Evaluation of lower extremity bypass grafts with use of color duplex sonography.

This article reviews the wide variety of graft procedures currently used to bypass lower extremity atherosclerotic disease and the means used to evaluate the grafts, which can be biologic, synthetic, or a combination of both. Graft failure rate can be as high as 10% within the first 10-14 days after placement, leveling off to approximately 2%-4% per year thereafter. Many of the early complications associated with graft placement can be attributed to technical errors in bypass construction. Although angiography remains the standard of reference for the evaluation of these grafts, duplex ultrasound is increasingly being utilized to document patency and detect suspected complications such as intimal flap, perigraft collection, arteriovenous fistula, pseudoaneurysm, and stenosis or occlusion. Sonography is able to clearly depict the echogenic walls of synthetic grafts and demonstrate whether blood flow wave-forms and blood flow velocity in both synthetic and biologic grafts are normal, thus enabling a more accurate diagnosis of suspected complications to be made. Familiarity with the normal sonographic appearance of these grafts, their anastomoses, potential complications, and the pitfalls in making a diagnosis is essential if an accurate diagnosis is to be made.     

Modified use of the arrow-trerotola percutaneous thrombolytic device for the treatment of thrombosed hemodialysis access grafts.

PURPOSE: To assess the safety and efficacy of using the Arrow-Trerotola percutaneous thrombolytic device (PTD) as the sole means of mechanical thrombolysis in hemodialysis access grafts, including in situ treatment of the arterial plug. PATIENTS AND METHODS: Fifty consecutive patients (22 women, 28 men; mean age, 58 years; mean graft age, 29 months), in whom mechanical thrombolysis of a thrombosed hemodialysis access graft using the PTD was planned, were included in the study. In all patients, the PTD was used to treat the arterial plug in situ at the arterial anastomosis, instead of using a Fogarty catheter to reposition the plug, as indicated in the PTD product labeling. Prospective data collection included demographic information, technical details of the procedure, immediate outcomes, and complications. Patients were followed for 3 months using definitions and data forms that were identical to those used in the original clinical trial of the PTD. A sample of procedures drawn from the PTD clinical trial database (n = 54) served as control. RESULTS: Immediate technical patency was 100%. Complications included arterial embolization (6% versus 2% control; P = NS; all successfully treated with backbleeding); venous rupture (6% versus 2% control; P = NS); and sepsis (n = 1), probably due to occult graft infection. Adjunctive therapy with an Adherent Clot catheter was needed in two procedures (4%). Three month patency using life-table analysis was 42% (versus 39% control; P = NS). The number of subsequent interventions (surgical/percutaneous) to the arterial limb of the graft did not differ from the PTD trial, and no native arterial stenoses were detected during the follow-up period. CONCLUSIONS: The PTD is safe and effective when used as the sole means of mechanical thrombolysis of hemodialysis grafts. Treating the arterial plug in situ with the PTD eliminates the need for a Fogarty or Adherent Clot catheter in 96% of procedures. A slight increase in arterial embolic complications was observed but these were easily treated with backbleeding.     

Evaluation and complications of direct graft puncture in thrombolysis and other interventional techniques

Purpose: To evaluate the value and complications of direct graft puncture in conducting interventional procedures in synthetic vascular bypass grafts. Methods: We retrospectively reviewed 65 direct graft punctures in 50 patients undergoing a variety of interventional vascular procedures. In two patients the grafts were found to be infected and the procedures abandoned. Results: Complications encountered included hematomas that did not require treatment in three patients, and four hematomas requiring surgical drainage. One graft became infected (despite prophylactic cefuroxime), after three consecutive punctures over a 10-day period for a variety of interventions. All the patients who developed hematomas had undergone pharmacological thrombolysis. Conclusion: Direct graft puncture is a relatively safe technique, with a minimal risk of infection and hemostatic complications attributable to thrombolysis. In 31 of the 41 patients undergoing successful thrombolysis, additional percutaneous procedures were undertaken, and these were facilitated by the direct graft puncture route.     

Hemodialysis graft: use as access for upper and lower extremity arteriography and interventional procedures--initial experience.

