Salvage of thrombosed dialysis access grafts with venous anastomosis stents

BACKGROUND: Thrombosis of arteriovenous (AV) grafts caused by stenosis at the venous anastomosis is a well-described problem. Surgical thrombectomy and conventional angioplasty with mechanical thrombectomy have provided good success rates in achieving immediate graft patency but with generally dismal graft survival rates in the range of 11% to 36% at 6 months' follow-up. The role of intravascular stents in patients who have failed angioplasty or surgical revision at the venous anastomosis has not been fully elucidated, particularly in older grafts that have previously undergone multiple procedures. METHODS: In this series, 34 patients had self-expanding nitinol stents placed at the venous anastomosis following graft thrombectomy and angioplasty procedures. Patients were selected for stent placement if conventional angioplasty alone was unsuccessful due to immediate elastic recoil or residual stenosis. All patients were followed after stent placement and evaluated for duration of graft patency and need for repeated endovascular procedures. RESULTS: The average graft age at the time of stent placement was 17.9 months. Eight-eight percent of grafts were functioning at 6 months' follow-up, and 63% of the entire group had survived without the need for additional procedures. Among those with need for repeat interventions, 81% had new lesions outside of the stent, and 57% had new lesions within the stent. In 38% of cases, new stenoses were located both outside and within the stent. Among grafts no longer being used, only 19% of the time was it due to disease recurring within the stent. CONCLUSION: Polytetrafluoroethylene (PTFE) graft longevity is improved when venous anastomosis stenoses are treated with stents in selected cases of older grafts that would have normally undergone abandonment or surgical revision.     

A comparison of patch angioplasty and stenting for axillary venous stenoses of thrombosed hemodialysis grafts

The efficacy of balloon angioplasty with stent placement is compared to surgical patch angioplasty for thrombosed upper arm hemodialysis grafts with stenotic lesions at the venous anastomosis. Patients with thrombosed hemodialysis grafts terminating at the axillary vein were reviewed. Thirty-eight stents were placed after thrombectomy and venous balloon angioplasty in 26 patients. Fifteen case-matched controls underwent 23 polytetrafluoroethylene patch angioplasties for similar lesions. Kaplan-Meier survival analysis was used for statistical comparison. Primary patency for stent placement compared with patch angioplasty was not statistically different at any time through 1-year follow-up (37% vs 55% at 3 months, 25% vs 45% at 6 months, and 25% vs 15% at 12 months, respectively; p = 0.37). Secondary patency rates were slightly better for patch angioplasty compared with stent placement (78% vs 59% at 3 months, 78% vs 48% at 6 months, and 54% vs 32% at 12 months, respectively) however these differences were not statistically significant (p = 0.13). There was no difference in complication rates between groups. Sustained patency is poor for both angioplasty with stent placement and surgical patch angioplasty when revising thrombosed dialysis grafts with anastomotic axillary vein stenosis. These data suggest slightly better patency for the routine use of patch angioplasty for these lesions. However, the endovascular approach appears to be a reasonable alternative when surgical exposure is difficult.     

Salvaging prosthetic dialysis fistulas with stents: forearm versus upper arm grafts

OBJECTIVE: We compared results of angioplasty with those of concomitant stent placement to treat thrombosed forearm hemodialysis grafts with results for upper arm grafts. MATERIAL AND METHODS: Between October 1998 and July 2002, stents were deployed in 61 patients undergoing balloon angioplasty because of venous anastomotic stenosis causing graft thrombosis. Stents were used only in cases of inadequate angioplasty results. Twenty-three forearm grafts and 38 upper arm grafts were treated. All procedures were performed in an endovascular operating suite, with fistulography. Primary and secondary patency rates were analyzed and compared for graft location with the life table method. RESULTS: Grafts had undergone a mean of 1.56 previous revisions because of thrombosis (forearm: 1.52, upper arm: 1.58; P = NS). Excluding early thrombosis, a single graft infection was the only procedural complication. Cumulative primary patency rate at 3, 6, and 12 months (from stent placement) was 36.4%, 15.6%, and 0%, respectively, for forearm grafts, which was inferior to the 59.5%, 34.0%, and 17.0% primary patency rate observed for upper arm grafts (P =.0307) Secondary patency rate was 40.9%, 40.9%, and 30.7%, respectively, for forearm grafts, and 64.9%, 42.3%, and 19.7% for upper arm grafts (P = NS). CONCLUSION: Stent deployment can salvage thrombosed dialysis grafts. However, sustained patency occurs infrequently, with better results for upper arm grafts than for forearm grafts. Inasmuch as surgical revision of forearm grafts is usually straightforward, stenting should be reserved for use in high axillary grafts and other sites where surgical repair is difficult.     

