Showing papers in "Journal of Vascular Access in 2004"

Complications and management of long-term central venous access catheters and ports.

Abstract: Purpose: Although prolonged venous access devices (PVADs) are used in case prolonged intravenous therapy is required, implantation and use of these devices is associated with complications. The purpose of this study was to evaluate perioperative and long-term complications associated with PVADs and the management of these complications. Methods: A retrospective review was undertaken of 225 PVADs implanted in 217 patients from February 1993 to June 2004. This included 144 single-lumen port infusion systems, 49 single-lumen Hickman ® catheters and 32 double-lumen Groshong ® catheters. The PVADs were inserted using either the percutaneous Seldinger method (n=183) or cutdown access to the subclavian vein (n=42). Indications for placement were as follows: chemother- apy in 66.2% of patients, drug-infusion treatment in 31.6% of patients and total parenteral nutrition in 2.2% of patients. Results: Perioperative complications occurred in 13 patients (5.7%): catheter malposition in seven patients (3.1%), pneumothorax in three patients (1.3%), hemorrhage in two patients (0.9%) and catheter embolization in one patient (0.4%). Long-term complications appeared in 15 patients (6.6%): infection in five patients (2.2%), thrombosis in three patients (1.3%), extravasation in three patients (1.3%), and catheter fracture in four patients (1.8%). The fractured fragments were removed by the Amplatz ® snare device. In 10 patients (4.4%) only were PVADs removed prior to completion of the intended therapy. Indications for removal were catheter infection in five patients (2.2%) and catheter fracture in five patients (2.2%). Conclusions: PVAD implantation is associated with some risk of serious perioperative and long-term complica- tions. Care of the catheter and the patient should be maintained with the proper and immediate evaluation of the perioperative and long-term complications. (The Journal of Vascular Access 2004; 5: 174-8)

Emerging role of Enterococcus spp in catheter-related infections: biofilm formation and novel mechanisms of antibiotic resistance.

Abstract: Enterococci are gram-positive bacteria that are part of the normal human intestinal flora and can colonize the upper respiratory tract, biliary tract and vagina of otherwise healthy people. Althoug...

Evaluation of Vascular Access Complications in Acute and Chronic Hemodialysis

Abstract: PurposeThis work aimed to determine the incidence of vascular access (VA)-related complications of temporary venous catheters in acute hemodialysis (HD) prescription, to study the survival rate of ...

Comparison of different techniques of hemodialysis vascular access flow evaluation.

Abstract: Measurement of vascular access flow (QVA) has been suggested as a method of choice for vascular access quality (VAQ) monitoring. Besides traditional duplex Doppler, a number of bedside methods based mostly on the Krivitski principle of QVA evaluation from recirculation at reversed needles (RX), have been developed. This work compares ultrasonic dilution (UD), taken as a reference, HD01, Transonic Systems; duplex Doppler (DD); thermodilution (TD), BTM, Fresenius; optodilutional RX measurement (ORX), Critline III, R-mode, HemaMetrics; direct optodilutional QVA evaluation from jumpwise changes in ultrafiltration rate at both normal and reversed needles connection (OABF), Critline III, ABF-mode; and direct transcutaneous optodilutional QVA evaluation (TQA), Critline III TQA. Firstly, reproducibility of each method was assessed by duplicate measurement at unchanged conditions. This was followed by paired measurement with each method performed at controlled change in relevant measurement condition (two different extracorporeal blood flows in UD and TD, changed sensor position in TQA). Finally paired measurements by each method and the reference method performed at identical conditions were evaluated to assess accuracy of each method. The simple Krivitski formula QVA= QB(1-RX)/RX was used wherever manual QVA calculation was needed. Very high reproducibility was seen in UD, both for measurement at the same extra corporeal blood flow (QB) (correlation coefficient of duplicate measurement r= 0.9702, n= 58) and for measurement at two different QB (r= 0.9735, n= 24), justifying its current status of a reference method in QVA evaluation. Slightly lower reproducibility of TD measurement at the same QB (r= 0.9197, n= 40) and at two different QB (r= 0.8508, n= 168) can be easily overcome by duplicate measurement with averaging. High correlation of TD vs. UD (r= 0.9543, n= 54) makes TD a viable clinical alternative in QVA evaluation. Consistently different QVA obtained at two different QB should prompt closer investigation of anatomical conditions of the access. Use of the simple Krivitski formula in TD (which measures total recirculation, i.e. sum of access recirculation and cardiopulmonary recirculation) brings about underestimation of QVA, which progressively increases from QVA of about 600 ml/min up. Good correlation, although with significant scatter (r= 0.8691, n= 27) was found between the DD- and UD-based QVA. By far the worst reproducibility at the same QB from among the investigated methods was found in ORX (0.6430, n= 23). Also the correlation of ORX vs. UD was lower than in other methods (r= 0.702, n=33) and general overestimation of QVA by about 25% was noted. Correlation of OABF vs. UD (r= 0.6957, n= 26) was slightly better than that of ORX and it gave less overestimated values. The TQA method showed very high reproducibility (r= 0.9712, n= 85), however only for unchanged sensor position. Correlation of QVA measured at two different sensor positions was much worse (r= 0.7255, n= 22). Correspondence of TQA vs. UD was satisfactory (r= 0.8077, n= 36). Skilled and experienced operators are a must with this method.

