Regional infusion of urokinase into occluded lower-extremity bypass grafts: long-term clinical results

2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease" provides recommendations to guide clinicians in the treatment of patients with lower extremity peripheral artery disease across its multiple clinical presentation subsets (ie, asymptomatic, chronic symptomatic, chronic limb-threatening ischemia, and acute limb ischemia).

METHODS

A comprehensive literature search was conducted from October 2020 to June 2022, encompassing studies, reviews, and other evidence conducted on human subjects that was published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through May 2023 during the peer review process, were also considered by the writing committee and added to the evidence tables where appropriate.

STRUCTURE

Recommendations from the "2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with peripheral artery disease have been developed.

2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease" provides recommendations to guide clinicians in the treatment of patients with lower extremity peripheral artery disease across its multiple clinical presentation subsets (ie, asymptomatic, chronic symptomatic, chronic limb-threatening ischemia, and acute limb ischemia).

METHODS

A comprehensive literature search was conducted from October 2020 to June 2022, encompassing studies, reviews, and other evidence conducted on human subjects that was published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through May 2023 during the peer review process, were also considered by the writing committee and added to the evidence tables where appropriate.

STRUCTURE

Recommendations from the "2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with peripheral artery disease have been developed.

Reduction of death rate due to acute myocardial infarction in subjects with cancers through systemic restoration of impaired nitric oxide

Introduction

Excessive aggregation of platelets at the site of plaque rupture on the coronary artery led to the formation of thrombus which is reported to precipitate acute myocardial infarction (AMI). Nitric oxide (NO) has been reported to inhibit platelet aggregation and induce thrombolysis through the in situ formation of plasmin. As the plasma NO level in AMI patients from two different ethnic groups was reduced to 0 µM (median) compared to 4.0 µM (median) in normal controls, the effect of restoration of the NO level to normal ranges on the rate of death due to AMI was determined.

Methods and Results

The restoration of plasma NO level was achieved by a sticking small cotton pad (10×25 mm) containing 0.28 mmol sodium nitroprusside (SNP) in 0.9% NaCl to the abdominal skin of the participants using non-toxic adhesive tape which was reported to normalize the plasma NO level. The participants (8,283) were volunteers in an independent study who had different kinds of cancers and did not wish to use any conventional therapy for their condition but opted to receive SNP “pad” for their condition for 3 years.

The use of SNP “pad” which normalized (≈4.0 µM) the plasma NO level that in consequence reduced the death rate due to AMI, among the participants, was found to be significantly reduced compared to the death due to AMI in normal population.

Conclusion

Our data suggested that the use of SNP “pad” significantly reduced the death due to AMI.

Trial Registration

www.ctri.nic.in004236

Primary stent placement for late complete occlusion after aortoiliac reconstructive surgery: report of a case

We report a case that was successfully treated by primary stent placement without thrombolysis or thrombectomy for graft thrombosis after aortoiliac reconstructive surgery. A 79-year-old man presented with a 2-month history of severe intermittent claudication of the right leg. He had undergone a surgical repair of abdominal aortic aneurysm with a bifurcated polyester graft 3 years before presentation. Digital subtraction angiography revealed total occlusion of the right limb of the graft. He underwent primary stent placement on the lesion, and completion angiography showed revascularization of the right limb. Primary stent placement can be performed to decrease the risks of surgery and increase the salvage of a graft with chronic total occlusion.

Thrombolysis as Initial Treatment of Peripheral Native Artery and Bypass Graft Occlusions in a General Community Hospital