Is Surgical Salvage of Arteriovenous Grafts Feasible after Unsuccessful Percutaneous Mechanical Thrombectomy?

Treatment of thrombosed dialysis ateriovenous (AV) grafts in the radiology interventional suite requires percutaneous mechanical thrombectomy, along with angioplasty of the underlying stenotic lesion. We analyzed the anatomic reasons for unsuccessful percutaneous thrombectomy of AV grafts, and assessed the feasibility of surgical salvage. The radiologic reports of all thrombosed AV grafts undergoing unsuccessful percutaneous mechanical thrombectomy during a 5-year period were analyzed for the specific problem precluding restoration of graft patency. We also compared the features of patients with unsuccessful graft thrombectomy to those with successful thrombectomy. Of 77 AV grafts undergoing unsuccessful percutaneous thrombectomy, only six (or 8%) could be revised surgically. Inability to salvage the graft surgically was because of: severe draining vein occlusion or stenosis (30 patients); severe central vein lesion (12); multiple intragraft stenoses (11); large pseudo-aneurysms (six); venous anastomotic occlusion (six); and arterial anastomotic occlusion (four). When compared with 211 patients with successful graft thrombectomy, those with unsuccessful thrombectomy were more likely to have a forearm graft (53% vs. 27%, p < 0.001), and more likely to have a lesion in the draining vein (42% vs. 10%, p < 0.001), the central vein (17% vs. 3%, p < 0.001), or within the graft itself (23% vs. 1%, p < 0.001). An unsuccessful percutaneous graft thrombectomy is more likely in forearm than in upper arm grafts, and more likely if there is a lesion in the draining vein, central vein, or within the graft itself. Surgical salvage of a thrombosed AV graft after an unsuccessful percutaneous intervention is rarely feasible. Most patients have a severe anatomic lesion that cannot be repaired, and require creation of a new vascular access.     

Results of aggressive graft surveillance and endovascular treatment on secondary patency rates of Vectra Vascular Access Grafts

OBJECTIVE: The aim of the present study was to determine the effect of an aggressive graft surveillance and endovascular treatment protocol on secondary patency rates of a polyetherurethaneurea vascular access graft, specially designed to provide early access and rapid hemostasis. METHODS: One hundred and ninety Vectra Vascular Access Grafts (C. R. Bard, Inc, Murray Hill, NJ) were placed in 176 patients (78 females and 98 males, mean age 61.7 years). There were 41 forearm grafts, 145 upper arm grafts and four thigh grafts. Graft surveillance was performed by using clinical and hemodialysis parameters to detect a failing/failed graft and followed by endovascular treatment, rheolytic thrombectomy (AngioJet, Possis Medical Inc, Minneapolis, Minn) and/or angioplasty +/- stenting of the anatomical lesion (arterial anastomosis, graft, venous outflow, draining or central veins). RESULTS: Hemodialysis started after a median of 15.5 days, as soon as from the day of the operation in some cases. Bleeding complications occurred in six patients (3.2%), venous hypertension in seven (3.7%), steal syndrome in two (1.1%), neurological complications in two (1.1%), while late infection (range 2.7-14.6 months) was seen in six patients (3.2%). Thrombectomy and angioplasty (median number of sessions 1, interquartile range 1-2) was performed in 43 grafts. Isolated angioplasty, not associated with thrombosis (median number of sessions 1, interquartile range 1-2), was performed in 50 grafts. These interventions increased primary assisted patency from 69% and 63% at 12 and 18 months, respectively to a secondary patency rate of 86%. Taking into account grafts removed for late infection, functional secondary patency rate dropped to 83% and 81%, at 12 and 18 months, respectively. Arterial anastomosis angioplasty was performed more frequently in thrombosed grafts (28.6%) than failing grafts (6.7%), P < .001 and had a significant negative predictive value on secondary patency rates at 12 and 18 months, which were 60.5% compared with 89% for grafts that had no interventions performed (P = .007) and 90.9% for grafts that had any intra-graft, venous outflow, or draining or central vein stenosis treated with angioplasty at any stage (P = .002). Multivariate analysis identified the presence of arterial anastomosis stenosis as the single predictor of secondary patency (relative risk 0.247, P = .002). CONCLUSIONS: Aggressive graft surveillance and endovascular treatment increases significantly secondary patency rates of Vectra Vascular Access Grafts. Longer follow-up will determine the effectiveness of this policy. The role of inflow stenosis on graft longevity and alternative treatment options warrant further investigation.     

