Endovascular obliteration of in situ saphenous vein arteriovenous fistulas during tibial bypass

Current methods of ligating venous branches during in situ vein tibial bypass are associated with significant wound complications, especially in diabetics. Making only proximal and distal wound incisions could avoid these wound problems. We report the use of endovascular techniques with coils and balloons guided by intraoperative arteriography and angioscopy to obliterate arteriovenous (AV) fistulas in three elderly diabetic patients undergoing tibial bypass. In all cases the proximal and distal vessels were first isolated and deemed suitable for bypass. The greater saphenous vein was prepared for the proximal and distal anastomosis, and angioscopically guided valvulotomy was performed. An introducer sheath was placed through a large proximal saphenous side branch for vascular access. With the use of fluoroscopy, AV fistulas were serially identified and cannulated with a guidewire. A guide catheter, passed over the wire into the side branch, served as the conduit through which coils and balloons were placed. Proximal and distal anastomoses were completed and arteriography performed. We were successful in obliterating AV fistulas in all three patients, but completion arteriography revealed additional AV fistulas requiring surgical ligation in two patients. Furthermore, operative time was increased by 1 1/2 to 5 hours. Two of three patients had wound infections, one at the proximal and one at the distal incision. All patients were discharged with a functioning bypass and no AV fistulas were seen on duplex scans. Endovascular obliteration of AV fistulas is feasible but is currently limited by prolonged operative time and incomplete obliteration.Presented in part at the Annual Winter Meeting of the Peripheral Vascular Surgical Society, Breckenridge, Colo., January 25–27, 1992, and at the Eleventh Annual Meeting of the Southern California Vascular Surgical Society, Dana Point, Calif., September 18–20, 1992.     

前臂远端贵要静脉转位建立自体血管内瘘手术

目的 探讨前臂远端贵要静脉转位建立自体血管内瘘的方法.方法 自2007年12月至2009年12月我们对26例维持性血液透析患者进行前臂远端贵要静脉转位建立自体血管内瘘手术治疗.26例中有17例为原桡动脉-头静脉内瘘因并发症失去功能,9例初次行血管内瘘手术.手术方式采用贵要静脉转位与肱动脉端侧吻合;贵要静脉转位与桡-动脉端端吻合;贵要动脉与尺动脉端侧或端端吻合,吻合口直径为5.0～8.0 mm.结果 26例患者中有1例因术后血肿压迫闭塞,2例因术后内瘘成熟不良,其余手术患者一次取得成功,术后血流量达200～350 ml/min.对患者的心功能未造成不良影响,也未出现严重并发症.结论 只要适应证选择合适,前臂远端贵要静脉转位建立自体血管内瘘手术,是尽量利用自身血管条件,建立内瘘的一种行之有效的方法.     

Serial duplex scans elucidate the evolving hemodynamics of distal arteriovenous fistulas

Arteriovenous fistulas at the distal anastomosis have been suggested to improve the patency of prosthetic femorocrural bypasses. We have followed nine patients with bypasses to the crural vessels and distal arteriovenous fistulas using physical examination, pulse volume recordings, and segmental pressure indices. Duplex scans of the distal anastomosis were employed to determine the contribution of arterial and venous outflow to total graft flow. Early graft patency was achieved in all patients. One patient went on to amputation at one week postoperatively for progressive ischemia despite a patent graft. The other eight patients achieved successful revascularization. Healing of ulcers, relief of rest pain, the presence of palpable pulses, good pulse wave amplitude, and normal pressure indices are consistent findings as long as the bypass is patent. One patient died on the fourth postoperative day from a myocardial infarction. The remaining patients have been followed from one to 23 months with follow-up examination every three to four months. Sequential duplex scans show that flow continues into distal arteries while venous outflow diminishes. This corresponds to a reduction in the diameter of the outflow veins while the caliber of arterial runoff is maintained. Patency has been achieved up to 23 months with a mean of 12 months. Venous outflow occlusion precedes graft thrombosis by two to 15 months. Graft occlusion has uniformly necessitated amputation. It may be possible to improve long-term graft patency and limb salvage by surgical revision of the distal anastomosis to reestablish venous outflow.Presented at the Fifteenth Annual Meeting of the Peripheral Vascular Surgery Society, June 2, 1990, Los Angeles, California.     

Doppler detection of arteriovenous fistulas after in situ saphenous vein bypass

Use of the continuous Doppler flow probe in the manner described herein is a simple, reliable, and versatile physiologic method of detecting and accurately localizing significant arteriovenous fistulas after arterial reconstruction using the in situ saphenous vein.     

