Results of 100 cases of pulse-spray thrombolysis for acute and subacute leg ischaemia

Acute limb ischemia: contemporary approach

Acute limb ischemia is a critical condition with high mortality and morbidity even after surgical or endovascular intervention. Early recognition is important, but a delayed presentation is not uncommon. Viability of the limb is assessed by motor and sensory function and with interrogating Doppler flow signals in pedal arteries and popliteal veins as categorized by Rutherford. Category IIa indicates mild-to-moderate threat to limb salvage over a time frame without revascularization. Limb ischemia is critical without prompt revascularization in category IIb. Because the risk of reperfusion injury is high in this group of patients, perioperative management is important. In category III, reperfusion is not indicated except for embolism within several hours of onset. Intimal injury should be avoided by careful tactile control of a balloon with a smaller size catheter and under radiographic monitoring. Adjunctive treatment with catheter-directed thrombolysis or bypass surgery is sometimes necessary. Endovascular treatment is a promising option for thrombotic occlusion of an atherosclerotic artery. Ischemia-reperfusion injury is a serious problem. Controlled reperfusion with low-pressure perfusion at a reduced temperature and use of a leukocyte filter should be considered. The initial reperfusate is hyperosmolar, hypocalcemic, slightly alkaline, and contains free radical scavengers such as allopurinol. Immediate hemodialysis is necessary for acute renal injury caused by myoglobinemia. Compartment syndrome should be managed with assessment of intra-compartment pressure and fasciotomy.

Endovascular treatment of peripheral vascular disease

Peripheral arterial disease (PAD) affects about 27 million people in North America and Europe, accounting for up to 413,000 hospitalizations per year with 88,000 hospitalizations involving the lower extremities and 28,000 involving embolectomy or thrombectomy of lower limb arteries. Many patients are asymptomatic and, among symptomatic patients, atypical symptoms are more common than classic claudication. Peripheral arterial disease also correlates strongly with risk of major cardiovascular events, and patients with PAD have a high prevalence of coexistent coronary and cerebrovascular disease. Because the prevalence of PAD increases progressively with age, PAD is a growing clinical problem due to the increasingly aged population in the United States and other developed countries. Until recently, vascular surgical procedures were the only alternative to medical therapy in such patients. Today, endovascular practice, percutaneous transluminal angioplasty with or without stenting, is used far more frequently for all types of lower extremity occlusive lesions, reflecting the continuing advances in imaging techniques, angioplasty equipment, and endovascular expertise. The role of endovascular intervention in the treatment of limb-threatening ischemia is also expanding, and its promise of limb salvage and symptom relief with reduced morbidity and mortality makes percutaneous transluminal angioplasty/stenting an attractive alternative to surgery and, as most endovascular interventions are performed on an outpatient basis, hospital costs are cut considerably. In this monograph we discuss current endovascular intervention for treatment of occlusive PAD, aneurysmal arterial disease, and venous occlusive disease.

Thrombolysis for Acute Lower Limb Ischaemia—A Prospective, Randomised, Multicentre Study Comparing Two Strategies

OBJECTIVES

To test if initial high-dose, pulse-spray thrombolysis improves the early and late outcome of lower limb ischaemia as compared with low-dose infusion alone.

DESIGN

Prospective randomised multicentre study.

MATERIAL AND METHODS

Patients with acute and sub-acute (<30 days) lower limb ischaemia were randomised following angiography. Group 1 (n=58) received pulse-spray infusion of recombinant plasminogen activator (rt-PA, 15 mg/h) for 2h followed by low-dose infusion if needed. Group 2 (n=63) were only treated with low-dose infusion (0.5mg/h) of rt-PA for 48 h. Underlying lesions were corrected if required.

RESULTS

The study was stopped prematurely. Complications were equally frequent in both groups. More than 75% lysis was accomplished in 78 versus 67% of the patients (p=0.21). Primary endpoints (re-occlusion, incomplete lysis, life-threatening complication, amputation, or death) were reached in 24 versus 32% of the patients (p=0.35). Neither vascular patency nor clinical parameters differed during the first year, but re-interventions tended to be more frequent (p=0.040 at 1 month; p=0.090 at 1 year) and of a greater magnitude (p=0.028) in group 2.

CONCLUSIONS

There was no obvious advantage with initial high-dose thrombolysis, which may be a type-2 error. A reduction of major re-interventions was recorded.

Safety of Thrombolytic Therapy with Urokinase or Recombinant Tissue Plasminogen Activator for Peripheral Arterial Occlusion:A Comprehensive Compilation of Published Work

PURPOSE

To report a comprehensive literature review focused on comparing the risk of complications with urokinase versus recombinant tissue plasminogen activator (rtPA) for thrombolytic treatment of peripheral arterial occlusions.

