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

Short-term complications and outcomes in pharmaco-mechanical thrombolysis first and catheter-directed thrombolysis first in patients with acute lower limb ischemia

BACKGROUND

Pharmaco-mechanical thrombolysis (PMT) has emerged as a treatment option in patients with acute lower limb ischemia (ALI), especially Rutherford IIb (motor deficit) for rapid revascularization, but supportive data is scarce. The aim of the present study was to compare effect of thrombolysis, complications, and outcomes of PMT first versus catheter-directed thrombolysis (CDT) first in a large cohort of patients with ALI.

BASIC PROCEDURES

All endovascular thrombolytic/thrombectomy events in patients with ALI performed between January 1^st 2009 and December 31^st 2018 (n=347) were included. Successful thrombolysis/thrombectomy was defined as complete or partial lysis. Reasons for use of PMT was described. Complications such as major bleeding, distal embolization, and new onset of renal impairment, and major amputation and mortality at 30 days were compared between PMT (AngioJet™) first and CDT first groups in a multi-variable logistic regression model with adjustment for age, gender, atrial fibrillation, and Rutherford IIb.

MAIN FINDINGS

The most common reason for initial use of PMT was need of rapid revascularization, and the most common reason for use of PMT after CDT was insufficient effect of CDT. Presentation of Rutherford IIb ALI was more common in the PMT first group (36.2% vs 22.5%, respectively, p=0.027). Among 58 patients receiving PMT first, 36 (62.1%) were terminated within a single session of therapy without need of CDT. The median duration of thrombolysis was shorter (p<0.001) for the PMT first group (n=58) compared to the CDT first (n=289) group (4.0 hours vs 23.0 hours, respectively). There was no significant difference in amount of tissue plasminogen activator given, successful thrombolysis/thrombectomy (86.2% and 84.8%), major bleeding (15.5% and 18.7%), distal embolization (25.9% and 16.6%), major amputation or mortality at 30-day (13.8% and 7.7%) in the PMT first compared to the CDT first group, respectively. The proportion of new onset of renal impairment was higher in the PMT first compared to the CDT first group (10.3% versus 3.8%, respectively), and the increased odds (Odds ratio 3.57, 95% CI 1.22 - 10.41) was maintained in the adjusted model. In Rutherford IIb ALI, no difference in rate of successful thrombolysis/thrombectomy (76.2% and 73.8%), complications or 30-day outcomes was found between PMT first (n=21) and CDT (n=65) first group.

CONCLUSION

PMT first appears to be a good treatment alternative to CDT first in patients with ALI, including Rutherford IIb. The found renal function deterioration in the PMT first group needs to be evaluated in a prospective, preferably, randomized trial.

Comparison of pharmaco-mechanical thrombolysis and catheter-directed thrombolysis for treating thrombotic or embolic arterial occlusion of the lower limb

BACKGROUND

Whether pharmaco-mechanical thrombolysis (PMT) results in superior outcomes to catheter-directed thrombolysis (CDT) in treating thrombotic or embolic arterial occlusion of the lower limbs is unclear.

METHODS

We enrolled 94 patients with Rutherford class I-IIb due to thrombotic or embolic arterial occlusion in the lower limbs and who received emergency endovascular treatment. Baseline demographics, laboratory data, angiography and clinical outcomes were collected through chart reviews and fluoroscopic imaging. The procedural characteristics (thrombolytic drug dosage, treatment duration, and additional procedures), immediate angiographic outcomes (patency of calf vessels, and complete lysis), complications (major bleeding, and fasciotomy), and primary composite end-points (30-day mortality, amputation, and reocclusion) were compared between patients who received CDT versus PMT.

RESULTS

Compared with CDT, PMT was independently associated with lower total UK dosage (standardised coefficientβ= - 0.44; p < 0.01) and higher prevalence of complete lysis (odds ratio = 1.78, 95% confidence interval: 1.03 - 3.06; p = 0.04) after adjustments of covariates. The PMT group had significantly shorter treatment duration (23.00 [7.25 - 39.13] vs. 41.00 [27.00 - 52.50]; p < 0.01). No significant intergroup differences were observed for the primary composite end point (10.7% vs. 9.1%; p = 0.81), or prevalence of the major bleeding (9.1% vs. 0.0%; p = 0.10) despite the PMT group comprising patients with more.advanced chronic kidney disease and more diffuse thrombosis.

