INTRODUCTIONAn arteriovenous fistula (AVF) is the preferred method for haemodialysis in patients with end-stage renal failure. Previous studies have shown value in attempting percutaneous transluminal angioplasty (PTA) to salvage AVFs that fail to mature, but they are relatively small in size and mainly reported in Western populations. We reviewed our data of PTA in non-maturing AVFs to establish whether this technique is translatable to our local multiethnic population.

MATERIALS AND METHODSWe retrospectively reviewed the medical records and procedural images of 105 patients who had PTA for non-maturing AVFs performed at our department from January 2008 to January 2011. Technical success was defined as ≤30% residual stenosis after angioplasty. Clinical success was defined as at least 1 successful haemodialysis session within 4 weeks after PTA.

RESULTSAll 105 patients underwent angioplasty for at least 1 haemodynamically significant stenosis. Six (5.7%) had additional embolisation of accessory veins. Technical success was achieved in 95.2% of cases. The clinical success rate was 76.2%. Primary patency rates at 3, 6 and 12 months were 83%, 45% and 28%, respectively. Secondary patency rates at 3, 6 and 12 months were 90%, 79% and 70%, respectively. The minor complication rate was 18.1%. No major complications were encountered. An average of 1.7 interventions per access-year was required to maintain AVF patency. Patients with a preoperative vein size >2.0 mm and age <55 years were more likely to achieve clinical success, although not statistically significant.

CONCLUSIONPTA is a viable option to help salvage non-maturing AVFs in a multiethnic Asian population.

Angioplasty ; methods ; Arteriovenous Shunt, Surgical ; Constriction, Pathologic ; therapy ; Embolization, Therapeutic ; Female ; Humans ; Kidney Failure, Chronic ; therapy ; Male ; Middle Aged ; Renal Dialysis ; Reoperation ; Retrospective Studies ; Singapore ; Veins

Angiography ; Arteriovenous Shunt, Surgical ; Brachiocephalic Veins ; diagnostic imaging ; Collateral Circulation ; Constriction, Pathologic ; diagnostic imaging ; Female ; Humans ; Jugular Veins ; diagnostic imaging ; Kidney Failure, Chronic ; therapy ; Male ; Middle Aged ; Phlebography ; Renal Dialysis ; methods ; Subclavian Vein ; diagnostic imaging ; Vascular Access Devices

OBJECTIVE: To evaluate the technical aspects and outcomes of endovascular recanalization of a thrombosed native arteriovenous fistula (AVF) complicated with an aneurysm. MATERIALS AND METHODS: Sixteen patients who had a thrombosed AVF complicated with an aneurysm (two radiocephalic and 14 brachiocephalic) were included in this study. Recanalization procedures were performed by mechanical thrombectomy using the Arrow-Trerotola percutaneous thrombectomy device and adjunctive treatments. We evaluated dose of thrombolytic agent, underlying stenosis, procedure time, technical and clinical success, and complications. The primary and secondary patency rates were calculated using the Kaplan-Meier analysis. RESULTS: The thrombolytic agents used were 100000 U urokinase mixed with 500 IU heparin (n = 10) or a double dose of the mixture (n = 6). The thrombi in aneurysms were removed in all but two patients with non-flow limiting residual thrombi. One recanalization failure occurred due to a device failure. Aspiration thrombectomy was performed in 87.5% of cases (n = 14). Underlying stenoses were found in the outflow draining vein (n = 16), arteriovenous anastomosis or juxtaanastomosis area (n = 5), and the central vein (n = 3). Balloon angioplasty was performed for all stenoses in 15 patients. Two patients with a symptomatic central vein stenosis underwent insertion of a stent after balloon angioplasty. Mean procedure time was 116.3 minutes. Minor extravasation (n = 1) was resolved by manual compression. Both technical and clinical success rates were 93.8% (n = 15). The primary patency rates at 3, 6, and 12 months were 70.5%, 54.8%, and 31.3%, respectively. The secondary patency rates at 3, 6, and 12 months were 70.5%, 70.5%, and 47.0%, respectively. CONCLUSION: Thrombosed AVF complicated with an aneurysm can be successfully recanalized, and secondary patency can be prolonged with endovascular treatment.
Aged ; Aged, 80 and over ; Aneurysm/complications/*surgery ; Angioplasty, Balloon ; Arteriovenous Fistula/*surgery ; Arteriovenous Shunt, Surgical/adverse effects ; Constriction, Pathologic/complications ; Endovascular Procedures ; Equipment Failure ; Female ; Fibrinolytic Agents/therapeutic use ; Heparin/therapeutic use ; Humans ; Kaplan-Meier Estimate ; Male ; Middle Aged ; Retrospective Studies ; Stents/adverse effects ; Thrombectomy/instrumentation/*methods ; Thrombosis/etiology/*surgery ; Urokinase-Type Plasminogen Activator/therapeutic use ; Vascular Patency ; Veins

