow obstruction and complicated CVD (C3-C6) ameliorates venous claudication, normalizes outflow, and enhances calf muscle pump function, compounded by a significant clinical improvement of CVD. The significant increase in the amount of venous reflux of the stented limbs indicates that elastic or inelastic compression support of the successfully stented limbs would be pivotal in preventing disease progression.

Percutaneous treatment of deep vein thrombosis in May-Thurner syndrome

BACKGROUND/PURPOSE

May-Thurner syndrome is an uncommon disease entity in which the left common iliac vein is compressed by the right common iliac artery with subsequent development of deep vein thrombosis and chronic venous insufficiency. We report our experience on the treatment of extensive iliofemoral deep venous thrombosis due to May-Thurner syndrome using endovascular techniques.

METHODS

The study group comprised 21 patients (8 men, 13 women; mean age 51 years) diagnosed with May-Thurner syndrome by venogram. Eighteen patients were treated with catheter-guided thrombolysis; 3 patients with short segment involvement did not require thrombolysis. After completion of the thrombolytic therapy, the residual venous narrowing was treated by balloon angioplasty and/or placement of a self-expandable stent.

RESULTS

The mean total dose of urokinase was 4.28 +/- 1.89 million units, and the mean duration of infusion was 72 +/- 35 hr. Eighteen of the 21 patients received stent deployment. The mean diameter of the stents was 12.9 +/- 2.0 mm. Initial technical successes with immediate symptom resolution were achieved in 20 of the 21 patients (95%). We performed a follow-up venogram 6 months after procedure and checked clinical symptoms at outpatient clinics (mean follow-up duration 10.8 months). Among the patients who received stent implantation, 2 had recurrent thrombotic occlusion during the follow-up period. Three patients, who did not receive stent implantation, all had recurrent thrombosis. There were no major bleeding complications except in 1 patient who developed retroperitoneal hematoma.

CONCLUSION

Catheter-guided thrombolysis and angioplasty with stent implantation is a safe and effective method for the treatment of May-Thurner syndrome.

Prophylactic implantation of inferior vena cava filter during interventional radiological treatment for deep venous thrombosis of the lower extremity

The purpose of this study was to evaluate the filtering effect of the Gunther tulip retrievable vena cava filter (GTF) during treatment of deep venous thrombosis (DVT) in the lower extremity using various interventional radiological procedures. Subjects of the study were all 17 consecutive patients (8 women, 9 men; age range 18-87 years; mean age 55.9 years) with symptomatic lower limb DVT referred for interventional radiological treatment between February 2001 and September 2004. In all of these patients, the GTF was implanted during interventional radiological treatment. Trapped thrombus in the filter was evaluated with venocavography performed repeatedly during the treatment for DVT. Implantation of a total of 29 GTFs was successfully performed in the 17 patients. In 10 (58.8%), more than 2 filters were subsequently implanted to prolong implantation time. Also in 10 patients, the DVT resolved after therapy and retrieval of the final GTF was successful with one exception. Worsening of or new formation of pulmonary embolism was avoided in all patients. In 8 (47.1%) of the 17 patients, a trapped thrombus in the GTF was observed during treatment for DVT. In six patients the trapped thrombus was large, filling more than half the height of the filter. In conclusion, we found that the GTF is effective in filtering the relieved thrombus from DVT in the lower extremity and in protecting against movement of the thrombus to the pulmonary artery during therapies with interventional radiological procedures.

Placement of Self-expanding Stents with Different Diameters in the Porcine Venous System: An Experimental Study

PURPOSE

To study the vascular histologic response after placement of oversized self-expanding stents in the porcine venous system.

MATERIALS AND METHODS

Twenty-four oversized stents (range of oversizing, 119.5%-216.0%) were deployed in jugular and iliac veins of six miniature pigs divided into two groups with follow-up times of 1 and 3 months. Necropsy with histologic evaluation of each stent was performed, and the areas of neointimal proliferation were calculated with slices obtained during follow-up from each stent at 5 mm from the proximal and distal edges and at the midpoint.