Functioning hemodialysis grafts were used as access sites for peripheral vascular arteriography and interventional procedures. In 11 patients with end-stage renal disease and ischemia, upper extremity (n = 8) or lower extremity (n = 3) arteriography was performed successfully. Angioplasty and other interventional procedures were performed via the same route in two of the patients. No bleeding complications occurred, and all patients were ambulatory immediately after the procedure.     

Thrombolysis of the occluded prosthetic graft with tissue-type plasminogen activator--technique, results and problems in 23 patients.

Over a 12 month period all patients but one presenting to our hospital with occluded prosthetic grafts were treated by thrombolysis using local pulsed administration of tissue-type plasminogen activator (t-PA). There were 30 interventions in 23 patients but in one patient no thrombolytic was given after aspiration of pus from the graft. Thrombolysis was attempted in the remaining 29 procedures. 22/29 (76%) of these procedures were performed by direct puncture and catheterization of the occluded graft and in a further six (21%) access was from a non-occluded femoral artery or graft. In one case the graft was accessed surgically. Supplementary angioplasties were performed in 15 cases (52%). Complications requiring surgery occurred in four (14%) with a further seven minor complications. There were no deaths. A lower rate of complications occurred in the grafts entered by direct puncture. Thrombolysis was achieved in all but one case taking an average of only 2.5 h but was only maintained beyond the end of the procedure in 21/29 (72%). An underlying cause for occlusion was identified and treated where possible, e.g. haematological or clotting abnormalities or inflow or outflow stenoses. There was a high rate of reocclusion but with repeat procedures when necessary patency was maintained in 10/22 patients (45%) on follow-up at 1 to 12 months. The best results were obtained with lysis of occluded femoro-femoral crossover grafts.     

Pharmacomechanical thrombectomy with the Castañeda brush catheter in thrombosed hemodialysis grafts and native fistulas

PURPOSE: To evaluate the safety and efficacy of the Casta?eda brush catheter in the treatment of thrombosed hemodialysis fistulas and grafts. MATERIALS AND METHODS: Twenty-six revascularization procedures with the Casta?eda brush catheter combined with urokinase were retrospectively analyzed in 21 patients (mean age, 69 years; range, 35-87 y). Hemodialysis shunts were native arteriovenous (AV) fistulas (n=15; 16 procedures) or polytetrafluoroethylene grafts (n=6; 10 procedures). Major outcomes included procedure time, anatomic and clinical success rates, complication rate, and primary, primary assisted, and secondary patency. RESULTS: In 26 procedures, the brush catheter was used in combination with a mean dose of 239,792 IU urokinase (range, 60,000-300,000 IU). Additional angioplasty was performed in all procedures; five procedures (19%) required additional stent implantation. Mean procedure time was 99.2 minutes (range, 49-261 min). Anatomic and clinical success rates were 100% and 96.2%, respectively. Two minor complications (8%) occurred, neither of which was device-related: one case of extravasation treated by balloon tamponade and one hematoma at the distal puncture site without the need for surgery or transfusion. Primary patency rates were 87%, 62%, and 50% at 3, 6, and 12 months, respectively, for AV fistulas, and 50%, 33%, and 17%, respectively, for grafts. Assisted primary patency rates were 93%, 77%, and 70% at 3, 6, and 12 months, respectively, for AV fistulas, and 50%, 33%, and 17%, respectively, for grafts. At 3, 6, and 12 months, secondary patency rates were 93%, 85%, and 80%, respectively, for AV fistulas, and 83%, 67%, and 50%, respectively, for grafts. CONCLUSIONS: The Casta?eda brush catheter is a safe and effective pharmacomechanical thrombectomy device for the treatment of thrombosed hemodialysis grafts and native fistulas.     