METHODS

The English-language literature between 1985 and 2002 was searched for studies that used tissue-derived urokinase or rtPA in the treatment of peripheral arterial occlusions. Forty-eight studies (22 urokinase, 22 rtPA, and 4 that included both treatments) were identified, encompassing 2226 urokinase-treated patients and 1927 rtPA-treated patients. The safety of each thrombolytic agent was assessed based on the incidence of major hemorrhage, intracerebral hemorrhage, major limb amputation, transfusions, and mortality.

RESULTS

The review revealed a wide range of study protocols, patient conditions, ages of occlusions, dosages/delivery methods of lytic agents, and criteria for reporting complications. The incidence of major hemorrhage varied widely, but the overall rate was lower among urokinase-treated patients (6.2%) than for patients treated with rtPA (8.4%, p=0.007). The overall incidence of intracerebral hemorrhage was also significantly lower for urokinase (0.4% versus 1.1% for rtPA, p=0.020). The major amputation rate was similar for both treatments (urokinase 7.9%, rtPA 7.2%), but the mortality rate was significantly lower for urokinase (3.0% versus 5.6% for rtPA, p<0.001). The need for transfusions was less frequent with urokinase (11.1% versus 16.1%, p=0.002).

CONCLUSIONS

These results from a large body of published literature suggest that urokinase may be associated with a lower incidence of complications than rtPA in the treatment of peripheral arterial occlusions.

National Audit of Thrombolysis for Acute Leg Ischemia (NATALI): clinical factors associated with early outcome

OBJECTIVE

The National Audit of Thrombolysis for Acute Leg Ischemia (NATALI) database is a consecutive series of patients who underwent intra-arterial thrombolysis to treat acute leg ischemia in one of 11 centers in the United Kingdom. The purpose of the study was to analyze the factors associated with outcome after 30 days.

METHODS

The data were collected over 10 years on standard pro formas, and registration was completed at the end of 1999. Since then, data from each unit have been verified and missing data included when available. Univariate and multivariate analyses were performed, with the outcomes of amputation-free survival (AFS), amputation with survival, and death.

RESULTS

A total of 1133 thrombolytic events were included. Outcome results at 30 days for the entire group were AFS, 852 (75.2%); amputation, 141 (12.4%); and death, 140 (12.4%). Results for the entire group improved from the first half of the database, when AFS ranged from 65% to 75%, to almost 80% for the last few years of the study, although this was not statistically significant. Preintervention factors associated with lower AFS at multivariate analysis included diabetes (P =.002), increasing age (P <.001), short-duration ischemia (P =.027), Fontaine grade (P =.001), and ischemia with neurosensory deficit (P =.004). AFS was improved in patients receiving warfarin sodium at the time of the arterial occlusion (P =.04). Mortality was higher in women (P =.006) and in older patients (P <.001), and in patients with native vessel occlusion (P <.001), emboli (P =.02), or a history of ischemic heart disease (P <.001). Amputation risk was greatest in younger men (P <.001) and in patients with more severe ischemia (P =.02), graft occlusion (P <.001), or native vessel thrombotic occlusion (P =.02).

CONCLUSION

Experienced surgeons and radiologists can achieve an AFS of about 80% in selected patients with acute leg ischemia. Information from the NATALI database can be used in selection of an appropriate intervention in the individual patient.

Novel simultaneous combination chemical thrombolysis/rheolytic thrombectomy therapy for acute critical limb ischemia: The power-pulse spray technique

The novel power-pulse spray (P-PS) technique maximizes and combines the advantages and minimizes the disadvantages of both chemical thrombolysis (CT) and rheolytic thrombectomy (RT). Forty-nine consecutive patients with iliofemoral thrombotic occlusion were treated via P-PS technique. Using a 6 Fr RT catheter, saline prime was exchanged for thrombolytic solution [group 1, 10-20 mg tenecteplase (TNK)/50 cc saline, n = 25; group 2, 1,000,000 urokinase (UK)/50 cc saline, n = 24]. The outflow port was closed, then the catheter was advanced at 1 mm increments while pulsing lytic agent. After 30-min lysis time, RT and definitive treatment of the underlying stenosis were performed. Procedure success was 23/25 (92%) and 22/24 (91.6%) for group 1 and 2, respectively. The mean total procedure time was 72 and 75 min in group 1 and 2, respectively. Thirty-day limb salvage was 91% in both groups. There were no major surgical complications. The P-PS technique is safe and effective using either UK or TNK, offering several potential advantages over monotherapy, including more rapid revascularization, decreases systemic lytic exposure and bleeding complications while facilitating both CT and RT capacity and efficacy.