Steal Syndrome of the Hemodialysis Vascular Access: Diagnosis and Treatment:

Abstract: PURPOSE: Steal syndrome is an uncommon but serious condition of arterial insufficiency distal to a permanent hemodialysis fistula. The management of the condition is a great challenge to the surgeo ...

ProCol vascular bioprosthesis for vascular access: midterm results.

Abstract: Background/AimsThis study aimed to evaluate the safety and efficacy of the ProCol, vascular bioprostheses as vascular access (VA) material, especially in patients with a history of prior failed acc...

Steal syndrome after brachiocephalic fistula for vascular access: correction with a new simple surgical technique.

Abstract: PURPOSE: Steal syndrome is the condition of arterial insufficiency distal to a permanent haemodialysis fistula Three treatment options have been recommended: ligation of the fistula, banding of the fistula, and distal revascularization We report an alternative simple surgical technique for correction of steal syndromeMETHODS: Two patients were treated for steal syndrome after brachiocephalic fistula operation The treatment of the steal syndrome was done by interponating an ePTFE graft loop tunnelated subcutaneously in the upper armRESULTS: At follow-up one year later both fistula were patent without any reoperation and with normal flow at haemodialysis There were no symptoms of stealCONCLUSION: This new method for correction of steal syndrome seems to be an attractive alternative

Advantages of a nurse-led central venous vascular access service.

Abstract: Inserting central venous catheters for patients requiring parenteral nutrition (PN) is expensive and time consuming, particularly if operating theatre facilities are used. Expanding the role of a c...

Salvage insertion of tunneled central venous catheters in the internal jugular vein after accidental catheter removal.

