Use and limitations of thrombolytic therapy in the treatment of peripheral arterial ischemia: results of a multi-institutional questionnaire

Consultations on Patients with Venous or Arterial Diseases

Advances in vascular biology and drug development, as well as improved interventional techniques, are yielding multiple new treatments for patients with venous and/or arterial thrombosis. Hematologists who are providing consultations for these patients often participate in a multidisciplinary approach to provide optimal care. New anticoagulants, simplified and validated tests for detecting vascular disease, and improved interventional procedures can all reduce the morbidity and mortality that result from venous and arterial thrombosis. In this chapter, different aspects of the diagnosis and treatment of these disorders are addressed by a hematologist, an expert in vascular medicine, and a vascular surgeon.

The key to the prevention and treatment of venous and arterial thrombosis is anticoagulant and antiplatelet therapy. In Section I, Dr. Charles Francis, a hematologist with expertise in thrombosis and hemostasis, describes the clinical trials that have resulted in the approval of newer anticoagulants such as fondaparinux and the thrombin- specific inhibitors. He also reviews the clinical trials that have shown the efficacy of the new oral anticoagulant ximelagatran. Although currently under study primarily for the prevention and treatment of venous thrombosis, these anticoagulants are likely to undergo evaluation for use in arterial thrombosis.

Peripheral arterial disease (PAD), which affects as many as 12% of individuals over the age of 65 years, provides a diagnostic and therapeutic challenge to physicians across multiple subspecialties. Dr. William Hiatt, a specialist in vascular medicine, discusses in Section II the epidemiology and manifestations of PAD, the best ways in which to diagnose this disorder and determine its severity, and the most appropriate pharmacologic treatment.

In Section III, Dr. Mark Jackson, a vascular surgeon, describes interventional procedures that have been developed or are under development to treat arterial thrombosis. He also reviews the status of inferior vena caval filters that are retrievable.

Initial clinical results of tenecteplase (TNK) in catheter-directed thrombolytic therapy

PURPOSE

To investigate the safety and immediate efficacy of 2 different doses of tenecteplase (TNK) in peripheral catheter-directed thrombolytic therapy of arterial occlusions and deep vein thrombosis (DVT).

METHODS

Over a 20-month period, 63 nonconsecutive patients underwent catheter-directed thrombolytic therapy with either 0.25 mg/h or 0.50 mg/h of TNK in a nonrandomized, open-label study. Of these, 55 patients (60 limbs) were treated for DVT (36 limbs in 16 men and 15 women; mean age 41 years, range 21-73) or peripheral arterial occlusions (24 limbs in 16 men and 8 women; mean age 63 years, range 32-91). The primary endpoints were major bleeding complications and angiographic reduction in clot burden.

RESULTS

The mean duration of infusion was 18 +/- 4 hours in patients with arterial occlusions and 30 +/- 13 in those with DVT. Twenty-one (87.5%) patients with occlusive disease had marked or complete lysis of clot. Thirty (83.3%) limbs with DVT had either marked or complete resolution of thrombus. There were 4 (7.3%) episodes of minor bleeding with 1 (1.8%) major hemorrhagic event. Fibrinogen levels dropped by an average of 23%.

CONCLUSIONS

Preliminary evidence suggests that TNK doses of 0.25 mg/h to 0.50 mg/h appear to be safe and effective. The potential benefits of TNK therapy warrant further investigation.

Thrombolysis for native arterial occlusions of the lower extremities: clinical outcome and cost

INTRODUCTION

Intra-arterial thrombolysis is commonly used as the initial treatment of acute or subacute lower extremity ischemia.

METHODS

To evaluate the efficacy and cost of thrombolysis, we retrospectively analyzed 100 consecutive cases (87 patients) in which intra-arterial lysis (urokinase) was used as the initial treatment for native arterial lower extremity occlusive disease. The mean age of patients was 67 years, 57% of the patients were male, and preexisting peripheral vascular disease was present in 74%. Presenting symptoms were limb-threatening ischemia (53%) and claudication (47%). Acute symptoms (< 2 weeks' duration) were present in 48%.