Large series with long-term follow-up of thrombolytic therapy in the treatment of lower limb arterial occlusion from a single, general, non-university hospital are absent. We studied retrospectively the results of 129 consecutive patients who underwent thrombolysis with intraarterial urokinase as initial treatment for lower limb native artery or bypass graft occlusions. The mean age of patients was 71 years; 55% of the patients were male, and preexisting peripheral arterial disease was present in 47%. Presenting symptoms were disabling claudication (31%) and limb-threatening ischemia (69%). Forty-two percent of the patients presented with acute symptoms (<1 week duration). The mean follow-up of patients still alive at the time of analysis was 36 months (range 1-120 months). Thrombolytic treatment was successful in 93 patients (72%). In 53% of the patients acute surgical intervention could be avoided: 28 patients (22%) did not need any additional procedure and 40 (31%) underwent a concomitant angioplasty. When thrombolysis failed, 6 patients (5%) underwent successful surgical revascularization and 11 patients (8%) eventually underwent major amputation during their hospital stay. Amputation-free survival at 6 months and at last follow-up was 88% and 83%, respectively. The mortality rates were 4% at 30 days, 5% at 6 months, and 30% at last follow-up. Thrombolysis was significantly less successful when patients had diabetes (62% vs. 81%, p = 0.019) or preexisting peripheral arterial disease (61% vs. 80%, p= 0.018). Successful radiological treatment (thrombolysis+/-angioplasty) could less often be performed in patients with preexisting peripheral arterial disease (41% vs. 59%, p = 0.011) and in patients with occluded bypass grafts (33% vs. 62%, p= 0.002). Duration of symptoms and Fontaine stage at presentation did not predict thrombolysis outcomes. Thrombolytic-related complications occurred in 17 patients (13%), with significant bleeding from the puncture site in 3 patients (2%). Thrombolysis can safely and effectively be performed in a general community hospital with results comparable to those reported from specialized university centers and large randomized trials.

Catheter-directed Thrombolytic Therapy for Limb Ischemia: Current Status and Controversies

Absence of urokinase from the United States market for the past 4 years has resulted in increasing experience with other plasminogen activators in catheter-directed thrombolytic therapy. The differences in the pharmacologic properties and biologic behavior of these agents may translate into clinical outcomes that are distinct. Some of these manifestations can be predicted based on the existing large clinical trials in the acute myocardial infarction literature. However, because of the fundamental differences in techniques and thrombolytic regimens, extrapolation of the coronary data may not always predict the performance of these agents in peripheral catheter-directed fibrinolysis. In this article, the current status of the available lytic agents in the treatment of limb ischemia is reviewed.

Catheter-directed Thrombolytic Therapy for Limb Ischemia: Current Status and Controversies

Absence of urokinase from the United States market for the past 4 years has resulted in increasing experience with other plasminogen activators in catheter-directed thrombolytic therapy. The differences in the pharmacologic properties and biologic behavior of these agents may translate into clinical outcomes that are distinct. Some of these manifestations can be predicted based on the existing large clinical trials in the acute myocardial infarction literature. However, because of the fundamental differences in techniques and thrombolytic regimens, extrapolation of the coronary data may not always predict the performance of these agents in peripheral catheter-directed fibrinolysis. In this article, the current status of the available lytic agents in the treatment of limb ischemia is reviewed.

Lysis/balloon angioplasty versus thrombectomy/ open patch angioplasty of failed femoropopliteal polytetrafluoroethylene bypass grafts

PURPOSE

Several studies have reported on the outcome of lysis/percutaneous transluminal balloon angioplasty (PTA) of failed or failing femoropopliteal bypass grafts (FPGs) with mixed results. None of these studies have compared the results of lysis/PTA versus thrombectomy/open patch repair for failed above-knee polytetrafluoroethylene (PTFE) FPGs.

METHODS

Patients with failed (thrombosed) above-knee FPGs (PTFE, Goretex) during a 10-year period were given the option to choose between thrombectomy/open patch repair for localized anastomotic short stenosis (less-than-or-equal2 cm; group A, 31 patients) and lysis/PTA or thrombectomy/balloon angioplasty when lysis failed or was contraindicated (group B, 26 patients). The cumulative patency rates were compared by using a Kaplan-Meier life table analysis. All patients underwent routine color duplex ultrasound scanning/ankle brachial index measurements at 30 days, 6 months, and every 6 months thereafter.

RESULTS

Demographic and clinical characteristics and indications for intervention were comparable in both groups. The mean follow-up period was 54.1 and 46.2 months in group A and group B, respectively. There were four perioperative complications in group A (13%) and seven perioperative complications in group B (27%). Initial technical success and 30-day secondary graft patency rates were 100% in both groups. Overall, 17 of 31 patients (55%) had open grafts, with no further revisions in group A and six of 26 patients (23%) in group B requiring further revisions (P =.012). Nine of 31 grafts (29%) failed in group A versus 15 of 26 grafts (58%) in group B (P =.027). The rate of limb loss was comparable in both groups (6% vs 12%). The overall cumulative secondary patency rates at 6 months and 1, 2, 3, 4, and 5 years were 100%, 93%, 85%, 72%, 67%, and 62% for group A and 100%, 96%, 88%, 76%, 63%, and 45% for group B (P =.035). Thirty-five further interventions were needed to maintain graft patency in group B (mean, 1.35; range, 0-3) versus five further interventions in group A (mean, 0.16; range, 0-1; P <.05).

