Utility of covered stents as a bypass for the treatment of central venous occlusion: a case report.

BACKGROUND: Central venous occlusion (CVO) is difficult to treat with percutaneous transluminal angioplasty because the guidewire cannot pass through the occluded segments. In this study, we devised a new method for establishing an extra-anatomic bypass between the right subclavian vein and the superior vena cava via a covered stent to treat whole-segment occlusion of the right brachiocephalic vein (BCV) with calcification. CASE PRESENTATION: We present the case of a 58-year-old female patient who complained of right arm swelling present for 1.5 years. Twelve years prior, the patient began hemodialysis because chronic glomerulonephritis had progressed to end-stage renal disease. During the first 3 years, a right internal jugular vein (IJV)-tunneled cuffed catheter was used as the dialysis access, and the catheter was replaced once. A left arteriovenous fistula (AVF) was subsequently established. Owing to occlusion of the left AVF, a new fistula was established on the right upper extremity 1.5 years prior to this visit. Angiography of the right upper extremity revealed complete occlusion of the right BCV and IJV with calcification. Because of the failure to pass the guidewire across the lesion, we established an extra-anatomic bypass between the right subclavian vein and the superior vena cava with a covered stent. Angiography confirmed the patency of whole vascular access system. After 3 months of follow-up, the patient's AVF function and the bypass patency were satisfactory. CONCLUSIONS: As a new alternative for the treatment of long, angled CVO with or without calcification, a covered stent can be used to establish an extravascular bypass between central veins.

A retrospective cohort study comparing high and low balloon inflation pressure on technical success and patency for treating central venous lesions in patients on chronic hemodialysis.

BACKGROUND: We aimed to analyze the success rates and the access patency rates at 12 months between patients on chronic hemodialysis with symptomatic central venous stenosis (CVS) or occlusion (CVO), receiving high or low balloon inflation pressure for treatment. METHODS: We performed a retrospective study in which angioplasty balloons were inflated using a low-pressure or a high-pressure for the management of hemodialysis patients with CVS/CVO. The outcomes of this study were the success rate and the access patency rates at 12 months after balloon angioplasty, and the differences between groups were compared. RESULTS: We included a total of 74 patients on hemodialysis and assigned them to the low-pressure or the high-pressure groups. Success rates in patients of the high-pressure group (94.12%) were higher than those in patients of the low-pressure group (67.50%) (p = 0.005). With a total of 59 patients with technical success, at 6 and 12 months after angioplasty, the rates of access patency in the low-pressure group were 68 and 48%, respectively; on the other hand, the primary patency rates in the high-pressure group were 86.67% (6-months) and 76.67% (12-months). The 6 and 12 months post-interventional patency rates were higher in patients of the high-pressure group than those in patients of the low-pressure group (p = 0.10 at 6 months and p = 0.03 at 12 months). CONCLUSIONS: Compared to balloon angioplasty using a low inflation pressure, hemodialysis patients with CVS/CVO receiving angioplasty using a high inflation pressure have significantly higher technical success and 12-month patency rates.

High resolution, 3-dimensional Ferumoxytol-enhanced cardiovascular magnetic resonance venography in central venous occlusion.

BACKGROUND: Although cardiovascular magnetic resonance venography (CMRV) is generally regarded as the technique of choice for imaging the central veins, conventional CMRV is not ideal. Gadolinium-based contrast agents (GBCA) are less suited to steady state venous imaging than to first pass arterial imaging and they may be contraindicated in patients with renal impairment where evaluation of venous anatomy is frequently required. We aim to evaluate the diagnostic performance of 3-dimensional (3D) ferumoxytol-enhanced CMRV (FE-CMRV) for suspected central venous occlusion in patients with renal failure and to assess its clinical impact on patient management. METHODS: In this IRB-approved and HIPAA-compliant study, 52 consecutive adult patients (47 years, IQR 32-61; 29 male) with renal impairment and suspected venous occlusion underwent FE-CMRV, following infusion of ferumoxytol. Breath-held, high resolution, 3D steady state FE-CMRV was performed through the chest, abdomen and pelvis. Two blinded reviewers independently scored twenty-one named venous segments for quality and patency. Correlative catheter venography in 14 patients was used as the reference standard for diagnostic accuracy. Retrospective chart review was conducted to determine clinical impact of FE-CMRV. Interobserver agreement was determined using Gwet's AC1 statistic. RESULTS: All patients underwent technically successful FE-CMRV without any adverse events. 99.5% (1033/1038) of venous segments were of diagnostic quality (score ≥ 2/4) with very good interobserver agreement (AC1 = 0.91). Interobserver agreement for venous occlusion was also very good (AC1 = 0.93). The overall accuracy of FE-CMRV compared to catheter venography was perfect (100.0%). No additional imaging was required prior to a clinical management decision in any of the 52 patients. Twenty-four successful and uncomplicated venous interventions were carried out following pre-procedural vascular mapping with FE-CMRV. CONCLUSIONS: 3D FE-CMRV is a practical, accurate and robust technique for high-resolution mapping of central thoracic, abdominal and pelvic veins and can be used to inform image-guided therapy. It may play a pivotal role in the care of patients in whom conventional contrast agents may be contraindicated or ineffective.