RESULTS

The 30-day morbidity rate was 31%, and four patients died. Complications were significant bleeding (23%), ischemic stroke (1%), and renal failure with (2%) and without (2%) dialysis. Concomitant angioplasty was performed in 63%. Complete or significant lysis as demonstrated with angiography was achieved in 75% of iliac, 58% of femoropopliteal, and 41% of crural vessels (P <.001). Within 30 days of lysis, 9% of patients underwent major amputation and 20% surgical revascularization (in 3 patients the extent of revascularization was lessened by the lytic therapy). Amputation-free survival was 83% and 75% at 6 months and 2 years, respectively. Relief of ischemia (defined as relief of claudication or limb salvage without major surgical intervention) was achieved in only 70% and 43% of patients at 30 days and 2 years, respectively (Kaplan-Meier analysis; mean follow-up, 31 months). Patients with aortoiliac disease had significantly better outcomes than those with infrainguinal disease (P =.03). Duration or type of presenting symptoms did not predict outcome. The cost of the initial hospitalization per patient for thrombolysis was $18,490.

CONCLUSION

Thrombolysis can be as or more costly than surgery and is associated with a suboptimal outcome in a significant number of patients. These data lead us to caution against a uniform policy of initial thrombolysis for patients who present with lower extremity ischemia.

Complications associated with the use of urokinase and recombinant tissue plasminogen activator for catheter-directed peripheral arterial and venous thrombolysis

PURPOSE

Catheter-directed thrombolytic dissolution of peripheral arterial and venous thrombus is in widespread use, yet the frequency and nature of associated complications remain ill defined. In an effort to better characterize the complications associated with urokinase (UK) and recombinant tissue plasminogen activator (rt-PA), the clinical course of patients treated for lower extremity vascular occlusions at a single institution was reviewed.

MATERIALS AND METHODS

Over a 9-year period, 653 consecutive patients were treated for lower extremity arterial (527 patients) or venous (126 patients) occlusions with catheter-directed UK (483 patients), rt-PA (144 patients), or both (26 patients). Decisions regarding the choice of thrombolytic agent were made by the clinician. In-hospital complications were subcategorized into hemorrhagic and nonhemorrhagic events and the rate of intracranial hemorrhage was specifically tabulated.

RESULTS

There were no significant differences in the demographics or clinical presentation of patients treated with either UK or rt-PA. Bleeding complications occurred less often in the patients treated with UK (insertion site hematoma 21.9% vs. 43.8%, P<.0001, any bleeding necessitating transfusion 12.4% vs. 22.2%, P = .004, and intracranial hemorrhage 0.6% vs. 2.8%, P = .031). Cardiopulmonary complications necessitating transfer to the intensive care unit occurred more frequently in the patients treated with rt-PA (4.9% vs. 1.5%, P = .015). The risk of mortality was not statistically different between the UK and rt-PA treated patients (2.7% vs. 6.2%, P = .221).

CONCLUSIONS

Thrombolysis appears safer with UK than with rt-PA, with a lower incidence of hemorrhagic complications. It is possible that this finding is related to differential dosing regimens or intrinsic pharmacologic differences between the agents. The observations of this retrospective analysis require confirmation with a prospective, randomized evaluation.

Coronary and Peripheral Thrombolysis: Current Status and Recommendations

Thrombolytics are mainly indicated in acute myo cardial infarction (AMI), with limited evidence of usefulness in stroke and acute peripheral arterial occlusion (PAO). Throm bolytics can successfully dissolve thrombi in any vessel, but clinical benefit varies according to the involved vascular bed. The anticipated clinical benefit of thrombolytics in treating AMI, stroke, and PAO must be carefully balanced against the risk of bleeding (especially intracranial hemorrhage). In AMI, fibrinolytic agents reduce mortality rates by as much as 30% when started within 6 h of symptom onset and by as much as 50% if given within 1 to 2 h. Therefore, the timing of fibrino lytic therapy largely determines the magnitude of reduction in mortality after AMI. Streptokinase is a well-documented treat ment for AMI, with r-TPA plus IV heparin enabling better results, specially in anterior MI and in the elderly. Reteplase was not superior to alteplase in GUSTO-III and TNK-TPA is in the early phase of investigation. However their ease of admin istration and potential for more potent and specific clot lysis may prove advantageous. In acute stroke, the most recently reported phase III trials of streptokinase and recombinant tissue plasminogen activator (r-TPA) have stressed the importance of the clinical benefit/hemorrhage risk balance. These studies sup ported the viewpoint that the use of fibrinolytic agents for stroke must be limited to r-TPA in well-characterized patients and with a narrow time window. Finally, local administration of thrombolytic agents in acute arterial thrombosis, mainly in the limbs, is commonly used by interventional radiologists. Goods results have been reported in terms of safety and effec tiveness in the treatment of acute lower extremity ischemia. The preliminary results of the Thrombolysis or Peripheral Ar terial Surgery (TOPAS) trial suggest that recombinant uroki nase therapy (4,000 IU/min) is associated with limb salvage and patient survival rates similar to those achieved with sur gery, concurrent with a reduced need for complex surgery after thrombolytic intervention.