RESULTS

Neointimal proliferation was observed inside the stent lumen. All segments were patent in both groups. However, one jugular stent in the 1-month group and one jugular stent in the 3-month group had migrated at follow-up and were excluded from analysis. There were no significant differences in neointimal growth between the stent edges (proximal and distal) and middle segments of the stents at follow-up in the 1-month group (P = .970) or in the 3-month group (P = .694). Simple linear regression showed strong positive correlation between stent oversizing and neointimal proliferation in the 1-month model (r = 0.791; P < .001) and the 3-month model (r = 0.718; P < .001). There were no significant differences between 1-month and 3-month groups in the degree of neointimal proliferation (P = .072). Also, branched vessels showed no neointimal proliferation at their intersections with the stent-implanted segments.

CONCLUSION

Stent oversizing showed a strong positive correlation with neointimal growth in each follow-up model in this study.

Mid-term results of endovascular treatment for symptomatic chronic nonmalignant iliocaval venous occlusive disease

BACKGROUND

The goal of this article is to present clinical and patency results of endovascular treatment of nonmalignant, iliocaval venous obstructive disease and to discuss the evolution of technical details.

METHODS

From November 1995 to June 2004, 44 patients (female-male ratio, 3.9:1; left-right lower limb ratio, 8.6:1; median age, 42 years; range, 21-80 years) had treatment for chronic disabling obstructive venous insufficiency with iliocaval stenosis or occlusion. The clinical class of CEAP was 2 in 11 limbs, 3 in 31, 4 in 4, 5 in 1, and 6 in 1; etiology was primary in 32 patients, secondary in 10, and congenital in 2. Anatomic involvement included superficial veins in 16 patients and perforator veins in 11. Obstruction was associated with superficial reflux in 4 patients, deep reflux in 13, and both in 13. Ten patients had occlusion. All procedures were performed in the operating room with perioperative angiography and angioplasty with or without self-expanding stent implantation. Venous clinical severity and disability scores were obtained before and after treatment. Patency and restenosis were evaluated by duplex Doppler ultrasonography.

RESULTS

No perioperative death or pulmonary embolism occurred. The technical success rate was 95.5% (two recanalization failures), and two (4.5%) perioperative stent migrations occurred. One early thrombosis (2.4%) was treated by thrombectomy and creation of an arteriovenous fistula. One late death and one thrombosis occurred. Restenoses were found in five patients and were all treated successfully (four needed iterative stenting). Median follow-up was 27 months (range, 2-103 months). Median venous clinical severity score improved from 8.5 to 2, and median venous disability score improved from 2 to 0. Cumulative primary, assisted primary, and secondary patency rates of the venous segments at 36 months were 73%, 88%, and 90%, respectively, in intention to treat. The survival rate was 100% at 12 months and 97.3% at 60 months.

CONCLUSIONS

Endovascular treatment of benign iliocaval occlusive disease is a safe and efficient minimally invasive technique with good mid-term patency rates. Moreover, it improves cases with obstruction only, as well as cases with associated reflux and obstruction. Primary stenting should always be performed by using self-expanding stents deployed under general anesthesia to avoid lumbar pain. In case of failure, the endovascular procedure does not preclude further surgical reconstruction.

Gunther Tulip Inferior Vena Cava Filter Placement During Treatment for Deep Venous Thrombosis of the Lower Extremity

PURPOSE

To evaluate the efficacy and safety of Gunther tulip retrievable vena cava filter (GTF) implantation to prevent pulmonary embolism during intravenously administered thrombolytic and anticoagulation therapy and interventional radiological therapy for occlusive or nonocclusive deep venous thrombosis (DVT) of the lower extremity.

METHODS

We evaluated placement of 55 GTFs in 42 patients with lower extremity DVT who had undergone various treatments including those utilizing techniques of interventional radiology.

RESULTS

Worsening of pulmonary embolism in patients with existing pulmonary embolism or in those without pulmonary embolism at the time of GTF insertion was avoided in all patients. All attempts at implantation of the GTF were safely accomplished. Perforation and migration experienced by one patient was the only complication. Mean period of treatment for DVT under protection from pulmonary embolism by the GTF was 12.7 +/- 8.3 days (mean +/- SD, range 4-37 days). We attempted retrieval of GTFs in 18 patients in whom the venous thrombus had disappeared after therapy, and retrieval in one of these 18 cases failed. GTFs were left in the vena cava in 24 patients for permanent use when the DVT was refractory to treatment.