Novel experience of laser-assisted 'inside-out' central venous access in a patient with bilateral subclavian vein occlusion requiring pacemaker implantation.

AIM: This new laser facilitated 'inside-out' technique was used for transvenous pacemaker insertion in a pacemaker-dependent patient with bilateral subclavian occlusion and a failed epicardial system who is not suitable for a transfemoral approach. METHOD AND RESULTS: Procedure was undertaken under general anaesthesia with venous access obtained from right femoral vein and left axillary vein. 7F multipurpose catheter was used to enter proximal edge of the occluded segment of subclavian vein via femoral approach, which then supported stiff angioplasty wires and microcatheters to tunnel into the body of occlusion. When encountered with impenetrable resistance, 1.4 mm Excimer laser helped delivery of a Pilot 200 wire, which then progressed towards the distal edge of occlusion. Serial balloon dilatations allowed wire tracked into subintimal plane, advanced towards left clavicle using knuckle wire technique, which was then externalized with blunt dissection from infraclavicular pocket area. It was later changed to Amplatz superstiff wire exiting from both ends to form a rail, which ultimately allowed passage of pacing leads after serial balloon dilatation from clavicular end. CONCLUSION: Our hybrid 'inside-out' technique permitted transvenous pacemaker insertion without complication and this is, to our knowledge, the first case using laser in this context.

Plastic bronchitis: a rare complication of long-term haemodialysis catheter placement in a child.

BACKGROUND: Despite peritoneal dialysis being the preferred mode of renal replacement therapy in neonates and infants, long-term haemodialysis may be necessary in a minority of patients with its attendant risks. CASE DIAGNOSIS/TREATMENT: This case identifies plastic bronchitis as a rare yet serious complication of long-term large bore vascular access when a vessel-sparing approach is not possible. CONCLUSIONS: An appropriately sized catheter should be used for the dialytic therapy required and to optimize access survival.

The feasibility and safety of a through-and-through wire technique for central venous occlusion in dialysis patients.

BACKGROUND: To retrospectively compare the operation time, success rate and efficacy between unidirectional and bidirectional procedures in the treatment of central venous occlusion diseases (CVOD), assess the advantages of the bidirectional approach, and determine the characteristics of CVOD appropriate for the bidirectional approach treatment. METHODS: A total of 49 patients who underwent endovascular interventions with all relevant data between January 2011 and December 2015 at the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China, were included in this retrospective study, and were categorized into two groups: the 19 patients in group 1 had undergone percutaneous transluminal venoplasty (PTV) via a conventional technique (unidirectional procedure from the vein distal or proximal to the obstructive lesion), and the 30 in group 2 had undergone flossing wire technique (bidirectional procedure from femoral vein and the vein distal to obstructive lesion and using a flossing wire technique). The technical success rate, the fluoroscopy time in the procedure, perioperative complications, and patency were evaluated retrospectively. RESULTS: Compared with group 1, group 2 had a higher initial technical success rate (83.33% vs. 47.36%, p = 0.012) but a shorter fluoroscopy time (82.6 ± 26.1 vs. 116.1 ± 42.1, p = 0.048). Receiver operating characteristic (ROC) analysis indicated that a lesion with a length of 6.5 cm was the best predictor of technique success (p = 0.02) in group 1, but no cut-off value was identified for group 2. There were no significant differences in perioperative complications between these two groups. The complication rates were 31.58% (6/19) in group 1 and 6.67% (2/30) in group 2, (p = 0.043), respectively. No significant difference was observed between these two groups with respect to the stent patency rate. CONCLUSION: Compared with the conventional technique, the flossing wire technique has a higher success rate, shorter fluoroscopy time, fewer complications and similar patency rate. It is a feasible treatment for CVOD, especially for long obstructive lesions.

