A systematic review of intra-arterial thrombolytic therapy for lower-limb ischaemia

Safety and Efficacy of Vacuum Assisted Thrombo-Aspiration in Patients with Acute Lower Limb Ischaemia: The INDIAN Trial

OBJECTIVE

The aim was to evaluate the short term safety and effectiveness of the Penumbra/Indigo aspiration thrombectomy Systems (Penumbra Inc.) in patients with acute lower limb ischaemia. (ALLI). Recently, endovascular vacuum assisted thrombectomy devices, similar to those used in the management of acute ischaemic stroke, have become available for peripheral arteries, but data are still scarce.

METHODS

To assess vessel patency, a modified Thrombolysis in Myocardial Infarction (TIMI) classification, called TIPI (Thrombo-aspiration In Peripheral Ischaemia), is proposed. The TIPI flow is assessed at presentation, immediately after treatment with the study device, and after all adjuvant procedures. The primary outcome is the technical success of the thrombo-aspiration with the investigative system, defined as near complete or complete revascularisation TIPI 2 - 3. Safety and clinical success rate were collected at one month.

RESULTS

One hundred and fifty patients were enrolled. The mean age was 72.4 years and 73.3% were male. Rutherford grade on enrolment was I in 16%, IIa in 40.7%, and IIb in 43.3% with a mean ankle brachial index of 0.19. Primary technical success (TIPI 2 - 3 flow) was achieved in 88.7% of patients. Adjunctive procedures included angioplasty/stenting of chronic atherosclerotic lesions (n = 39), thrombolysis (n = 31), covered stenting (n = 15), and supplementary Fogarty embolectomy (n = 6). After all interventions, assisted primary technical success was 95.3% (TIPI 2 - 3 in 143/150). No systemic bleeding complications or device related serious adverse events were reported. At one month follow up, one death, and one below the knee amputation were recorded. Primary patency was 92% (138/150), and the re-intervention rate was 7.33%, resulting in an assisted primary and secondary patency of 94% and 99.33%, respectively.

CONCLUSION

Results from the INDIAN registry reveal that mechanical thrombectomy using the Indigo system is safe and effective for revascularisation of ALLI as a primary therapy.

Mid-Term Outcomes of Thrombolysis for Acute Lower Extremity Ischemia at a Tertiary Care Center

BACKGROUND

Acute limb ischemia (ALI) is challenging to treat because of high morbidity and mortality. Endovascular-first options beginning with thrombolysis are technically feasible with similar results to open surgery. We examined our experience with thrombolysis to identify patients and target conduits that are predictive of improved outcomes.

METHODS

We performed a retrospective review of our institutional database of thrombolysis cases for arterial lower extremity disease. Thrombolysis was the index procedure, and any subsequent treatment was a reintervention. Conversion to open surgery perioperatively such as thromboembolectomy or bypass was considered a technical failure. Primary outcomes included primary patency, secondary patency, amputation-free survival (AFS), and survival. Secondary outcomes included conversion to open, reintervention <30 days, and amputation <30 days. Descriptive statistics and analysis of variance were performed for preoperative and intraoperative risk factors. Kaplan-Meier estimation and Cox proportional hazard models were used for primary and secondary outcomes.

RESULTS

Ninety-nine patients with ALI were treated with thrombolysis from 2007 to 2017. Thrombolysis was attempted on native artery (40%), vein bypass (7%), prosthetic bypass (33%), and stent (19%). Rutherford class distribution was 50% class 1, 41% class 2a, 5% class 2b, and 3% class 3. Technical success was 70%, characterized by an all-endovascular approach, patency at 30 days, and AFS for 30 days. Primary patency at 1- and 2-years was 31% and 22%, respectively. Secondary patency at 1- and 2-years was 39% and 27%, respectively. Overall, 30% required conversion to open surgery at the time of the index procedure, 7% reintervention <30 days, 5% mortality <30 days, and 5% major amputation <30 days. Prosthetic grafts and vein bypasses had the worst primary and secondary patency (P < 0.05). Five out of 7 vein bypasses required open conversion. Thrombolysis of native arteries was most successful maintaining primary patency (P < 0.05), secondary patency (P < 0.05), and AFS (P < 0.05). Patients who had adjunctive procedures at the time of thrombolysis had a significantly greater primary patency (P < 0.05) and secondary patency (P < 0.05) but not greater AFS.