Abstract: Purpose Tunneled catheters are widely used for intermediate to long-term hemodialysis (HD) access, but are prone to several complications that can require catheter replacement. Replacing malfunctioning catheters with a new line, placed in a different access site, can lead to problems with multiple vein occlusions. This has led many nephrologists to continue using the same vein as long as possible by guidewire catheter exchanges, to preserve other veins for future use. We describe a guidewire exchange technique for the Ash-Split catheter in the internal jugular vein. Methods In three patients, the exchange was performed because of partial catheter removal, as evidenced by the outward dislocation of the Dacron cuff. In these patients, the guidewire was inserted through the catheter. In two additional patients, the catheter had been completely removed by accident: the replacement of the dislodged tunneled venous catheters was attempted 5 hr and 1 day after accidental removal. In these patients, the guidewire was inserted through the previous tunnel. After guidewire placement, a skin incision was made in the supraclavicular region. The metal guidewire was easily located inside the fibrous structure that had previously surrounded the catheter. The guidewire was then extracted from the subcutaneous tunnel and used to insert a new catheter safely and easily after creating a new tunnel. Patients were routinely given antibiotic prophylaxis (1 g of cefazolin) immediately before the procedure. A strict aseptic technique was used, including several sterile glove changes. Results No infections developed following this procedure, which has the potential for bacterial contamination. All procedures were successful. Only in one patient did we have to convert to a different catheter: it was not possible to replace the old Ash-Split catheter with the same dual-lumen catheter because of difficulties in inserting the peel away introducer-catheter complex. In this patient, rather than forcing it with larger dilators or trying to disrupt the fibrin sheath with balloon dilatation, a single lumen Tesio catheter was successfully placed. In both patients who completely lost the previous catheter, the guidewire was readily reinserted through the subcutaneous tunnel into the vein. Catheter function was excellent in all patients, with a test blood flow rate on the 1st catheter use >350 ml/min. Conclusions We described a new method for catheter exchange, which allows the easy insertion of a new catheter and the creation of a new and safer subcutaneous tunnel. In addition, we demonstrated that in cases of complete catheter removal, it is possible to reinsert a catheter in the same vein through a guidewire, even when reinsertion was attempted up to 1 day later.

Treatment of dialysis catheter infections in 2004.

Abstract: Hemodialysis catheter associated infections are a major source of morbidity and mortality in end stage renal disease patients. There is disagreement about the management of catheter infections, particularly concerning the removal of potentially infected tunneled dialysis catheters. A dialysis catheter should generally be removed when an infection involves a temporary hemodialysis catheter, a septic patient, a patient with a tunnel tract infection, or a patient with evidence of a metastatic infectious complication. In treating stable patients with clinically mild catheter associated bacteremia, parenteral antibiotics alone have a low success rate in eliminating the infection. Antibiotic locks are an emerging strategy for treating these patients, but at present higher rates of success and lower costs are achieved by exchanging the catheter over a guidewire. Antibiotic lock solutions, antibiotic coated catheters, and totally implantable dialysis access systems may play a large role in prevention of catheter associated infections in the future; however, further randomized controlled trials of these strategies are needed. Future efforts should concentrate on limiting the use of traditional tunneled cuffed hemodialysis catheters by early referral to vascular surgery for the creation of an arterio-venous fistula.

Incidence of sepsis in central venous catheter-bearing patients with hematologic malignancies: preliminary results.

Abstract: BACKGROUND Indwelling central venous catheters (CVCs) are essential devices in the management of patients with hematological disorders treated with chemotherapy. However, their nature predisposes patients to unwanted complications. METHODS CVC-related complications were retrospectively analyzed in 227 hematologic patients who were consecutively admitted to our hematology department between May 2002 and April 2004. Patients' diagnoses comprised acute myeloid leukemia (36.8%), acute lymphoid leukemia (7.3%), lymphoproliferative disorders (28.3%), multiple myeloma (19.5%), myeloproliferative syndromes (5%) and others (3.1%). The CVCs used were polyurethane three lumen 7-Fr (111 patients) for chemotherapy and 12-Fr (114 patients) for chemotherapy and peripheral blood stem cell apheresis, plus two tunneled catheters. RESULTS The pathological events were: bacteriaemias (n=46); occlusions (n=10); exit tunnel infections (n=8); thrombosis (n=6); lung emboli (n=2). Among febrile patients the bacteriemia frequency was 20%, of which 13.6% were CVC-related (with a higher incidence in leukemia patients (p=0.027). Among the isolates, gram-positive bacteria were found in 29 cases (23 CVC-related cases), and gram-negative bacteria in 16 cases (8 CVC-related cases). Only one patient had Candida albicans sepsis. At univariate and multivariate analysis significant risk factors for infection (p<0.0001) were only the number of days/catheters and neutropenia duration. CONCLUSIONS In our hematologic patients, the CVC complications were mainly septic, with only 10.1% of CVC-related bacteriemias, despite prolonged catheterization duration. Acute leukemia patients were at major risk for sepsis, probably due to a more severe neutropenia and prolonged catheterization duration.