Remote distal arteriovenous fistula to improve infrapopliteal bypass patency

The results of the use of prosthetic materials for femorocrural bypass surgery have been less than optimal. The creation of a distal anastomotic arteriovenous fistula to augment blood flow and velocity through the graft is well known. However, it may create turbulence at the anastomosis and steal blood flow away from the distal artery. A canine model was developed to evaluate the effect of fistula size on graft/arterial hemodynamics. In 16 patients we have constructed a distal arteriovenous fistula, which is remote from the distal anastomosis, and we studied the effect of such fistulas on bypass patency and distal arterial hemodynamics. Patients selected for this procedure had multiple previously failed reconstructions and limb-threatening ischemia and did not have usable autogenous vein. Femorotibial bypass graft reconstructions were performed with polytetrafluoroethylene followed by the creation of a side-to-side arteriovenous fistula 5 to 15 cm below the distal anastomosis in the same artery and accompanying veins. We have achieved a 1-year patency of 67% with a 75% limb salvage rate. We also serially measured blood flow and velocity within the bypass, the arteriovenous fistula, and the distal outflow vessel using duplex scanning after surgery. Mean estimated blood flow through the bypass during the immediate postoperative period was 264 ml/min, the arteriovenous fistula was 157 ml/min, and the distal artery was 19 ml/min. Unlike an arteriovenous fistula created at the distal anastomosis, a remote distal arteriovenous fistula not only increases graft blood flow but also augments native arterial blood flow between the distal anastomosis and fistula and thus may improve distal limb perfusion.     

Preventive haemostasis with an inflatable tourniquet for microsurgical distal arteriovenous fistulas for haemodialysis

The creation of a distal arteriovenous fistula for haemodialysais is made easier by using preventive haemostasis with an inflatable tourniquet. Preventive haemostasis reduces the duration of the surgery and reduces the arterial spasm provoked by the dissection. When microsurgical techniques and preventive haemostasis are used, it is possible to create fistulas even in very small children. © 1993 Wiley-Liss Inc.     

远端动脉旁路移植附加动静脉吻合治疗严重下肢缺血21例

目的 探讨严重下肢动脉病变伴有远端流出道动脉不通畅的动脉旁路移植手术方法，以避免截肢或降低截肢平面。方法 分析2000年7月至2004年12月采用动脉旁路移植手术并辅助远端吻合口处的动静脉吻合治疗的21例（21条患肢）下肢远端流出道动脉不良患者的临床资料。结果 21例患者中，除1例因为远端动脉的“虚灌”而再次手术外，其余患者均一次手术成功，成功率95．2％。出院时血管通畅率100％，足部创面的愈合率33．3％。结论 伴有远端流出道动脉不良的严重缺血，在下肢动脉血流重建中采用远端吻合口的动静脉吻合可以明显提高血管的通畅率，可以达到避免截肢或降低截肢平面的目的。     

Randomized clinical trial of distal anastomotic interposition vein cuff in infrainguinal polytetrafluoroethylene bypass grafting

BACKGROUND: The aim was to examine the effect of a Miller vein cuff at the distal anastomosis on the medium- to long-term patency and limb salvage rates of femoral to above-knee and femoral to below-knee popliteal artery polytetrafluoroethylene (PTFE) bypasses. METHODS: This study involved extended follow-up of the original cohort of patients included in a previously reported multicentre randomized clinical study. Outcome measures were bypass graft patency and limb salvage. RESULTS: Two hundred and sixty-one bypass operations were originally randomized. For this study, full data were available on 235 (120 with a Miller cuff, 115 without). The cumulative 5-year patency rate for above-knee bypasses with a Miller cuff was 40 per cent, compared with 42 per cent for non-cuffed bypasses (P = 0.702). The cumulative 3-year patency rate for below-knee bypasses with a Miller cuff was 45 per cent, compared with 19 per cent for non-cuffed bypasses (P = 0.018). A Miller cuff had no significant effect on limb salvage for above-knee or below-knee bypasses. CONCLUSION: Three-year patency rates of femoral to below-knee popliteal PTFE bypasses were improved by a Miller cuff. Miller cuffs had no effect on patency rates for femoral to above-knee popliteal bypasses at 5 years and did not improve limb salvage in either group.     

Treatment of dural arteriovenous fistulas

Opinion statement  The treatment of a dural arteriovenous fistula (DAVF) depends on the severity of the symptoms, its angiographic characteristics, and the risk it presents for intracranial hemorrhage. In many instances, therapy may involve a combination of more than one modality. Low-risk DAVFs, either incidental or with minimal symptoms, can be treated conservatively (observation, blood pressure control, manual carotid compressions). If the patient does not tolerate the symptoms, definite or palliative treatment can be offered. All high-risk DAVFs (Borden Grade II or III) should receive treatment because they carry a high probability of intracranial hemorrhage or neurologic deterioration. For small, well-circumscribed fistulas, radiosurgery can have excellent results, but thrombosis can occur many months after the treatment. For large DAVFs with severe symptoms (vision deterioration, ophthalmoplegia with diplopia, seizures, or neurologic deficit) or with high risk for hemorrhage (cortical venous drainage or venous varices), the first treatment option should be endovascular embolization. With the combination of modern materials and techniques, this procedure can yield a high rate of cure with minimal complications. In patients not amenable to embolization or after incomplete embolization, surgery should be considered if the DAVF is located in an easily accessible area, because of its immediate and definite results. Surgery can be facilitated by preoperative embolization of the fistula to reduce the arterial supply and minimize intraoperative bleeding. Radiosurgery can also be used adjunctively after embolization or surgery has significantly reduced the size of large DAVFs.     

