Y-shaped stenting of brachiocephalic vein in a symptomatic hemodialysis patient

Stenosis or obstruction of neck great veins represent a frequent and severe complication in hemodialysis patients. Endovascular treatment with percutaneous transluminal angioplasty and/or stenting of these veins is the gold standard to restore patency. However, the jugular vein is frequently overstented in these cases and this might lead to persistent symptomatology of those patients also losing an access for future catheter placement. Herein, we present the 6-months performance of a Y-shaped stenting of the brachiocephalic and internal jugular vein leading to complete resolution of the symptoms, and maintenance of the jugular vein access.

Comparison between radiocephalic and brachiocephalic arteriovenous fistula in octogenarians: A retrospective single center study

PURPOSE

The number of older patients who need vascular access for end-stage renal disease is rapidly increasing. However, determining the optimal vascular access for older patients is difficult. We aimed to compare the outcomes of radiocephalic (RC) and brachiocephalic (BC) arteriovenous fistula (AVF) in patients aged >80 years.

METHODS

This study included 94 patients undergoing hemodialysis who underwent the procedure for the first time between 2013 and 2019 in Korea University Guro Hospital. The primary outcomes were primary patency (PP) and cumulative patency (CP). The secondary outcome was maturation failure and death with functional vascular access.

RESULTS

Of the 94 patients (mean age, 83.9 ± 2.97 years), 66 (70.2%) and 28 (29.8%) patients belonged to the RC and BC AVF groups, respectively. One-year PP was worse in the RC AVF group than in the BC AVF group (59.6% vs. 87.4%, p = 0.013). However, no significant difference was observed in 1-year CP between the groups (87.4% vs. 91.2%, p = 0.441). The unassisted maturation rate was higher in the BC AVF group than in the RC AVF group (74.2% vs. 96.4%, p = 0.011). During follow-up (649 ± 612 days), only 6 (6.4%) patients required secondary fistula placement. Eighteen patients (19.1%), all of whom had functional AVF, died.

CONCLUSION

BC AVF showed better PP and a smaller number of interventions than RC AVF in octogenarians. Therefore, BC AVF could be a primary choice of vascular access in the octogenarian patient. However, further research is warranted to confirm these findings.

Computational modeling of the cephalic arch predicts hemodynamic profiles in patients with brachiocephalic fistula access receiving hemodialysis

Background

The most common configuration for arteriovenous fistula is brachiocephalic which often develop cephalic arch stenosis leading to the need for numerous procedures to maintain access patency. The hemodynamics that contributes to the development of cephalic arch stenosis is incompletely understood given the inability to accurately determine shear stress in the cephalic arch. In the current investigation our aim was to determine pressure, velocity and wall shear stress profiles in the cephalic arch in 3D using computational modeling as tools to understand stenosis.

Methods

Five subjects with brachiocephalic fistula access had protocol labs, Doppler, venogram and intravascular ultrasound imaging performed at 3 and 12 months. 3D reconstructions of the cephalic arch were generated by combining intravascular ultrasounds and venograms. Standard finite element analysis software was used to simulate time dependent blood flow in the cephalic arch with velocity, pressure and wall shear stress profiles generated.

Results

Our models generated from imaging and flow measurements at 3 and 12 months offer snapshots of the patient’s cephalic arch at a precise time point, although the remodeling of the vessel downstream of an arteriovenous fistula in patients undergoing regular dialysis is a dynamic process that persists over long periods of time (~ 5 years). The velocity and pressure increase at the cephalic bend cause abnormal hemodynamics most prominent along the inner wall of the terminal cephalic arch. The topology of the cephalic arch is highly variable between subjects and predictive of pathologic stenosis at later time points.

Conclusions

Low flow velocity and wall pressure along the inner wall of the bend may provide possible nidus of endothelial activation that leads to stenosis and thrombosis. In addition, 3D modelling of the arch can indicate areas of stenosis that may be missed by venograms alone. Computational modeling reconstructed from 3D radiologic imaging and Doppler flow provides important insights into the hemodynamics of blood flow in arteriovenous fistula. This technique could be used in future studies to determine optimal flow to prevent endothelial damage for patients with arteriovenous fistula access.

Percutaneous Extra-Anatomic Double-Barrel Bypass for Salvage of Hemodialysis Access and Treatment of Venous Occlusive Disease

A woman with an upper extremity brachioaxillary arteriovenous dialysis graft presented with a 9-month history of profound ipsilateral arm swelling and numbness secondary to chronic axillosubclavian vein occlusion. Previous endovascular and open venous recanalization attempts were unsuccessful. A totally percutaneous extra-anatomic venous bi-bypass was created to salvage the dialysis access circuit and reconstruct the deep venous system. Using overlapping Viabahn stent-grafts, two parallel bypasses were created from the arteriovenous graft and brachial vein, respectively, to the brachiocephalic vein. The hemodialysis graft regained function. Upper extremity symptoms resolved within 48 h. This is the first reported percutaneous double-barrel technique of extra-anatomic venous bypass creation for simultaneous management of a failed dialysis access and chronic venous occlusive disease.

Percutaneous intervention for symptomatic central vein stenosis in patients with upper limb arteriovenous dialysis access

Central venous stenosis is an important hindrance to long-term maintenance of arteriovenous access in the upper extremities in dialysis patients.

Aim

The present study was done to determine feasibility and clinical success of endovascular approach for the treatment of symptomatic central venous stenosis associated with significant ipsilateral limb edema in dialysis patients with vascular access in the upper limb.

Methods

A database of hemodialysis patients who underwent endovascular treatment for central venous stenosis from January 2014 to January 2017 at our institute was retrospectively reviewed. Follow-up was variable.