CONCLUSION

Thrombectomy/open surgical repair is superior to lysis/PTA (or thrombectomy/balloon angioplasty) for the treatment of failed above-knee PTFE FPGs with anastomotic stenoses. Therefore, balloon angioplasty should be reserved for patients who are at high risk for surgery.

Indications for directed thrombolysis or new bypass in treatment of occlusion of lower extremity arterial bypass reconstruction

The long-term results after directed thrombolytic therapy for thrombosis of infrainguinal arterial bypass reconstructions are disappointing if broad indications are applied. This work presents criteria for determining the indications for thrombolysis or the insertion of a new bypass. In a retrospective study we compared the secondary cumulative patency after bypass thrombolysis (n = 82) and after replacement bypass (n = 143). Using multivariate analysis, the influence of prognostic factors on secondary long-term patency was investigated. Our results showed that brief occlusions (< or = 3 days) in older bypasses (> or = 11 months) should be treated by thrombolysis. In all other cases, efforts should be made to replace the bypass with autologous vein. In the absence of autologous vein, we found umbilical vein to be a suitable material for vessel replacement.

A multi-modal approach to the management of bypass graft failure

Bypass graft failure is an unsolved problem in the contemporary treatment of peripheral arterial occlusion. Thrombolysis of a failed bypass graft is performed with instillation of plasminogen activators directly into the substance of the thrombus. Thrombolytic techniques can restore the bypass graft to its pre-occlusive state, clearing the inflow and outflow tracts of propagated thrombus and unmasking the causative lesion responsible for graft occlusion. Open surgery, or an endovascular modality, can then be employed to directly address these lesions. Recent randomized trials have demonstrated the safety and efficacy of a thrombolytic treatment strategy when the graft occlusion is acute, that is, when the patient presents within 2 weeks of the event. The appropriate management of the patient with an acutely occluded bypass graft includes thrombolysis, endovascular modalities and open surgery, employed in conjunction, to improve patient outcome over that observed with an immediate operation alone.

Results of a prospective, randomized trial of surgery versus thrombolysis for occluded lower extremity bypass grafts

PURPOSE

The purpose of this study was to prospectively evaluate the treatment of patients with occluded lower extremity bypass grafts, comparing surgical revascularization with catheter-directed thrombolysis.

MATERIALS AND METHODS

One hundred twenty-four patients (68% male and 32% female) with lower limb bypass graft occlusion (46 autogenous and 78 prosthetic) were prospectively randomized to surgery (n = 46) or intra-arterial catheter-directed thrombolysis (n = 78) with recombinant tissue plasminogen activator (rt-PA) 0.1 mg/kg/h modified to 0.05 mg/kg/h for up to 12 hours, or urokinase (UK) 250,000 U bolus followed by 4,000 U/min for 4 hours, then 2,000 U/min for up to 36 hours. A composite clinical outcome including death, amputation, ongoing/recurrent ischemia, and major morbidity was analyzed on an intent-to-treat basis at 30 days and 1 year.

RESULTS

The average duration of graft occlusion was 34.0 days, with 58 (48%) presenting with acute ischemia (0 to 14 days) and 64 (52%) with chronic ischemia (> 14 days). Thirty-nine percent randomized to lysis failed catheter placement and required surgical revascularization. Overall, there was a better composite clinical outcome at 30 days (P = 0.023) and 1 year (P = 0.04) in the surgical group compared with lysis, due predominately to a reduction in ongoing/recurrent ischemia, most notable in autogenous grafts. However, following successful catheter placement, patency was restored by lysis in 84%, and 42% had a major reduction in their planned operation. One-year results of successful lysis compared favorably with the best surgical procedure, which was new graft placement. Acutely ischemic patients (0 to 14 days) randomized to lysis demonstrated a trend toward a lower major amputation rate at 30 days (P = 0.074) and significantly at 1 year (P = 0.026) compared with surgical patients, while those with > 14 days ischemia showed no difference in limb salvage but higher ongoing/recurrent ischemia in lytic patients (P < 0.001). Patients with occluded prosthetic grafts had greater major morbidity than did those with occluded autogenous grafts (P < 0.02).