Review of Sharp Recanalization Techniques in Central Venous Occlusions.

Benign central venous occlusions are frequently associated with long-term central venous access. Most of these occlusions can be recanalized with conventional endovascular technique. When conventional technique fails, sharp recanalization techniques (SRTs) can increase technical success. The SRTs include single low-profile needles, needle coaxial systems, re-entry catheter, the back end of stiff guidewires, and systems that can deliver radiofrequency energy or laser. This review on SRTs presents technical details and outcomes of the most common techniques used in central venous recanalization.

The outcome of sharp recanalization of chronic central venous occlusions in patients undergoing hemodialysis.

BACKGROUND: Patients on hemodialysis are particularly vulnerable to central venous occlusion (CVO). Endovascular treatment has gained wide acceptance for the treatment of CVO. However, difficulties in crossing the occluded segment can be encountered during conventional endovascular management. Sharp recanalization has been adopted when conventional endovascular methods could not recanalize the obstructed region. This study aimed to assess the outcome of the sharp venous recanalization technique with angioplasty and stenting in the treatment of CVO in Egyptian patients undergoing hemodialysis. METHODS: This retrospective study is based on data from a prospectively maintained department database of patients under regular hemodialysis who underwent the sharp venous recanalization technique for CVO. Routinely, the patients were followed up at 3, 6, and 12 months with a clinical examination. The primary outcomes were technical success and primary patency. Secondary outcomes included complication rates and clinical success. RESULTS: This study included 40 patients. Thirty-six patients (90%) achieved technical and clinical success. Seven patients (17.5%) had immediate postoperative complications. Four cases had minor complications (10%) and three patients had major complications (7.5%): hemothorax in two patients (5.1%) and pneumothorax in one patient (2.6%). At the 1-year follow-up, reintervention was required in nine patients (22.5%), with primary patency rate of 77.5% and a secondary patency rate of 100%. CONCLUSIONS: Sharp recanalization offers a solution for patients undergoing hemodialysis who developed CVO and failed to be recanalized using the conventional endovascular method. It offered promising technical success, clinical improvement, and good primary patency rates.

Endovascular recanalization for filter-bearing inferior vena cava occlusion in a dialysis patient.

Central venous occlusion (CVO) or stenosis (CVS) is a common complication of long-term hemodialysis catheters. Endovascular intervention, primarily balloon angioplasty and occasionally stent placement, is the primary approach for managing CVS/CVO lesions. The presence of a filter within the inferior vena cava (IVC) lumen makes recanalization of the IVC more challenging. Here we present a complex case of a 47-year-old female with end-stage kidney disease (ESKD), systemic lupus erythematosus, and recurrent deep venous thrombosis, necessitating an IVC filter, who became catheter-dependent via the right femoral vein and presented with total IVC occlusion below the filter. The occlusion was managed successfully with sequential angioplasty and stenting of the stenotic lesions. This intervention restored venous flow through the IVC into the right atrium and maintained dialysis access through the catheter. This case underscores the complexity of managing CVS/CVO in dialysis patients, especially with the presence of filters within the vascular dialysis conduit.

Recanalization of a long segment occluded superior vena cava by puncturing the remnant calcified fibrin sheath of the internal jugular vein: A case report.

A fibrin sheath with central venous occlusion is a common complication after central venous catheterization, and these patients often experience catheter dysfunction. A calcified fibrin sheath can cause a catheter to be stuck, and typically necessitates catheter removal or replacement. From another point of view, a calcified fibrin sheath can be seen in ultrasound and computed tomography, and the original fibrin sheath channel between the internal jugular vein and the atrium is unusually strong. When central vein occlusion occurs, the remnant calcified fibrin sheath of the internal jugular vein can be punctured under ultrasound guidance, allowing the guidewire to enter the atrium directly through the fibrin sheath. Here, we report a case in which we achieved easy recanalization of a long segment occluded superior vena cava by puncturing the remnant calcified fibrin sheath of the internal jugular vein.

Femoral to abdomen tunneling at the bedside for medium/long term venous access.

