Percutaneous embolization of idiopathic renal arteriovenous fistula using Amplatzer vascular plug II

Renal arteriovenous fistula (AVF) presents a rare but important condition that can be acquired, congenital, or idiopathic. Embolization techniques have recently been considered the first-line therapy in the treatment of these lesions, but they carry a possible high risk of distal migration of embolic agents into the venous and pulmonary circulation. This risk is especially important with large, high-flow fistulas. In this report, we present a case in which a 31-year-old man with a symptomatic idiopathic AVF was treated with embolization using the Amplatzer vascular plug II after unsuccessful superselective embolization using coils. This method allowed for complete occlusion of the high-flow fistula with good preservation of arterial supply to the renal parenchyma.     

Prosthetic arteriovenous fistula for vascular access in hemodialysis.

Vascular access through subcutaneous prosthetic arteriovenous fistulas was studied in eighteen dogs. Dacron velour and woven Dacron grafts (6 mm diameter) were constructed across the lower abdomen between the common femoral artery and the opposite common femoral vein. In heparinized animals 197 percutaneous punctures were made with a "14 guage hemodialysis cannula at weekly intervals. Over a period of one and a half years there was no instance of infection. One of the fourteen Dacron velous and all four woven Dacron fistulas thrombosed. These data suggested the feasibility of achieving repetitive blood access through Dacron velour vascular prostheses. Nineteen Dacron velour fistula bypasses between the brachial artery and median basilic vein were performed in fifteen selected patients for a total dialysis period of ninety-six months. Failed standard subcutaneous fistulas or absence of suitable vessels in the upper extremity were indications for the primary procedure. Of three looped forearm fistulas, two thrombosed at twenty-two and two months. Complications among sixteen straight bypasses in the arm included two graft infections and one cannula tract infection. There were no instances of thrombosis in this group. The advantages of single needle dialysis in these high risk patients have been emphasized. Eleven grafts are presently functioning two to nine months postoperatively. Our preliminary results suggest that a Dacron velour fistula merits consideration as an alternative for vascular access in maintenance hemodialysis.     

Proximal radial artery arteriovenous fistula for hemodialysis vascular access

Objective

This study reviewed our experience with proximal radial artery-based arteriovenous fistulas (PRA-AVFs) for hemodialysis vascular access, evaluating characteristics of the patients, functional patency, risk of steal syndrome, survival of the patient, and technical considerations.

Carotid to subclavian bypass and Amplatzer vascular plug subclavian endovascular occlusion before thoracic open or endovascular repair

ObjectiveThe aim of this study was to evaluate the safety and effectiveness of endovascular occlusion of the prevertebral subclavian artery (SA) using an Amplatzer vascular plug after prophylactic revascularization with carotid-subclavian bypass (CSB) in the setting of endovascular thoracic stent grafting or open arch repair with frozen elephant trunk.MethodsAll patients who underwent SA plug embolization (SAPE) and CSB from September 2009 to December 2018 were enrolled in a registered study (SAPE study: clinicaltrials.gov NCT03620006). The primary end point was technical success, defined as complete occlusion of the origin of the SA, and how it was influenced by SA anatomy. The secondary end points were access vessel complications, cerebrovascular events, and CSB patency.ResultsThe 101 SAPE procedures were performed using a type I (35 patients) or a type II (66 patients) Amplatzer vascular plug. A percutaneous ipsilateral upper extremity access was used in 66% of patients and a radial artery access was used in 50% of procedures. The 30-day primary technical success rate was 95% (five patients received an additional plug during the index); five type IC endoleaks were observed and successfully treated either with surgical ligation (in open arch repair procedures) or secondary embolization procedure (thoracic endovascular aneurysm repair group). Three access vessel complications (3%) were recorded with percutaneous brachial approach. At a median follow-up time of 11 months (range, 2-19 months), no new-onset type IC endoleak was observed, and the CSB patency rate was 97%.ConclusionsSAPE after CSB is feasible and safe, and has low incidence of type IC endoleaks. Further device developments are needed to better adapt to the subclavian anatomy.     

Proximal embolization of splenic artery in acute trauma: Comparison between Penumbra occlusion device versus coils or Amplatzer vascular plug

Purpose

To compare intervention duration and fluoroscopy time for proximal embolization of splenic arteries in acute trauma using the Penumbra occlusion device (POD^®), coils or Amplatzer? vascular plug (AVP).