Results

The study included ten patients (6 men and 4 women) with a mean age of 45.2 years, who underwent thirteen interventions during a period of 3 years. The technical success rate for endovascular treatment was 100%. One patient underwent primary PTA (percutaneous transluminal angioplasty). Seven patients underwent primary PTA and stenting. Three patients underwent secondary PTA. One among these patients underwent secondary PTA twice along with fistuloplasty. One patient underwent secondary PTA with stenting. No immediate complications were encountered during the procedure. Our study shows a primary patency rate of 67% and 33% at 6 months and 12 months for PTA with stenting. Our study also shows secondary or assisted primary patency of 75% at 6 months of follow-up.

Conclusions

Endovascular therapy (PTA) with or without stenting for central venous stenosis is safe, with low rates of technical failure. Multiple additional interventions are the rule and long-term patency rate is not very good.

Thrombosis in an Internal Jugular Vein and an Upper Limb Deep Vein Treated with Edoxaban

A 45-year-old man complained of swelling of the left side of his neck and left upper limb. Ultrasonography and enhanced computed tomography (CT) revealed thrombosis of the left internal jugular, subclavian, and brachiocephalic vein. Based on various examinations, the patient was diagnosed with idiopathic venous thrombosis early in his clinical course. There were no findings to suggest malignancy or abnormal coagulability. However, two months after the start of treatment, the patient was diagnosed with gastric cancer. Despite the presence of Trousseau syndrome, treatment with edoxaban (an oral anticoagulant), reduced the swelling dramatically without any bleeding complications.

Large thoracic aortic aneurysm and dissection with rare complication

Thoracic aortic aneurysms can be found incidentally, however, patients can also present with acute dissection and or rupture that can be fatal. Symptoms that might indicate dissection include chest and back pain as well as lightheadedness. The diagnosis can be made with imaging studies such as computed tomography or magnetic resonance angiogram and sometimes transesophageal echocardiogram. Management is based on the aneurysmal size, location, extension, and the presence of complications. Although smaller localized and slow growing aneurysms can be monitored, larger and or complicated ones may warrant immediate repair. Less-common complications include compression over anatomic structures in the vicinity including vessels and the mediastinum. We report a unique case of a 71-year-old man who presented with a very large thoracic aortic aneurysm with dissection causing compression over the brachiocephalic veins and the mediastinum leading to facial and upper extremity swelling, dysphagia, and cough. This case represents a rare but significant complication of thoracic aortic aneurysm and emphasizes the challenges of its management.

Cephalic arch stenosis: mechanisms and management strategies

Cephalic arch is a frequent site for the development of stenosis in patients with brachiocephalic fistulae. This is in part owing to the anatomic constraints of the cephalic arch region and the exertion of hemodynamic forces at this site caused by the creation of a brachiocephalic fistula. Multiple interventions have been used to correct stenosis and subsequent fistula dysfunction. These include percutaneous balloon angioplasty using conventional and cutting balloons, endovascular stent insertion, and surgical interventions. It is important to emphasize that the stenosis in this region frequently recurs, is more resistant to angioplasty, and shows a higher rate of rupture during the percutaneous balloon angioplasty procedure compared with peripheral lesions at other sites. Because hemodynamic forces have been postulated to be one of the culprits for the development of stenosis, a new technique of flow reduction has been introduced to combat this problem. This article discusses the etiology, pathophysiology, and current management of cephalic arch stenosis.

Perioperative management of a levoatrial cardinal vein in the absence of the brachiocephalic vein

Levoatrial cardinal vein is a rare congenital anomaly of the systemic veins. It is commonly associated with left-sided obstructive conditions such as aortic atresia, mitral atresia, and cor triatriatum. We report the case of a 14-year-old boy who was undergoing surgery for correction of a secundum atrial septal defect. Intraoperatively, we discovered that he had a levoatrial cardinal vein and no brachiocephalic vein. However, collateral vessels provided adequate flow to the right atrium, and the patient's left-sided venous pressure was not excessive, so we ligated the levoatrial cardinal vein and directly repaired the septal defect. Postoperatively, the left venous drainage was satisfactory and the patient was asymptomatic. In addition to our patient's case, we discuss the embryology, diagnosis, and treatment of levoatrial cardinal vein.

A case of extrinsic chronic cerebrospinal venous insufficiency in a patient with multiple sclerosis

We aim to present a very rare case of chronic cerebrospinal venous insufficiency due to both brachiocephalic vein obstruction by aberrant right subclavian artery and internal jugular vein distal compression by first cervical vertebra transverse process, demonstrated by multislice computerized tomography in a patient with multiple sclerosis.

Superior vena cava thrombosis and paradoxical embolic stroke due to collateral drainage from the brachiocephalic vein to the left atrium

Thrombosis involving a permanent infusion catheter in the subclavian vein and superior vena cava is relatively common, especially in cancer patients. Edema of the arms and head is a well-known clinical consequence of this thrombosis, with an intrinsic risk of pulmonary embolism; however, systemic embolization into the cerebral circulation has not been reported as a sequela. Herein, we describe the case of a 56-year-old man with metastatic prostate cancer who developed superior vena cava syndrome due to extensive thrombosis in the presence of a central venous catheter that was used for long-term chemotherapy. The patient's case was complicated by a cerebrovascular accident that was most likely caused by a paradoxical air embolism. A clear mechanism for the embolism was provided by a network of collateral veins, which developed between the brachiocephalic vein and the left atrium due to the superior vena cava obstruction and resulted in a right-to-left shunt. We discuss diagnosis and treatment of the condition in our patient and in general terms.