CONCLUSIONS

Proper catheter positioning currently limits the potential of catheter-directed thrombolysis for lower extremity bypass graft occlusion. Patients with graft occlusion > 14 days have a significantly better outcome when treated surgically, with a new bypass being the best surgical option. However, in patients with acute limb ischemia (< 14 days) successful thrombolysis of occluded lower extremity bypass grafts improves limb salvage and reduces the magnitude of the planned surgical procedure. Patients with occluded prosthetic grafts suffer more major morbid events compared with occluded autogenous grafts.

Thrombolysis theraphy in patients with femoropopliteal synthetic graft occulsions

BACKGROUND

The aim of this study was to evaluate the efficiency of thrombolysis in the presence of an occluded femoropopliteal synthetic graft.

PATIENTS AND METHODS

Over a 3-year period, 46 occluded femoropopliteral grafts were treated with urokinase and reconstruction. The cases were divided into three groups: group 1 (n=25), complete thrombolysis followed by reconstruction or angioplasty or both; group 2 (n=5), complete thrombolysis alone; and group 3 (n=16), failure of thrombolysis requiring reconstruction or leading to amputation. Patients were completely observed after treatment for more than 1 year.

RESULTS

There are no fatal complications among patients with thrombolytic therapy. In group 1, the 3-year patency rates were 12% and the 3-year limb salvage rates were 77%. In group 2, the 3-year patency rates and the limb salvage rates were 20% and 80%, respectively. The group 3 patency rates and the limb salvage were 8% and 40%, respectively. The best results were achieved in patients who had thrombolysis followed by reconstruction (group 1) and in those who had thrombolysis alone (group 2). limb salvage was poor in patients with failure of lytic therapy regardless of the reconstruction (P<0.01).

CONCLUSION

The use of intra-arterial urokinase followed by secondary vascular reconstructive procedures was studied. The patient with synthetic graft occlusion still has a reasonably favorable prognosis for long-term limb salvage when thrombolysis is successful.

The merit of polytetrafluoroethylene extensions and interposition grafts to salvage failing infrainguinal vein bypasses

PURPOSE

The purpose of this study was to evaluate the merit of polytetrafluoroethylene (PTFE) extensions and interpositions for the management of failing infrainguinal vein bypass grafts.

METHODS

The treatment of 133 failing vein grafts in 125 patients over a 10-year period was retrospectively reviewed. Twenty-two graft-threatening lesions were detected in patients who did not have a usable autogenous vein conduit as determined by preoperative and intraoperative evaluations. A PTFE extension or interposition graft was used for the necessary reconstruction in all cases.

RESULTS

Ten lesions were within the vein graft, 11 were proximal to the graft in the femoral or popliteal artery segments, and one was distal to the graft in the popliteal artery. The treatment of these lesions included 19 extensions and three mid graft interpositions. The vein graft lesions developed significantly sooner (mean 10.6+/-2.5 months) after the bypass (p<0.05) than the arterial lesions (mean 28.0+/-6.1 months). The 3-year cumulative secondary patency rate for these vein grafts treated with PTFE extensions or interpositions was 84%+/-8%. This was not significantly different from the 3-year cumulative secondary patency rate for vein grafts treated with vein extensions or interpositions at our institution over the same time period (82%+/-10%). The 3-year limb salvage rates were 95% and 89%, respectively.

CONCLUSIONS

These results indicate that PTFE extensions and interpositions can be used successfully to maintain the patency of failing vein grafts and may serve to prolong limb salvage in patients without any usable autogenous vein. Early reintervention with a PTFE conduit in this difficult group of patients is appropriate to salvage a failing vein graft.

The case for better research standards in peripheral thrombolysis: poor quality of randomized trials during the past decade

RATIONALE AND OBJECTIVES

We assessed how well published randomized controlled trials (RCTs) of peripheral thrombolysis have been designed and how they adjusted for patient characteristics that may influence responses to therapy.

METHODS

RCT studies published between 1984 and 1994 were reviewed to determine whether they included nine crucial elements: sample size calculations, description of unenrolled eligible participants, homogeneous samples, balanced experimental groups, equal potency therapies, equal follow-up of outcomes, appropriate statistical inference, multivariable or subgroup analyses, and anonymous review of subjective endpoints.

