Quality of anticoagulant therapy and the incidence of in-stent thrombosis after venous stenting.

BACKGROUND: In patients with a venous outflow obstruction following iliofemoral deep vein thrombosis stenting of the venous tract to prevent or alleviate postthrombotic syndrome is applied with increasing frequency. The impact of the quality of anticoagulant therapy with vitamin K antagonists (VKAs) on the development of in-stent thrombosis is currently unknown. OBJECTIVES: To determine the association between the quality of postinterventional VKA treatment and the occurrence of in-stent thrombosis. METHODS: Seventy-nine patients with iliofemoral and/or caval venous stent placement for obstruction of the venous outflow were included in this study. All patients received postinterventional VKA. The quality of VKA anticoagulant therapy was expressed as the time within therapeutic range (TTR) calculated using the linear interpolation method and as the proportion of International Normalized Ratio (INR) values < 2.0. In-stent thrombosis was assessed by the use of duplex ultrasound. Survival analysis (Kaplan-Meier curves, Cox regression) was used to analyze the data. RESULTS: In-stent thrombosis developed in 16 patients (20.3%). The total population had a mean TTR of 64.0% (±19.0) and a mean proportion of INR values < 2.0 of 11.6% (±12.0). Overall, a TTR < 49.9% was associated with an increased risk of in-stent thrombosis. The multivariable adjusted analysis showed a hazard ratio (HR) of 0.96 (95% confidence interval [CI], 0.92-0.99; P = .02) per 1% increase in TTR. The proportion of INR values < 2.0 had no significant association with the occurrence of in-stent thrombosis: HR 0.98 (95% CI, 0.91-1.06; P = .66). CONCLUSIONS: We conclude that the quality of anticoagulant treatment reflected in the TTR following a venous stenting procedure is an important independent determinant for the risk of in-stent thrombosis. The role of anticoagulant treatment for the prevention of in-stent thrombosis following stenting procedures therefore merits further research.

The Effect of Stenting on Venous Hypertension: Results Using a Treadmill Stress Test with Invasive Pressure Measurements in Patients with Iliofemoral Venous Obstruction.

OBJECTIVES: The primary aim was to investigate whether stenting of post-thrombotic iliofemoral obstruction reduces venous hypertension. The secondary aim was to establish whether improvement in haemodynamic parameters impacts on quality of life. METHODS: In this prospective observational study, 12 participants with unilateral post-thrombotic obstruction of the iliac and/or common femoral veins (CFVs) underwent a treadmill stress test with invasive pressure measurements in the CFVs and dorsal foot veins of both affected and non-affected limbs. This was performed the day before and 3 months after stenting the obstructed tract. Paired sample t-tests were used to compare the treatment effect and univariable linear regression analysis to determine the association with improvement in quality of life. RESULTS: Before treatment, CFV pressure increased 34.8 ± 23.1 mmHg during walking in affected limbs compared with 3.9 ± 5.8 mmHg in non-affected limbs. This pressure rise decreased to 22.3 ± 24.8 mmHg after 3 months follow up compared with a 4.0 ± 6.0 mmHg increase in non-affected limbs (-26.2 mmHg difference; 95% CI -41.2 to -11.3). No such effect was found in the dorsal foot veins. The VEINES-QOL increased 25.3 ± 11.3 points after stenting and was significantly associated with a decrease in CFV pressure rise during walking (regression coefficient 0.4; 95% CI 0.1-0.6). CONCLUSION: Stenting of post-thrombotic iliofemoral obstruction significantly reduces venous hypertension in the common femoral vein and correlates with an improvement in the quality of life. Larger studies with a broader range of degree of obstruction need be performed to assess whether pre-stenting pressure measurements can predict post stenting clinical success.

The inability of venous occlusion air plethysmography to identify patients who will benefit from stenting of deep venous obstruction.

Background The aim of this study was to assess whether venous occlusion plethysmography can be used to identify venous obstruction and predict clinical success of stenting. Method Receiver operated characteristic curves were used to determine the ability of venous occlusion plethysmography to discriminate between the presence and absence of obstruction, measured by duplex ultrasound and magnetic resonance venography, and to discriminate between successful and non-successful stenting, measured by VEINES-QOL/Sym. Result Two hundred thirty-seven limbs in 196 patients were included. Areas under the curve for post-thrombotic obstruction were one-second outflow volume 0.71, total venous volume 0.69 and outflow fraction 0.59. Stenting was performed in 45 limbs of 39 patients. Areas under the curve for identifying patients with successful treatment at one year after stenting were 0.57, 0.54 and 0.63, respectively. Conclusion Venous occlusion plethysmography cannot be used to identify venous obstruction proximal to the femoral confluence or to distinguish which patients will benefit from treatment.