Superficialization of the wrist native arteriovenous fistula for effective hemodialysis vascular access construction

BACKGROUND: It is commonly known that the best type of vascular access for chronic hemodialysis, defined as the one with the lowest number of complications and longest use, is the primary (Brescia-Cimino) radiocephalic fistula. One reason for the impossibility of its creation is that the vein vessel on the forearm is located too deeply, which is primarily caused by the patients' obesity. METHODS: In 24 obese patients the superficialization procedure of the venous part of fistula under the skin was performed. RESULTS: In 23 patients of this group, an easy and uncomplicated fistula puncturing was achieved. One patient had the complication of fistula clotting. CONCLUSION: Subcutaneous transposition of the arterialized median antebrachial vein is a simple and effective method of an adequate distal native fistula creation in patients with deeply located forearm veins.     

A comparison between transposed brachiobasilic arteriovenous fistulas and prosthetic brachioaxillary access grafts for vascular access for hemodialysis

OBJECTIVE: Patients requiring access for hemodialysis in whom radiocephalic or brachiocephalic arteriovenous fistulas cannot be formed or have failed present a significant clinical challenge. We compare outcomes in patients undergoing transposed brachiobasilic arteriovenous fistulas (BBAVF) with expanded polytetrafluoroethylene brachioaxillary access grafts in a single European center. METHODS: We identified all patients undergoing a first upper limb tertiary-access procedure-that is, either BBAVF or brachioaxillary access graft for hemodialysis-between January 1, 2000, and December 31, 2005. The median follow-up was 18.1 months (interquartile range, 8.7-34.9 months). Successful use for dialysis, primary patency, secondary patency, and patient survival was assessed. RESULTS: A total of 185 patients were identified; 71 had a BBAVF, and 114 had an access graft. The median age was 64.3 years (interquartile range, 50.7-74.4 years). The groups were well matched for age, sex, ethnicity, diabetes, and number of prior access procedures. Significantly fewer BBAVFs were successfully used for dialysis: 69.0% BBAVFs compared with 89.4% access grafts (P = .001; chi(2)). One- and two-year primary patency rates were 45.3% and 40.0%, respectively, for BBAVF and were 56.4% and 43.2% for access grafts (P = .579; log rank). Furthermore, there was no significant difference in secondary patency between the two procedures (P = .868; log rank). We found that surgeons in training had no influence on the primary patency of either BBAVF or access grafts. However, infective complications necessitating an operation were significantly higher in the access graft group (6.2% vs 0%; P = .031; Fisher exact test). CONCLUSIONS: Although more difficult to establish, BBAVFs provide patency at least equivalent to that of brachioaxillary access grafts. However, infective complications are fewer in the BBAVF group. As such, we believe that BBAVF should be the first choice of the vascular access surgeon when fistulas using the cephalic vein are not possible or have failed.     

PTFE graft arteriovenous fistulae for hemodialysis access

The use of expanded PTFE graft arteriovenous fistulae for hemodialysis access is becoming increasingly popular. Its low infection rate, low thrombogenicity, low body reactivity, and longevity make it an ideal vascular substitute. From May 1976 to June 2, 1978 we have placed 102 grafts in 89 patients, many of whom represent management problems of other access means. Major complications are pseudointimal proliferation at the venous anastomosis, pseudoaneurysm formation, and thrombosis, usually associated with low blood volume. These problems are, however, readily rectifiable. Other types of grafts, according to the literature, have not been successful for hemodialysis access.     

Dacron velour arteriovenous fistula for hemodialysis access

Dacron velour arteriovenous fistulas were created in the necks of 12 dogs. Sham dialysis was performed three times per week for one month in six animals, and for six months in an additional six animals. One prosthesis became infected, and perigraft bleeding occurred twice. There were no false aneurysms, and all prostheses remained patent. Dacron velour appears to be a satisfactory prosthetic material for use as an arteriovenous fistula for chronic hemodialysis access. The enhanced fibrous tissue adherence of Dacron velour may account for the few complications encountered.     

Ultrafiltration method for measuring vascular access flow rates during hemodialysis.