RESULTS

The nine RCTs complied with a median of three of nine standards (range = 2-6). Each report exhibited serious flaws that may affect generalizability and external validity. None adequately adjusted for sample heterogeneity or sought to identify characteristics that may affect responses to therapy.

CONCLUSION

Failure to address prognostic or confounding variables restricts the utility of peripheral thrombolysis RCTs and helps explain why contentious debates about this therapy persist. A model for future thrombolysis trials is proposed.

Treatment of anastomotic bypass graft stenosis with directional atherectomy: short-term and intermediate-term results

PURPOSE

Areas of anastomotic stenosis in lower-extremity bypass grafts (BPGs) were treated by means of directional atherectomy (DA) in hopes of achieving better patency rates than have been reported with percutaneous transluminal angioplasty (PTA).

MATERIALS AND METHODS

During a 4-year period, 17 patients (11 men and six women) with 23 areas of anastomotic stenosis in 18 lower-extremity BPGs were selected for treatment with DA. Urokinase thrombolysis was initially performed in eight BPGs that were thrombosed at the time of presentation. Adjunctive preatherectomy PTA was performed in six lesions, and postatherectomy PTA was performed in three lesions.

RESULTS

The technical success rate for DA was 92% (23 of 25 sites). There was less than 50% restenosis at 74% of the areas of stenosis (14 of 19 sites), with a mean follow-up time for the sites of 13 months. The graft patency rate was 88% (14 of 16 grafts), with a mean follow-up time for the grafts of 14 months. Areas of stenosis treated with DA alone had the same patency rates as those treated with DA and PTA.

CONCLUSIONS

DA is an effective treatment method for anastomotic peripheral arterial BPG stenosis. The intermediate-term patency rates following DA are superior to those reported for PTA and similar to those reported for surgical revision.

Is thrombolysis of occluded popliteal and tibial bypass grafts worthwhile?

PURPOSE

We analyzed the short- and long-term results for patients undergoing thrombolysis of occluded infrainguinal bypass grafts at our institution over a 62-month period.

METHODS

Thirty-one patients with 40 episodes of graft thrombosis in 33 grafts managed by thrombolysis were retrospectively reviewed. The effects of graft age, material, and anatomy, symptoms, treatment, anticoagulation, and occlusion duration were evaluated for impact on patency after thrombolysis. Dose and duration of therapy with use of the technique of pulse-spray thrombolysis was assessed.

RESULTS

Thrombolysis successfully reestablished patency in 92% of grafts treated. Mean lysis time and urokinase dose were 118 minutes and 607,000 units, respectively. Responsible lesions were identified and treated by angioplasty or surgery in 35 of 37 cases. The patency rate after thrombolysis was 28% at 30 months, and the secondary patency rate was 46% at 18 months. Duration of occlusion, symptoms, treatment, graft anatomy, and prior graft revision did not impact on patency. Mean secondary patency was 21.5 months in grafts in place over 1 year and 7.0 months in grafts in place for less than 1 year. Mean secondary patency was 23.8 months in polytetrafluoroethylene grafts and 8.4 months in vein grafts. The limb salvage rate was 84% at 30 months, and the patient survival rate was 84% at 42 months.

CONCLUSIONS

Pulse-spray thrombolysis is effective in rapidly recanalizing thrombosed infrainguinal grafts. Grafts failing in the first year after placement should generally be replaced, reserving thrombolysis and revision for grafts greater than 1 year old. Vein grafts tolerate thrombosis less well than synthetic conduits and have decreased long-term patency.

A comparison of thrombolytic therapy with operative revascularization in the initial treatment of acute peripheral arterial ischemia

PURPOSE

Despite the widespread use of intraarterial thrombolytic therapy for peripheral arterial occlusive disease, a randomized study comparing its efficacy with that of operative intervention has never been performed. This study evaluates the potential of intraarterial urokinase infusion to provide clinical benefits in patients with acute peripheral arterial occlusion.

METHODS

Patients with limb-threatening ischemia of less than 7 days' duration were randomly assigned to intraarterial catheter-directed urokinase therapy or operative intervention. Anatomic lesions unmasked by thrombolysis were treated with balloon dilation or operation. The primary end points of the study were limb salvage and survival.