In summary, AMI represents the most important indication for thrombolysis, with large amounts of data supporting its use. In acute stroke, there is less evidence of efficacy and it is limited to a few well-characterized patients, whereas local ad ministration in patients with acute PAO may favorably affect patient outcome despite of the absence of evidence of improved limb salvage. Key Words: Thrombolysis—Myocardial infarc tion—Stroke—Acute peripheral arterial occlusion.

Intraarterial urokinase for acute native arterial occlusion of the limbs

Since 1988, 49 limbs of 47 patients underwent intraarterial urokinase infusion for acute native artery occlusion. The time from the onset of ischemic symptoms ranged from 1 to 45 days (mean = 17.5). The arterial sectors involved were femoropopliteal in 32 cases, followed by aortoiliac in 13 cases, distal in three cases, and subclavian in one case. Treatment consisted of placing a catheter in the clot and the infusion of 4400 U/kg in 20', followed by a series of 4400 U/kg weight/hour during 6 hours. Clinical evaluation, hemodynamic and coagulation parameters, and angiographical changes were assessed periodically. Infusion time ranged from 6 to 24 hours (mean = 13.2 hours). Improvement of ischemic was achieved in 43 (87.75%) patients. In five patients (12.25%) there was no improvement. Total immediate lysis was achieved in 35 cases (71.5%), and among them, 13 patients (26%) required no associated treatment, 16 (48%) underwent PTA, and four (12%) had surgery of underlying peripheral aneurysms revealed after thrombolysis. Partial lysis was achieved in 13 cases (26.5%), that was enough in four of them, but the remaining nine required further treatment (four PTA, and five arterial surgery). In one case no lysis was achieved, and arterial surgery was carried out. No mortality was recorded, and major complications included one upper gastrointestinal bleeding, and one cerebral hematoma. Late follow-up of successfully treated patients who did not require further surgery shows a cumulative patency rate of 81% at 24 months.

Intra-arterial thrombolysis for the acutely ischaemic leg: experience in a district general hospital

Intra-arterial thrombolytic therapy (IATT) is a recognized treatment for acute on chronic lower limb ischaemia due to thrombosis when duration of therapy will not compromise limb viability. In this prospective study at a district general hospital, 36 consecutive patients (mean age 73.6 +/- 1.7 years) with acute lower limb ischaemia, presenting as severe and worsening claudication or rest pain, underwent urgent IATT using streptokinase (n = 35) or tPA (n = 1). Thrombolysis was monitored by daily angiography. IATT was performed alone in 26 patients and in conjunction with angioplasty in a further 10 patients. Mean treatment duration was 2.27 + 0.25 days. The 30 day mortality was 11.1% Complications abbreviated IATT in 8.3%. The 30 day primary limb salvage rate for IATT +/- angioplasty was 44.4% (16/36). The mean ABPI pre IATT +/- angioplasty was 0.19 +/- 0.04(n = 35) compared with 0.52 +/- 0.08 after IATT +/- angioplasty (n = 31) (P < 0.011). Eight patients without clinical benefit underwent salvage surgery with a secondary limb salvage rate of 61%. ABPI post-salvage surgery was similarly increased to 0.54 +/- 0.17. Intra-arterial thrombolytic therapy for the acutely ischaemic leg in a district general hospital, may contribute to limb salvage.

Limb arterial injuries associated with limb fractures: clinical presentation, assessment and management

OBJECTIVES

Review of limb arterial injuries associated with limb fractures.

DESIGN

Retrospective study.

SETTING

University Hospital.

MATERIALS AND METHODS

The clinical presentation, assessment and management of 25 patients with upper (seven) and lower (18) limb arterial injuries associated with limb bone fractures has been retrospectively reviewed.