The use of covered nitinol stents to salvage dialysis grafts after multiple failures

The increasing number of patients requiring hemodialysis and the limited number of access sites have resulted in an increase in multiple graft revisions to maintain access for hemodialysis. Venous outflow or anastomotic stenoses in vascular grafts tend to recur and contribute to the difficulty in maintaining a functioning graft. Thus, extending the life of a failed graft becomes an important objective of this study, which was to assess the use of covered nitinol stents to salvage expanded polytetrafluoroethylene (ePTFE) grafts with venous anastomotic or outflow stenosis that have failed after multiple revisions. This is a review of 8 failed non-autogenous ePTFE grafts with isolated venous anastomotic or proximal outflow stenoses that had undergone multiple previous revisions, had failed percutaneous transluminal angioplasty (PTA), and required placement of a covered nitinol stent. Graft locations were forearm (2), upper arm (4), and femoral (2). The mean number of interventions per patient before stent placement was 5.87 thrombectomies (range 2-28) and 3.38 balloon angioplasties (range 2-19). Five patients had 0.62 interposition grafting and 3 had patch angioplasty. All 8 patients (100%) underwent successful dialysis after thrombectomy and stenting. The primary and secondary patency rates after stent placement were 50% and 75%, and 25% and 75%, at 3 and 6 months, respectively. Percutaneous thrombectomy, balloon angioplasty, and concomitant covered nitinol stent placement extend the function of hemodialysis access grafts that have previously failed multiple times.     

Use of stents and stent grafts to salvage angioplasty failures in patients with hemodialysis grafts

To determine the efficacy of using stents and stent grafts for treatment of hemodialysis graft-related stenoses which have failed angioplasty. This retrospective study was composed of 51 patients with polytetrafluoroethylene hemodialysis grafts who underwent angioplasty of a graft-related stenosis but subsequently required insertion of a stent or stent graft. The study group included 40 patients with >30% residual stenosis and 11 patients with angioplasty-induced venous ruptures. The patient's medical records and radiology reports were reviewed. Patient demographics, indication for stent placement, and the type of stent were recorded. Stent patency was determined using Kaplan-Meier analysis. A total of 70 stents were used; most (57.7%) were deployed across the venous anastomosis. A variety of different types of stents and stent grafts were used including 26 SMART, 18 Viabahn, 13 aSpire, and 13 other stents. The technical success rate for insertion of the device was 100%. Following insertion of the device the primary patency of the vascular access was 81%, 70%, and 54% at 1, 3, and 6 months, respectively. The secondary patency of the vascular access was 89%, 82%, and 74% at 3, 6, and 12 months, respectively. The primary patency of the stent or stent graft was 96%, 93%, 87%, and 47% at 1, 3, 6, and 12 months, respectively. Stents and stent grafts are useful for salvaging failed angioplasty procedures and thereby maintaining patency of the hemodialysis graft. By inserting a stent, the resultant patency rates are similar to those following a successful angioplasty procedure. Importantly, the primary patency of the stent was substantially better than the primary patency of the entire vascular access.     