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.

Economic value of thrombolysis with adjunctive abciximab in patients with subacute peripheral arterial occlusion

BACKGROUND AND OBJECTIVE

Glycoprotein (GP) IIb/IIIa receptor inhibitors enhance thrombolysis in patients with acute coronary syndromes. This analysis evaluates the economic impact of abciximab, a GP IIb/IIIa inhibitor, as an adjunct to urokinase in peripheral artery occlusions of less than 6 weeks duration.

STUDY DESIGN

A post-hoc economic analysis was performed using clinical data and inpatient resource utilisation derived from the prospective comparative phase II Platelet Receptor Antibodies in Order to Manage Peripheral Artery Thrombosis (PROMPT) pilot study. Study endpoints were amputation-free survival and survival without open surgery or major amputation after 90 days, and the rate of major complications at 30 days.

PERSPECTIVE

Third-party payer and the societal perspective.

PATIENTS AND METHODS

Seventy patients with lower extremity thrombi were randomised (2 : 5 ratio) to urokinase plus placebo or to urokinase plus abciximab. Economically relevant data were retrospectively derived from the clinical study database from a specific evaluation of patient records and from expert opinion.

RESULTS

From the viewpoint of the society, average total per-patient direct and indirect costs accruing over 3 months were more favourable for treatment with abciximab plus urokinase than for urokinase alone [9723 euros (EUR) vs EUR10 322; 2000 values], despite higher initial hospitalisation costs of the combination therapy. Abciximab plus urokinase was the dominant strategy at 3 months due to a clinically higher rate of survival without amputation or bypass surgery coupled with a lower average per-patient cost. From the perspective of the third-party payer, treatment with abciximab plus urokinase was economically also superior to urokinase alone (EUR8773 vs EUR9663).

CONCLUSIONS

Based on the preliminary findings of the PROMPT trial, the use of abciximab as an adjunct to urokinase in patients with subacute peripheral artery occlusions may be the favourable strategy compared with urokinase alone, in terms of clinical and economic outcomes. Further trials are needed to confirm these clinical and economic findings. The preliminary clinical benefits experienced by patients treated with abciximab plus urokinase in the PROMPT trial translated into cost savings in terms of reduced direct medical costs at 3 months. These cost savings more than offset the cost of abciximab. The use of abciximab as an adjunct to urokinase in patients with subacute peripheral artery occlusions may be the favourable strategy compared with urokinase-alone in terms of clinical and economic outcomes, but further trials are needed to confirm the these clinical and economic findings.

Peripheral artery occlusion: treatment with abciximab plus urokinase versus with urokinase alone--a randomized pilot trial (the PROMPT Study). Platelet Receptor Antibodies in Order to Manage Peripheral Artery Thrombosis

PURPOSE

To evaluate the combination of a platelet glycoprotein IIb/IIIa complex receptor inhibitor and urokinase for treatment of recent (<or=6 weeks) arterial occlusion of the legs.

MATERIALS AND METHODS

Seventy patients with lower extremity arterial occlusion of less than 6 weeks duration were randomly separated into two treatment groups: urokinase plus abciximab or urokinase plus placebo. Primary end points were the rate of major complications at 30 days after randomization and the rates of amputation-free survival and survival without open surgery or major amputation at follow-up of 90 days. Two readers unaware of the patients' treatment group assignments analyzed digital subtraction angiograms as they related to the study end points, with a final consensus reading.

RESULTS

Thrombolysis relative to clot length was faster in the urokinase-plus-abciximab group (odds ratio, 0.52; 95% CI: 0.35, 0.76; P < .001). There were no procedure-related deaths or intracranial hemorrhages, but the rate of nonfatal major bleeding was higher with urokinase plus abciximab (four of 50 patients) than with urokinase alone (none of 20 patients; P = .32). At 90 days, amputation-free survival was 96% (48 of 50 patients) in the urokinase-plus-abciximab group compared with 80% (16 of 20 patients) in the urokinase alone group. The hazard ratio for the two Kaplan-Meier curves was 0.42 (95% CI: 0.16, 0.96; P = .04).

CONCLUSION

In patients with lower extremity arterial occlusion who were undergoing urokinase thrombolysis, adjunctive abciximab treatment resulted in faster thrombus dissolution and improved amputation-free survival, despite an increase in major bleeding.