CONCLUSIONS

PMT with a Rotarex is a safe and effective strategy for treating thrombotic or embolic lower limb ischemia. It significantly reduced the thrombolytic drug dosage, and resulted in the complete lysis being more likely.

Infusion techniques for peripheral arterial thrombolysis

BACKGROUND

Acute limb ischaemia usually is caused by a blood clot blocking an artery or a bypass graft. Severe acute ischaemia will lead to irreversible damage to muscles and nerves if blood flow is not restored in a few hours. Once irreversible damage occurs, amputation will be necessary and the condition can be life-threatening. Infusion of clot-busting drugs (thrombolysis) is a useful tool in the management of acute limb ischaemia. Fibrinolytic drugs are used to disperse blood clots (thrombi) to clear arterial occlusion and restore blood flow. Thrombolysis is less invasive than surgery. A variety of techniques are used to deliver fibrinolytic agents. This is an update of a review first published in 2004.

OBJECTIVES

To compare the effects of infusion techniques during peripheral arterial thrombolysis for treatment of patients with acute limb ischaemia.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, and CINAHL databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registries to 20 October 2020. We undertook reference checking to identify additional studies.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) comparing infusion techniques for fibrinolytic agents in the treatment of acute limb ischaemia.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures as recommended by Cochrane. We assessed the risk of bias in included trials using the Cochrane 'Risk of bias' tool. We evaluated certainty of evidence using GRADE. For dichotomous outcomes, we calculated the odds ratio (OR) with the corresponding 95% confidence interval (CI). We were not able to carry out meta-analyses due to clinical heterogeneity, so we have reported the results and performed the comparisons narratively. The main outcomes of interest were amputation-free survival or limb salvage, amputation, mortality, vessel patency, duration of thrombolysis, and complications such as cerebrovascular accident and major and minor bleeding.

MAIN RESULTS

Nine studies with a total of 671 participants are included in this update. Trials covered a variety of infusion techniques, dosage regimens, and adjunctive agents. We grouped trials according to types of techniques assessed (e.g. intravenous and intra-arterial delivery of the agent, 'high-' and 'low-dose' regimens of the agent, continuous infusion and 'forced infusion' of the agent, use of adjunctive antiplatelet agents). We assessed the certainty of evidence as very low to low due to the limited power of individual studies to deliver clinically relevant results, small and heterogeneous study populations, use of different inclusion criteria by each study in terms of severity and duration of ischaemia, considerably different outcome measures between trials, and use of different fibrinolytic agents. This heterogeneity prevented pooling of data in meta-analyses. No regimen has been shown to confer benefit in terms of amputation-free survival (at 30 days), amputation, or death. For vessel patency, complete success was more likely with intra-arterial (IA) than with intravenous (IV) infusion (odds ratio (OR) 13.22, 95% confidence interval (CI) 2.79 to 62.67; 1 study, 40 participants; low-certainty evidence); radiological failure may be more likely with IV infusion (OR 0.02, 95% CI 0.00 to 0.38; 1 study, 40 participants; low-certainty evidence). Due to the small numbers involved in each arm and design differences between arms, it is not possible to conclude whether any technique offered any advantage over another. None of the treatment strategies clearly affected complications such as cerebrovascular accident or major bleeding requiring surgery or blood transfusion. Minor bleeding complications were more frequent in systemic (intravenous) therapy compared to intra-arterial infusion (OR 0.03, 95% CI 0.00 to 0.56; 1 study, 40 participants), and in high-dose compared to low-dose therapy (OR 0.11, 95% CI 0.01 to 0.96; 1 study, 63 participants). Limited evidence from individual trials appears to indicate that high-dose and forced-infusion regimens reduce the duration of thrombolysis. In one trial, the median duration of infusion was 4 hours (range 0.25 to 46) for the high-dose group and 20 hours (range 2 to 46) for the low-dose group. In a second trial, treatment using pulse spray was continued for a median of 120 minutes (range 40 to 310) compared with low-dose infusion for a median of 25 hours (range 2 to 60). In a third trial, the median duration of therapy was reduced with pulse spray at 195 minutes (range 90 to 1260 minutes) compared to continuous infusion at 1390 minutes (range 300 to 2400 minutes). However, none of the studies individually showed improvement in limb salvage at 30 days nor benefit for the amputation rate related to the technique of drug delivery. Similarly, no studies reported a clear difference in occurrence of cerebrovascular accident or major bleeding. Although 'high-dose' and 'forced-infusion' techniques achieved vessel patency in less time than 'low-dose' infusion, more minor bleeding complications may be associated (OR 0.11, 95% CI 0.01 to 0.96; 1 study, 72 participants; and OR 0.48, 95% CI 0.17 to 1.32; 1 study, 121 participants, respectively). Use of adjunctive platelet glycoprotein IIb/IIIa antagonists did not improve outcomes, and results were limited by inclusion of participants with non-limb-threatening ischaemia.