Treatment of solitary arteriovenous fistulas

Four patients with a solitary arteriovenous fistula were treated by transvascular balloon embolization technique, which resulted in complete fistula closure in three patients and partial closure in one. There were two vertebral arteriovenous fistulas, one peroneal arteriovenous fistula, and one radial arteriovenous fistula. The first two fistulas were spontaneous, the other two were traumatic. The only partial occlusion of the peroneal fistula was, in our opinion, due to a technical failure, the balloon was inflated slightly proximal to the fistular orificium instead of in the orificium itself. There were no complications, and there was no morbidity. In our opinion transvascular balloon embolization technique is the treatment of choice for solitary arteriovenous fistulas.     

The effect of distal anastomotic site on PTFE graft patency in lower extremity bypass

The site of distal anastomosis of polytetrafluorethylene (PTFE) lower extremity bypass grafts may significantly affect results. We examined patency in 144 cases; 45 femoro-popliteal above knee (AK), 55 femoro-popliteal below the knee (BK) and 44 femoro-distal (D) PTFE bypasses, the groups being comparable with regard to other risk factors studied. Cumulative graft patency at 3 years was 71.3% for AK, 36.7% for BK, 16.4% for D and overall 35%. The site of distal anastomosis is an important determinant, of PTFE lower extremity bypass patency. We have abandoned the use of PTFE for BK and D, but feel that AK PTFE is a suitable alternative to autogenous reversed saphenous vein.     

Local thrombolysis in the treatment of thrombosed arteries, bypass grafts, and arteriovenous fistulas

We reviewed the results, systemic effects, and complications associated with the selective infusion of low-dose streptokinase in 151 patients. Successful thrombus lysis was achieved in 78% of atherosclerotic thrombotic occlusions less than 30 days old, in 81% of post-procedural occlusions less than 14 days old, and in 87% of patients with thrombosed arteriovenous fistulas no more than 4 days old. During the first 12 hours of treatment 81% to 84% of patients had greater than 50% decrease in plasma fibrinogen levels and 100% showed the same decline after 24 hours of treatment. The thrombin time was prolonged to at least 1 1/2 times the control thrombin time in 33% to 42% of patients measured at 4 hours of therapy and in 93% to 97% of patients measured at 24 hours of treatment. Fifteen patients (9.9%) had major complications. Eleven of these had hemorrhagic complications, two had significant distal emboli, one had a thrombosed brachial artery, and one had a false aneurysm at the catheter entry site. We have found that selective low-dose streptokinase is effective in the treatment of acute and chronic thrombotic occlusions and is a useful adjuvant to vascular reconstruction or percutaneous transluminal angioplasty. Although the local infusion dose is substantially lower than the usual systemic dose, a systemic lytic effect was seen in all patients. Hemorrhagic complications occurred despite customary precautions.     

Hemodynamics of an anastomotic arteriovenous fistula

Various vascular surgical techniques have been employed to increase both graft patency and limb survival when the prognosis for limb salvage in arteriosclerotic patients is especially poor due to a diseased outflow tract. Ibrahim et al described the creation of an anastomotic arteriovenous fistula in distal tibial bypasses as the reconstructive procedure of choice in severely ischemic extremities unsalvageable by more conventional methods. This study presents the hemodynamics of an anastomotic arteriovenous fistula under such circumstances. Four adult mongrel dogs were anesthesized, and a femoral artery and vein were exposed from the groin to the knee. The femoral artery was ligated in midthigh, and the ligated segment was than bypassed using an umbilical vein graft. The distal anastomosis included an arteriovenous fistula. Flow was measured electromagnetically, and pressure was measured with intravascular catheters attached to strain gauges. The creation of an anastomotic arteriovenous fistula rapidly leads to a reversal of flow in the distal artery, distal arterial hypotension, and distal venous hypertension. Its clinical use in contraindicated as a result of our experimental observations.     

Imaging of cerebral arteriovenous malformations and dural arteriovenous fistulas

Imaging plays a major role in the identification, grading, and treatment of cerebral arteriovenous malformations and cerebral dural arteriovenous fistulas. Digital subtraction angiography is the gold standard in the diagnosis and characterization of these vascular malformations, but advances in both magnetic resonance imaging and computed tomography, including advanced imaging techniques, have provided new tools for further characterizing these lesions as well as the surrounding brain structures that may be affected. This article discusses the role of conventional as well as advanced imaging modalities that are providing novel ways to characterize these vascular malformations.