Outcomes of Percutaneous Mechanical Thrombectomy of Arteriovenous Fistulas in Hemodialysis Patients

Thrombosis of arteriovenous fistulas is usually superimposed on underlying stenosis in the arterial anastomosis, draining vein, or central vein. Restoring the patency of thrombosed fistulas requires mechanical thrombectomy, in conjunction with angioplasty of the underlying lesion. We evaluated the success rate of percutaneous thrombectomy of fistulas at our medical center. We retrospectively queried a prospective, computerized vascular access database to identify 41 patients with thrombosed fistulas treated percutaneously. Technical success was defined as the ability to use the fistula for at least one dialysis session. Primary patency was defined as time to the next intervention, and secondary failure as the time to permanent fistula failure. Of the 41 thrombosed fistulas, 21 were in the forearm and 20 in the upper arm. Percutaneous thrombectomy was technically successful in 31 of 41 patients (76%). The technical success rate was similar for upper arm and forearm fistulas (85% vs. 66%, p = 0.43). An underlying stenotic lesion was present at the arterial anastomosis in 13 patients (31%), in the draining vein in 37 (90%), and in the central vein in 3 patients (7%). Twelve patients (29%) had concurrent stenoses at two locations. At 6 months, the primary patency was 20%, and the secondary patency was 54%. In conclusion, percutaneous treatment of thrombosed fistulas can restore fistula patency about three‐fourths of patients. However, the primary fistula patency is fairly short‐lived, and the fistulas require repeated interventions to achieve long‐term survival.     

Equivalent secondary patency rates of upper extremity Vectra Vascular Access Grafts and transposed brachial-basilic fistulas with aggressive access surveillance and endovascular treatment

OBJECTIVES: The 2006 update of the DOQI guidelines has stated that in patients with end-stage renal disease, autogenous radial-cephalic, or brachial-cephalic fistulas are the preferred access modalities, followed by transposed brachial-basilic (TBB) fistulas and prosthetic arteriovenous (AV) grafts. AV grafts are in general least preferred; however, there is very limited data comparing directly the last two modalities. The aim of the present study is to compare outcomes of the TBB fistula and the Vectra Vascular Access Graft. METHODS: Seventy-six patients had a prosthetic brachial-axillary Vectra graft placed, while in 41 patients brachial-basilic upper arm transposition was performed. Graft surveillance to detect a failing/failed access was followed by endovascular treatment, rheolytic thrombectomy (AngioJet, Possis Medical), and/or angioplasty +/- stenting of the responsible anatomical lesion(s). RESULTS: Use of Vectra grafts and TBB fistulas started after a median (interquartile range) of 14 (7-30) and 70 (52-102) days, respectively (P < .001), as early as the operative day in some patients with grafts. Postoperative complications were more frequent in TBB fistulas and late complications (mainly access thrombosis) in Vectra grafts. Total number of thrombectomy sessions performed for graft or fistula occlusion was 45 and 7, respectively (P = .032); total number of isolated angioplasty sessions, performed for failing graft or fistula was 31 and 45, respectively (P = .004). Although primary patency of the two access modalities was equivalent, primary assisted patency was significantly reduced in Vectra grafts (70% at 12 months and 58% at 18 months), compared with TBB fistulas (82% at 12 months and 78% at 18 months, P = .033); however, as a result of endovascular intervention, secondary patency rates at 12 months (87% vs 88%) and 18 months (87% vs 83%) were equivalent (P = .91). Presence of arterial anastomosis stenosis treated with angioplasty at any stage had a significant negative predictive value on secondary patency rates at 12 and 18 months which were 61%, compared with 96% for Vectra grafts that had any intra-graft, venous outflow, draining or central vein stenosis treated with angioplasty at any stage (P = .010). CONCLUSIONS: Aggressive graft surveillance and endovascular treatment methods can yield equivalent long-term secondary patency rates between Vectra graft and TBB fistulas. The advantage of earlier use of Vectra graft must be balanced against the need for more frequent secondary interventions and the risk of graft infection.     

Prospective randomized comparison of surgical versus endovascular management of thrombosed dialysis access grafts

Purpose: Salvage of thrombosed prosthetic dialysis shunts can be performed using surgical or endovascular techniques. A prospective randomized trial was designed to compare the efficacy of these two methods in restoring dialysis access function.Methods: One hundred fifteen patients with thrombosed dialysis shunts were randomized prospectively to surgical (n = 56) or endovascular (n = 59) therapy. In the surgical group, salvage was attempted with thrombectomy alone in 22% and with thrombectomy plus graft revision in 78%. In the endovascular group, graft function was restored with mechanical (82%) or thrombolytic (18%) graft thrombectomy followed by percutaneous angioplasty.Results: Stenosis limited to the venous anastomotic area was the cause of shunt thrombosis in 55% of patients, and long-segment venous outflow stenosis or occlusion was the cause in 30%. In 83% of the surgical group and in 72% of the endovascular group, graft function was immediately restored ( p = NS). The postoperative graft function rate was significantly better in the surgical group ( p < 0.05). Thirty-six percent of grafts managed surgically remained functional at 6 months and 25% at 12 months. In the endovascular group, 11% were functional at 6 months and 9% by 12 months. Patients with long-segment venous outflow stenosis or occlusion had a significantly worse patency rate than those with venous anastomotic stenosis ( p < 0.05).Conclusions: Neither surgical nor endovascular management resulted in long-term function for the majority of shunts after thrombosis. However, surgical management resulted in significantly longer primary patency in this patient population, supporting its use as the primary method of management in most patients in whom shunt thrombosis develops.     