Long-term follow-up of management of failing in situ saphenous vein bypass grafts using endovascular intervention techniques

PURPOSE: To report the long-term follow-up of previously reported cases of salvaging failing or failed in situ bypass grafts using endovascular techniques, to include previously unreported cases, and to include the results of thrombolysis for the salvage of occluded in situ venous bypass grafts. MATERIALS AND METHODS: Between 1985 and 1995, 352 patients underwent distal bypass via the in situ saphenous vein. Seventy-three of these patients underwent endovascular interventions for (i) graft stenoses (65 lesions in 40 patients) treated by balloon angioplasty (PTA), (ii) AV residual fistulas to veins (AVF) (23 patients) occluded by coil embolotherapy, (iii) graft occlusion (21 occluded grafts in 19 patients) treated by catheter-directed high-dose thrombolytic infusion and PTA or surgical revision of uncovered stenoses, and (iv) retained valve leaflets causing stenoses (five patients) treated by valvectomy and/or PTA. Cumulative patency rates were determined by the Kaplan-Meier method. Twenty-nine of 73 patients had been previously reported by the authors. RESULTS: PTA was successful in 39 of 40 patients, cumulative patency after bypass PTA was 0.79 (SE +/- 0.07) for 12 months and 0.63 (SE +/- 0.12) for 5 years. The only complication of PTA was a graft anastomotic disruption that was successfully treated by surgery. Longer lesions and lesions requiring repeated PTA were more likely to restenose. For thrombolysis, there were 13 of 19 successful infusions and five delayed occlusions. The cumulative patency for both 12 months and 5 years was 0.43 (SE +/- 0.12). AVF embolization was successful in 21 of 23 patients. Cumulative patency for 12 months and 5 years was 0.87 (SE +/- 0.07) and 0.81 (SE +/- 0.09), respectively. Five successful valvectomy procedures were performed by stripping residual valves with endocardial forceps. CONCLUSION: In experienced hands, PTA and AVF embolization can be performed on failing in situ saphenous vein bypass grafts with good long-term patency. Thrombolysis results were less favorable but can prolong patency of grafts.     

Short-duration, high-dose urokinase infusion for recanalization of occluded saphenous aortocoronary bypass grafts

Thrombolytic recanalization of arterial bypass grafts has been pursued aggressively in the peripheral circulation but not in the coronary circulation. In an attempt to apply peripheral transcatheter thrombolytic techniques to the coronary circulation, nine patients with 10 occluded saphenous aortocoronary bypass grafts underwent recanalization procedures using a short-duration, high-dose urokinase infusion. Urokinase was infused at the occluded graft orifice at a rate of 600 units/min. The average infusion time was 1 hr, 26 min. The average urokinase dose was 435,000 units. Graft recanalization was achieved in eight (80%) of 10 grafts, although only six (60%) of 10 grafts were widely patent at the end of the procedure. All successfully recanalized grafts required balloon angioplasty of underlying stenoses. No complications, specifically myocardial infarction or cerebrovascular accident, were encountered. We have shown that occluded aortocoronary bypass grafts can be recanalized successfully by using a short-duration, high-dose urokinase infusion. It appears that, with attention given to angiographic techniques that minimize clot manipulation, recanalization can be accomplished safely in a majority of cases.     

Endovascular stent placement for angioplasty-induced venous rupture related to the treatment of hemodialysis grafts.

PURPOSE: To assess the use of endovascular stents for treating rupture after percutaneous transluminal angioplasty (PTA) in the maintenance of hemodialysis grafts. MATERIALS AND METHODS: From February 1, 1994, to August 1, 1997, 683 hemodialysis-related angioplasty procedures were performed on 277 patients to treat thrombosed or poorly functioning polytetrafluoroethylene (PTFE) hemodialysis bridge grafts. In each of these procedures, angioplasty of the venous anastomosis or the outflow vein was performed. This study is a retrospective review to analyze uncovered endovascular stents placed to treat ruptures after PTA. RESULTS: Fourteen ruptures were treated with use of an uncovered metal stent. Stent placement was technically successful in 11 of 14 patients, with clinical success in 11 of 14 cases. The primary patencies at 30, 60, 90, and 120 days were calculated by means of Kaplan-Meier life-table analysis; these were 63%, 54%, 46%, and 46%, respectively. The secondary patencies at 60, 120, and 180 days were 85%, 75%, and 75%, respectively. No complications were attributable to stent placement. The results are comparable to those of stents placed for reasons other than rupture, and support the efficacy of their use for this indication. CONCLUSION: Endovascular stent placement is a safe and effective means of salvaging angioplasty-induced rupture that occurs during the treatment of hemodialysis grafts.     

Retrospective comparison of the Amplatz thrombectomy device with modified pulse-spray pharmacomechanical thrombolysis in the treatment of thrombosed hemodialysis access grafts.