RESULTS

A total of 57 patients were randomized to the thrombolytic therapy group, and 57 patients were randomized to the operative therapy group. Thrombolytic therapy resulted in dissolution of the occluding thrombus in 40 (70%) patients. Although the cumulative limb salvage rate was similar in the two treatment groups (82% at 12 months), the cumulative survival rate was significantly improved in patients randomized to the thrombolysis group (84% vs 58% at 12 months, p = 0.01). The mortality differences seemed to be primarily attributable to an increased frequency of in-hospital cardiopulmonary complications in the operative treatment group (49% vs 16%, p = 0.001). The benefits of thrombolysis were achieved without significant differences in the duration of hospitalization (median 11 days) and with only modest increases in hospital cost in the thrombolytic treatment arm (median $15,672 vs $12,253, p = 0.02).

CONCLUSIONS

Intraarterial thrombolytic therapy was associated with a reduction in the incidence of in-hospital cardiopulmonary complications and a corresponding increase in patient survival rates. These benefits were achieved without an appreciable increase in the duration of hospitalization and with only modest increases in hospital cost, suggesting that thrombolytic therapy may offer a safe and effective alternative to operation in the initial treatment of patients diagnosed with acute limb-threatening peripheral arterial occlusion.

Role of angioscopy in reoperation for the failing or failed infrainguinal vein bypass graft

The purpose of this retrospective study is to review our ongoing experience with the use of angioscopy during reoperation for failed or failing infrainguinal vein bypass grafts and define the role of angioscopy in the management of this clinically demanding patient group. All hospital records, arteriograms, and intraoperative angioscopic video recordings of 79 consecutive failed or failing grafts (76 patients) examined with angioscopy during reoperation between 1987 and 1993 were reviewed. Clinical and intraoperative data, comparison of the preoperative arteriogram and intraoperative angioscopic findings, and surgical decisions or interventions resulting from the additional angioscopic findings were collated and analyzed according to a predetermined protocol. Sixty-six additional angioscopic findings were noted during the 79 reoperations and resulted in 61 additional interventions and surgical decisions with salvage of all or part of the graft in 90.9% in the early (< 30 day) failed (group 1), 84.6% in the late (> 30 day) failed (group 2), and 90.3% in the late (> 30 day) failing grafts (group 3). The amount of residual thrombus within the graft, as assessed by angioscopy after all interventions, was the critical determinant for overall early graft patency (p < 0.001) and long-term patency for all the subgroups after reoperation (group 1, p < 0.001; group 2, p = 0.0016; and group 3, p = 0.0194). Intraoperative angioscopy has an important role in these challenging procedures. It provides additional and useful information that not only influences the conduct and extent of the reoperative surgery but may provide insights into the pathogenesis of graft failure.

Continuous postoperative intra-arterial urokinase infusion in the treatment of no reflow following revascularization of the acutely ischemic limb

The loss of distal tissue perfusion sufficient for limb salvage following restoration of inflow to an acutely ischemic extremity has been referred to as the "no-reflow" phenomenon. We hypothesized that patients with no reflow and limb-threat ischemia might benefit from prolonged postoperative intra-arterial infusion of the thrombolytic agent urokinase (UK). Twelve patients with arteriographic and clinical evidence of no reflow following a lower extremity arterial thrombectomy and/or bypass procedure were treated with a continuous intra-arterial UK infusion in the immediate postoperative period. The mean duration of UK infusion was 47 hours (range 15 to 112 hours). The mean rate of infusion was 58,000 units/hr (range 30,000 to 100,000 units/hr). Seven patients required transfusion for bleeding from the treated extremity (mean 3.4 units packed cells) and one required reoperation for a groin hematoma. Plasma fibrinogen levels remained within the normal range in all patients, and no systemic bleeding complications were encountered. The intra-arterial UK infusion resulted in limb salvage in 7 of 12 patients. Six patients have viable, functional extremities at a mean follow-up interval of 24.9 months (range 6.4 to 49.7 months). One patient required below-knee amputation 6 months after treatment for progressive ischemia. The other five patients required below-knee amputation during the same hospitalization after UK failed to restore distal perfusion. The postoperative period is widely considered to be a contraindication to thrombolytic therapy. Our experience indicates that while UK may cause bleeding from the treated extremity, which in some cases requires transfusion, there is no evidence of systemic fibrinolysis or systemic hemorrhage.(ABSTRACT TRUNCATED AT 250 WORDS)