球囊扩张联合覆膜支架植入治疗人造血管动静脉内瘘狭窄

目的 探讨球囊扩张联合覆膜支架植入治疗人造血管动静脉内瘘(AVG)狭窄的临床疗效.方法 前瞻性选取15例经皮腔内血管成型术(PTA)疗效欠佳的AVG狭窄患者,且具备以下特点:狭窄长度不超过7 cm,狭窄程度大于50％;PTA后3个月内狭窄复发2次或以上;扩张后残余狭窄＞30％或狭窄部位立即弹性回缩.所有患者在数字减影血管造影(DSA)下行球囊扩张后植入不同内径的聚四氟乙烯覆膜支架.结果 男3例,女12例,平均年龄(66±12)岁.支架植入前内瘘平均使用时间为(19.5±15.0)个月.共植入支架16枚,技术成功率100％,植入部位为静脉吻合口9例(9/15);静脉流出道6例(6/15),其中头静脉3例,肱静脉2例,腋静脉1例.首次开通率3个月为40％,6个月为19％,12个月为13％.再次开通率3个月为93％,6个月为88％,12个月为87％.术后平均随访时间为(14.9±5.3)个月,再窄狭率为87％(13/15).术后PTA 36例次,支架内狭窄36％ (13/36);支架远端狭窄8％ (3/36);支架近端狭窄22％(8/36);与支架无关的狭窄33％ (12/36).AVG中位生存时间为25个月.结论 球囊扩张联合覆膜支架植入治疗AVG狭窄技术成功率高,并发症少,首次开通率不高,但再次开通率令人满意.     

Improved patency of prosthetic arteriovenous grafts with an acute anastomotic angle and flow diffuser

OBJECTIVE: Conventional end-to-side anastomosis to establish venous outflow for prosthetic arteriovenous grafts often requires operative patch angioplasty within 1 year because of venous stenosis. Rather than conventional venous anastomosis, a modified end-to-side anastomosis at a 15-degree angle with a flow diffuser was constructed. Such diffusers allow decreased flow velocity and increased pressure, inhibiting boundary layer separation. METHODS: Ten brachial artery to axillary vein 6 mm straight se-polytetrafluoroethylene prosthetic arteriovenous grafts were created with this technique. Patients included 6 men and 4 women (mean age, 66.4 years; range, 54-80 years), all with renal failure and a history of diabetes. The degree of stenosis at the venous anastomosis was determined with duplex scanning at intervals of 6 months. Analysis of survival and cumulative primary patency estimates were determined with the Kaplan-Meier method. RESULTS: Primary cumulative patency estimate of 100% for the modified group at 18 and 24 months was significantly greater than that for age-matched historic control fistulas with the conventional end-to-side anastomosis (n = 20): 18 months, 32%; 24 months, 32% (P <.05). Although venous stenosis could not be quantitated for thrombosed conventional fistulas, modified anastomoses had minimal stenosis at 24 months: mean area reduction, 30% (range, 20%-45%). CONCLUSION: Incorporation of a flow diffuser and a 15-degree anastomotic angle significantly increases patency of prosthetic brachial artery to axillary vein grafts.     

Reversed vein graft stenosis: early diagnosis and management.