AUTHORS' CONCLUSIONS

There is insufficient evidence to show that any thrombolytic regimen provides a benefit over any other in terms of amputation-free survival, amputation, or 30-day mortality. The rate of CVA or major bleeding requiring surgery or blood transfusion did not clearly differ between regimens but may occur more frequently in high dose and IV regimens. This evidence was limited and of very low certainty. Minor bleeding may be more common with high-dose and IV regimens. In this context, thrombolysis may be an acceptable therapy for patients with marginally threatened limbs (Rutherford grade IIa) compared with surgery. Caution is advised for patients who do not have limb-threatening ischaemia (Rutherford grade I) because of risks of major haemorrhage, cerebrovascular accident, and death from thrombolysis.

In acute ischemic stroke patients with smoking incidence, are more women than men more likely to be included or excluded from thrombolysis therapy?

Background:

Clinical factors associated with exclusion from recombinant tissue plasminogen activator in both men and women are not completely understood. The aim of this study is to determine whether there is a gender difference in clinical risk factors that excluded ischemic stroke patients with a history of smoking from recombinant tissue plasminogen activator.

Methods:

Retrospective data from a stroke registry were analyzed, and multivariable linear regression models were used to determine gender differences. Logistic regression models determined exclusion clinical risk factors for thrombolysis in male and female acute ischemic stroke patients with a history of smoking, while sequentially adjusting for sociodemographic, clinical, and stroke-related variables. The Kaplan–Meier survival analysis was used to determine the exclusion probabilities of men and women with a history of smoking within the stroke population.

Results:

Of the 1,446 acute ischemic stroke patients eligible for recombinant tissue plasminogen activator, 379 patients with a history of smoking were examined, of which 181 received recombinant tissue plasminogen activator while 198 were excluded from receiving recombinant tissue plasminogen activator. Of the 198 patients, 75 females and 123 males were excluded from receiving recombinant tissue plasminogen activator. After multivariable adjustment for age, National Institutes of Health scores, and stroke-related factors, females who present with weakness/paresis on initial examination (OR = 0.117, 95% CI, 0.025–0.548) and men who present with a history of previous transient ischemic attack (OR = 0.169, 95% CI, 0.044–0.655), antiplatelet medication use (OR = 0.456, 95% CI, 0.230–0.906), and weakness/paresis on initial examination (OR = 0.171, 95% CI, 0.056–0.521) were less likely to be excluded from recombinant tissue plasminogen activator (thrombolysis therapy).

Conclusions:

In an ischemic stroke population with a history of smoking, female smokers are more likely to be excluded from thrombolysis therapy in comparison to men, even after adjustment for confounding variables.

A systematic review and meta-analysis of endovascular and surgical revascularization techniques in acute limb ischemia

BACKGROUND

The initial treatment of patients with acute limb ischemia (ALI) remains undefined. The aim of this article was to compare the safety and effectiveness of catheter-driven thrombolysis (CDT) with surgical revascularization and evaluate the various fibrinolytic agents, endovascular, and pharmacochemical approaches that aim for thrombectomy.