INTRODUCTIONThe key to treatment of a thrombosed dialysis graft is restoration and maintenance of function as long as possible. The objective of this study was to compare the outcomes of pharmacomechanical thrombolysis and surgical thrombectomy in the treatment of thrombosed haemodialysis grafts.

MATERIALS AND METHODSDuring a 3-year period, 108 patients with 114 thrombosed dialysis grafts were referred to our institute for treatment. Fifty thrombosed dialysis grafts underwent pulse-spray catheter thrombolysis using recombinant tissue plasminogen activator (rt-PA) with angioplasty, and 64 thrombosed dialysis grafts underwent surgical thrombectomy. The procedural success rates, complications and average patency times and patency rates were compared between the 2 procedures. P values less than 0.05 were considered to be statistically significant.

RESULTSThere were no statistically significant differences between the pharmacomechanical thrombolysis group and the thrombectomy group in the procedural success rates (94% and 93.8%, P = 0.15) or average patency times (6.24 months and 6.30 months, P = 0.17). The primary and secondary patency rates at 12 months were 28.0% ± 8.4% and 54.3% ± 7.8% for the thrombolysis with angioplasty group, and 30.0% ± 6.3% and 57.0% ± 4.8% for the thrombectomy group, respectively (P = 0.65 and P = 0.49, respectively). There were no procedural-related major complications.

CONCLUSIONOur study found no differences in outcomes between patients treated with pharmacomechanical thrombolysis and surgical thrombectomy for thrombosed haemodialysis grafts. Pharmacomechanical thrombolysis can be considered as an alternative treatment for dialysis graft thrombosis.

Aged ; Arteriovenous Shunt, Surgical ; Female ; Humans ; Male ; Middle Aged ; Retrospective Studies ; Thrombectomy ; methods ; Thrombosis ; drug therapy

BACKGROUNDHilar cholangiocarcinoma is a malignant tumor that is difficult to cure. The aim of this study was to observe the effects of flow-controlled partial portal vein arterializations (PPVA) on liver regeneration after hepatectomy in minipigs with chronic obstructive jaundice.

METHODSEight minipigs were made into chronic obstructive jaundice models. United semi-hepatectomy, which imitates extended radical surgery for treatment of hilar cholangiocarcinoma, was then performed. The eight minipigs were randomly divided into groups A and B (n = 4 minipigs each). PPVA was performed in Group A but not in Group B. The effects of flow-controlled PPVA on live regeneration after hepatectomy were observed for 30 days after hepatectomy.