PURPOSE: To retrospectively evaluate the Amplatz thrombectomy device (ATD) in the treatment of thrombosed hemodialysis grafts and compare it with modified pulse-spray pharmacomechanical thrombolysis (PPT). MATERIALS AND METHODS: During a 4-month period, 79 patients presented with 126 episodes of graft occlusion. Percutaneous recanalization was performed by using the ATD (n = 57) or the modified PPT technique (n = 69). Evaluation included the technical success, complications, and primary patency rates. RESULTS: Technical success was achieved in 93% (53 to 57) of the cases treated with the ATD and in 96% (66 of 69) of the cases treated with modified PPT (P = .70). Complications occurred in 6% (four of 69) of modified PPT procedures and 16% (nine of 57) of ATD procedures. This difference was not statistically significant (P = .08); however, there were significantly more local complications in the ATD group (P = .04). The primary patency rates at 30, 90, and 180 days were 65% and 65%, 36% and 50%, and 26% and 33% for modified PPT and ATD, respectively. Survival curves were found not to differ significantly (P = .49). CONCLUSION: The ATD and modified PPT were similarly successful in the recanalization of thrombosed hemodialysis access grafts and achieved comparable primary patency rates. The higher rate of local complications and technical difficulties encountered with use of the 8-F ATD limit its usefulness for this indication.     

Reteplase with or without abciximab for peripheral arterial occlusions: efficacy and adverse events

PURPOSE: To retrospectively evaluate reteplase in thrombolysis of peripheral arterial occlusion (PAO). MATERIALS AND METHODS: Forty limbs in 36 patients were treated with reteplase (0.5 U/h) with or without abciximab (bolus and 12-hour infusion). Twenty-four occlusions were in bypass grafts and 16 were in native arteries. Nineteen patients were treated with reteplase alone and 21 patients were treated with reteplase and abciximab. Chart review provided data from procedures and follow-up at 30 days and 6 months. Multivariable, analysis of variance, and Student t test comparisons of results and complications were performed. RESULTS: Reteplase infusions averaged 31 hours in duration (range, 12-72 hours). The technical success rate was 80%. The clinical success rates were: immediate, 80%; 30-day, 65%; and 6-month, 45%. Major bleeding complications occurred in 20% of cases and intracranial hemorrhage occurred in 2.5%. The 6-month amputation-free survival rate was 78%. Major, minor, and lack of complications were statistically associated with mean decreases in fibrinogen levels from baseline of 72%, 46%, and 15%, respectively (P =.000013). Complications were not associated with length of infusion or use of abciximab (P =.77). Patients with grafts accounted for 89% of the major complications (eight of nine; P =.009) and had worse clinical success immediately (71%), at 30 days (50%), and at 6 months (21%; P =.002, P =.003, P =.00001). CONCLUSIONS: There was significant fibrinogen depletion with use of reteplase for PAO. The percent decrease in fibrinogen level correlates with lack of complications and incidence of minor and major complications. Abciximab use did not increase the complication rate. Thrombolysis of grafts is associated with increased incidence of complications and worse outcomes compared with thrombolysis of native arteries.     

Tc-99m MAG3 evaluation of recipients with En bloc renal grafts from pediatric cadavers

Tc-99m MAG3 scintigraphy is a well-established test to monitor patients who have received renal grafts. The shortage of available kidneys has forced the development of alternative sources of donors. En bloc pediatric renal grafts have been used for more than 10 years with good results, but mechanical complications are still a concern. No reports have illustrated the Tc-99m MAG3 scintigraphic aspect of the most common complications resulting from en bloc pediatric renal grafts. The authors describe three recipients of en bloc renal graft. One patient had thrombosis of one of the two grafts, one patient had postrenal obstruction of only one of the grafts, and a third patient progressed normally.     

Reteplase in the treatment of thrombosed hemodialysis grafts.