BACKGROUND: Femoral to abdomen tunneling of small-bore central venous catheters is a bedside technique for patients with contraindications to a thoracic approach, or as an alternative to a lower extremity catheter exit site. METHOD: A femoral to abdomen tunneling technique was implemented for patients receiving medium and long-term intravenous treatments with contraindications to the thoracic venous approach or as an alternative to a lower extremity catheter exit site. All venous access devices were inserted with ultrasound guidance under local anesthesia, and catheter tip placement assessed by post procedural radiography. RESULTS: In this case series, from January 2020 to January 2023, a total of eight FTA-tunneled venous access devices were inserted. There were seven ambulatory patients and one bedbound patient. The median length of the subcutaneous tunnel was 20 cm, ranging from 15 to 27 cm. The median length of the intravenous catheter to the terminal tip was 31 cm, ranging from 23 to 40 cm. Tip location was confirmed by post-procedural abdominal radiograph. The catheter tip locations were interpreted to be at the level of T8-T9 (2), T12 (1), L4 (2), L2 (2), L1(1).No insertion or post insertion related complication was reported. Six patients completed the scheduled intravenous treatment. One patient was unable to be tracked due to transfer to an outside facility. One catheter initially demonstrated to be coiled over the left common iliac vessel was repositioned using a high flow flush technique. There was one reported catheter dislodgment by the nurse providing care and maintenance. The overall implant days were 961, with a median dwell time of 125 days ranging from 20 to 399 days. CONCLUSION: Femoral to abdomen tunneling provides an alternative exit site useful in select patients with complex intravenous access. The data of this small retrospective review suggests this a safe and minimally invasive bedside procedure.

Long-term patency of bypass to the right atrium as a last resort in two hemodialysis patients: case report.

Introduction: Central venous occlusion (CVO), which is caused by central venous catheters in haemodialysis patients , remains a challenge in vascular surgery. Case presentation: The authors report data evaluating bypass graft patency and complications of two patients with CVO who have benefited from a subclavian artery to right atrium bypass using polytetrafuloroetylene. The first patient , underwent three times an angioplasty of the atrio prothetic anastomosis , finally the graft failed at 12 month. The second one, presented a steal syndrome with ischaemia of the right upper limb immediately postoperatively. Three months after the procedure , she underwent an angiographic control that showed a stenosis of the protheto atrial junction. Clinical discussion: Central venous occlusion in patients with end-stage kidney disease is most often due to central venous catheters. Although the endovascular therapy is the first-line approach to the treatment of CVO, the surgical bypass to the right atrium is often the last resort to preserve adequate vascular access in haemodialysis patients, with CVO. The autologous vein and bovine arterial bypass remains better than polytetrafuloroetylene grafts in terms of long-term patency. Only few cases have been reported un the literature , besides no long-term outcome data has been previously reported. Conclusion: Long-term secondary patency of bypass to the right atrium can be achieved, but requires strict follow-up, and multiple endovascular procedures to maintain the bypass access.

Percutaneous superior vena cava puncture for hemodialysis catheter placement.

OBJECTIVE: Central venous occlusion (CVO) refractory to endovascular angioplasty is a critical challenge that threatens hemodialysis vascular access. In the present study, we evaluated the efficacy and safety of tunneled, cuffed central venous catheter (tCVC) placement via percutaneous superior vena cava (SVC) puncture in patients with refractory CVO. METHODS: Patients requiring maintenance hemodialysis with refractory CVO who had undergone percutaneous SVC puncture and tCVC insertion at a university-affiliated hospital from January 2016 to June 2020 were included. The patients were followed up until May 2021. The demographic information, complications, and catheter patency were analyzed. RESULTS: A total of 205 patients (105 women [51.2%]; mean age, 61 ± 15 years) were included. The SVC puncture and tCVC insertion were successfully performed in 194 patients, for a technical success rate of 94.6%. One patient had experienced a pleura injury and hemothorax and had required urgent thoracotomy. A total of 37 patients had presented with mild chest pain and were prescribed oral nonsteroidal anti-inflammatory drugs. During follow-up of the 194 patients with a successful procedure, catheter dysfunction due to thrombosis had occurred in 66 patients, catheter malposition had occurred in 5 patients, and catheter-related blood stream infection had developed in 6 patients. The 3-year primary patency rate was 64.2%, and the 3-year secondary patency rate was 76.3%. CONCLUSIONS: A tCVC placed through a percutaneous SVC puncture had a satisfactory technical success rate and long-term patency rate in patients requiring hemodialysis, providing an optional vascular access for those with exhausted central vein resources. SVC puncture also avoided the use of left-sided catheters and preserved central vein resources. Caution should be given to avoid potential complications such as pleura injury and hemothorax.