MAIN RESULTS

Five patients presented with life threatening injuries and classic signs of acute limb ischaemia, 15 patients had an obvious limb arterial injury, and 5 presented with a suspected limb arterial injury. The site of arterial damage was: superficial femoral (4); popliteal (11); tibioperoneal trunk (3); anterior tibial (4); posterior tibial (3); peroneal (2); axillary (1); brachial (5); radial (4); and ulnar artery (4). The types of arterial repair were: autogenous vein interposition or bypass grafting (17); P.T.F.E. (2); end-to-end anastomosis (14); and ligation (8). The popliteal vein was injured in six cases, repaired in four and ligated in two; the superficial femoral vein was injured in four cases, repaired in three and ligated in one; and the axillary vein was injured in one case and was ligated. Primary nerve repair was employed in six out of seven injured nerves. Skeletal fixation preceded vascular repair in 21 patients and in four a Javid shunt was used. Intraoperative fasciotomy was performed in 12 out of 18 patients with lower limb ischaemia. Completion arteriography revealed residual thrombi in the distal foot of four patients, in whom intraarterial thrombolysis was effective. During the follow-up period of 1.5 to 2 years, the upper and lower limb preservation rate was 100 and 89%, respectively. The upper limb function was judged excellent in five patients, good in one and fair in one. In the lower limbs it was excellent in 11 patients, good in three, fair in one and poor in one.

CONCLUSIONS

To ensure life and functional limb salvage of patients with devastating vascular injuries, a well organised multidisciplinary approach is necessary.

Results of a prospective randomized trial evaluating surgery versus thrombolysis for ischemia of the lower extremity. The STILE trial

PURPOSE

This study was designed to evaluate intra-arterial thrombolytic therapy as part of a treatment strategy for patients requiring revascularization for lower limb ischemia caused by nonembolic arterial and graft occlusion.

MATERIALS AND METHODS

Patients with native arterial or bypass graft occlusion were randomized prospectively to either optimal surgical procedure or intra-arterial, catheter-directed thrombolysis with recombinant tissue plasminogen activator (rt-PA) or urokinase (UK). Thrombolysis patients required successful catheter placement into the occlusion before infusion of either rt-PA at 0.05 mg/kg/hr for up to 12 hours or UK of 250,000 units bolus followed by 4000 units/min x 4 hours, then 2000 units/min for up to 36 hours. A composite clinical outcome of death, ongoing/recurrent ischemia, major amputation, and major morbidity was the primary endpoint. Additional endpoints were reduction in surgical procedure, clinical outcome classification, length of hospitalization, and outcome by duration of ischemia.

RESULTS

Randomization was terminated at 393 patients because a significant primary endpoint occurred by the first interim analysis. Failure of catheter placement occurred in 28% of patients who were randomized to lysis, and thus, were considered treatment failures. Thirty-day outcomes demonstrated significant benefit to surgical therapy compared with thrombolysis (p < 0.001), primarily because of a reduction in ongoing/recurrent ischemia (p < 0.001). However, clinical outcome classification at 30 days was similar. Stratification by duration of ischemia indicated that patients with ischemic deterioration of 0 to 14 days had lower amputation rates with thrombolysis (p = 0.052) and shorter hospital stays (p < 0.04). Patients with ischemic deterioration of > 14 days who who were treated surgically had less ongoing/recurrent ischemia (p < 0.001) and trends toward lower morbidity (p = 0.1). At 6-month follow-up, there was improved amputation-free survival in acutely ischemic patients treated with thrombolysis (p = 0.01); however, chronically ischemic patients who were treated surgically had significantly lower major amputations rates (p = 0.01). More than half of thrombolysis patients (55.8%) had a reduction in magnitude of their surgical procedure (p < 0.001). There was no difference in efficacy or safety between rt-PA and UK; however, in the thrombolysis group as a whole, fibrinogen depletion predicted hemorrhagic complications (p < 0.01).

CONCLUSIONS

Surgical revascularization of patients with < 6 months of ischemia is more effective and safer than catheter-directed thrombolysis. Although ongoing/recurrent ischemia is greater in the patients undergoing thrombolysis, 30-day clinical outcomes are similar, probably because of cross-over treatment to surgery. There is no difference in efficacy or safety between rt-PA and UK, although bleeding occurs in patients with greater fibrinogen depletion. A significant reduction in planned surgical procedure is observed after thrombolysis. Patients with acute ischemia (0-14 days) who were treated with thrombolysis had improved amputation-free survival and shorter hospital stays. However, for patients with chronic ischemia (> 14 days), surgical revascularization was more effective and safer than thrombolysis. Combining a treatment strategy of catheter-directed thrombolysis for acute limb ischemia with surgical revascularization for chronic limb ischemia offers the best overall results.