PURPOSE: To prospectively evaluate the efficacy and safety of reteplase with percutaneous transluminal angioplasty (PTA) in the treatment of thrombosed polytetrafluoroethylene hemodialysis arteriovenous grafts (AVGs). MATERIALS AND METHODS: Forty-two patients were entered into the study. Sixty-two procedures in 43 grafts were performed. One unit of reteplase and 4,000 units of heparin were administered into the AVGs. Routine venography and percutaneous transluminal angioplasty (PTA) was then performed. Patients were transferred for hemodialysis immediately after the procedure. RESULTS: Technical success was achieved in 92% of the cases. Four cases involved intentional repeat thrombosis because of poor outflow and/or need for a new graft site. Minor complications occurred in 6.5% of the cases. No major complications occurred. The mean procedure time for experienced versus less-experienced interventionalists was significantly shorter (P <.001). Primary patency rates were 50%, 34%, and 34% at 30, 90, and 180 days, respectively. CONCLUSION: Reteplase in conjunction with heparin and PTA is a safe and effective means of thrombolysis of AVGs. Its efficacy is comparable to that of other available thrombolytic drugs.     

Detection and treatment of acute thromboembolic events in the lower extremities

Acute procedural thromboembolic events are serious complications affecting both short- and long-term outcome. Patients at high risk include those undergoing catheter-based interventions for acute limb ischemia and long segment de novo or stented occlusions of the lower limb arteries. Additionally, debulking procedures and angioplasty/stenting of complex lesions in patients with advanced disease have also been associated with a higher risk of distal embolization and in situ thrombosis. This article includes a discussion of detection methods as well as preventive and treatment strategies.     

Detection of prosthetic vascular complications: comparison of CT and angiography

The value of CT and angiography to detect complications of prosthetic arterial grafting was compared in 24 patients. There was a total of 27 grafts including 18 aortic or aortofemoral, five femoral-popliteal, two femoral-femoral, and two axillary-femoral reconstructions. Nineteen grafts were uninfected; eight were infected. In the absence of infection, the complications and the percentages detected by the two procedures were as follows: five graft occlusions (CT 80%, angiography 100%), six pseudoaneurysms (CT 100%, angiography 83%), three with perigraft fluid (CT 100%, angiography 0%), and one with pseudointimal hyperplasia (CT 100%, angiography 0%). Seven grafts were normal and without abnormalities on both CT and angiography. In the presence of infection the results were as follows: eight with perigraft fluid (CT 100%, angiography 0%), four with perigraft or intragraft gas (CT 100%, angiography 0%), three pseudoaneurysms (CT 100%, angiography 100%), two open groin wounds (CT 100%, angiography 0%), and two graft occlusions (CT 100%, angiography 100%). In addition, three patients with infected grafts had graft enteric fistulae. All three had fluid around the proximal anastomosis and two had gas around the graft as well. The data show that angiography is sufficient for patients with graft occlusion if there is no suspicion of infection, postoperative hemorrhage, or anastomotic pseudoaneurysm. In these cases CT has an ancillary role in detecting hemorrhage and defining pseudoaneurysms. CT is superior to angiography in patients with graft infection.     

Esophageal resection: indications, techniques, and radiologic assessment.

Various surgical procedures are performed for benign and malignant esophageal lesions. These procedures include transthoracic esophageal resection through a right or left thoracotomy and transhiatal blunt esophageal resection (esophagectomy) without thoracotomy. The whole stomach, colon, gastric tube, jejunum, and free revascularized grafts may be used as substitutes for the resected esophagus. Bypass procedures including substernal stomach bypass surgery and substernal or subcutaneous colon bypass surgery are performed for tracheoesophageal fistula, previous esophagectomy without reconstruction, or obstruction due to lye ingestion. The mortality rate for esophageal resection depends on the stage of the tumor, the patient's condition, and the surgeon's skill and is quite low when the procedure is performed by a highly skilled surgeon. The most frequent sources of morbidity related to esophageal surgery include pneumothorax, pleural effusion, pneumonia, and respiratory failure. Mediastinitis and sepsis due to disruption at an anastomosis site cause serious postoperative morbidity and mortality; therefore, thoracic anastomotic leaks require aggressive surgical treatment. Familiarity with these surgical options, the resultant anatomic changes associated with each option, and the expected findings at postoperative imaging is essential for evaluating the effectiveness of surgical procedures and for the early detection and management of surgery-related complications.     