Recurrent syncope due to central venous occlusion in a patient undergoing hemodialysis.

A 66-year-old male patient receiving maintenance hemodialysis with arteriovenous fistula of the right upper limb was admitted to the hospital because of intermittent syncope, dizziness, and distension. Central venography indicated occlusion of the right brachiocephalic vein (RBV), and the contrast agent flowed from the right internal jugular vein into the intracranial vein, then into the contralateral internal jugular vein, and finally returned into the superior vena cava. Percutaneous transluminal angioplasty was performed to dilate the RBV. Postoperatively, the contrast agent flowed smoothly into the right atrium through the RBV and the superior vena cava. Craniocerebral magnetic resonance angiography and magnetic resonance venography indicated that the intracranial venous reflux disappeared. The patient did not experience syncope again; moreover, dizziness and distention improved, as well as right facial swelling and right eye congestion, and he was discharged 2 days later. Two months later, the patient complained of dizziness. Venography under digital subtraction angiography showed severe stenosis at the RBV and percutaneous transluminal angioplasty was performed; moreover, stent placement was performed. The contrast agent flowed smoothly into the right atrium through the RBV and the superior vena cava again. Ultimately, the headaches and dizziness improved significantly postoperatively. Hence, if hemodialysis patients present with neurological symptoms, intracranial venous congestion should be monitored; nonetheless, most patients have a good prognosis when treated appropriately.

Thoracic central venous occlusion from the interventional radiology perspective.

Central venous occlusion is a common condition in certain patient populations, with significant associated morbidity. Symptoms range from mild arm swelling to respiratory distress and can be particularly troublesome in the end stage renal disease population when related to dialysis access and function. Crossing completely occluded vessels is often the most challenging step and various techniques exist to accomplish this. Traditionally, blunt and sharp recanalization techniques are used to cross occluded vessels and are described in detail. Even with experienced providers there are lesions which prove to be too difficult and are refractory to traditional approaches. We discuss advanced techniques such as with radiofrequency guidewires as well as newer technologies which offer an alternative pathway to re-establishing access. These emerging methods have demonstrated procedural success in the majority of cases where traditional techniques were futile. Following recanalization, angioplasty with or without stenting is typically performed and restenosis is a commonly encountered complication. We discuss angioplasty and the emerging use of drug-eluting balloons in venous thrombosis. Subsequently, in regards to stenting we discuss the indications and multitude of available types including novel venous stents with their respective strengths and drawbacks. Potential feared complications such as venous rupture with balloon angioplasty and stent migration are discussed along with our recommendations to reduce their risk of occurrence and promptly manage them when they do unfortunately occur.

Left brachiocephalic venous occlusion with spontaneous arteriovenous fistula presenting with severe edema in left upper extremity and face: A case report.

INTRODUCTION AND IMPORTANCE: The coexistence of central venous occlusion and arteriovenous fistulas (AVF) is rare among non-dialysis patients. Herein, we describe a case of left brachiocephalic venous occlusion with spontaneous AVF, presenting with severe edema in left upper extremity and face. CASE PRESENTATION: A 90-year-old woman presented to our hospital with gradually worsening edema in her left arm and face for eight years. Contrast-enhanced computed tomography revealed left brachiocephalic venous occlusion and severe edema in her left upper extremity and face. Computed tomography also revealed abundant collateral veins; thus, it seemed unnatural for severe edema to occur with such well-developed collateral pathways. Therefore, the presence of AVF was suspected. After careful re-examination of the patient, a continuous murmur was heard in the post-auricular region. Magnetic resonance imaging and angiogram revealed a dural AVF. Considering the patient's age and treatment difficulty for the dural AVF, we performed a stent insertion into the left brachiocephalic vein. After the procedure, edema in her left upper extremity and face improved dramatically. CLINICAL DISCUSSION: In cases of persistent swelling of the upper extremities or face, there could be a factor that increases venous inflow. Therefore, any condition that may increase venous inflow must be aggressively investigated and therapeutic interventions should be applied to treat such conditions. CONCLUSION: Central venous occlusion and AVF is a possible underlying cause for severe refractory edema in the upper extremity and face. Therefore, both AVF and brachiocephalic occlusion should be assessed for treatment indications under these conditions.