Stent extension into a single inflow vessel is a valuable option after endophlebectomy.

Background Venous stenting with an endophlebectomy and arteriovenous fistula can be performed in patients with extensive post-thrombotic changes. However, these hybrid procedures can induce restenosis, sometimes requiring stent extension, into a single inflow vessel. This study investigates the effectiveness of stenting into a single inflow vessel. Methods All evaluated patients had temporary balloon occlusion of the arteriovenous fistula to evaluate venous flow into the stents. When stent inflow was deemed insufficient, AVF closure was postponed and additional stenting was performed. Patency rates and clinical outcomes were evaluated. Results Twenty-four (38%) of 64 patients had additional stenting. The primary, assisted primary and secondary patency were 60 %, 70% and 70% respectively. Villalta score reduced by 6.1 points ( p < 0.001), and venous clinical severity score by 2.7 points ( p = 0.034). Conclusion Stenting through the femoral confluence into a single inflow vessel is a feasible bailout option if primary hybrid intervention fails with relative high patency rates and clinical improvement.

Risk factors of postthrombotic syndrome before and after deep venous thrombosis treatment.

Postthrombotic syndrome is the most common complication after deep venous thrombosis. Postthrombotic syndrome is a debilitating disease and associated with decreased quality of life and high healthcare costs. Postthrombotic syndrome is a chronic disease, and causative treatment options are limited. Prevention of postthrombotic syndrome is therefore very important. Not all patients develop postthrombotic syndrome. Risk factors have been identified to try to predict the risk of developing postthrombotic syndrome. Age, gender, and recurrent deep venous thrombosis are factors that cannot be changed. Deep venous thrombosis location and extent seem to predict severity of postthrombotic syndrome and are potentially suitable as patient selection criteria. Residual thrombosis and reflux are known to increase the incidence of postthrombotic syndrome, but are of limited use. More recently developed treatment options for deep venous thrombosis, such as new oral factor X inhibitors and catheter-directed thrombolysis, are available at the moment. Catheter-directed thrombolysis shows promising results in reducing the incidence of postthrombotic syndrome after deep venous thrombosis. The role of new oral factor X inhibitors in preventing postthrombotic syndrome is still to be determined.

Abdominal and pubic collateral veins as indicators of deep venous obstruction.

OBJECTIVE: Chronic deep venous obstruction can cause a significant loss of quality of life, although it can be treated successfully by stenting. A clear referral pattern for additional imaging is warranted in patients with lower limb complaints. The aim of this study was to determine the value of clinically visible abdominal wall collateral veins in the diagnosis of a potentially treatable deep venous obstruction. METHODS: A total of 295 patients referred for evaluation at a tertiary venous clinic with a collateral vein on the abdominal wall or pubic bone, visible on physical examination, were retrospectively analyzed and compared with a randomly selected control group of 365 patients without such a collateral vein. Duplex ultrasound, magnetic resonance venography, computed tomography venography, and conventional venography were used to determine the presence or absence of deep venous obstruction. RESULTS: Mean age of the group with a positive collateral was 43.5 ± 13.7 (6-76) years compared with 44.7 ± 14.2 (16-89) years in the control group. In the collateral group, 66.1% were female compared with 63.3% in the control group. Sensitivity of the abdominal wall collateral vein for any obstruction at the level of the groin or more proximal was 53% (95% confidence interval [CI], 48-57); specificity, 86% (95% CI, 79-91); positive predictive value, 93% (95% CI, 90-96); and negative predictive value, 32% (95% CI, 28-37). Sensitivity was 68% (95% CI, 62-73) for higher degrees of post-thrombotic obstruction and 27% (95% CI, 19-36) in iliac vein compression. CONCLUSIONS: A collateral vein on the abdominal wall or across the pubic bone in patients with complaints of the lower limb has an excellent positive predictive value for deep venous obstructive disease at the level of the groin or higher. Such collateral veins should therefore not be removed, and symptomatic patients could be offered further diagnostics and treatment.

The value of hemodynamic measurements by air plethysmography in diagnosing venous obstruction of the lower limb.