METHODS

PubMed, Embase, and the Cochrane Library were searched for studies on the management of ALI by means of surgical or endovascular recanalization, returning 520 studies. All randomized, controlled trials, nonrandomized prospective, and retrospective studies were included comparing treatment of ALI.

RESULTS

Twenty-five studies, investigating a total of 4689 patients, were included for meta-analysis spread across nine different comparisons. No differences were found in limb salvage between thrombectomy and thrombolysis. More major vascular events were seen in the thrombolysis group (6.5% compared with 4.4% in the surgically treated group; odds ratio [OR], 0.33; 95% confidence interval [CI], 0.13-0.87; P = .02; I² = 20%). Comparable limb salvage was found for high- and low-dose recombinant tissue plasminogen activator (r-tPA). No significant differences were found in major vascular event between low r-tPA (14%) and high r-tPA (10.5%; P = .13). The 30-day limb salvage rate was 79.7% for r-tPA treatment and 60.4% for streptokinase (OR, 3.14; 95% CI, 1.26-7.85; P = .01; I² = 0%). AngioJet showed more limb salvage at 6 months compared with r-tPa (OR, 2.21; 95% CI, 1.17-4.18; P = .01; I² = 0%).

CONCLUSIONS

Both CDT and surgery have comparable limb salvage rates in patients with ALI; however, CDT is associated with a higher risk of hemorrhagic complications. No conclusions can be drawn regarding the risk of hemorrhagic complications regarding thrombolytic therapy by means of r-tPA, streptokinase, or urokinase. Insufficient data are available to conclude the preference of using a hybrid approach, ultrasound-accelerated CDT, heated r-tPA. or novel endovascular (rheolytical) thrombectomy systems. Future trials regarding ALI need to be constructed carefully, ensuring comparable study groups, and should follow standardized practices of outcome reporting.

Contemporary trends and outcomes of thrombolytic therapy for acute lower extremity ischemia

Objective

Acute limb ischemia is a common vascular emergency requiring immediate intervention. Thrombolysis has been widely utilized for acute limb ischemia; the purpose of this study is to analyze contemporary trends, outcomes and complications of thrombolysis for acute limb ischemia.

Methods

Patients were identified from the Nationwide Inpatient Sample (2003–2013) using ICD-9. Patients undergoing emergency thrombolysis for acute limb ischemia were evaluated. Three groups were analyzed: thrombolysis alone, thrombolysis and endovascular procedure (T+ENDO), and failed thrombolysis requiring open surgery (T+OPEN).

Results

A total of 162,240 patients with acute limb ischemia were estimated: 33,615 patients (20.7%) underwent thrombolysis as the initial treatment. Mean age was 66.2 ± 34.9 years with 54% male. The utilization of thrombolysis increased significantly during the study period (16.8–24.2%, p < 0.0001). The most common group was thrombolysis and endovascular procedure (40.7%), followed by thrombolysis alone (34.1%), and T+OPEN (25.2%). Thrombolysis and endovascular procedure increased significantly over time (31.6–47.8%, p < 0.0001) whereas thrombolysis alone and T+OPEN significantly decreased (39.6–28.6% and 28.7–23.6%, respectively, p < 0.0001). Overall mortality was 4.9%; thrombolysis and endovascular procedure compared to thrombolysis alone and T-OPEN had a lower mortality rate (3.2% vs. 6.1% and 5.9%, p < 0001). The overall stroke rate was 1.9%; thrombolysis alone had the highest stroke rate (3.0%, p < 0.0001) with thrombolysis and endovascular procedure the lowest (1.2%) and T+OPEN 1.7%. The highest amputation rate was T+OPEN (11.6%, p < 0.001) compared to thrombolysis and endovascular procedure (5.1%) and thrombolysis alone (5.3%). T+OPEN had the highest incidence of cardiac (5.5%), respiratory (7.3%) and renal complications (12.5%), pneumonia (4.0%), and fasciotomy (16.8%) (all p < 0.0001).