BACKGROUND: The vascular access blood flow rate (QA) has been shown to be an important predictor of vascular access failure; therefore, the routine measurement of QA may prove to be a useful clinical method of vascular access assessment. METHODS: We have developed a new ultrafiltration (UF) method for determining QA during HD from changes in arterial hematocrit (H) after abrupt changes in the UF rate with the dialysis blood lines in the normal (DeltaHn) and reverse (DeltaHr) configurations. This method accounts for cardiopulmonary recirculation and requires neither intravenous saline injections nor accurate knowledge of the dialyzer blood flow rate. Clinical studies were conducted in 65 chronic HD patients from three different dialysis programs to compare QA determined by the UF method with that determined by saline dilution using an ultrasound flow sensor. RESULTS: Arterial H increased (P<0.0001) after abrupt increases in the UF rate when the lines were in the normal and reverse configurations. An increase in the UF rate from the minimum setting to 1.8 liter/hr resulted in a DeltaHn of 0.3+/-0.2 (mean +/- SD) H units and a DeltaHr of 1.6+/-1.0 H units. Q(A) values determined by the UF method (1050+/-460 ml/min) were 16+/-25% higher (P<0.001) than those determined by saline dilution (950+/-440 ml/min); the calculated QA values by the UF and saline dilution methods correlated highly with each other (R = 0.92, P<0.0001). The average coefficient of variation for duplicate measurements of QA determined by the UF method in a subset of these patients (N = 21) was approximately 10% when assessed in either the same dialysis session or consecutive sessions. CONCLUSIONS: The results from this study show that changes in arterial H after abrupt changes in the UF rate can be used to assess Q(A).     

Flow reduction in high-flow arteriovenous access using intraoperative flow monitoring

PURPOSE: This study used intraoperative monitoring of the access flow to evaluate the results of flow reduction in the management of high-flow arteriovenous access-related symptoms of distal ischemia and cardiac insufficiency. METHODS: A retrospective study was conducted of 95 patients (78 with ischemia, 17 with cardiac failure) who underwent flow reduction between 1999 and 2005. A preoperatively measured access flow-volume rate > 800 mL/min for autogenous accesses (n = 77) and > 1200 mL/min for prosthetic accesses (n = 18) was the selection criterion for the use of a flow reduction procedure. Flow reduction was achieved using a spindle-like narrowing suture near the anastomosis and final placement of a polytetrafluoroethylene strip while a flow meter was used for intraoperatively measuring the access flow. The desired postoperative flow was 400 mL/min for autogenous and 600 mL/min for prosthetic accesses. RESULTS: The mean preoperative access flow was 1469 +/- 633 mL/min in patients with ischemia and 2084 +/- 463 mL/min in patients with cardiac failure, without significant differences between access types. The flow was reduced to 499 +/- 175 mL/min for autogenous accesses and to 676 +/- 47 mL/min for prosthetic accesses. The mean follow-up was 25 months (range, 1 to 73 months). Complete long-term relief of symptoms was observed in 86% of patients with ischemia and in 96% of patients with cardiac failure. Reconstruction significantly increased the digital-brachial index (0.41 +/- 0.12 vs 0.74 +/- 0.11; P < .05) and mean distal arterial pressure (47 +/- 17 mm Hg vs 79 +/- 21 mm Hg; P < .05) in patients with ischemia. Primary patency rates were significantly better for reconstructed autogenous accesses compared with rates of prosthetic accesses (91% +/- 4% vs 58% +/- 12% at 12 months; 81% +/- 6% vs 41% +/- 14% at 36 months; P < .001). The low patency of reconstructed prosthetic accesses is due to the high thrombosis risk of accesses that have a flow < 700 mL/min. CONCLUSIONS: Flow reduction using intraoperative access flow monitoring is an effective and durable technique allowing for the correction of distal ischemia and cardiac insufficiency in patients with a high-flow autogenous access. The desired postoperative access flow of 400 mL/min is not associated with an increased risk of thrombosis. Flow reduction of prosthetic access is as effective; however, a higher access flow than the desired 600 mL/min seems to be necessary to achieve an acceptable patency in prosthetic accesses.     

Comparison of different techniques of hemodialysis vascular access flow evaluation

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.     

Measurement of hemodialysis vascular access flow using extracorporeal temperature gradients

A reduction in vascular access flow poses a risk for thrombosis. We present a new technique to measure vascular access flow during dialysis based on extracorporeal temperature gradients, and their changes, on reversing the extracorporeal bloodlines without having to inject an indicator. Fistula temperatures were measured by the blood temperature monitor with normal line position and after manual switching of the bloodlines using the same extracorporeal blood flow. The access flow by our temperature gradient method (TGM) was compared to access flow derived by saline dilution with measurements in the same patients repeated in subsequent weeks. In 70 pairs of TGM and saline dilution measurements in 35 patients, the repeatability of the TGM measurements was not significantly different from that of saline dilution. There was a highly significant correlation between the two techniques with an acceptable confidence level for limits of agreement for the difference between them. It took about 9 min to complete the TGM method and about 5 min for saline dilution. Our studies show that the novel TGM method showed excellent agreement and reproducibility with the saline dilution method without the need for indicator dilution.