Revascularization of the limbs with urokinase and TEC catheter endarterectomy for occluded bypass grafts

Occlusion of a femoral-popliteal or a femoral-tibial bypass graft on a prior occluded superficial femoral artery or the popliteal artery (in cases of ischemia of the legs) creates a complicated problem that may result in limb loss. The revascularization of such limbs with a repeat femoral-tibial or peroneal bypass is difficult and results in a high rate of limb loss from failure of the repeat grafts. Therefore, attempts were made to re-open the grafts through urokinase administration and thrombolysis for the grafts. To address the distal critical stenosis, or occlusion, the urokinase administration and thrombolysis were followed by endovascular endarterectomy using a thromboembolytic catheter (TEC). From 1990 to 1992, the above protocol was followed with 15 patients. In all patients, the protocol included 24 to 48 hours of urokinase administration with 60,000 to 120,000 U of urokinase per hour. A distal pathology was detected in all 15 patients, of whom 8 had complete occlusion at the site of distal anastomosis, 7 had critical stenosis ranging from 90% to 99%, and 1 was found to have a proximal critical stenosis at the femoral-graft junction. TEC catheter endarterectomy was performed to address the problem of occlusion and critically stenosed distal anastomotic lesions; a 100% success rate was immediately achieved, with flow being re-established to the distal limb. Fourteen of 15 patients remained well revascularized for more than 1 year. One patient experienced re-occlusion after 8 months; the occlusion was re-opened using the same technique of urokinase administration and the use of the TEC catheter, in which case the graft subsequently remained open. The longest follow-up of one patient is more than 2 years, during which time the graft has stayed open. With the aforementioned results, after revascularization of the ischemic limbs from occluded bypass grafts, it is strongly recommended that urokinase administration, along with TEC endovascular endarterectomy, be used to establish the circulation when occluded grafts threaten limb loss.

Thrombolytic therapy of synthetic graft occlusions before vascular reconstructive procedures

The objective of this study was to evaluate the impact of thrombolysis of synthetic grafts before urgent vascular reconstruction. In 29 patients, 41 thrombosed synthetic grafts that underwent intraarterial thrombolysis were studied. The cases were divided into three groups: group I--complete thrombolysis followed by reconstruction; group II--complete thrombolysis alone; and group III--incomplete lysis requiring reconstruction or sympathectomy. Follow-up ranged from 1 to 556 days (mean: 149 days). Kaplan-Meier analysis was used to determine patency and limb salvage rates. One-year patency and limb salvage rates were 53% and 95%, 34% and 67%, and 38% and 48%, respectively, for groups I, II, and III. Eighteen complications occurred in 16 of the 41 (39%) episodes. One patient died of intracranial hemorrhage. The best results were achieved when complete lysis was followed by appropriate reconstruction. Patency was equally poor in complete thrombolysis alone and reconstructions required by incomplete thrombolysis. Limb salvage was better after complete thrombolysis, regardless of the appropriate reconstruction.

Low-dose urokinase regimen for the treatment of lower extremity arterial and graft occlusions: experience in 132 cases

In a retrospective review, a low-dose urokinase (UK) infusion regimen (mean, 87,000 U of UK per hour and 100 U of heparin per hour) was evaluated for lower extremity arterial and graft occlusions. Results of 132 infusions in 111 patients were analyzed to determine efficacy, limb salvage, and complications. Angiographic success was achieved with 126 infusions (95%), and amelioration of presenting signs and symptoms was achieved after 116 infusions (88%). Patients who underwent additional percutaneous procedures were more likely to have a successful outcome. There was no significant difference in success rates for patients receiving low-dose heparin through the arterial sheath (n = 101) versus those receiving concomitant systemic heparinization (n = 29), (P = .08) [corrected]. Of 88 threatened extremities (with rest pain, cold, ulcers, or gangrene), nine were amputated (limb salvage = 90%), accounting for 82% (nine of 11) of amputations in the overall study. Patients with zero- or one-vessel runoff before infusion were more likely to require limb amputation compared with the group with two- or three-vessel runoff before infusion (P less than .01). Major periprocedural complications occurred in nine of 132 (7%) infusions, five of which necessitated specific surgery and/or transfusion for bleeding. Pericatheter thrombosis was not encountered in either subgroup. This standard local low-dose infusion represents a safe and effective treatment for lower extremity arterial and graft occlusions.