Conscientious surveillance of intrainguinal bypass grafts is mandatory to detect vein graft stenoses, which, if uncorrected, can lead to graft occlusion. It is now widely accepted that noninvasive vascular laboratory studies are the best way to detect these lesions. However, controversy still exists over treatment, specifically whether balloon angioplasty is an acceptable substitute for surgery (patch angioplasty or short jump grafts) in the treatment of these lesions. We have always favored balloon angioplasty as primary treatment and have summarized our experience with treating 72 stenotic reversed femoropopliteal and femorotibial vein grafts, which represent 12% of 521 bypass grafts performed at our institution. Prosthetic and in situ grafts are specifically excluded from this report, as well as occluded grafts, found to have stenotic lesions after lytic therapy. The most common stenotic lesion occurred within 4 cm of the proximal anastomosis (29/72 = 40%). The other sites were near the distal anastomosis (7/72 = 10%), and in the middle of the graft (15/72 = 12%). Eighty-one percent (58/72) of the lesions were treated initially by balloon angioplasty with a 31% recurrence. Twenty-nine percent of the 14 grafts treated surgically by vein patch angioplasty or short jump grafts experienced recurrence. Overall 61% (44/72) of the stenotic grafts were treated by balloon angioplasty alone. The 5-year life-table assisted primary patency after correction of the stenotic lesion was 61%. The patency of the grafts from the time of initial bypass surgery, however, was 80%. Location of the stenosis within the graft was a major determinant of patency. Lesions in the proximal graft, proximal anastomosis, and distal graft taken as a group had significantly better patency than the midgraft and distal anastomotic lesions (5-year patency, 65% vs 48%, p less than 0.001 log rank test). We continue to recommend balloon angioplasty as primary therapy for vein graft stenosis except for those occurring in the midgraft and distal anastomosis. Fortunately, this group accounts for only 36% of lesions seen with reversed veins. Recurrent stenosis after balloon angioplasty should be repaired surgically.     

Is surgical thrombectomy to salvage failed autogenous arteriovenous fistulae worthwhile?

The Dialysis Outcomes Quality Initiatives guidelines emphasize placement of autogenous arteriovenous (AV) fistulae for patients on hemodialysis. This recommendation is based on studies that demonstrate enhanced patency for AV fistulae compared with grafts. However, closer review of the data demonstrates that although primary patency of AV fistulae is superior to grafts, the secondary patency rates are equivalent. This suggests that secondary procedures to maintain fistula patency are inferior to those performed on arteriovenous grafts. Surgical thrombectomy of AV fistulae can be challenging. It is often difficult to completely remove thrombus adjacent to the anastomosis of the fistula, and pseudoaneurysms within the fistula can prevent passage of the thrombectomy catheter and complete removal of thrombus from the fistula. Consequently, some surgeons simply abandon thrombosed AV fistulae and place a new access. We have developed a method for completely clearing thrombus from failed AV fistulae by locating the fistulotomy close to the arterial anastomosis and using a technique to manually extract thrombus from the fistula before passing a thrombectomy catheter. The purpose of this study was to review our results with this procedure. Between 2001 and 2004, 10 patients with a previously functioning AV fistula presented with thrombosis. There were seven brachiocephalic fistulae and three radiocephalic fistulae. All patients underwent surgical thrombectomy and fistulography. Five patients underwent balloon angioplasty of a venous stenosis and one patient underwent surgical revision of an arterial stenosis. Technical success, defined as being able to completely clear thrombus from the fistula and treat the cause for fistula failure, was achieved in 70 per cent (7/10) of cases. Technical failure was caused by vein rupture during the balloon angioplasty in two cases and a central venous occlusion that could not be treated in one case. The 6-month primary and secondary patency for cases that were technically successful was 51 and 69 per cent, respectively. Our conclusion was that surgical thrombectomy can significantly extend fistula functionality in patients who present with thrombosis.     

Cutting balloon angioplasty for resistant venous anastomotic stenoses

Conventional angioplasty of stenoses at the venous anastomosis has been demonstrated to be an important endovascular adjunct to mechanical thrombectomy of clotted arteriovenous dialysis grafts. In some cases, however, severe venous anastomosis stenosis is resistant to angioplasty. Cutting balloon angioplasty may have an advantageous role in these difficult situations in order to avoid surgical revision. In this series of 350 patients receiving percutaneous, endovascular declotting procedures, 9 patients had high-grade venous anastomotic stenoses (opening less than 2 mm) that could not be remedied with either conventional or high-pressure noncompliant peripheral angioplasty balloons. These nine patients had the lesions opened with the use of 4 mm x 10 mm cutting balloons and placement of self-expanding nitinol stents at the venous anastomosis during the same angiography procedure. Patients were followed for patency and functionality of the graft. In all cases, immediate technical success occurred. Among these patients, the vessels have remained patent for as long as 20 months of follow-up and grafts have remained functional. Cutting balloon angioplasty may have a potential therapeutic role in resistant venous anastomotic stenoses.     