Bridge graft to a small distal artery after fistula ligation for angioaccess-induced ischemia: report of two cases.

Abstract: Angioaccess-induced ischemia is an infrequent but cumbersome problem, because both limb ischemia correction and access salvage should be undertaken during the same procedure. This paper reports two cases that we successfully managed with a bridge graft to a small distal artery after fistula ligation.

New graft for low friction tunneling in vascular access surgery.

Abstract: PurposeProsthetic accesses of the upper extremity have been in use for more than 25 years. Many different conduits have been employed; investigators have continually searched for a graft with super...

Vacutainer filling time through subcutaneous venous access devices

Abstract: INTRODUCTION The functionality of subcutaneous venous access devices is evaluated at least every time the device is accessed. This evaluation is subjective and actions are only undertaken when blood withdrawal and/or fluid injection become problematic. The function of these devices has rarely been evaluated objectively. The present study tried to find an objective and standardized way to evaluate the withdrawal speed of a newly inserted port. METHODS Between October 2001 and December 2002, a prospective randomized study of 3 types of ports was carried out. The ability to infuse heparinized normal saline and to withdraw blood was evaluated by recording the filling time of a 10 ml Vacutainer tube in 876 newly inserted central venous ports at the end of the surgical procedure. RESULTS The patient groups were comparable in age, gender and insertion procedure characteristics (vein used, position of the port on the body and length of the catheter). The median time needed to fill a 10 ml Vacutainer tube in all ports was 17.00 sec (range 11.43-63.62 sec). The median filling time for BardPort was 16.36 sec (range 13.48-39.00 sec), for Celsite 18.35 sec (range 12.03-40.00 sec) and for Port-a-cath 16.43 sec (range 11.43-63-62 sec). A significant difference in filling time was found between the large bore catheters (BardPort, Port-a-cath) and the small bore catheter (Celsite) of 2 seconds median value. CONCLUSION Measurement of withdrawal speed provides an objective criterion for the quality description of blood withdrawal immediately after insertion. A value of more than 20 seconds for filling a 10 ml Vacutainer tube could therefore be suggested a useful trigger for further investigation.

Arterio-arterial prosthetic duct (AAD) as a vascular access in hemodialysis.

Abstract: Vascular access (VA) is mainly a problem confronting patients undergoing hemodialysis (HD). In some cases, peripheral veins are damaged or thrombosed because of repeated vein punctures and subsequent thrombophlebitis or accompanying ailments like diabetes or other kinds of vasculitis, making the use of conventional VA methods unsuitable. In this study, we present our experience using a synthetic vascular graft as an arterio-arterial duct (AAD) in the upper arm of patients undergoing HD, in whom other procedures had failed. In this procedure, we used a synthetic vascular prosthesis of polytetrafluoroethylene(ePTFE) (Gore-Tex) or Vasculink as an AAD, subcutaneous in the media aspect of the upper arm. HD was performed for this duct. Twenty patients were selected in whom all other VA means had failed. Patient age ranged from 33-83 yrs. In two patients (12%), early graft thrombosis was the cause of failure. In the remaining 14 patients (87%), a suitable flow was established. In another two patients, after several dialysis sessions the duct stopped functioning. We believe the reason for this malfunction was too much pressure on the graft to control bleeding due to the inadequate training of the HD personnel. The remaining 12 patients (75%) used the duct for >6 months. With this method, because we used only the artery for placing the conduit, complications relating to the vein such as limb ischemia, edema and venous hypertension did not prevail. On the other hand, because the conduit is an accessory duct, should it have become thrombosed, arterial flow to the limb would be unhindered. Therefore, we believe when all other conventional VA methods have failed, AAD is a suitable technique.