CONCLUSION

Outcomes in thrombolysis for ALI have not significantly improved 20 years after the STILE trial. Technical success and mid-term patency rates are modest at best. Thrombolysis of vein bypasses and prosthetic grafts have poor technical success and primary patency compared with native arteries. However, aggressive adjunctive interventions during thrombolysis appear to improve primary and secondary patency.

Fast-track thrombolysis protocol for acute limb ischemia

OBJECTIVE

Catheter-directed thrombolysis in the treatment of acute lower extremity arterial occlusions often requires several interventional sessions to generate successful outcomes. It is typically an expensive procedure, necessitating extended hospital length of stay (LOS) that may be associated with an increase in both local and systemic hemorrhagic complications. Five years ago, we created the fast-track thrombolysis protocol for arteries (FTTP-A) to deal with these concerns. The goal of our protocol is to re-establish patency during the first session of thrombolysis, thus decreasing costs and complications associated with prolonged periods of thrombolytic exposure.

METHODS

A retrospective study of 42 patients who were treated for acute limb ischemia at our institution by FTTP-A from January 2014 to February 2019 was performed. FTTP-A includes periadventitial lidocaine injection at the arterial puncture site under ultrasound guidance, contrast arteriography of the entire targeted segment, pharmacomechanical rheolytic thrombectomy of the occluded arterial segment, tissue plasminogen activator infusion along the occluded segment, balloon maceration of the thrombus, and (if deemed necessary) placement of a stent in an area of significant (≥30%) stenosis that is refractory to balloon angioplasty and thrombolysis. After the stenosis or thrombus is cleared, patients are prescribed an oral anticoagulant agent.

RESULTS

Primary FTTP-A (50 total interventions) was performed in 42 patients. The median age of patients was 67.2 ± 12.2 years (range, 41-98 years), and 54.8% were male; 59.5% of the procedures were performed on the left lower extremity. Initial arterial access was obtained through the common femoral artery in 39 of 42 cases (92.9%); in the remaining 3 cases, it was obtained in a left bypass access site, a right femoral-popliteal graft, and a right femoral-femoral graft. The mean operative time was 148.9 ± 62.9 minutes (range, 83-313 minutes), and the mean volume of tissue plasminogen activator infused was 9.7 ± 4.0 mg (range, 2-20 mg). The median cost including medications and interventional tools was $4673.19 per procedure. The mean postoperative LOS was 3.1 ± 4.5 days (range, 1-25 days). Median postoperative LOS was 1 day. Mean postoperative follow-up was 27 ± 19.2 months (range, 0-62 months). Single-session FTTP-A was successful in 81% (n = 34/42) of patients; the remaining 8 patients (19%) required a single additional session. Of the 42 patients, 34 (81%) required arterial stenting. Periprocedural complications consisted of one patient with hematuria, which resolved, and one patient with thrombocytopenia, which resolved. No patients experienced rethrombosis within 30 days of FTTP-A. During the 5-year study period, there was no significant local or systemic hemorrhage, limb loss, or mortality related to this protocol.

CONCLUSIONS

FTTP-A appears to be a safe, efficacious, and cost-effective procedure in the resolution of acute lower extremity arterial occlusions.

Acute on chronic limb ischemia: From surgical embolectomy and thrombolysis to endovascular options

After the invention of the balloon catheter by Fogarty in 1963, surgical thromboembolectomy was considered the gold standard treatment for many years in patients with acute lower limb ischemia (ALLI). ALLI is a dramatic event, carrying a high risk of amputation and perioperative morbidity and mortality. The evolution of endovascular technologies has resulted in a variety of therapeutic options to establish arterial patency. In the 1970s, Dotter first introduced the idea of clot lysis in the treatment of ALLI, which was modified to catheter-directed thrombolysis, and now clot aspiration techniques. Currently, the majority of ALLI (about 70%) is arterial thrombosis, which generally occurs in the setting of preexisting vascular lesion. This condition is very common in patients with diabetes. Clinical presentation in case of thrombosis on atherosclerotic stenosis (so called "acute on chronic ischemia") may be less severe, but treatment is generally more challenging than ALLI due to embolism, considering the complexity in device trackability through the diseased vessels, potential vessel injury, incomplete revascularization, and need of correction of underlying vascular lesions. Although surgery is still a treatment option, especially for ALLI, endovascular interventions have assumed a prominent role in restoring limb perfusion. In this review, the treatment options for ALLI are detailed from surgical thromboembolectomy to thrombolysis and current endovascular techniques, including mechanical fragmentation, rheolytic thrombectomy, and aspiration thrombectomy. The evolution to endovascular therapies has resulted in improved clinical outcomes and lower rates of morbidity.