CONCLUSION

The ability of the GTF to protect against pulmonary embolism during treatment of DVT was demonstrated. Safety in both placement and retrieval was clarified. Because replacement with a permanent filter was not required, use of the GTF was convenient when further protection from complicated pulmonary embolism was necessary.

Stents in Common Iliac Vein Obstruction with Acute Ipsilateral Deep Venous Thrombosis: Early and Late Results

PURPOSE

To evaluate, by imaging and clinical follow-up, the effectiveness and long-term results of stent placement in cases of common iliac vein obstruction associated with ipsilateral deep vein thrombosis (DVT).

MATERIALS AND METHODS

Retrospective analysis of 22 patients (13 women, nine men; median age, 58 years) with common iliac vein obstruction with ipsilateral DVT was performed for this study. All patients presented with leg edema or pain and were treated with catheter-directed thrombolysis (1,000-2,000 U urokinase per kg body weight per hour; n = 19), aspiration thrombectomy (n = 21), or angioplasty (n = 14) followed by stent placement (n = 22) via an ipsilateral popliteal vein approach (right, n = 2; left, n = 20) under ultrasonographic (US) guidance. Patients were then followed by duplex US, and patency rates were determined by Kaplan-Meier survival analysis.

RESULTS

The mean procedure time was 15 hours (range, 1-23 hours) and the mean urokinase dose was 1,980,000 U (range, 600,000-3,600,000 U) before the implantation of 27 stents. Three patients did not receive urokinase. The technical success rate was 96% (26 of 27 stents) and the clinical success rate was 95% (21 of 22 patients). The causes of common iliac vein obstruction were May-Thurner syndrome (n = 16), pelvic mass (n = 2), and unknown (n = 4). The early complications included upward stent migration in one patient and a spinal epidural hematoma in another. The late complication was partial stent obstruction, which was successfully treated by thrombolysis and angioplasty in one patient. Follow-up lasted 1-41 months (mean, 21.4 months). Overall, the 1-year and 2-year primary patency rates were both 95% and the 1-year and 2-year secondary patency rates were both 100%.

CONCLUSION

Directed catheter thrombolysis and aspiration of DVT are relatively safe, and the use of stents improves patency results in cases of common iliac vein obstruction.

Effects of stent stiffness on local haemodynamics with particular reference to wave reflections

The placement of a rigid stent within an elastic vessel produces wave reflection sites at the entrance to and exit from the stent. The net haemodynamic effects of these reflections depend critically on the degree of stiffness of the stent and on its length and position within the diseased vessel, variables that have been found to affect the clinical performance of a stent. Here these effects are examined analytically, using a segmented tube model. The results indicate that the presence of the stent within the larger diseased vessel has the effect of producing higher pressure at the vessel entrance than that at exit. This pressure difference, when superimposed on the underlying pressure distribution within the vessel, has the net effect of actually aiding rather than impeding the flow, but the extent of this depends on the length and position of the stent. A short stent placed near the entrance of the diseased vessel may be favoured clinically for producing the least perturbation in the underlying haemodynamics and thus reducing the chance of restenosis, while a long stent placed near the exit may be favoured for producing a positive pressure difference and thus aiding the flow.

Thromboembolic Events in the Cancer Patient

Thromboembolic events are a major cause of morbidity in cancer patients and may be harbingers of occult malignancy. Trousseau's syndrome (TS) is probably the best known thromboembolic syndrome in the cancer patient, encompassing a variety of paraneoplastic thromboembolic disorders. These include spontaneous recurrent or migratory venous thromboses and arterial emboli caused by nonbacterial thrombotic endocarditis in a patient with malignancy. Although linked to almost all cancers, venous thromboembolism (VTE) is a terminal event in many cancers occurring in women, such as breast, uterine, and lung cancers (Monreal et al. Thrombosis and Haemostasis 1997;78:1316). Appropriate recognition of the syndrome is paramount because TS often requires careful medical surveillance and management. Significant complications of thromboembolic events in the cancer patient include limb ischemia and deep venous thrombosis/pulmonary embolism, which can cause devastating and permanent consequences. The rehabilitation management of these complications is reviewed, with an emphasis on diagnostic and therapeutic approaches in this patient population.