RESULTSThe portal vein PO(2) at the immediate time point and on postoperative day 30 was higher in Group A ((47.33 ± 2.43) and (48.50 ± 4.44) mmHg) than in Group B ((35.38 ± 4.06) and (35.55 ± 2.55) mmHg respectively, all P < 0.01). The mitotic index of liver cells on postoperative days 14 and 21 was higher in Group A (12.55% ± 2.85% and 15.25% ± 1.99% respectively) than in Group B (6.85% ± 2.10% and 11.88% ± 1.15% respectively, all P < 0.05). The regeneration rate of residual liver on postoperative days 14 and 21 was higher in Group A (24.56% ± 6.15% and 70.63% ± 9.83% respectively) than in Group B (11.96% ± 5.43% and 44.92% ± 7.42% respectively, P < 0.05 and P < 0.01 respectively).

CONCLUSIONFlow-controlled PPVA can promote liver regeneration after hepatectomy and prevent liver failure in minipigs with chronic obstructive jaundice.

Acepromazine ; therapeutic use ; Animals ; Arteriovenous Shunt, Surgical ; methods ; Atropine ; therapeutic use ; Female ; Hepatectomy ; methods ; Jaundice, Obstructive ; surgery ; Ketamine ; therapeutic use ; Liver Regeneration ; physiology ; Portal Vein ; surgery ; Swine ; Swine, Miniature

To evaluate the feasibility and accuracy of contrast-enhanced ultrasonography (CEUS) for the measurement of hemodialysis access recirculation (AR) and access flow rate (Qa), a two pump system was used to simulate access and dialyzer flow. AR and Qa under different conditions, such as reversal connection of dialysis lines and the needle orientation, were compared with each other. The value of access flow and recirculation flow were calculated based on the formulas introduced in this paper, and the correlation and consistency between true flow rate and calculated values were analyzed. The measured R correlated well with true value of flow rate (r = 0.57, P = 0.038, Qa > Qb; r = 0.95, P = 0.001, Qa < Qb). The Bland-altman test showed good agreement between the calculated value based on CEUS and true values. The CEUS can be used as a new advanced technology for AR and Qa measurement.
Arteriovenous Shunt, Surgical ; Blood Flow Velocity ; Computer Simulation ; Contrast Media ; Humans ; Kidney Failure, Chronic ; blood ; therapy ; Models, Biological ; Monitoring, Physiologic ; instrumentation ; Regional Blood Flow ; Renal Dialysis ; methods ; Ultrasonography

OBJECTIVE: We applied a modified pharmacomechanical thrombolysis (PMT) technique to endovascular treatment of thrombosed arteriovenous (AV) grafts without the use of any mechanical thrombectomy devices. The aim of this study was to evaluate the efficacy of the PMT technique in the treatment of thrombosed AV grafts by analyzing the long-term patency. MATERIALS AND METHODS: Eighty-two patients with thrombosed AV grafts were treated with the PMT technique. AV graft surveillance to detect failing/failed access was followed by endovascular treatment. RESULTS: The technical and clinical success rates were 95% and 95%, respectively. The total number of thrombolysis sessions was 279. A post-intervention primary patency rate was 45% and 22% at 12 and 24 months, respectively. The secondary patency rate was 96% and 91% at 12 and 24 months, respectively. No major complications were noticed. CONCLUSION: The modified PMT technique is effective in endovascular treatment of thrombosed AV grafts.
Adult ; Aged ; Aged, 80 and over ; Angiography ; Angioplasty, Balloon ; *Arteriovenous Shunt, Surgical ; Female ; Graft Occlusion, Vascular/*therapy ; Hemostatic Techniques ; Humans ; Male ; Middle Aged ; Polytetrafluoroethylene ; Proportional Hazards Models ; Radiography, Interventional ; Renal Dialysis ; Retrospective Studies ; Stents ; Thrombolytic Therapy/*methods ; Treatment Outcome ; Vascular Patency

INTRODUCTIONOne complication of autogenous arteriovenous fistula (AVF) for haemodialysis is the formation of a venous aneurysm.

CLINICAL PICTUREThe clinical picture is typically an expanding aneurysm leading to skin atrophy and ulceration with the risk of rupture and infection. Aneurysm also reduces the potential cannulation area.