Extracranial Doppler sonographic criteria of chronic cerebrospinal venous insufficiency in the patients with multiple sclerosis

AIM

The aim of this open-label study was to assess extracranial Doppler criteria of chronic cerebrospinal venous insufficiency in multiple sclerosis patients.

METHODS

Seventy patients were assessed: 49 with relapsing-remitting, 5 with primary progressive and 16 with secondary progressive multiple sclerosis. The patients were aged 15-58 years and they suffered from multiple sclerosis for 0.5-40 years. Sonographic signs of abnormal venous outflow were detected in 64 patients (91.4%).

RESULTS

We found at least two of four extracranial criteria in 63 patients (90.0%), confirming that multiple sclerosis is stronghly associated with chronic cerebrospinal venous insufficiency. Additional transcranial investigations may increase the rate of patients found positive in our survey. Reflux in internal jugular and/or vertebral veins was present in 31 cases (42.8%), stenosis of internal jugular veins in 61 cases (87.1%), not detectable flow in internal jugular and/or vertebral veins in 37 cases (52.9%) and negative difference in cross-sectional area of the internal jugular vein assessed in the supine vs. sitting position in 28 cases (40.0%). Flow abnormalities in the vertebral veins were found in 8 patients (11.4%). Pathologic structures (membranaceous or netlike septa, or inverted valves) in the junction of internal jugular vein with brachiocephalic vein were found in 41 patients (58.6%), in 15 patients (21.4%) on one side only and in 26 patients (37.1%) bilaterally.

CONCLUSION

Multiple sclerosis is highly correlated with chronic cerebrospinal venous insufficiency. These abnormalities in the extracranial veins draining the central nervous system can exist in various combinations. The most common pathology in our patients was the presence of an inverted valve or another pathologic structure (like membranaceous or netlike septum) in the area of junction of the IJV with the brachiocephalic vein.

[Functional profile of cephalic arch stenosis]

Cephalic arch stenosis (CAS) is a unique type of vascular access stenosis. For example, the etiology of CAS is under investigation and the prevalence of CAS can be lower in diabetic patients. Three cases of CAS were identified during our vascular access stenosis surveillance program by blood flow rate measurements using the Delta-H method. We evaluated the prevalence, etiology, relationship with diabetes and functional profile of CAS. To date, this is the first functional report published about this type of stenosis.

Proximal radial artery ligation after distalization of a high flow brachio-cephalic fistula. A novel approach to inflow reduction

High flow fistulae present a common challenge to vascular access (VA) surgeons and many strategies have been described, each with their benefits and limitations. There are no NK-DOQI guidelines for the management of high flow fistulae or indeed the management of those refractory to more conventional approaches. We discuss a novel technique to inflow reduction in a previously distalized brachiocephalic fistula and recommend the technique of proximal radial artery ligation.

[Correlation between indices of 24-h monitoring of blood pressure and disturbed venous cerebral outflow in hypertensive patients]

AIM

To study relations between disturbances of cerebral venous circulation and parameters of 24-h blood pressure monitoring in hypertensive patients.

MATERIAL AND METHODS

A total of 72 patients aged 28 to 60 years with essential hypertension of stage II have undergone 24-h blood pressure monitoring and MR-venography of the brachiocephalic veins on a low-field MR-tomograph using 2D TOF angiography.

RESULTS

Symptoms of disturbed cerebral venous circulation were found in 60% patients. Major venous collectors were asymmetric in 79.2% patients, 40.3% had marked asymmetry, 14% had severe asymmetry. Disturbances of venous outflow significantly more frequently occurred in non-dippers and night-peakers as well as in high variability of blood pressure. Patients with marked asymmetry of venous collectors had elevated nocturnal systolic and diastolic blood pressure, high load indices of nocturnal systolic and diastolic pressure, a low degree of nocturnal fall of blood pressure.

CONCLUSION

Disturbance of venous cerebral outflow in hypertensive patients is closely related with alterations of a circadian profile of blood pressure: circadian index of blood pressure, variability of blood pressure.

Risk factors for the development of cephalic arch stenosis

PURPOSE

The creation of a vascular access is necessary in hemodialysis patients, including those with marginal vessels. Upper arm fistulae are attractive due to the ease of creation and of achieving high access flow rates. Cephalic arch stenosis (CAS) can lead to failure of upper arm fistulae and is increasingly identified. We hypothesized that CAS is promoted by high blood flow rates, brachiocephalic fistulae, and an angle of cephalic vein insertion approaching 90 degrees.

METHODS

All patients requiring a fistulogram between January 2004 and May 2006 had surveillance fluoroscopy of the central veins. Demographic, clinical and laboratory parameters were collected and the angle of the cephalic vein insertion measured by 3 blinded independent observers.

RESULTS

Fifty-eight patients had fistulograms and CAS was detected in 18 subjects. Significant differences between the CAS and non-CAS groups were brachiocephalic fistula site (p = 0.046), access flow (mL/min) (p = 0.012), and absence of diabetes (p = 0.03). Univariate predictors of CAS include access flow (per 100 mL/min) (p = 0.042), platelet count (p = 0.031) and calcium-phosphate product (p = 0.026). The relationship of brachiocephalic site and CAS was confounded by access flow [(per 100 mL/min)*brachiocephalic fistula site (p = 0.016)] and fistula age [brachiocephalic fistula site*fistula age (p = 0.017)]. In multivariate analysis, renovascular disease, calcium-phosphate product, platelet count and access flow (per 100 mL/min)*brachiocephalic fistula predicted CAS (p < 0.001, Negelkerke's R-Square = 0.55). The angle of insertion of the cephalic vein was not predictive for CAS.