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.

Open or endovascular revascularization in the treatment of acute lower limb ischaemia

Background

Consensus is lacking regarding intervention for patients with acute lower limb ischaemia (ALI). The aim was to study amputation‐free survival in patients treated for ALI by either primary open or endovascular revascularization.

Methods

The Swedish Vascular Registry (Swedvasc) was combined with the Population Registry and National Patient Registry to determine follow‐up on mortality and amputation rates. Revascularization techniques were compared by propensity score matching 1 : 1.

Results

Of 9736 patients who underwent open surgery and 6493 who had endovascular treatment between 1994 and 2014, 3365 remained in each group after propensity score matching. Results are from the matched cohort only. Mean age of the patients was 74·7 years; 47·5 per cent were women and mean follow‐up was 4·3 years. At 30‐day follow‐up, the endovascular group had better patency (83·0 versus 78·6 per cent; P < 0·001). Amputation rates were similar at 30 days (7·0 per cent in the endovascular group versus 8·2 per cent in the open group; P = 0·113) and at 1 year (13·8 versus 14·8 per cent; P = 0·320). The mortality rate was lower after endovascular treatment, at 30 days (6·7 versus 11·1 per cent; P < 0·001) and after 1 year (20·2 versus 28·6 per cent; P < 0·001). Accordingly, endovascular treatment had better amputation‐free survival at 30 days (87·5 versus 82·1 per cent; P < 0·001) and 1 year (69·9 versus 61·1 per cent; P < 0·001). The number needed to treat to prevent one death within the first year was 12 with an endovascular compared with an open approach. Five years after surgery, endovascular treatment still had improved survival (HR 0·78, 99 per cent c.i. 0·70 to 0·86) but the difference between the treatment groups occurred mainly in the first year.

Conclusion

Primary endovascular treatment for ALI appeared to reduce mortality compared with open surgery, without any difference in the risk of amputation.

Endovascular may save lives

Thrombolysis in peripheral artery disease

Peripheral artery disease (PAD) has been associated with severe morbidity and mortality worldwide, affecting the quality of life for millions of patients. Acute thrombosis has been identified as a major complication of PAD, with proper management including both open as well as endovascular techniques. Thrombolysis has emerged as a reasonable option in the last decades to treat such patients although data produced by randomized trials have been limited. This review aims to present major aspects of thrombolysis in PAD regarding its indications and contraindications, technique tips as well as to review literature data in order to produce useful conclusions for everyday clinical practice.

Early versus late thrombolysis in acute arterial occlusion of lower extremity

BACKGROUND

Acute arterial occlusion in lower extremity is an urgent condition which occurs when there is an abrupt interruption of blood flow into an extremity. Reperfusion through early intervention can increase limb salvage and decrease mortality. There was no common agreement when is the best to start thrombolysis in treating acute arterial occlusion. This study was designed to study the efficacy of an early thrombolysis compared with a late thrombolysis.

METHOD

We identified all patients discharged from the Gwangju Veterans hospital with a diagnosis of acute arterial occlusion between 2006 and 2014. 72 patients were eligible, and every patient had treated with catheter-directed thrombolysis on the day or 1day after admission. Among them, 42 patients had undergone an early thrombolysis (less than 7days after the onset of symptoms) and the other 30 patients had undergone a late thrombolysis (more than 7days after the onset of symptoms). The primary outcome was amputation rate at 6months. The secondary outcomes were all cause mortality at 6months and increase of ankle brachial index (ABI).

RESULTS

Amputation rate at 180days in the early thrombolysis group was 7.1% as compared with 30% in the late thrombolysis group. All cause mortality at 6months and increase of ABI were not different between two groups. In multivariable Cox-regression analysis, late thrombolysis was independent predictor of amputation at 6months.

CONCLUSION

Early thrombolysis was superior in preventing amputation than late thrombolysis.