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.

Failure of thrombolytic therapy to improve long-term vascular patency

PURPOSE

Few data are available on long-term follow-up of arterial segments subjected to thrombolysis. We reviewed all cases of vascular occlusion treated with urokinase to identify early success and determine the influence of postlysis intervention and the nature of the thrombosed segment (i.e., artery vs graft) on long-term patency.

METHODS

Data on 134 cases (58 arteries, 76 grafts) treated with high-dose urokinase infusion in the lower limbs over a 7-year period were analyzed. Limbs were divided into five groups on the basis of therapy after lytic infusion to determine long-term efficacy: group I, success with no additional therapy; group II, percutaneous angioplasty alone; group III, limited surgical procedure (operative angioplasty, jump graft); group IV, extensive procedure (new bypass); and group V, revascularization after lytic failure. Long-term results were assessed by life-table analysis and groups compared by log-rank test (Mantel-Haenszel).

RESULTS

Initial patency was established in 87 (64.9%) of 134 cases with 5 deaths (3.7%), 11 amputations (8.2%), and 16 complications (11.9%). Follow-up was available in 68.6% of cases for a mean of 10.9 months. No difference was seen between grafts and native arteries. Patency was analyzed at 6, 12, 18, and 24 months. The 24-month patency rate after lysis alone (group I-25.9%) was inferior (p < 0.05) to results after lysis and any subsequent intervention (groups II, III, and IV). The type of intervention did not influence subsequent patency. Twenty-four-month patency of procedures performed after failed thrombolysis (group V, 41.4%) was not different from those after successful lysis (groups I to IV). Twenty-four-month patency in groups II and III (minor interventions, 62.9%) was not significantly different from that of groups IV and V (major interventions, 53.2%) (p > 0.25).

CONCLUSIONS

Operative intervention is required to produce long-term arterial patency, even after successful thrombolysis. No statistically significant benefit of thrombolysis on vascular patency was seen in our series.

Thrombolysis in acute peripheral arterial occlusion: predictors of immediate success

Thrombolytic therapy is frequently used for the treatment of peripheral arterial occlusion, but clinical predictors of success have not yet been defined. We prospectively evaluated 80 consecutive patients receiving intra-arterial urokinase for acute (< 14 days) ischemia. Fifty-five patients (69%) were treated for bypass graft occlusion and 25 patients (31%) for native arterial occlusion. Two primary outcome measures were evaluated using multivariate techniques (stepwise logistic regression) to determine the independent predictors of immediate arteriographic success: successful (> 80%) thrombolysis and avoidance of adjuvant operative or endovascular procedures. Independent variables examined included age, sex, comorbid conditions, severity, duration, etiology and location of the ischemic process, and positioning of the infusion catheter and guidewire. Overall, successful lysis was achieved in 57 patients (71%) and adjuvant procedures were avoided in 22 patients (28%). Successful outcome was more frequent in prosthetic graft (78%) and native arterial (72%) occlusions than in vein graft occlusions (53%, p = 0.017) and in nondiabetics than in diabetics (80% vs. 52%, p = 0.031). Lysis was dependent on placement of the catheter into the substance of the thrombus (85% vs. 0% success, p = 0.004) and passage of a guidewire through the occlusive process (92% vs. 10% success, p = 0.001). The only parameter independently predictive of successful outcome without the use of adjuvant procedures was the location of the occlusion; additional procedures were necessary in 88% of aortoiliac and 82% of infrainguinal occlusions vs. only 17% of upper extremity occlusions (p = 0.005).(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: A Comprehensive Review of Its Use in Clinical Medicine. Part II

The second part of this comprehensive review of thrombolytic therapy in clnical medicien focuses on its use in a wide renge of thrombotic disorders, including pulmonary embolism, deep venous thrombosis, arterial thrombocmbolism, catheter-related thrombosis, arterial thrombocmbolism, catheter-relted thrombosis, and prosthetic valve occlusion. New experimental applications in the management of unstable angina and cerebrovascular disease are also discussed.

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.