CONCLUSIONS

CAS may be a long-term consequence of high blood flow rates. The interaction of access flow and brachiocephalic fistula supports the hypothesis that high flow through a brachiocephalic fistula promotes CAS. The multiple factors influencing cephalic arch remodeling require further research.

Functional patency of autogenous AV fistulas for hemodialysis

BACKGROUND

Although AV fistulas are the preferred access for hemodialysis and have low complication rates, failure to function remains high and time to first dialysis may be several months.

METHODS

Data from a Computerized Patient Record System of patients undergoing AV fistula from October 2000 to March 2006 were reviewed for type of fistula, interval from AV fistula construction to first hemodialysis, patency period, and complication rate.

RESULTS

129 patients were identified who underwent 155 autogenous AV fistula constructions. The average age was 62.1 (range 40-84) years old. 114 radiocephalic and 41 brachiocephalic fistulas were performed. 57 (50%) radiocephalic fistulas allowed successful hemodialysis after an average length of 13+/-5 weeks with a primary patency of 13+/-4 months. 24 (42%) fistulas subsequently thrombosed, 7 (12%) developed fistula stenosis, and 2 (4%) developed steal syndrome. 28 (68%) brachiocephalic fistulas reached successful hemodialysis after 6+/-2 weeks with a primary patency of 16+/-7 months. Eleven (42%) of the brachiocephalic fistulas that reached hemodialysis remained patent while four (15%) thrombosed. Two (8%) brachiocephalic fistulas thrombosed before reaching hemodialysis. There were two incidences (5%) of steal syndrome in the brachiocephalic group with one case being severe leading to tissue loss in the hand.

CONCLUSION

Brachiocephalic fistulas were superior to radiocephalic in both time to maturity, primary patency, and functional primary patency. Brachiocephalic fistulas had a higher maturation rate and were less likely to fail once hemodialysis began. Vascular surgeons should develop better patient selection to predict which fistulas will function successfully rather than risk complications of prolonged central catheters.

Evaluation of the efficacy of the transposed upper arm arteriovenous fistula: A single institutional review of 190 basilic and cephalic vein transposition procedures

INTRODUCTION

Although autogenous brachial-basilic upper arm transpositions (BVT) have been extensively utilized, there has been significant disparity in published patency rates. Very little is known about the efficacy of autogenous brachial-cephalic upper arm transpositions (CVT). We evaluated our experience with transposed upper arm arteriovenous fistulas (tAVF) in order to assess patency and identify factors that affect efficacy. We then compared our tAVF patients with a cohort of upper arm arteriovenous grafts (AVG).

METHODS

A retrospective review was conducted of tAVF performed at our institution from 1998 to 2004. The tAVF group consisted of 119 BVT and 71 CVT procedures. We compared these with 164 AVG. tAVF were placed only for veins >/=2.5 mm in diameter by duplex ultrasonography.

RESULTS

Mean follow-up was 28 months. With the exception of mean vein diameter, the patients in the BVT and CVT groups had similar demographic parameters and complication rates. Primary and secondary patency rates were 52% and 62% at 5 years for BVT and 40% and 46% at 5 years for CVT, respectively (P = NS). Multivariate analysis revealed that hemodialysis dependence at the time of fistula placement and history of previous upper arm access independently affected primary patency. History of upper torso dialysis catheters independently affected secondary patency. Comparison of the tAVF and AVG groups revealed that tAVF patients were significantly younger, more likely to be male, less likely to be African American (AA) and less likely to have a history of previous AV access. The primary patency rate for tAVF was significantly higher than for AVG: 48% vs 14% at 5 years (P < .001). The secondary patency rate for tAVF was also significantly higher than for AVG: 57% vs 17% at 5 years (P < .001). Among the tAVF procedures, 9% required one or more revisions to maintain secondary patency, compared to 51% with the AVG group (P < .001). Multivariate analysis revealed that presence of AVG and a history of previous upper arm access negatively affected primary and secondary patency.

CONCLUSIONS

Autogenous BVT and CVT have similar, high patency rates. Transposed upper arm arteriovenous fistulas have higher patency rates than upper arm AVG and require significantly fewer revisions. Our data strongly support the contention that as long as the patient is a candidate for an upper arm tAVF, based on anatomical criteria, a tAVF should always be considered before an AVG.

Catheter motion during atrial ablation due to the beating heart and respiration: Impact on accuracy and spatial referencing in three-dimensional mapping

BACKGROUND

The accuracy of three-dimensional mapping systems is affected by cardiac contraction and respiration.

OBJECTIVE

The study sought to determine relative motion of cardiac and thoracic structures to assess positional errors and guide the choice of an optimized spatial reference.

METHODS

Motion of catheters placed at the coronary sinus (CS), pulmonary vein (PV) ostia, left atrial (LA) isthmus and roof, cavotricuspid isthmus (CTI), and right atrial appendage (RAA) were recorded for 30 patients using Ensite-NavX. The right subclavian vein, left brachiocephalic vein, azygos vein, pulmonary arteries, and a static reference were included. The displacement from a mean position was calculated for each pair of sites. Respiration effects were assessed by the shift of the motion curve during in- and expiration phases.

RESULTS

The PVs showed a mean interpair displacement of 4.1 +/- 0.2 mm and a shift of 5.0 +/- 0.5 mm. Proximal CS references for all LA structures (4.0 +/- 1.1 mm) were superior to the static reference (4.9 +/- 0.7 mm; P = .01). In addition, the shift due to respiration was less pronounced at 3.5 +/- 0.8 mm versus 4.9 +/- 0.5 mm (P = .004), respectively. Motion of extracardiac vessels was influenced by a mean shift of 6.8 +/- 1 mm. The remote subclavian and brachiocephalic veins were more affected (7.6 +/- 0.7 mm) than the pulmonary arteries (5.9 +/- 0.4 mm; P = .002). For the CTI, a minimized mean displacement of less than 4.6 +/- 2.0 mm relative to the proximal CS, RAA, and azygos vein was found.