Percutaneous interventions in subclavian artery-to-contralateral subclavian vein "necklace" hemodialysis grafts: experience in five patients

PURPOSE: To describe clinical outcomes of endovascular interventions in the setting of thrombosis or dysfunction of anterior chest wall ("necklace") arteriovenous (AV) hemodialysis grafts. MATERIALS AND METHODS: Eight percutaneous interventions (balloon angioplasty, pharmacologic thrombolysis, and mechanical thrombectomy) were performed in five patients with anterior chest wall AV grafts. Primary, assisted, and secondary patencies, as well as technical success and complication rates, were determined. RESULTS: The technical success rate of percutaneous interventions in re-establishing a normal blood flow pattern within the AV grafts was 100%. Primary patency ranged from one to 23 months (median, 5 months). Primary assisted patency and secondary patency were 36 months and 8 months, respectively, in two patients who underwent more than one intervention. Postintervention access patency ranged from 5 to 36 months (median, 9 months), whereas graft lifetime ranged from 12 to 45 months (median, 24 months). There were no complications related to revascularization procedures. CONCLUSION: Percutaneous interventions can be performed safely and effectively in anterior chest wall AV grafts. Technical success and long-term patency rates appear to be similar to those of percutaneous interventions in upper-extremity hemodialysis AV grafts.     

Balloon angioplasty of venous structures

Percutaneous transluminal angioplasty was attempted in 20 patients with stenoses of venous structures. It concerned one stenosis in a native subclavian vein, 12 stenoses in venous bypass grafts and 7 stenoses in hemodialysis-access fistulas. Primary results were excellent for the procedures in the native vein and the venous bypass grafts with success in all patients (13/13). In the arteriovenous fistulas for hemodialysis, dilatation of the venous stenoses was only possible in 5 out of 7 patients. The subclavian vein stenosis did not recur within a follow-up period of 3 years. Of the stenoses in the venous bypass grafts, two lesions reoccluded within one week and 6 lesions recurred within one year. Two of these lesions were successfully redilated so that 6 lesions remain patent with a follow-up of more than one year. Of the 5 successful dilatations in hemodialysis-access fistulas, two lesions recurred within 2 months. Only 3 veins are still accessible for hemodialysis. It is concluded that attempts at balloon dilatation of stenoses in venous bypass grafts or hemodialysis-access fistulas are meaningful in order to prolong the life of these surgical procedures. Recurrence of stenoses is however likely to occur within one or two years.     

Balloon dilatation of biliary-enteric strictures in children

OBJECTIVE: The objective of our study was to evaluate the efficacy and safety of balloon dilatation in the treatment of anastomotic strictures in children with liver transplants. MATERIALS AND METHODS: For a period of 7 years, we treated 20 consecutive biliary-enteric strictures in 19 children (age range, 13 months to 17.9 years, mean, 7.3 years) with balloon dilatation. Dilatation was performed between 30 days and 8.4 years (mean, 2.6 years) following surgical creation of the biliary-enteric anastomosis. Thirteen patients had left lateral segment liver transplant grafts, one patient had a split-liver, left-lobe graft, and five patients had whole liver grafts. RESULTS: Technical success was 100% and there were no procedure-related complications. One patient with a patent anastomosis underwent repeat transplantation 183 days after the procedure for chronic rejection. In 58% (11/19) of the remaining procedures, balloon dilatation resulted in biliary-enteric patency at one year, and continued patency ranges from 1.4 to 5.4 years (mean, 3.6 years). In 40% (8/20) of the procedures, the biliary-enteric stricture persisted after balloon dilatation, and these patients eventually underwent surgical revision, retransplantation, or endobiliary metallic stent placement. CONCLUSION: Balloon dilatation is a safe and effective treatment for biliary-enteric strictures following pediatric liver transplantation.     

Intra-operative digital angiography as a control of the in situ saphenous vein by-pass grafts

Forty-two patients undergoing in situ saphenous vein by-pass grafting procedures, in two patients bilaterally, were examined intra-operatively with digital subtraction angiography. In 19 (43%) of the examinations the graft and the anastomoses appeared adequate. In 8 cases (18%) significant abnormalities were found, including stenoses (11%), deficient anastomoses (5%) and graft kinking (2%). Remaining arteriovenous fistulas were found in 17 patients (39%). In most cases immediate correction was possible avoiding later re-operation. At follow up 11 of the 44 grafts were occluded, 10 of these during the first five months and of these five during the first week.