Thrombolytic therapy with use of alteplase (rt-PA) in peripheral arterial occlusive disease: review of the clinical literature. The Advisory Panel

PURPOSE

The clinical literature describing the use of alteplase in the treatment of peripheral arterial occlusive (PAO) disease is reviewed.

MATERIALS AND METHODS

The literature database was acquired by a MEDLINE search using the Boolean keyword string: tissue plasminogen activator and/or rt-PA and peripheral not animal. A review was performed to identify the dose range of alteplase, technique of infusion, use of anticoagulation, clinical success rates, and risk of complications.

RESULTS

Forty-six clinical studies were identified. There are few prospective, randomized clinical trials and a lack of standardized protocols and endpoints. Use of catheter-directed infusions of recombinant tissue plasminogen activator (rt-PA) may be beneficial versus surgery in the initial management of acute limb ischemia (< 14 days) and in reducing the magnitude of subsequent surgical or percutaneous revascularization. For patients with chronic limb ischemia (> 14 days), irreversible acute limb ischemia, or advanced diabetic arteriopathy, catheter-directed infusion of rt-PA or other plasminogen activators may be unsuitable. The risk of adverse bleeding appears related to the overall dose and duration of infusion. These risks appear similar to those of urokinase. The role of heparin in increasing adverse bleeding during rt-PA therapy is unclear.

CONCLUSIONS

There is no generally accepted dose or technique for administering catheter-directed thrombolysis using alteplase; however, several studies have demonstrated its clinical safety and efficacy. Formal studies will be required to determine the optimal dose, technique of infusion, the role of anticoagulation, and complication rates when alteplase is used for PAO disease.

The surgical management of acute limb ischaemia due to native vessel occlusion

OBJECTIVES

Data from the STILE study have indicated that for patients with subacute limb ischaemia due to native vessel occlusion, surgery is both more effective, and durable than thrombolysis. The purpose of this study was to evaluate the outcome of an aggressive surgical approach in patients presenting with acute limb-threatening ischaemia.

DESIGN

Details of patients presenting with salvageable acute limb ischaemia due to native artery occlusion over a 6-year period in a University hospital vascular unit setting were obtained from the vascular audit and the outcome of the surgical management of these patients was analysed.

RESULTS

One hundred and seventy-four consecutive patients underwent surgery for acute native vessel limb ischaemia (76% lower, 24% upper limb). Fogarty thrombectomy or embolectomy was initially performed in 153 (89%) patients. Of these, 37 (24%) immediately underwent a further procedure: 28 (18%) had on-table thrombolysis and 14 (9%) underwent vascular reconstruction. Twenty-six patients (15%) underwent further limb salvage surgery within 30 days. Life table analysis demonstrated a limb salvage rate of 88% and 76% at 30 days and 2 years, respectively. Patient survival was 75% and 48% at the same time intervals.

CONCLUSIONS

These results demonstrate that a role for aggressive surgical intervention still exists, resulting in high limb salvage rates.

Augmented pulse-spray thrombolysis with tPA by early pulsed intrathrombic plasminogen enrichment

PURPOSE

This study was designed to evaluate the efficacy of plasminogen enrichment of subacute thrombus in further accelerating pulse-spray pharmacomechanical thrombolysis (PSPMT) with urokinase (UK) or tissue plasminogen activator (tPA) in a rabbit model.

MATERIALS AND METHODS

With use of a subacute rabbit inferior vena cava (IVC) thrombosis model, 78 rabbits were divided into eight groups according to the agents used for thrombolysis: (i) controls (IVC thrombosis, no lysis performed), (ii) pulse-spray thrombolysis with saline only, (iii) PSPMT with UK, (iv) PSPMT with UK, plus interim pulse-spray plasminogen enrichment after 14 minutes, (v) pulse-spray plasminogen enrichment, followed at 10 minutes by PSPMT with UK, (vi) PSPMT with tPA, (vii) PSPMT with tPA, plus interim plasminogen enrichment, and (viii) pulse-spray plasminogen enrichment, followed at 10 minutes by PSPMT with tPA.

RESULTS

Intrathrombic pulsed injection of glu-plasminogen after 14 minutes of tPA PSPMT demonstrated significant augmentation of lysis (approximately 31% decrease in residual thrombus) compared with tPA alone (P = .006). Lysis was not augmented significantly when plasminogen was sprayed into thrombus before tPA, or before or after UK.

CONCLUSION

Plasminogen enrichment of thrombus after onset of PSPMT with tPA significantly accelerated thrombolysis in a subacute in vivo rabbit model. A clinical trial of this method may be warranted.