CONCLUSION

Respiration is the major source of relative motion, which increases with distance from the heart. For LA procedures, a proximal CS reference position is superior to a static reference position.

Novel repair of venous aneurysms secondary to arteriovenous dialysis fistulae

This report describes the surgical management of 12 hemodialysis patients with arteriovenous fistulae in whom non-infected, fusiform venous aneurysms developed that compromised access for dialysis. The venous aneurysmal changes were too extensive to permit excision and primary veno-venous anastomosis. To avoid the use of synthetic interpositional grafts, the venous aneurysms were left in situ and reduced in size to match the diameters of the veins entering and exiting the aneurysms. After decompression, the lumens of the venous aneurysms were reduced by firing staple lines along the longitudinal axes of the venous aneurysms and excision of the aneurysmal tissue anterior to the staple lines. Twenty-eight aneurysms were repaired by this method of reduction aneurysmoplasty, in 15 operations on 12 patients over the past 10 years. There were no wound infections or dehiscences and no bleeding or hematomas. After the operations, the arteriovenous fistulae were used continuously for hemodialysis until the patients died (7 patients for 36 months -/+ 28 SD), were lost to follow-up (1 patient at 30 days postoperatively), until the arteriovenous fistulae thrombosed following revision of the arteriovenous anastomosis (1 patient at 41 months postoperatively), or until the arteriovenous fistulae was ligated to relieve pain in the upper arm (1 patient at 6 months postoperatively). Two patients continue to use their arteriovenous fistulae until and including the time of this report at 10 and 11 months, respectively. Reduction aneurysmoplasty as described in this report offers an effective and low-risk option for the management of venous aneurysms secondary to arteriovenous fistulae in hemodialysis patients.

Dialysis Fistulae Patency and Preoperative Diameter Ultrasound Measurements

BACKGROUND

This study was designed to investigate the possibility of defining a vascular diameter with a practical cut-off point, which predicts a successful patency for radiocephalic arteriovenous fistulae in dialysis patients.

METHODS

This is a retrospective analysis of prospectively gathered data. Consecutive patients (n=148) with chronic renal failure, needing vascular access for haemodialysis, were included if they underwent duplex ultrasound examination to evaluate preoperatively the vascular status and diameters for radiocephalic arteriovenous fistulae (RCAVF) construction. The associations between the diameter of the radial artery and cephalic vein and primary failure at six weeks, primary and secondary patency at one year were investigated.

RESULTS

There was no significant association between either radial artery diameter or dilated cephalic vein diameter and primary failure. There was an association between radial artery diameter and primary patency (Overall P=0.042). Males had a significantly larger mean radial artery diameter than females (P=0.005). Gender did not influence primary patency.

CONCLUSION

We recommend using radial artery diameters of > or = 2.1 mm and < or = 2.5 mm for RCAVF construction, this diameter category having the highest patency at 1 year. A single cut-off guideline cannot be recommended.

Creation of secondary AV fistulas from failed hemodialysis grafts: the role of routine vein mapping

Pre-existing forearm grafts lead to dilatation of upper arm veins of the ipsilateral arm that greatly facilitates the creation of secondary arteriovenous fistulas (AVF). In this retrospective review of 18 patients, the routine and periodical revision of failed grafts were discontinued. Vein mapping by physical examination or Duplex studies was performed prior to graft failure and a secondary AVF was created when the graft failed. Using this management strategy, an AVF creation success rate of 95% was achieved despite high incidence of co-morbidity factors within the patient population. This success rate demonstrates the value of vein selection by vascular mapping prior to graft failure and early vascular access planning in the successful creation of secondary AVF.

Salvage of arteriovenous fistula by angioplasty of collateral veins establishing a new channel

Patents with end-stage renal disease depend on the patency of their dialysis access. As these patients have only finite access options, and no access lasts indefinitely, it is imperative that each access should be maintained for as long as possible. This report describes a case of salvage of an upper arm fistula by repeated angioplasty of the collateral veins after the main out flow vein was occluded and could not be recanalyzed.

Stent fracture in the left brachiocephalic vein

A 68-year-old male hemodialysis patient presented with severe congestion in his left arm. Left arm venography showed a completely occluded left brachiocephalic vein. We chose a self-expandable stent for treating this vein. However, restenosis occurred once at 8 months and again after six additional months. The cause of the restenosis was considered to be a stent fracture. On the first restenosis, we performed redilation with a balloon; on the second restenosis, we chose stent-in-stent with a balloon-expandable stent. At least 9 months after the stent-in-stent procedure, there has been no edema in his left arm. Therefore, stent-in-stent is one of the useful strategies for stent fracture in central venous obstruction.

Hemodynamic changes in the cephalic vein of patients with hemodialysis arteriovenous fistula

PURPOSE

To assess via Doppler sonography the hemodynamic changes in the cephalic vein after creation of an arteriovenous fistula, and to compare radiocephalic and brachiocephalic fistulas.

METHODS

Thirty-three hemodialysis patients and 54 controls were enrolled in the study. The cephalic vein was examined with a 7.5-MHz linear-array transducer. Doppler waveform parameters (resistance index, pulsatility index), time-averaged maximum flow velocity (TAV), peak systolic velocity (PSV), end-diastolic velocity (EDV), and the cross-sectional area of the vessel (A) were measured. Cephalic vein flow volume (CVFV) was calculated as TAV x A.