BRAVO I: A pilot study of vascular brachytherapy in polytetrafluoroethylene dialysis access grafts

Hemodialysis vascular access dysfunction owing to stenosis and thrombosis in polytetrafluoroethylene dialysis access grafts is a huge clinical problem for which there are currently no long lasting durable therapies. Vascular brachytherapy has been used successfully for the prevention of coronary restenosis following angioplasty and stent placement. The Beta Radiation for Treatment of Arterial-Venous Graft Outflow I study was a pilot study of vascular brachytherapy in hemodialysis patients with patent but dysfunctional grafts. Twenty-five patients were randomized to receive either radiation therapy (a single dose of 18.4 Gy) or sham radiation, following angioplasty. The primary efficacy end point of the study was target lesion primary patency at 6 months. The primary safety end point was a composite of death, emergency surgery on the graft, venous rupture, or aneurysm formation. Forty-two percent of the radiated grafts achieved the target lesion primary patency end point at 6 months as compared to 0% of the control group (P = 0.015), but this did not translate into an improvement in secondary patency at either 6 or 12 months. Radiation therapy was found to be safe in the setting of hemodialysis vascular access dysfunction. Our results suggest that vascular brachytherapy is an intervention that is worthy of further examination in the setting of non-thrombosed dialysis access grafts.     

Surgical Thrombectomy for Thrombosed Dialysis Grafts: Comparison of Adjunctive Treatments

Background Vascular surgeons often encounter dialysis graft failure in hemodialysis patients during their daily practice. Despite advances in percutaneous treatment, there remains a role for surgical thrombectomy of thrombosed dialysis grafts. This study was designed to investigate the long-term outcome of dialysis graft thrombectomy and to examine the indications for and effectiveness of therapies adjuvant to Fogarty thrombectomy. Methods Surgical outcomes of 590 consecutive dialysis graft thrombectomies performed between 2001 and 2003 were retrospectively reviewed. The 590 cases were classified into four groups based on the procedure performed adjuvant to Fogarty thrombectomy: group A, surgical thrombectomy by Fogarty thrombectomy catheter alone; group B, thrombectomy plus intraoperative angioplasty of graft outlet; group C, thrombectomy plus sequential balloon angioplasty in subsequent intervention; group D, thrombectomy plus graft outlet surgical revision. Age, gender, co-morbidity, and primary patency of grafts were reviewed and analyzed. Result The four groups exhibited similar demographic features and comorbidities (p > 0.05). Mean primary patency in the four groups was 1.99 ± 4.02, 7.21 ± 7.61, 8.35 ± 9.53, and 7.26 ± 6.99 (months), respectively. Survival curves for each group were determined by Kaplan-Meier methods. Primary patency in group A was statistically inferior to all of the other three groups, whereas groups B, C, and D did not significantly differ with regard to graft patency. Conclusions Surgical thrombectomy alone is inadequate for treating a thrombosed dialysis graft. The underlying graft outlet stricture requires direct surgical revision or balloon angioplasty during surgery or intervention in the angiography suite to ensure long-term patency of the graft.     

Surgical Thrombectomy and Transluminal Balloon Angioplasty for Failed Above-knee Femoropopliteal Polytetrafluoroethylene Bypass Grafts