Levels of anxiety and pain during chemotherapy with peripheral versus central vascular access: an experimental evaluation.

Abstract: PURPOSE The purpose of this research was to evaluate pain and anxiety levels in patients undergoing chemotherapy via central venous catheter (CVC) and peripheral venous access (PVA). METHOD The sample consisted of 56 cancer patients undergoing at least one chemotherapy treatment cycle. They were divided into two groups based on the administration method of the chemotherapeutic drug: the experimental group (patients with CVC) and the control group (patients with PVA). The instruments used were the following: for multidimensional pain evaluation the Italian Pain Questionnaire (QUID, devised by De Benedettis et al), and the Visual Analogue Scale (VAS) Chart of Pain. To evaluate the state and anxiety traits, the State-Trait Anxiety Inventory (STAI questionnaire, by D. Spielberg) was used, and we used structured interviews for the statistical survey. RESULTS Analyzing the data from the STAI questionnaire, it appeared that the state-trait anxiety levels of the experimental group and the control group were not significantly different (analysis of the mean difference made using the Student's t-test). The average scores of the STAI questionnaire for both groups fell within the normal range. This indicated that the anxiety level was unaffected by the introduction of the device (the CVC). The data collected with the QUID questionnaire and subsequent statistical analysis demonstrated that the difference between the means (Student's t-test) of the experimental group and the control group was significantly lower, as regards perception of the sensorial and evaluative quality of pain (p=0.05) in the experimental group. From the evaluation of the VAS method, it appeared that the difference between the means was not significant in either group, although the distribution of frequency tended towards lower values in the experimental group with respect to the control group. This confirms previous QUID research where a lower pain level is recorded. CONCLUSIONS Analysis of the data collected via the structured interview revealed that most of the CVC sample did not respond to catheter insertion as a sign of a worsening of their illness.

The role of surveillance in mature arteriovenous fistula management.

Abstract: The existing guidelines recommend arteriovenous fistulae (AVF) surveillance by access blood flow (Qa) measurement and the correction of hemodynamically significant stenoses to prolong access survival. Unfortunately, many studies supporting these recommendations are inadequate methodologically; therefore, both the optimal criteria for surveillance and the value of preventive stenosis repair in AVF remain controversial. Recent literature confirms that Qa measurement allows an accurate identification of both stenosis (area under the curve (AUC) ranging from 0.80-0.93) and access at risk of failure (AUC ranging from 0.82-0.98) in AVFs and suggests a Qa 25% as optimal predictors for stenosis and a Qa <400 ml/min for incipient thrombosis. Recent prospective studies evaluated whether Qa surveillance could improve AVF patency rates compared to monitoring based on clinical and dialysis-related criteria alone. The majority of studies have historical, rather than concurrent, control groups and provide conflicting results, some showing a reduction and some showing no change in thrombosis rates by Qa monitoring. On the other hand, the few randomized controlled studies available show that Qa surveillance, when coupled with preemptive intervention, reduces the already low thrombosis rate in AVF and suggest that the functional access life can be prolonged. However, there is still the need for additional methodologically adequate studies to understand fully the role of surveillance in AVF management.

Preserving the left arm vein in cases of hemodialysis access generating left internal mammary artery steal syndrome.

Abstract: In patients undergoing chronic hemodialysis (HD) through an arm arteriovenous fistula (AVF), coronary insufficiency can occur if the patient undergoes a coronary artery bypass graft (CABG) using the ipsilateral internal mammary artery (1-4). Therefore, the creation of a new AVF after CABG should avoid using the arm ipsilateral to the side where the internal thoracic artery was used. In cases where coronary syndrome appears when this advice is not followed, treatment should be offered aimed at overcoming the hemodynamic interference between the diminished coronary supply through the left or right internal mammary artery by closure of the existing fistula, with or without temporary central venous line insertion until the maturation of a new fistula. We suggest a different approach by moving only the arterial inflow site of the AVF to the controlateral subclavian artery, but in addition, leaving the well functioning venous outflow tract intact. In cases of left internal mammary steal it is achieved by creating a conduit running from the right subclavian artery to the left cephalic vein; therefore, creating a new arterial inflow source, connected to the existing functioning old venous outflow tract to maintain an immediately functioning new fistula without a coronary steal.