RESULTS

CVFV, PSV, EDV, A, RI, and PI were 45.5, 7.2, 6.7, 7.7, 1.2, and 1.32 times higher, respectively, in the cephalic vein of hemodialysis patients compared with controls. Both CVFV and A were higher in brachiocephalic patients compared with radiocephalic patients (1,983 +/- 1,199 versus 870 +/- 322 ml/min [p < 0.05] and 50.3 +/- 38.9 versus 21.0 +/- 7.8 mm(2) [p < 0.05], respectively).

CONCLUSION

The increase in cross-sectional area and flow volume of the cephalic vein is larger in patients with brachiocephalic fistulas than in those with radiocephalic fistulas; however, flow velocities and waveform parameters are not different.

Retrograde flow in the dural sinuses detected by three-dimensional time-of-flight MR angiography

INTRODUCTION

Retrograde flow in the left dural sinuses is sometimes detected by three-dimensional time-of-flight (3D-TOF) magnetic resonance (MR) angiography. The purpose of this study was to evaluate the incidence of this phenomenon and its characteristic features on 3D-TOF MR angiograms.

METHODS

We retrospectively reviewed cranial MR angiography images of 1,078 patients examined at our institution. All images were obtained by the 3D-TOF technique with one of two 1.5-T scanners. Maximum intensity projection (MIP) images in the horizontal rotation view were displayed stereoscopically. We reviewed the source images, inferosuperior MIP images, and horizontal MIP images and identified retrograde flow in the dural sinuses.

RESULTS

We found retrograde flow in the dural sinuses of 67 patients on the source images from 3D-TOF MR angiography; the incidence was 6.2%. In 47 of the 67 patients, retrograde flow was identified in the left inferior petrosal sinus, in 13, it was seen in the left sigmoid sinus, and in 6, it was seen in the left inferior petrosal and left sigmoid sinuses. The remaining patient had retrograde flow in the left inferior petrosal and left and right sigmoid sinuses. The mean age of the patients with retrograde flow was slightly greater than that of the patients without this phenomenon (70 years vs 63 years).

CONCLUSION

Retrograde flow in the dural sinuses frequently occurs on the left side in middle-aged and elderly patients during 3D-TOF MR angiography performed with the patient in the supine position. This phenomenon should not be misdiagnosed as a dural arteriovenous fistula.

Safer video-assisted thoracoscopic thymectomy after location of thymic veins with multidetector computed tomography

BACKGROUND

Video-assisted thoracoscopic (VATS) thymectomy has been applied as a surgical option for autoimmune myasthenia gravis. Prior identification and fine division of the thymic veins are critical to the prevention of unexpected severe bleeding that may require conversion to open surgery. Until recently, such bleeding could be avoided only by meticulous dissection of thymic fat tissue away from the left brachiocephalic vein (LBV). With recent advances in computed tomography (CT), multidetector-row computed tomography (MDCT) can readily be obtained and provides three-dimensional (3D) images. This study explored its value for preoperative identification of the thymic veins draining into the LBV, and thus for prevention of injury to these veins during endoscopic thymectomy.

METHODS

Five patients with myasthenia gravis, thymoma, or both underwent enhanced MDCT preoperatively. The thymic veins draining into the LBV were visualized using both horizontal and sagittal/coronal CT images. Then 3D images were reconstructed to enable operators to simulate endoscopic views. During each VATS extended thymectomy, the numbers and branching patterns of the thymic veins were compared with the preoperative MDCT images.

RESULTS

The thymic veins draining into the LBV were clearly identified with MDCT in all five patients examined. Reconstructed 3D images clearly located their courses in the thymic/fat tissue and their entry routes into the LBV, thus simulating the actual intraoperative endoscopic views. All tributaries divided during surgery were identified preoperatively with MDCT.

CONCLUSIONS

Location of thymic veins with MDCT can provide precise preoperative information about thymic venous anatomy. This easy and less invasive examination has the potential to make VATS thymectomy easier and safer.

[Acute cardiac failure secondary to brachiocephalic arteriovenous fistula in patient on chronic haemodialysis]

Vascular access for hemodialysis is crucial for appropriate course of the treatment as well as for good prognosis for patients with chronic renal insufficiency. In this paper we present the case of chronically hemodialysed patient who developed high-output cardiac failure after several days before creation of the upper arm brachio-cephalic arteriovenous fistula. Ultrasonographic imaging of the fistula showed an over-functioning anastomosis with flow reaching 41/min. The surgical correction of the anastomosis length to 4 mm and reduction of the cephalic vein diameter to 5 mm, significantly improved general status of the patient, simultaneously maintaining an accurate function of the fistula, with the maximal flow up to 850 ml/min.

Retrograde flow in the left inferior petrosal sinus and blood steal of the cavernous sinus associated with central vein stenosis: MR angiographic findings

BACKGROUND AND PURPOSE

We attempted to identify the cause of abnormal venous flow seen during arterial MR angiography in the inferior petrosal sinus by use of in three female patients (aged 51, 48, and 70 years, respectively).

METHODS

Arterial 3D time-of-flight MR angiography was performed with a tilted optimized nonsaturating excitation pulse sequence (TR/TE, 31/7; flip angle, 20 degrees; section thickness, 65 mm; effective thickness, 1 mm; number of sections, 1 to 2); no magnetization transfer pulse sequence was used. Contrast-enhanced 3D MR angiography of the neck was performed with a 3D fast low-angle shot pulse sequence (TR/TE, 4.6/1.8; flip angle, 40 to 45 degrees; section thickness, 80 mm; intersection gap, 1.5 mm; acquisition matrix, 180 x 256; acquisition time, 27 s) on a system with a whole-body coil.