Conclusion

Thrombolysis remains an effective treatment for acute limb ischemia with increased utilization over time. There was a significant increase in thrombolysis and endovascular procedure leading to improved outcomes. Thrombolysis alone carried the highest mortality and stroke rate, with T+OPEN associated with the highest amputation and complications. Although thrombolysis is effective, 25% of patients required an open procedure suggesting that patient selection for thrombolysis first instead of open surgery continues to be a clinical challenge.

Outcome and complications after intra-arterial thrombolysis for lower limb ischaemia with or without continuous heparin infusion

Background

Thrombolysis is a common treatment for acute leg ischaemia. The purpose of this study was to evaluate different thrombolytic treatment strategies, and risk factors for complications.

Methods

This was a retrospective analysis of prospective databases from two vascular centres. One centre used a higher dose of heparin and recombinant tissue plasminogen activator (rtPA).

Results

Some 749 procedures in 644 patients of median age 73 years were studied; 353 (47·1 per cent) of the procedures were done in women. The aetiology of ischaemia was graft occlusion in 38·8 per cent, acute arterial thrombosis in 32·2 per cent, embolus in 22·3 per cent and popliteal aneurysm in 6·7 per cent. Concomitant heparin infusion was used in 63·2 per cent. The mean dose of rtPA administered was 21·0 mg, with a mean duration of 25·2 h. Technical success was achieved in 80·2 per cent. Major amputation and death within 30 days occurred in 13·1 and 4·4 per cent respectively. Bleeding complications occurred in 227 treatments (30·3 per cent). Blood transfusion was needed in 104 (13·9 per cent). Three patients (0·4 per cent of procedures) had intracranial bleeding; all were fatal. Amputation-free survival was 83·6 per cent at 30 days at both centres. In multivariable analysis, preoperative severe ischaemia with motor deficit was the only independent risk factor for major bleeding (odds ratio (OR) 2·98; P <0·001). Independent risk factors for fasciotomy were severe ischaemia (OR 2·94) and centre (OR 6·50). Embolic occlusion was protective for major amputation at less than 30 days (OR 0·30; P = 0·003). Independent risk factors for death within 30 days were cerebrovascular disease (OR 3·82) and renal insufficiency (OR 3·86).

Conclusion

Both treatment strategies were successful in achieving revascularization with acceptable complication rates. Continuous heparin infusion during intra-arterial thrombolysis appeared to offer no advantage.

Intravenous thrombolysis with recombinant tissue plasminogen activator (rt-PA) in acute lower limb ischaemia

For various reasons some patients are unable to undergo intra-arterial thrombolysis for acute limb ischaemia. This interventional case series study prospectively evaluated the effect of thrombolytic treatment with 100 mg recombinant tissue plasminogen activator (rt-PA), administered intravenously, in patients with acute thrombosis of the lower limb arteries and onset of symptoms within 12 h prior to treatment. During a 3-year period (2007-2009), 18 of 86 patients satisfied the inclusion criteria and were included in the study (age range 65-80 years; 11 women). Complete and partial thrombolysis was observed in eight (44.4%) and six (33.3%) patients, respectively. All patients experienced clinical improvement. There were no amputations during the 36-month follow-up period and no haemorrhagic complications in the first 30 days post-treatment. Five patients died (27.8%) during follow-up from unrelated causes. This small study demonstrated that thrombolytic treatment with intravenous rt-PA in selected patients with acute limb ischaemia is feasible.

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.

Do randomized trials of thrombolysis versus open revascularization still apply to current management: what has changed?

Several randomized trials of catheter-directed thrombolysis versus operative revascularization in patients with acute lower extremity ischemia were performed in the mid-1990 s. Although the outcomes of these trials were not definitive, they did provide insight into potential uses and techniques of catheter-directed thrombolysis and lytic agents. This article reviews the outcomes of these randomized trials and describes advances in thrombolytic techniques and technology, including percutaneous mechanical thrombectomy devices and innovative catheter designs that accelerate lysis and the development of direct-acting lytic agents.