Endovascular therapy offers an alternative to redo bypass or surgical graft revision for failed above-knee femoropopliteal PTFE bypass grafts. We evaluated the outcome of surgical thrombectomy and balloon angioplasty for the treatment of thrombosed bypass grafts. Thirty selected patients with thrombosed above-knee femoropopliteal PTFE bypass grafts were treated. Under local anesthesia, a surgical thrombectomy followed by bypass graft angiography and balloon angioplasty of perianastomotic stenoses was performed. Stents were used selectively for suboptimal angioplasty results. Patients underwent duplex scanning of the bypass graft postoperatively and at 6-month intervals. Life-table analysis and log-rank (Mantel-Cox) comparisons were performed. Patients were categorized into two groups on the basis of time elapsed from initial bypass graft construction to graft failure. Group 1 included 21 patients with a mean time to graft failure of 10 months (range, 0-20). Surgical thrombectomy was successful in 20 grafts (95%) and 17 patients had a stent placed after angioplasty. Rethrombosis occurred within 30 days in seven grafts (33%) in group 1 and major amputations were performed in six patients (28%). Group 2 included nine patients with a mean time to initial bypass graft failure of 48 months (range, 29-96). All patients in group 2 had a successful surgical thrombectomy and all received a stent. None of the grafts treated in group 2 reoccluded within 30 days of intervention and one patient (11%) went on to require a major amputation. By life-table analysis, the 6- and 12-month patency for group 1 was 15.3% and 5.1%, compared to 58.3% and 38.9% for group 2 (p = 0.027). Surgical thrombectomy along with balloon angioplasty has an unacceptably high rate of failure and limb loss in patients treated for early (<2 years) femoropopliteal PTFE bypass graft thrombosis. Surgical graft revision or redo bypass is recommended to achieve successful revascularization in these patients. Treatment with surgical thrombectomy and balloon angioplasty achieves significantly greater short-term patency results in patients with late (>2 years) bypass graft failure and may be a reasonable alternative for patients who cannot tolerate reoperation or lack autogenous conduit.Presented at the Twenty-eighth Annual Meeting of the Peripheral Vascular Surgery Society, Chicago, IL, June 7, 2003.     

Recognition and management of impending vein-graft failure. Importance for long-term patency

A previous report from this group indicated a very poor long-term patency rate (19%) for occluded femoro-distal vein grafts that require initial thrombectomy prior to patch angioplasty for documented stenosis. Patients with vein grafts were therefore followed up by Doppler pressure determinations of the ankle/brachial index (ABI) postoperatively at three weeks, six weeks, and every four months thereafter for two years in an effort to identify vein-graft failure prior to actual thrombosis. During the past six years we performed 322 vein grafts of which 29 grafts were identified by diminished Doppler ABI and were found to have stenotic segments on subsequent arteriography. Twenty-two of these patients (group 1) underwent reconstruction with patch angioplasty resulting in a five-year cumulative patency rate of 82%. The remaining seven patients (group 2) underwent percutaneous transluminal angioplasty of their stenotic segments yielding a significantly lower five-year patency rate of 43%. These two groups were compared with a third group fo 25 patients with thrombosed grafts mandating initial thrombectomy prior to patch angioplasty. The thrombectomized group 3 patients demonstrated a significantly lower five-year cumulative patency rate of 28%. These data suggest that patients with femoro-distal bypass vein grafts be followed up at frequent intervals early in their postoperative course with determinations of Doppler ABI measurements. Any significant reduction in Doppler ABI compared with the highest postoperative Doppler determination should be aggressively evaluated with digital-subtraction or routine angiography in an effort to locate a stenotic lesion prior to graft thrombosis. Patients found to have such a graft stenosis are then ultimately treated with patch angioplasty in anticipation of satisfactory long-term patency rates.     

Aggressive approach to late thrombosis of bovine heterografts.

Between January, 1977 and December, 1978, 26 patients presented with delayed thrombosis of bovine heterografts inserted for chronic hemodialysis. Time of presentation ranged from 2-29 months (mean 8.8 months) after insertion. At the time of presentation eight patients were not considered candidates for thrombectomy due to associated infection or physician preference. The remaining eighteen patients underwent thrombectomy, 13 of whom required concomitant revision of the graft (patch angioplasty at the venous anastomosis (6), dilatation (1), resection of intimal hyperplasia (2), resection of stenotic segment with interposition graft (2), resection of false aneurysm (1) and patch graft to mid graft stenosis (1)). Six grafts failed from eight days to seven months after thrombectomy and could not be salvaged. Two grafts functioned until death at three and four months after thrombectomy and the remaining ten grafts remain patent from 4-24 months (mean 13.1 months) after thrombectomy. Critical to success of thrombectomy is an incision over the venous limb with calibration of the venous anastomosis and patch angioplasty when indicated. At completion of thrombectomy arteriograms are mandatory to defect residual thrombosis, defects in the graft and adequacy of venous runoff. This standardized approach has resulted in a significant prolongation of bovine heterograft survival.