Segmentally enclosed thrombolysis in percutaneous transluminal angioplasty for femoropopliteal occlusions: a report from a pilot study

Segmentally enclosed thrombolysis (SET) was performed immediately following 34 percutaneous transluminal angioplasties (PTAs) for femoropopliteal occlusions. The dilated segment was sealed off with a double balloon catheter, and recombinant tissue plasminogen activator (rt-PA) 1 mg/ml and heparin 200 IU/ml were injected between the balloons. The catheter was removed after 30 min and heparin treatment was continued for 24 h. Alpha-2-antiplasmin was initially reduced by 13% and normalized 2 h after SET, indicating that only small amounts of free plasmin were liberated during thrombolysis. No clinically relevant changes in plasma fibrinogen occurred. Two puncture site hemorrhages did not coincide with the coagulopathy induced by SET. One-year patency was 80%. Early rethrombosis occurred in 9% versus 41% in our previous series on standard PTA for femoropopliteal occlusions (p less than 0.001). Therefore, SET is considered beneficial in reducing the incidence of early rethrombosis.

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.

Intra-arterial thrombolytic therapy in the management of acute and chronic limb ischaemia

A group of 54 patients with acute or chronic limb ischaemia were initially treated with low dose intra-arterial thrombolytic therapy using streptokinase (10,000 units h-1) or plasminogen activator (0.5 mg h-1). Complete thrombolysis was obtained in 90 per cent of patients with symptoms of less than 1 week duration, and in 50 per cent with symptoms of greater than 1 week (P less than 0.05). Successful lysis in 36 patients was followed by successful bypass surgery in seven, percutaneous angioplasty in 13, no further treatment in 13, repeat thrombolysis in two and amputation in one. Failed therapy was associated with major amputation in 40 per cent. One patient died of haemorrhage and another of stroke as a direct result of thrombolytic treatment. The most common complication was haematoma at the site of cannulation of the vessel. Intra-arterial thrombolytic therapy can be very useful for the management of acute and chronic limb ischaemia, but complications do occur and patients should be carefully selected.

Survey of the use of thrombolysis for acute limb ischaemia in the UK and Ireland

A total of 156 vascular surgeons from the UK and Ireland responded to a postal questionnaire on the use of thrombolysis in acute limb ischaemia. Almost half had used thrombolysis in the previous 12 months. Low dose intra-arterial streptokinase (89 per cent) was the regimen most frequently used, but 33 per cent had used intravenous streptokinase. Detailed results for 103 patients (limb salvage rate 60 per cent, amputation rate 35 per cent, mortality rate 5 per cent) were similar to those of previously published reports. Complications in most series were infrequent, but in the entire survey there were six bleeding-related deaths and one death from anaphylaxis. A total of 67 per cent of surgeons with working experience indicated that selected patients with acute arterial thromboses were most suitable for thrombolysis, particularly if there was no neurological deficit and no run-off for surgical bypass. Distal or late emboli and graft occlusions were regarded as appropriate by some surgeons. This study demonstrated that many vascular surgeons currently use thrombolysis, although sparingly and in selected cases. Patients with acute limb ischaemia should be managed by experienced vascular surgeons who are aware of the new therapeutic alternatives, an ideal supported by almost three-quarters of respondents to this survey.

A protocol for the safe treatment of acute lower limb ischaemia with intra-arterial streptokinase and surgery

Over a 5-year period 70 patients, presenting with subacute ischaemia of the lower limb (more than 12 h), were treated with low-dose intra-arterial streptokinase. There were 72 infusions and effective lysis was achieved in 52 (72 per cent), with an average infusion time of 25 h. A total of 23 (32 per cent) also underwent percutaneous transluminal angioplasty when lysis showed an underlying stenosis, and a further 19 (26 per cent) required surgery to remove persistent stenosis, organized thrombus or atheromatous debris. Significant bleeding occurred in 4 patients (6 per cent) and 13 (18 per cent) underwent amputation. There were five deaths (7 per cent), one of which was directly related to the infusion, while three were due to myocardial infarction. All of the major complications occurred in the early part of the study and both the selection of patients and the technique of infusion were modified to improve safety. Complementary treatment by percutaneous transluminal angioplasty and surgery was used more frequently in the later part of the study. The technique is not recommended for the white leg of acute ischaemia (less than 12 h), or for lysis of clot in a retroperitoneal Dacron graft, but may be uniquely valuable to demonstrate the cause of subacute ischaemia.