Recanalization of an occluded aortoiliac bypass graft with Palmaz stents

Four tandem Palmaz balloon-expandable vascular stents were used to recanalize the completely occluded limb of an aortoiliac bypass graft after failure of thrombolysis and conventional angioplasty. The resting peak-systolic pressure gradient across the occluded limb was reduced from 68 to 13 mm Hg. The patient's rest pain resolved, and the ankle-brachial index rose from 0.54 to 0.78. No embolization or stent-related complications occurred. The graft remains patent as determined with noninvasive studies obtained 8 months later.

Urokinase infusion of chronically occluded femoropopliteal Gortex bypass grafts via the popliteal approach

Thrombolysis of two occluded above-knee femoropopliteal Gortex bypass grafts utilizing the popliteal approach for catheter placement was successfully performed without complication. In both cases, the proximal anastomoses of the graft could not be identified. A percutaneous popliteal approach was used for catheter placement and delivery of urokinase. Angioplasty was performed on the unveiled stenoses that, presumptively, led to graft closure. Selective thrombolysis via catheter placed from popliteal approach is a new technique for recanalization of occluded femoropopliteal bypass grafts and warrants further investigation.

Thrombolytic therapy in the management of acute limb ischaemia

Acute limb ischaemia poses a threat to both the limb and life of a patient. Until recently, attempted revascularization by thromboembolectomy or vascular reconstruction held the best chance of limb salvage. Thrombolytic techniques afford an alternative method of management for this condition and are effective in selected patients. Low-dose intra-arterial streptokinase is the most established method of thrombolysis, although the recently developed tissue plasminogen activator offers a promising alternative. Intra-arterial thrombolysis is not an easy option, being labour intensive and requiring close co-operation between surgeon and radiologist. Thrombolytic and surgical techniques are not mutually exclusive but are best used to complement each other. Ideally patients with acute limb ischaemia should be managed by surgeons with knowledge of, and access to, optimal current surgical and non-surgical techniques.

Urokinase infusion: feasibility of monitoring for complications in a non-intensive care setting

In an effort to more effectively use critical care facilities and to reduce costs, during a 2 1/2-year period, the condition of 32 patients who received 37 local intraarterial urokinase (UK) infusions was monitored in a non-intensive care unit (ICU) setting. Techniques of infusion, mean total dose of lytic agent used (1.7 million IU), and mean duration of infusion (22 hours) were similar to those reported previously in series of patients monitored in the ICU. Complete lysis (no angiographically detectable residual clot within the treated segment) was achieved in 28 of 37 infusions (76%). Major complications occurred during two infusions (5.4%). In 33 of the 37 cases, systemic heparin was administered during UK infusion. No cases of pericatheter thrombosis were encountered. At the authors' institution, patients can be safely monitored during local UK infusion in a non-ICU setting without compromising effectiveness of therapy. This approach has resulted in enhanced cost-effectiveness of thrombolytic therapy and more effective use of critical care facilities.

Multilevel infusion catheter for use with thrombolytic agents

A new multilevel infusion catheter for administration of thrombolytic agents is described that provides near equal flow distribution through each of four infusion ports. Advantages of the catheter include fluoroscopically visible infusion length markers, small size (4.7 F), and secure positioning of the catheter within the occluded segment of graft or vessel. This catheter was used for infusion of urokinase in the treatment of 20 peripheral vascular occlusions. Complete or near complete thrombolysis was achieved in all cases.

Fibrinolytic therapy for infra-inguinal synthetic graft occlusions

The results of infra-inguinal graft fibrinolysis are variable, and the true success rates are frequently disguised by the inclusion of patients receiving adjunctive surgery, such as surgical thrombectomy, anastomosis revision and graft extension. Follow-up is sparse. As part of a larger prospective study, we have offered fibrinolysis using streptokinase to 10 patients with occluded infra-inguinal synthetic grafts. In one patient the graft could not be entered with a catheter. The remaining nine patients received local low-dose intra-arterial streptokinase. Six patients experienced complete lysis and were discharged with functioning grafts. Significant stenoses were dilated by transluminal angioplasty. The median graft patency duration was 7 months. Two patients have since required above-knee amputations. Our results using transluminal angioplasty are comparable to those results where adjunctive surgery has been used to treat underlying anastomotic stenoses. Further research into graft anastomotic stenosis management is indicated.