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.

[Arterial occlusive disease. Catheter-directed thrombolytic therapy]

Local catheter-directed thrombolysis of extremity artery or bypass thromboembolic occlusions is a promising therapeutic option with comparatively low complication rates, if the severity of the ischemia does not require urgent surgical revascularization. This therapeutic decision has to be made by a vascular team taking individual circumstances and contraindications into consideration. Apart from an adequate dosage, a strict intrathrombotic administration of the fibrinolytic agent and careful clinical monitoring including surveillance of the coagulation system is necessary and intensive care unit resources should be used. If necessary the thrombolysis therapy can be combined with mechanical thrombaspiration and balloon dilatation or surgical correction of an underlying lesion.

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.

Thromboembolic Therapies in Dogs and Cats: An Evidence-Based Approach

In veterinary medicine, we are forced to make use of less than ideal "evidence," such as extrapolation from experimental studies in dogs and cats without naturally occurring diseases and from clinical trials in other species (particularly human clinical trials), as well as limited information gained from veterinary clinical experience, small clinical trials, case studies, and anecdotal reports. In this article, specific treatment recommendations are made for each of the common thromboembolic conditions seen in dogs and cats. These recommendations are made with the important caveat that, to date, such suggested therapeutic approaches are based on limited evidence.

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.

Percutaneous endovascular treatment of acute sequential systemic emboli

A 65-year-old woman was evaluated for acute right lower-extremity ischemia secondary to embolization from atrial fibrillation and subtherapeutic anticoagulation. Her symptoms quickly evolved in a dynamic fashion to involve multiple vascular beds, including a transient ischemic attack, abdominal pain secondary to mesenteric ischemia, and contralateral lower-extremity ischemia. Synchronous emboli were treated by using mechanical and pharmacologic thrombolysis via an endovascular approach under local anesthesia. This intervention allows prompt evaluation of multiple vascular beds with good short-term outcomes and minimal morbidity.

Medical management of peripheral arterial disease

Whether symptomatic or not, peripheral arterial disease (PAD), atherosclerosis in the arteries of the lower extremities, is a common disorder in the general population. The prevalence increases with age and under the influence of vascular risk factors. The most classic symptomatic expression of PAD is intermittent claudication. However, the majority of patients with PAD is asymptomatic or has leg symptoms other than classic intermittent claudication. Both symptomatic and asymptomatic subjects with PAD have increased mortality rates, mainly due to cardiovascular and cerebrovascular expressions of atherosclerotic disease. This review focuses on the current available medical therapies for PAD, including risk-factor modification and antiplatelet therapies, as well as strategies for symptomatic relief in both patients with intermittent claudication and patients with critical limb ischemia. In general, risk factor modification and antiplatelet therapy is essential in all patients with PAD to prevent systemic atherosclerotic complications. Furthermore, for symptomatic relief exercise therapy is the main intervention while pharmacological treatment should be only complementary. In patients with critical limb ischemia, when revascularization therapy is not possible, an attempt should be made to avoid amputation with conservative treatment using analgesics, vasodilators and/or anticoagulants. In case of an acute onset of critical limb ischemia, thrombolysis is indicated.