TREATMENTThe cases described here used a surgical 'remodelling' technique involving complete skeletonisation of the venous aneurysm, reduction of lumen diameter and retention of vein wall using a Hegar dilatator to remodel a new fistula.

OUTCOMESix patients were treated using this method and the arterior venous shunt (AVS) was used for haemodialysis the following day. No recurrent aneurysm developed.

CONCLUSIONRemodelling of aneurysmal AVF is an effective and low-risk option for managing this kind of complication, allowing direct access for haemodialysis.

Aneurysm ; etiology ; surgery ; Arteriovenous Shunt, Surgical ; adverse effects ; Catheters, Indwelling ; Humans ; Postoperative Complications ; Renal Dialysis ; adverse effects ; methods ; Vascular Surgical Procedures

BACKGROUNDThe resection and reconstruction of the hepatic artery is often required in radical surgery for hilar cholangiocarcinoma. In this study, we report our experience in performing arterioportal shunting as an alternative for the arterial reconstruction.

METHODSFour patients with hilar cholangiocarcinoma underwent extended left hepatectomy and caudate lobectomy combined with en bloc resection of the hepatic artery and arterioportal shunting with restriction of the arterial caliber. The efficacy of arterioportal shunting was assessed by computed tomography angiography (CTA).

RESULTSAll the four patients recovered uneventfully without any complications. CTA showed a patent shunt and normal liver regeneration. No signs of portal hypertension were found at one year of follow-up.

CONCLUSIONSArterioportal shunting with restriction of the arterial caliber appears to be a feasible and safe alternative for the microvascular reconstruction after hepatic artery resection in radical surgery for hilar cholangiocarcinoma.

Arteriovenous Shunt, Surgical ; methods ; Bile Duct Neoplasms ; surgery ; Cholangiocarcinoma ; surgery ; Female ; Humans ; Male ; Middle Aged ; Portal Vein ; surgery ; Treatment Outcome

OBJECTIVE: The purpose of this study was to evaluate the fistulographic features of malfunctioning axillary loop-configured arteriovenous grafts and the efficacy of percutaneous interventions in failed axillary loop-configured arteriovenous grafts. MATERIALS AND METHODS: Ten patients with axillary loop-configured arteriovenous grafts were referred for evaluation of graft patency or upper arm swelling. Fistulography and percutaneous intervention, including thrombolysis, percutaneous transluminal angioplasty and stent placement, were performed. Statistical analysis of the procedure success rate and the primary and secondary patency rates was done. RESULTS: Four patients had graft related and subclavian venous stenosis, two patients had graft related stenosis and another four patients had subclavian venous stenosis only. Sixteen sessions of interventional procedures were performed in eight patients (average: 2 sessions / patient) until the end of follow-up. An interventional procedure was not done in two patients with central venous stenosis. The overall procedure success rate was 69% (11 of 16 sessions). The post-intervention primary and secondary patency rates were 50% and 63% at three months, 38% and 63% at six months and 25% and 63% at one year, respectively. CONCLUSION: Dysfunctional axillary loop-configured arteriovenous grafts almost always had subclavian venous and graft-related stenosis. Interventional treatments are helpful to overcome this and these treatments are expected to play a major role in restoring and maintaining the axillary loop-configured arteriovenous loop grafts.
Adult ; Aged ; Angioplasty, Balloon/*methods ; Arteriovenous Shunt, Surgical/*methods ; Blood Vessel Prosthesis Implantation/*methods ; Chronic Disease ; Constriction, Pathologic/therapy/ultrasonography ; Female ; Follow-Up Studies ; Graft Occlusion, Vascular/*therapy/ultrasonography ; Humans ; Kidney Failure, Chronic/*complications/therapy ; Male ; Middle Aged ; *Renal Dialysis ; Subclavian Vein/ultrasonography ; Survival Analysis ; Treatment Outcome ; Vascular Patency