Multi-slice computed tomographic angiography for stenosis detection in forearm hemodialysis arteriovenous fistulas.

PURPOSE: A method of diagnosing the extent and severity of arteriovenous fistula (AVF) stenoses is multislice computed tomographic angiography (MS-CTA). The aim of this prospective study was to assess the accuracy of MS-CTA for the detection and grading of stenoses in AVF in comparison to digital subtraction angiography (DSA), which was used as the gold standard of reference. METHODS: Fifteen hemodialysis (HD) patients with dysfunctioning forearm AVF were included. These AVFs were evaluated by both DSA and MS-CTA and were read in a prospective, blinded manner by two radiologists experienced in vascular imaging. RESULTS: ROC analysis revealed areas under the curve of 0.90+/-0.07 for observer I and 0.87+/-0.08 for observer II at a stenosis cut-off level of >or=50% diameter reduction. The combined results for MS-CTA showed sensitivity, specificity and positive and negative predictive values of 82%, 98%, 82% and 98% for stenoses>or=50% and 71%, 99%, 77% and 98% for stenoses>or=75%. Inter-observer agreement for the detection of stenoses>or=50% diameter reduction was 0.70 and 1.0, for MS-CTA and DSA, respectively. CONCLUSION: MS-CTA can provide good visualization of forearm HD access AVF and has moderate sensitivity, but high specificity for the detection of flow-limiting stenoses.

Vascular anatomy of the stomach related to gastric tube construction.

In view of constructing a gastric tube after esophagus resection, the vascular anatomy of the greater curvature of the stomach, especially the connection between the left and right gastro-epiploic arteries, was investigated. The vascular anatomy was studied in 20 embalmed human specimens. After dissection a gastric tube of 4 cm wide was constructed, using the greater gastric curvature. Various lengths of the arterial arcades were measured. In 70% an anastomosis between the right and left gastro-epiploic arteries was present. With the construction of an isoperistaltic gastric tube, in which the left gastro-epiploic artery is left in situ (ligating it at the splenic hilus), there is an 18.7% increase of length of arterial arcade along the gastric tube. Leaving the left gastro-epiploic artery in situ increases the feeding arterial arcaded-length along the gastric tube with 5.0 cm (19%).

Autogenous radial-cephalic or prosthetic brachial-antecubital forearm loop AVF in patients with compromised vessels? A randomized, multicenter study of the patency of primary hemodialysis access.

OBJECTIVE: The construction of an autogenous radial-cephalic direct wrist arteriovenous fistula (RCAVF) is the primary and best option for vascular access for hemodialysis. However, 10%-24% of RCAVFs thrombose directly after operation or do not function adequately due to failure of maturation. In case of poor arterial and/or poor venous vessels for anastomosis, the outcome of RCAVFs may be worse and an alternative vascular access is probably indicated. A prosthetic graft implant may be a second best option. Therefore, a randomized multicenter study comparing RCAVF with prosthetic (polytetrafluoroethylene [PTFE]) graft implantation in patients with poor vessels was performed. METHODS: A total of 383 consecutive new patients needing primary vascular access were screened for enrollment in a prospective randomized study. According to defined vessel criteria from the preoperative duplex scanning, 140 patients were allocated to primary placement of an RCAVF and 61 patients to primary prosthetic graft implantation. The remaining 182 patients were randomized to receive either an RCAVF (n = 92) or prosthetic graft implant (n = 90). Patency rate was defined as the percentage of AVFs that functioned well after implantation. RESULTS: Primary and assisted primary 1-year patencies were 33% +/- 5.3% vs 44% +/- 6.2% (P = .03) and 48% +/- 5.5% vs 63% +/- 5.9% (P = .035) for the RCAVF and prosthetic AVF, respectively. Secondary patencies were 52% +/- 5.5% vs 79% +/- 5.1% (P = .0001) for the RCAVF and prosthetic AVF, respectively. Patients with RCAVFs developed a total of 102 (1.19/patient-year [py]) vs 122 (1.45/py; P = .739) complications in the prosthetic AVFs. A total of 43 (0.50/py) interventions in the RCAVF group and 79 (0.94/py) in the prosthetic graft group were needed for access salvage (P = .077). CONCLUSIONS: Although there were more interventions needed for access salvage in the patients with prosthetic graft implants, we may conclude that patients with poor forearm vessels do benefit from implantation of a prosthetic graft for vascular access.

Radiocephalic wrist arteriovenous fistula for hemodialysis: meta-analysis indicates a high primary failure rate.

OBJECTIVE: To improve the precision of the estimates of primary failure rates and primary and secondary 1 year patency of radial-cephalic arteriovenous fistulas (RCAVF) for hemodialysis. DESIGN: Meta-analysis. MATERIALS AND METHODS: A Medline search was performed of the English language medical literature between January 1970 and October 2002. Key words that were searched included radiocephalic fistula, arteriovenous shunt, Brescia-Cimino fistula and patency. Primary failure, primary and secondary patency rates were analysed using the standard mixed effects model, which allows for variability between the different studies. RESULTS: Eight prospective and 30 retrospective studies were included. The analysis showed a pooled estimated primary failure rate of 15.3% (95% CI: 12.7-18.3%). In addition, the pooled estimated primary and secondary patency rates of 62.5% (95% CI: 54.0-70.3%) and 66.0% (95% CI: 58.2-73.0%), respectively, were calculated. Subgroup analysis concerning various study characteristics, including study year, gender and age, did not reveal statistically significant differences. CONCLUSION: Although, the autogenous RCAVF is considered to be the primary choice for vascular access, this meta-analysis indicates a high primary failure rate and only moderate patency rates at 1 year of follow-up.

The preperitoneal tissue dilemma in totally extraperitoneal (TEP) laparoscopic hernia repair: an anatomo-surgical study.

BACKGROUND: One of the a main reasons for the long learning curve associated with totally extraperitoneal (TEP) laparoscopic hernia repair is an insufficient understanding of the dissection of the proper preperitoneal space. In this study, we investigated the conditions required for the correct anatomical approach to the preperitoneal space. METHODS: The anatomo-surgical conditions for dissection of the correct preperitoneal space were evaluated in 10 video studies of TEP repairs. In addition, we also investigated the preperitoneal tissue layers in 10 embalmed human bodies. RESULTS: The proper preperitoneal space can only be approached after cleavage of the ventral component of a bilaminar preperitoneal fascia complex, also known as the posterior lamina of the transversalis fascia. The cleavage can be accomplished spontaneously by a fully expanded balloon correctly introduced into the plane between the rectus muscle and the posterior lamina of the transversalis fascia. CONCLUSIONS: The anatomy of the preperitoneal tissues in the inguinal region is complex. To gain expertise in laparoscopic totally extraperitoneal (TEP) hernia repair, the presence of a bilaminar fascia complex and the importance of the cleavage of the posterior lamina of transversalis fascia must be appreciated.