OBJECTIVE: Air plethysmography (APG) is a functional, noninvasive test that can assess volumetric changes in the lower limb and might therefore be used as a diagnostic tool in chronic deep venous disease. However, use of APG in chronic deep venous obstructive disease remains debatable. This study assessed the clinical value of APG in identifying chronic deep venous obstruction. METHODS: All patients referred to our tertiary, outpatient clinic between January 2011 and August 2013 with chronic venous complaints and suspected outflow obstruction underwent an outflow fraction (OF), ejection fraction (EF), and residual volume fraction (RVF) test using APG. Duplex ultrasound and magnetic resonance venography were used to establish whether and where obstruction was present. Diagnostic values of these tests were assessed for obstructions at different levels of the deep venous system. RESULTS: A total of 312 limbs in 248 patients were tested. Mean age was 45.5 ± 14.0 years, and 62.5% were female. In post-thrombotic disease, specificity and positive predictive value for OF were as high as 98.4% and 95.0%, respectively; however, sensitivity was 34.8% and negative predictive value was 29.6%, with no clinically relevant positive or negative likelihood ratios. No clinically relevant differences were observed in stratifying for level of obstruction. EF and RVF were as inconclusive. Neither could these parameters be used in diagnosing nonthrombotic iliac vein compression. CONCLUSIONS: We found a poor correlation between OF, EF, or RVF, determined by APG, and the presence of chronic deep venous obstruction. Therefore, use of its relative parameters is unwarranted in daily clinical practice.

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.

Minimally invasive treatment of chronic iliofemoral venous occlusive disease.

BACKGROUND: As one of the primary etiologies of the post-thrombotic syndrome, chronic venous occlusion is a huge burden on patient quality of life and medical costs. In this study, we evaluate the short-term and midterm results of endovenous recanalization by angioplasty and stenting in chronic iliofemoral deep venous occlusions. METHODS: This is a retrospective observational study set in a tertiary medical referral center. Patients with venous claudication or C4-6 venous disease combined with duplex and magnetic resonance-confirmed iliofemoral or caval occlusion were included. Patients with recent deep vein thrombosis (<1 year) were excluded. The intervention was endovascular deep venous recanalization, followed by angioplasty and stenting. Safety and feasibility were clinically evaluated during the procedure and during follow-up. Reocclusions and other treatment failures were evaluated during a maximum follow-up of 31 months by ultrasound imaging and venography. RESULTS: Seventy-five procedures were performed in 63 patients (average age, 44 years; range, 18-75 years), of whom 86% had a history of deep venous thrombosis. The mean time between the initial deep venous thrombosis and treatment with PTA and stenting was 12 years (maximum, 31 years). May-Thurner syndrome was present in 57%. Forty-two procedures were performed in the left, six in the right, and 11 in both lower extremities. The vena cava inferior was partially stented in 25 patients. An average of 2.6 stents (median, 2) were used per procedure. Primary patency was 74% after 1 year. Assisted primary and secondary patency rates were 81% and 96%, respectively, at 1 year. Secondary procedures included restenting, catheter-directed thrombolysis, endophlebectomy of the common femoral vein, and creation of an arteriovenous fistula. No clinically evident pulmonary emboli were noted. A bleeding complication occurred after six procedures and was deemed major in two. No patients died. Relief or significant improvement of symptoms of chronic venous occlusive disease was achieved in 81% of patients. CONCLUSIONS: Endovenous recanalization by angioplasty and stenting of chronically occluded iliofemoral vein segments is a safe and effective treatment with good short-term results, even when treatment takes place decades after the initial deep venous thrombosis. Most reocclusions can be adequately treated by a secondary procedure.

Chronic venous insufficiency in patients with absence of the inferior vena cava.

OBJECTIVE: Up until now, knowledge of absence of the inferior vena cava (AIVC) is limited to case reports and small case series, usually reported shortly after diagnosis. To characterize long-term evolution of outcomes of patients with AIVC, we performed a survey of current practice in Belgium, The Netherlands, and Luxembourg (Benelux). METHODS: Vascular surgeons and phlebologists in the Benelux area were asked to complete a questionnaire on medical history and treatment of each patient in follow-up at their practice with a diagnosis of AIVC. RESULTS: The Benelux survey yielded 35 patients with AIVC, with a follow-up ranging from 0 to 28 years. Their median age was 40 years (range, 14-65 years), and 26 (74%) were male. Diagnosis of AIVC was made in 26 patients at the time of presentation with deep vein thrombosis (DVT). DVT was bilateral in 15 patients and involved one or both iliac veins in 21 (81% of all AIVC patients with acute DVT). Computed tomography scanning was used to detect AIVC in 29 patients. Thrombophilia was present in 16 (46%). The CEAP C classification was C4-6 in 17 right legs (49%) and 15 left legs (43%). Unilateral or bilateral ulceration had occurred in 11 patients in the past, and three had active ulceration. Long-term conservative treatment consisted of oral anticoagulant treatment in 28 patients and compression stockings in 27. CONCLUSIONS: The results of this survey on AIVC illustrate the unfavorable long-term clinical evolution of these patients. They frequently present with advanced stages of chronic venous insufficiency at a relatively young age, with the development of unilateral or bilateral extensive DVT and subsequent moderate to severe post-thrombotic syndrome.