RESULTS

In all three patients, 3D time-of-flight MR angiography revealed abnormal vascular signal originating from the left cavernous sinus, continuing through the inferior petrosal sinus, and ending in the proximal internal jugular vein at the jugular bulb level. Abnormal vascular signal at the jugular bulb, sluggish flow and flow-related enhancement in the left internal jugular vein, and signal void in the contralateral jugular vein were noted. Contrast-enhanced delayed-phase MR angiography showed stenosis in the left brachiocephalic vein in all patients.

CONCLUSION

High signal intensity noted at the inferior petrosal sinus resulted from retrograde flow. Retrograde flow was due to blood stealing from the internal jugular vein toward the cavernous sinus because of venous stenosis in the brachiocephalic vein.

Incidence of central vein stenosis and occlusion following upper extremity PICC and port placement

The purpose of this study was to determine the incidence of central vein stenosis and occlusion following upper extremity placement of peripherally inserted central venous catheters (PICCs) and venous ports. One hundred fifty-four patients who underwent venography of the ipsilateral central veins prior to initial and subsequent venous access device insertion were retrospectively identified. All follow-up venograms were interpreted at the time of catheter placement by one interventional radiologist over a 5-year period and compared to the findings on initial venography. For patients with central vein abnormalities, hospital and home infusion service records and radiology reports were reviewed to determine catheter dwell time and potential alternative etiologies of central vein stenosis or occlusion. The effect of catheter caliber and dwell time on development of central vein abnormalities was evaluated. Venography performed prior to initial catheter placement showed that 150 patients had normal central veins. Three patients had central vein stenosis, and one had central vein occlusion. Subsequent venograms (n = 154) at the time of additional venous access device placement demonstrated 8 patients with occlusions and 10 with stenoses. Three of the 18 patients with abnormal follow-up venograms were found to have potential alternative causes of central vein abnormalities. Excluding these 3 patients and the 4 patients with abnormal initial venograms, a 7% incidence of central vein stenosis or occlusion was found in patients with prior indwelling catheters and normal initial venograms. Catheter caliber showed no effect on the subsequent development of central vein abnormalities. Patients who developed new or worsened central vein stenosis or occlusion had significantly (p = 0.03) longer catheter dwell times than patients without central vein abnormalities. New central vein stenosis or occlusion occurred in 7% of patients following upper arm placement of venous access devices. Patients with longer catheter dwell time were more likely to develop central vein abnormalities. In order to preserve vascular access for dialysis fistulae and grafts and adhere to Dialysis Outcomes Quality Initiative guidelines, alternative venous access sites should be considered for patients with chronic renal insufficiency and end-stage renal disease.

Reversal of pulmonary hypertension after ligation of a brachiocephalic arteriovenous fistula

The arteriovenous (AV) fistula is the access method of choice for long-term hemodialysis according to DOQI guidelines. Among the recognized complications of upper extremity AV fistulae fashioned for hemodialysis are infection, aneurysm formation, and high-output left ventricular failure. We describe a novel cardiopulmonary complication--secondary pulmonary hypertension resulting from an aneurysmal brachiocephalic AV fistula. The clinical presentation, investigation, management, and pathophysiology of this complication are discussed.

[The study of cerebral venous blood flow disturbance peculiarity in the norm and under the extravasal compression of brachiocephalic veins with the use of magnetic resonance venography and ultrasound duplex scanning]

The MR-venography of the veins and brain venous sinuses, brachiocephalic veins an internal jugular veins duplex scanning have been performed in order to study the distinctions of cerebral venous hemodynamics of healthy people and the patients with venous encephalopathy caused by the extravasal compression of the brachiocephalic veins at the neck level and the superior sections of mediastinum. It has been revealed that the blood flow reducing in transverse brain sinuses occurs not only in the case of outflow disorder in the distal sections of the venous system, but also in norm. This reducing depends on anatomic constitution of confluens sinuum and the venous angle type of brachiocephalic veins. The three venous angle types of brachiocephalic veins have been distinguished: y-type, mu-type and Y-type. It has been registered that in case of the mu-type angle the blood flow can be reduced in norm due to peripheral resistance increase at the physiological bends of nearly a right angle type. The distinctions of hemodynamics in case of venous obstruction in contrast to arterial obstruction have been described. It has been registered that in case of outflow trouble in one of the internal jugular veins the speed and the volume of the blood flow in it are progressively reduced depending on the duration and the manifestation of compression. All this results in narrowing of the vein diameter from the affected side, and in compensatory distention of the diameter and increase of blood flow volume in the contralateral internal jugular vein, vertebral and external jugular veins, in succession.

[Abnormality of hepatic perfusion in superior vena caval obstruction syndrome. A case report diagnosed by CT scan]

We describe a case of focal and intense contrast enhancement on hepatic CT due to superior vena caval obstruction and brachiocephalic vein obstruction. This phenomenon is explained by systemic portal venous shunting.

Left innominate vein compression by a brachiocephalic artery anomaly

An unique case of left innominate vein compression by a leftward origin of a brachiocephalic artery in conjunction with an aberrant right subclavian artery anomaly occurred in a young patient. Aortography and magnetic resonance imaging were invaluable in arriving at a diagnosis.

