Showing papers by "Jan H.M. Tordoir published in 2003"

Prospective evaluation of failure modes in autogenous radiocephalic wrist access for haemodialysis

Abstract: Introduction Radiocephalic wrist arteriovenous fistulae (RCAVF) are the primary and best option for vascular access for haemodialysis treatment However, 10‐24% of these AVFs fail due directly to thrombosis and non-maturation In a prospective study, the failure modes of radiocephalic AVFs and the impact of surgical and interventional treatment on fistula outcome were investigated Methods The rate of thrombosis and non-maturation was evaluated in 43 RCAVFs The selection of RCAVF creation was made on preoperatively determined duplex parameters Fistula function was evaluated post-operatively by clinical examination and non-invasively measured AVF blood flow A policy of a liberal use of radiological anduor surgical revision of non-functioning RCAVFs was made on the basis of duplex measured blood flow and angiographically detected vessel stenosis Results Primary fistula function was achieved in 26 of 43 patients (60%) Non-maturation and thrombosis occurred in 14 (33%) and three (7%) patients, respectively A total of 12 interventions (PTA 6; surgery 6) were needed, resulting in salvage of eight RCAVFs (47%) The blood flow in functioning AVFs was significantly higher compared to non-functioning AVFs at 1 (754 vs 440 ccumin), 7 (799 vs 524 ccumin) and 42 days (946 vs 532 ccumin) post-operatively At the end, 34 RCAVFs (79%) became functional as vascular access for haemodialysis treatment Conclusion Primary RCAVFs have a high rate of failure An aggressive approach towards early interventional treatment of these non-functional AVFs is worthwhile and leads to a considerable salvage rate Early post-operative AVF flow measurement indicates the chance of successful maturation of RCAVF

Shear stress depends on vascular territory: comparison between common carotid and brachial artery.

Abstract: Shear stress (SS) is thought to be constant throughout the vascular system. Evidence for this supposition is scarce, however. To verify this hypothesis in vivo, we assessed common carotid (CCA) and...

European guidelines for vascular access: clinical algorithms on vascular access for haemodialysis.

Abstract: SUMMARY Vascular access remains the Achilles heel of end-stage renal disease patients, receiving haemodialysis. The increase in the number of elderly dialysis patients with additional cardiovascular co-morbidities and diabetes mellitus makes the creation and maintenance of functioning vascular access, more difficult and cumbersome. Therefore, the development of guidelines for vascular access management seems logical. A team of multidisciplinary vascular access experts created a set of algorithms covering the whole spectrum from pre-operative vessel assessment, peri-operative access management and post-operative follow up and surveillance. Additionally, a range of various access complications with their diagnosis and treatment options were included in these algorithms. The new European guidelines for vascular access augment the knowledge of vascular access problems and their management. Additionally, the use of algorithms facilitates the decision-making when treating complications by all physicians dedicated to this field of healthcare.

Stenosis detection in forearm hemodialysis arteriovenous fistulae by multiphase contrast-enhanced magnetic resonance angiography: preliminary experience.

Abstract: Purpose To assess the feasibility and accuracy of multiphase contrast-enhanced magnetic resonance angiography (CE-MRA) in patients with dysfunctioning hemodialysis arteriovenous fistulae (AVF), using digital subtraction angiography (DSA) as the standard of reference. Materials and Methods Fifteen patients with dysfunctioning AVF (eight radiocephalic and seven graft AVF) underwent CE-MRA. Dysfunction was defined as a flow decline of more than 25% in 1 month measured by dilutional flow measurements. CE-MRA was performed during injection of 35 mL of gadolinium-DTPA. The CE-MRA sequence consisted of a time-resolved series of 10 scans, each lasting approximately 10 seconds. The technical parameters were TR/TE/FA/voxel = 5.4/1.6/40/3.1 mm3, and a rectangular surface reception coil was used. All patients were scheduled to undergo DSA at which an intervention was carried out when a stenosis ≥50% was seen. Two observers, unaware of each other's findings and the findings at DSA, quantified the number and degree of stenosis in the failing AVF. Image quality for CE-MRA and DSA was scored on a 3-point scale. The diagnostic performance of CE-MRA was analyzed with receiver-operator characteristic (ROC) analysis. Results CE-MRA and DSA examinations were performed without side effects in all 15 patients. Image quality was scored significantly better on CE-MRA (observer 1: CE-MRA, 2.0; DSA, 1.3; P =.001; observer 2: CE-MRA, 2.0; DSA, 1.4; P =.002). Interobserver agreement for detection of ≥50% stenosis was 0.81 (95% confidence interval (CI) = 0.71–0.92) for CE-MRA and 0.69 (95% CI = 0.55–0.84) for DSA. ROC analysis revealed a mean area under the curve of 0.78. On the patient level, at the ≥50% threshold, mean sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 100% (95% CI = 69%–100%), 10% (95% CI = 0%–78%), 70% (95% CI = 38%–92%), and 100% (95% CI = 50%–100%), respectively. At the ≥75% threshold, mean sensitivity, specificity, PPV, and NPV were 75% (95% CI = 20%–99%), 78% (95% CI = 39%–98%), 55% (95% CI = 12%–96%), and 89% (95% CI = 52%–100%), respectively. Conclusion CE-MRA is a useful diagnostic tool for detecting stenoses in flow-declined hemodialysis AVF prior to interventional DSA. J. Magn. Reson. Imaging 2003;17:54–64. © 2002 Wiley-Liss, Inc.

Detection of cell‐cycle regulators in failed arteriovenous fistulas for haemodialysis

Abstract: Background. Chronic renal failure (CRF) patients rely on arteriovenous fistulas (AVFs) for haemodialysis vascular access. Intimal hyperplastic stenoses result in failure of AVFs and frequent intervention is required to maintain vascular access. The extent of intimal hyperplasia depends on the interplay between cyclins and cyclin-dependent kinases (e.g. cdk2), positively regulating cell-cycle progression. cdk activity is negatively modulated by the interaction with cdk inhibitory proteins, such as p21 Waf1 and p27 Kip1 . Little is known about the expression of these proteins in the development of intimal hyperplasia in AVFs. Methods. p21 Waf1 ,p 27 Kip1 , cdk2 and Proliferating Cell Nuclear Antigen immunoreactivity was determined in 18 failed AVFs from 16 CRF patients and 10 non-diseased vessels (five arteries and five veins). Results. The percentage of p21 Waf1 -positive cells was significantly lower in AVFs (3"1%), compared with normal veins and arteries (62"4 and 63"4%, respectively; P-0.001). cdk2-positive cells were significantly higher in AVFs (40.7"3.7%) than in normal veins and arteries (2"1 and 0"0%, respectively; P-0.001). Although no difference in p27 Kip1 immunoreactivity was found between AVFs (37"17%) and veins (23"8%; Ps0.208), it was lower in healthy arteries (17"11%; Ps0.037). Conclusions. The data suggest that in failed AVFs, p21 Waf1 , but not p27 Kip1 , is related to intimal hyperplasia. This is the first report to show involvement of cell-cycle regulators in AVF-related human intimal hyperplasia.