Percutaneous treatment of thrombosed arteriovenous fistulae using the Gelbfish-Endovac aspiration thrombectomy device.

Abstract: PURPOSE To study the efficacy and safety of percutaneous treatment of thrombosed hemodialysis arteriovenous fistulae (AVF) using the Gelbfish-Endovac aspiration thrombectomy device (Gelbfish-Endovac). METHODS From September 2003 to May 2004, twenty-nine percutaneous thrombectomy procedures were performed in 27 patients (median age of 67 years, 14 females) with thrombosed hemodialysis AVF using the Gelbfish-Endovac. Prior interventions, procedure time, anticoagulation, use of additional devices/thrombolytic agents, technical success, clinical success, complication rates, and patency at 30, 60 and 90 days were evaluated. RESULTS Sixteen upper arm and 13 forearm AVF were declotted. Seventeen AVF had prior percutaneous interventions. Three AVF had not matured. Median AVF age was 9 months. Heparin was used in 14 procedures. Sixteen arterial lesions and 25 venous lesions were uncovered and treated. Two AVF required the additional use of the Arrow-Trerotola percutaneous thrombectomy device. One AVF underwent side branch ligation. No thrombolytic agents were used. Median procedure time was 70 minutes. Initial technical success was achieved in 24 AVF and clinical success was achieved in 22 AVF. Eleven complications occurred. Ten AVF remained open at 30 days, 10 at 60 days and 8 at 90 days without further interventions. With additional percutaneous interventions, 16 AVF remained open at 30 days, 16 at 60 days and 15 at 90 days. CONCLUSION The Gelbfish-Endovac aspiration thrombectomy device is safe and efficacious for percutaneous declotting of AVF.

The suitability of the femoral vein for permanent vascular access.

Abstract: In our dialysis unit, we commonly position permanent catheters (the Tesio twin catheter) in femoral veins with 'high' exit sites, in the abdominal area. We prefer this method because of its intrinsic safety in patients immediately requiring hemodialysis (HD), because there is no need for ultrasound guidance and a low incidence of complications during and after positioning. In addition, we consider that this method is suitable for older patients without good native vessels for an arteriovenous fistula (AVF). Sixty-nine femoral catheters were positioned in 61 patients (mean age 70.8 yrs): 307 observational months/patients (mean duration 4.45 months) demonstrated the following results: a) no incidents during catheter positioning; b) four iliac-femoral thromboses (in three cases complete recanalization with heparin treatment); c) two catheters were removed due to an infection of the tunnel; d) no generalized, life-threatening sepsis. Therefore, we recommend this solution as a 'bridge-access' between the immediate need for HD and the successive best strategy for the treatment of end-stage renal disease (ESRD).

Transparent film for intravascular catheter exit-site dressings

Abstract: Transparent polyurethane film is recommended for catheter site insertion dressing by the American guidelines for the prevention of infections associated with intravascular catheters. It has been pr...

Stretch expanded polytetrafluoroethylene graft with intrawall radial support system: an advance in vascular access graft design.

Abstract: Vascular access expanded polytetrafluoroethylene (ePTFE) grafts with external support systems consisting of parallel rings or in a spiral configuration are designed to resist kinking and compressio...

Early rupture of subclavian vein catheter: a case report and literature review.

Abstract: Prolonged venous access devices (PVADs) have become indispensable in antiblastic protocols for the treatment of cancer patients, in anti-infection protocols for acquired immunodeficiency syndrome (...

Experience with the use of uncuffed double-lumen silicone hemodialysis catheters.