Idiopathic left innominate vein stenosis manifested following the creation of arteriovenous fistula in uremia

A 48-year-old woman on maintenance hemodialysis was admitted with her left upper limb swollen and her left jugular vein dilated following the creation of an arteriovenous fistula on her left arm. The intracorporeal pressure during hemodialysis was found to be high. Venographic investigation showed severe stenosis of her left innominate vein accompanied by rich blood flow of the collaterals. Ligation of her fistula promptly reduced swelling of her left upper limb and dilatation of the left jugular vein. The exact cause of the stenosis could not be determined from venographic or computerized tomography findings. Idiopathic left innominate vein stenosis was diagnosed which we believe is the first case to be reported in a hemodialyzed patient.

Compression of the left brachiocephalic vein: cause of high signal intensity of the left sigmoid sinus and internal jugular vein on MR images

To study the asymmetry in signal intensity of the sigmoid sinuses, internal jugular veins (IJVs), or both sets of structures on magnetic resonance (MR) images, the authors reviewed 226 serial sets of routine MR imaging studies. Cerebral digital subtraction angiography was performed in 20 patients with a markedly higher intensity and/or enhancement on the left; 15 of them also underwent venography. With every sequence, the left sigmoid sinus, IJV, or both were higher in signal intensity significantly more often than the right (range, P = .0001 to .0129). Angiography revealed hemostasis in the left IJV in 16 patients that disappeared during full inspiration in 14. In 13, venography revealed that the left brachiocephalic vein was compressed to occlusion between the aortic arch and the sternum during tidal volume ventilation. The occlusion disappeared at full inspiration, when the distance between the aortic arch and the sternum increased. This hemostasis could be the major cause of the frequent increased signal intensity of the left sigmoid sinus and IJV on MR images.

[A case of superior vena cava syndrome caused by adenocarcinoma of the mediastinum--the significance of pulsed Doppler echocardiography in the SVC reconstruction]

We report a case of SVC syndrome caused by adenocarcinoma of the mediastinum, in which brachiocephalic vein flow was recorded by pulsed Doppler echocardiography before and after the SVC reconstruction. A 46-year-old man was admitted to the hospital with the chief complaints of edema of the face and the upper extremities. Although chest X-ray film showed no abnormalities, chest CT and SVC-graph demonstrated the obstruction of SVC and bilateral brachiocephalic veins. It was found that bilateral brachiocephalic vein flow displayed characteristic one-peak shaped pattern and the peak flow velocity was decreased. We removed SVC and bilateral brachiocephalic veins with the surrounding tissue, and SVC and tributaries were reconstructed with 10 mm ringed ePTFE grafts. Histological examination revealed carcinoma cell infiltration in the wall of SVC. Postoperative phlebography showed well patent grafts, and bilateral brachiocephalic vein flow pattern normalized and the peak flow velocity remarkably increased.

[Venous hum and innominate vein flow velocity in chronic anemia: a pulsed Doppler echocardiographic study]

To assess the hemodynamic correlates of the cervical venous hum in patients with chronic anemia, 14 patients (mean age; 49 years, mean hemoglobin (Hb); 7.3 g/dl) and 14 control subjects (mean age; 50 years, mean Hb; 14 g/dl) without cardiac disease were studied by auscultation, phonocardiography and Doppler echocardiography in two positions (supine and sitting). Venous hum was detected in the sitting position in 11 of the 14 anemic patients whose Hb was less than 9 g/dl, and in six anemic patients in the supine position, while venous hum was absent in the control subjects in both positions. Pulsed Doppler echocardiography with the transducer in the supraclavicular fossa revealed significantly (p less than 0.01) higher peak velocity in the innominate vein in the 11 anemic patients with venous hum (supine; 71 +/- 12, sitting; 111 +/- 24 cm/sec, mean +/- SD) than in the control subjects (supine; 46 +/- 15 sitting; 76 +/- 27 cm/sec) in both positions. Intensity of venous hum increased concomitantly with increased innominate vein flow velocity when the body position was changed from supine to sitting. Peak velocity in the innominate vein correlated significantly with Hb in all study subjects (r = 0.65, p less than 0.01). In conclusion, the cervical venous hum in patients with chronic anemia is related to the hemoglobin concentration and flow velocity in the innominate vein.

[Univentricular heart and pulmonary stenosis with a right-to-left shunt between the innominate and pulmonary veins after Glenn operation: a case report]

A 12-year-old girl with a univentricular heart and pulmonary stenosis, who had undergone Glenn operation at two years of age and Fontan operation at 11 years of age, had a right-to-left shunt via collaterals between the innominate and pulmonary veins. This right-to-left shunt was detected by two-dimensional contrast echocardiography. The contrast material was injected into the left antecubital vein appeared in the left atrium, and this was confirmed by innominate venography. The contrast material injected into the left innominate vein passed via the collaterals into the pulmonary veins bilaterally. No such cases have so far been reported. In our experience, in four of six cases after Glenn operation, including the present case, the abnormal collateral circulation from the superior vena cava to the atrium was detected by two-dimensional contrast echocardiography. This case is interesting embryologically and suggests that the connection between the pulmonary and systemic veins which is present in early fetal life, and subsequently disappears, was present after birth.

Innominate vein obstruction caused by intrathoracic goiter

Images

Symptomatic unilateral cannon "a" waves in a patient with a ventricular pacemaker

A 64-year-old woman was referred because of intermittent pulsations of the left side of the neck, face, and scalp that were first noticed after the insertion of a ventricular pacemaker. The pacemaker had been inserted because of symptomatic 2:1 atrioventricular block. Right cardiac catherization showed cannon "a" waves, and phlebographic studies revealed stenosis of the right innominate and internal jugular veins. The symptoms were abolished by conversion to an atrial synchronous pacing system. Comments are offered on the hemodynamic findings, the "pacemaking syndrome", and the use of atrial synchronous pacing.