Preoperative duplex examination in patients with dialysis access-related hand ischemia: indication for distal radial artery ligation.

PURPOSE: To demonstrate that treatment with distal radial artery ligation (DRAL), based on preoperative evaluation with duplex ultrasound, is effective for correction of hand ischemia related to distal radiocephalic arteriovenous fistula (AVF). METHODS: Two patients with symptoms of hemodialysis access-induced distal ischemia (HAIDI) related to radiocephalic AVF at wrist (necrotic lesion of fingers, pain at rest and loss of sensory function) were studied with preoperative duplex examination. Color Doppler ultrasound (CDU) showed low-normal flux (700 and 500 mL/min respectively), retrograde flow in the DRA and increased digital perfusion after manual occlusion of DRA. They were both treated by ligation of the DRA. RESULTS: Both patients had immediate improvement of ischemic symptoms. Reversed DRA flow disappeared and peripheral flow ameliorated. Postoperative AVF flow was 500 and 350 mL/min, stable at 16 and 8 months of follow-up, respectively. CONCLUSIONS: Preoperative CDU examination, simulating reversed DRA flow interruption, seems to be an effective tool to predict the success of DRAL procedure.

Preventive hemostasis for hemodialysis vascular access surgical reinterventions.

Surgical reinterventions for treatment of complications or ligation of haemodialysis vascular access (VA), when performed in or below the mid/lower part of the upper arm, could benefit from the use of preventive haemostasis with an inflatable tourniquet. This technique offers several advantages, such as the reduced risk of bleeding and the increased accuracy of dissection allowing for a minimally invasive approach. The use of preventive haemostasis is safe, economical and time-saving. All the secondary procedures on VA that could benefit from its use are reviewed.

Assessment of long-term vasoplegia induced by brachial plexus block: a favorable effect for hemodialysis angioaccess surgery?

PURPOSE: Loco-regional anesthesia, along with the neurosensitive inhibition causes arterial and venous vasodilatation, that could be of interest for vascular access surgery. We evaluated the long term vasoplegia persistence after brachial plexic block. METHODS: Five patients submitted to brachial plexus block for an orthopedic procedure have been observed. Both radial arteries, that of the blocked arm and the opposite as a control, were analyzed by ultrasound examination, at time 0 and 360 minutes after anesthesia induction. All patients were treated with the same anesthesiologic protocol: axillary approach, use of an electroneurostimulator, injection 10 ml of ropivacain 7.5% + 10 ml of mepivacain 2%. The parameters evaluated from the arterial ultrasound flowmetry were: peak systolic velocity (PSV), end diastolic velocity (EDV) and resistance index (RI). RESULTS: No modification of the arterial flow were observed in the control arm at 0 and 360'after block induction. The blocked arm instead showed a significant decrease of the resistive index, stable at 360 minutes. CONCLUSIONS: The vasoplegia accompaning plexic block lasted 6 hours after anesthesia induction. Whereas this longstanding haemodynamic effect is beneficial for early patency of vascular access for hemodialysis, needs to be ascertained by further investigations.

Progression of coronary artery calcification in renal transplantation and the role of secondary hyperparathyroidism and inflammation.

BACKGROUND AND OBJECTIVES: Transplantation should favorably affect coronary calcification (CAC) progression in dialysis; however, changes in CAC score in the individual patient are not reliably evaluated. DESIGN, SETTING, PARTICIPANTS & MEASUREMENTS: The authors used special tables of reproducibility limits for each score level to study, by multislice computed tomography and biochemistries, the 2-year changes in CAC in 41 transplant patients (age 48 +/- 13 yr, 25 men, dialysis vintage 4.8 +/- 4.3 yr, underwent transplant 6.2 +/- 5.5 yr prior). Thirty balanced dialysis patients served as controls. RESULTS: In the study group, Agatston score was stable, and C-reactive protein decreased, whereas fetuin and osteoprotegerin increased. In the control group, Agatston score increased, parathyroid hormone and phosphate decreased, and inflammation markers were persistently twice as high as in the study group. With regard to individual changes, 12.2% transplant patients worsened, compared with 56.6% of patients in dialysis (P < 0.0001). Patients without calcification at entry showed slower progression in transplantation (8.3%) than in dialysis (44.4%; P < 0.034), and the difference was similar to that observed in cases with CAC (17.6% versus 61.9%; P < 0.007). Discriminant analysis indicated parathyroid hormone, the modality of therapy (dialysis or transplantation), and erythrocyte sedimentation rate as the variables most associated with worsening. CONCLUSIONS: Renal transplantation lowers but does not halt CAC progression. Inflammation and hyperparathyroidism are associated with progression in the populations studied.

Morphometric X-ray absorptiometry in the assessment of vertebral fractures in renal transplant patients.

BACKGROUND: Bone mineral density (BMD) is widely employed to evaluate the risk of fractures, but more than mineral content is bone quality that accounts for bone strength. In fact, occasionally, subjects with normal or only mildly reduced BMD also experience pathologic fractures. In metabolic bone disease, like renal transplantation, the agreement between fractures and BMD is less predictable. We assessed the prevalence of vertebral fractures by means of a new, DEXA-based method (morphometric absorptiometry, MXA) and compared its concordance with the two mostly employed radiological techniques (Visual semi-quantitative, SQ, and morphometric radiography, MRX) in an asymptomatic population of transplanted patients. Moreover, the association of bone fractures with low BMD values was examined. METHODS: Fifty-three renal transplant patients underwent spinal radiographs and BMD measurements by DEXA. In order to obtain a morphometric assessment, a lateral DEXA scan was performed. RESULTS: Patients with vertebral fracture were 17/53 (32%) with both SQ and MRX, and 12/53 (23%) with MXA (chi(2) = n.s.). A single fracture was detected in 9/53 patients (17%) with SQ and MRX, and in 4/53 (7.5%) with MXA; multiple fractures were 8/53 (15%) with any technique. With SQ as the standard reference, predictive indexes were excellent with MRX (invariably 100%) and quite good with MXA (sensitivity 70.6%; specificity 100%). Of the total of 689 vertebrae, 49 were fractured with SQ, 54 with MRX and 41 with MXA. Mild deformities were present in 21 (SQ), 26 (MRX) and 13 (MXA) vertebral bodies, respectively, while moderate-severe deformities were 28 with any technique. Again, with SQ as standard reference, predictive indexes were good (MRX: sensitivity 100%, specificity 99.2%; MXA: sensitivity 83.7%, specificity 100%). When we classified patients according to BMD T-score values, SQ and MRX recognized fractures in 4/18 normal (22%), 10/22 osteopenic (45%) and 3/13 osteoporotic (23%). With MXA 3/18 (17%) normal, 6/22 (27%) osteopenic and 3/13 (23%) osteoporotic were fractured. The lower performance of MXA was very likely due to the poor quality of images from the upper thoracic spine of obese subjects. CONCLUSIONS: Prevalence of vertebral fractures in renal transplant patients is quite high and randomly associated with reduced BMD. A surveillance of the spine by Rx, implemented with vertebral morphometry, is therefore warranted to recognize the disease. (MXA is a reliable alternative technique, especially in more severely affected individuals.) MXA, although less sensitive than the conventional techniques because of possible technical biases, is very specific, and can be proposed for follow-up purposes in this population of patients.