Abstract: AimThis study aimed to describe our experience with the use of uncuffed double-lumen silicone hemodialysis catheters (USHDCs) that were used in 54 cases as a temporary vascular access (VA). Subject...

Safety of percutaneous internal jugular catheterization in cancer patients: prospective observational study.

Abstract: PurposeTo determine predictors for failure and early complications of percutaneous internal jugular catheterization (IJC) in cancer patients.MethodsSix hundred and thirty consecutive cancer patient...

Old and new tools in the diagnosis of central venous catheter-related bloodstream infections: is there a role for brushing?

Abstract: Bloodstream infections (BSIs) are the third most common nosocomial infections. Catheters and other medical devices are the first exogenous causes of preventable infections in hospital. The estimated attributable mortality for catheter-associated BSI ranges from 1-35%, mainly depending on etiological agents and underlying disease. In considering this, it is necessary to reduce central venous catheter- (CVC)-related BSI prevalence and to obtain a rapid and accurate method for an early diagnosis. This review indicates the advantages and the disadvantages of old and new tools for the early diagnosis of CVC-related BSIs.

In vitro and in vivo hemocompatibility evaluation of graphite coated polyester vascular grafts

Abstract: Attempts have been made in this study to prepare a homogeneous and stable coating of graphite on polyester vascular grafts (GPVG) using an electrophoresis method to evaluate thromboresistant and bl...

Thrombotic events of arteriovenous fistulae in hemodialysis patients related to the C677T thermolabile variant of methylenetetrahydrofolate reductase.

Abstract: Background: Hyperhomocysteinemia is a risk factor for thrombosis, a frequent complication of vascu- lar access (VA) in hemodialysis (HD). The enzyme methylenetetrahydrofolate reductase (MTHFR) is necessary for the remethylation of homocysteine (Hcy) to methionine. It has been postulated that patients homozygous and, to a lesser extent, heterozygous for the C677T thermolabile variant of this enzyme present a reduced catalytic ac- tivity, with secondary increases in plasmatic Hcy levels (normal: 10 ± 5 µmol/L) and an elevated risk of vascular thromboses. Methods: Sixty-two patients on chronic HD were divided into two groups: group A (n = 23, 37.1%) was normal for the enzyme (CC); group B (n = 39, 62.9%) was heterozygous (CT). Both groups were not different according to age, sex, time on HD, hematocrits (Hct), baseline levels of Hcy, folic acid and vitamin B12. After the 1st HD ses- sion patients were started on folic acid 10 mg/day and 500 µg/week of intravenous (i.v.) methylcobalamin. Results: Two years later, thrombotic events were not different between the two groups. Group A = 5 (21.7%) vs. group B = 12 (30.7%), Hcy levels were significantly different between final and baseline measurements (group A 21.5 ± 5.2 vs. 16.6 ± 3.9 µmol/L, p = 0.02; group B 22.1 ± 8.9 vs. 16.1 ± 3.9 µmol/L, p = 0.008), folic acid (group A 22.1 vs. 346.9 ng/ml, range (r) =166-527, p<0.001; group B 19.2 vs. 218.5 ng/ml, r = 138-298, p<0.001) and vit- amin B12 (group A 1489 vs. 3192.3 pg/ml, r = 1494-4890, p = 0.01; group B 1086 vs. 1513.8 pg/ml, r = 1092-1934, p = 0.02). Conclusions: HD patients heterozygous for the C677T variant of the enzyme MTHFR can present a similar risk of thrombotic events in arteriovenous fistulae (AVF) compared to patients normal for the enzyme at a 1-yr follow- up. These results could be explained by an adequate control of Hcy levels after folic acid and methylcobalamin replacement therapy. (The Journal of Vascular Access 2004; 5: 83-88)

Secondary migration of a central venous catheter: a rare complication.

Abstract: The Authors describe a case of spontaneous migration in the right jugular vein of a central venous catheter tip, properly positioned in the right atrium through the right subclavian vein two days before.