Central Vein Recanalization and Rehabilitation in Pediatric Patients: Changing the Paradigm for Chronic Occlusions.

Background: Chronic total occlusions in the central venous system limit access and increase morbidity in chronically ill pediatric patients. We report the results of transcatheter recanalization of occluded central veins using angioplasty and stenting. Methods: Patients undergoing successful intervention for venous chronic total occlusions at our institution between April 2013 and December 2019 were retrospectively reviewed. Results: Sixty-eight occluded central veins in 29 patients underwent recanalization with angioplasty (26 veins) or stenting (42 veins). The indications included limited access for catheterization or central line maintenance (19 patients), limb swelling (4 patients), superior vena cava syndrome (3 patients), and pleural effusion (3 patients). The primary risk factor for occlusion was a history of central venous lines after surgery or extracorporeal membrane oxygenation support in 76% of the patients. The median age and weight at the time of initial intervention were 5.8 years and 14.5 kg, respectively. There were no major complications. Of 10 patients with symptoms of venous congestion, 8 experienced symptomatic improvement. Twenty-two patients (59 veins) underwent 44 recatheterizations during a median follow-up duration of 288 days. Early reintervention was typically planned. The median time to recatheterization was 71 days. Twenty-one veins reoccluded and required repeat recanalization. Reocclusion was associated with persistent upstream collateral vein decompression, as determined using postintervention venography (odds ratio, 14.2; 95% CI, 3.3-62.6; P < .001), which was thought to indicate persistently poor venous inflow. Reinterventions were performed on 40 veins. Fifty-two veins that were followed up (88%) remained patent after the most recent intervention. Conclusions: Invasive transcatheter rehabilitation of occluded central veins has the potential to preserve critical access sites and improve the symptoms of venous congestion in pediatric patients. Reinterventions are common for reocclusion, restenosis, and somatic growth.

Veno-Venous Surgical Bypass for Central Vein Occlusion in a Child: The First in the Literature.

Introduction: During the past two decades, the incidence of chronic kidney disease (CKD) in children worldwide has steadily increased and, even in children, native arteriovenous fistula (AVF) remains the access of choice. Nevertheless, maintaining a well functioning fistula is limited by central venous occlusion due to the widespread use of central venous access devices before AVF creation. Report: A 10 year old girl with end stage renal failure dialysing through a left brachiocephalic fistula presented with left upper limb and facial swelling. She had previously exhausted the option of ambulatory peritoneal dialysis for recurrent peritonitis. A central venogram showed occlusion at the left subclavian vein, which was not amenable for angioplasty through either an upper limb or femoral approach. Given the precious fistula with concomitant worsening venous hypertension, an ipsilateral axillary vein to external iliac vein bypass was performed. Subsequently, her venous hypertension was significantly resolved. This report is the first in English literature on this surgical bypass in a child with central venous occlusion. Discussion: Central venous stenosis or occlusion rates are rising due to extensive central venous catheter use in the paediatric population with end stage renal failure. In this report, an ipsilateral axillary vein to external iliac vein bypass was used successfully as a safe temporary option to maintain AVF. Ensuring a high flow fistula pre-operatively and continued antiplatelet post-operatively will allow longer patency of the graft.

One-year outcomes and predictive factors for primary patency after stent placement for treatment of central venous occlusive disease in hemodialysis patients.

OBJECTIVE: The study purpose was to determine the outcomes and factors predictive of primary stent patency for the treatment of central venous occlusive disease (CVOD) in hemodialysis patients. METHODS: Data of 71 patients with CVOD treated with stent placement from January 2012 to December 2017 were analyzed. Univariate and multivariate analysis was performed to determine factors associated with stent patency. Adverse events related to stent placement were also examined. RESULTS: The median primary patency duration of the 71 patients was 16 ± 2.2 months. The cumulative 3-, 6-, 9-, and 12- month primary patency rates were 93%, 72%, 55%, and 51%, respectively. Independent predictors of longer primary patency were vessel diameter > 12 mm, the use of a covered stent, and absence of vessel calcifications. Median primary patency of covered stents was 21 months as compared with only 10 months for bare stents (p < 0.001). Procedure-related adverse events occurred in 17 patients (21.8%), and four events (5.1%) required medical intervention. No life-threaten complications occurred. CONCLUSIONS: A vessel diameter > 12 mm, the use of a covered stent, and no vessel calcifications are independently associated with a higher primary patency rate after treatment of CVOD in hemodialysis patients.