Antithrombotic Therapy in Peripheral Arterial Occlusive Disease

This chapter about antithrombotic therapy for peripheral arterial occlusive disease is part of the seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy: Evidence Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs, and Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading see Guyatt et al, CHEST 2004;126:179S-187S). Among the key recommendations in this chapter are the following: For patients with chronic limb ischemia, we recommend lifelong aspirin therapy in comparison to no antiplatelet therapy in patients with clinically manifest coronary or cerebrovascular disease (Grade 1A) and in those without clinically manifest coronary or cerebrovascular disease (Grade 1C+). We recommend clopidogrel over no antiplatelet therapy (Grade 1C+) but suggest that aspirin be used instead of clopidogrel (Grade 2A). For patients with disabling intermittent claudication who do not respond to conservative measures and who are not candidates for surgical or catheter-based intervention, we suggest cilostazol (Grade 2A). We suggest that clinicians not use cilostazol in patients with less-disabling claudication (Grade 2A). In these patients, we recommend against the use of pentoxifylline (Grade 1B). We suggest clinicians not use prostaglandins (Grade 2B). In patients with intermittent claudication, we recommend against the use of anticoagulants (Grade 1A). In patients with acute arterial emboli or thrombosis, we recommend treatment with immediate systemic anticoagulation with unfractionated heparin (UFH) [Grade 1C]. We also recommend systemic anticoagulation with UFH followed by long-term vitamin K antagonist (VKA) in patients with embolism [Grade 1C]). For patients undergoing major vascular reconstructive procedures, we recommend UFH at the time of application of vascular cross-clamps (Grade 1A). In patients undergoing prosthetic infrainguinal bypass, we recommend aspirin (Grade 1A). In patients undergoing infrainguinal femoropopliteal or distal vein bypass, we suggest that clinicians do not routinely use a VKA (Grade 2A). For routine patients undergoing infrainguinal bypass without special risk factors for occlusion, we recommend against VKA plus aspirin (Grade 1A). For those at high risk of bypass occlusion and limb loss, we suggest VKA plus aspirin (Grade 2B). In patients undergoing carotid endarterectomy, we recommend aspirin preoperatively and continued indefinitely (Grade 1A). In nonoperative patients with asymptomatic or recurrent carotid stenosis, we recommend lifelong aspirin (Grade 1C+). For all patients undergoing extremity balloon angioplasty, we recommend long-term aspirin (Grade 1C+).

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.

A national and single institutional experience in the contemporary treatment of acute lower extremity ischemia

OBJECTIVE

To determine the contemporary clinical relevance of acute lower extremity ischemia and the factors associated with amputation and in-hospital mortality.

SUMMARY BACKGROUND DATA

Acute lower extremity ischemia is considered limb- and life-threatening and usually requires therapy within 24 hours. The equivalency of thrombolytic therapy and surgery for the treatment of subacute limb ischemia up to 14 days duration is accepted fact. However, little information exists with regards to the long-term clinical course and therapeutic outcomes in these patients.

METHODS

Two databases formed the basis for this study. The first was the National Inpatient Sample (NIS) from 1992 to 2000 of all patients (N = 23,268) with a primary discharge diagnosis of acute embolism and thrombosis of the lower extremities. The second was a retrospective University of Michigan experience from 1995 to 2002 of matched ICD-9-CM coded patients (N = 105). Demographic factors, atherosclerotic risk factors, the need for amputation, and in-hospital mortality were assessed by univariate and multivariate logistic regression analysis.

RESULTS

In the NIS, the mean patient age was 71 years, and 54% were female. The average length of stay (LOS) was 9.4 days, and inflation-adjusted cost per admission was $25,916. The amputation rate was 12.7%, and mortality was 9%. Decreased amputation rates accompanied: female sex (0.90, 0.81-0.99), age less than 63 years (0.47, 0.41-0.54), angioplasty (0.46, 0.38-0.55), and embolectomy (0.39, 0.35-0.44). Decreased mortality accompanied: angioplasty (0.79, 0.64-0.96), heparin administration (0.50, 0.29-0.86), and age less than 63 years(0.27, 0.23-0.33). The University of Michigan patients' mean age was 62 years, and 57% were men. The LOS was 11 days, with a 14% amputation rate and a mortality of 12%. Prior vascular bypasses existed in 23% of patients, and heparin use was documented in 16%. Embolectomy was associated with decreased amputation rates (0.054, 0.01-0.27) and mortality (0.07, 0.01-0.57).

CONCLUSIONS

In patients with acute limb ischemia, the more widespread use of heparin anticoagulation and, in select patients, performance of embolectomy rather than pursuing thrombolysis may improve patient outcomes.

The current role of intra-arterial thrombolysis

BACKGROUND

the role of intra arterial thrombolysis (IAT) in the management of peripheral vascular disease has come under scrutiny. This study aims to assess current usage and indications for IAT in the U.K.

METHOD

the use of IAT was assessed at our own centre and a questionnaire was sent to all centres that provide data for the U.K. "Thrombolysis Study Group".

RESULTS

there has been a steady decline in the use of IAT at our centre from a peak of 40 cases per annum to zero. Response was received from 22 of 24 centres (92%). Nineteen (86%) reported a decline in IAT use. Main reasons were concerns over lack of efficacy (74%) and complication rate (63%). Most centres would use IAT for acute limb ischaemia (86%). However, for acute thrombosis in specific indications the results varied; synthetic graft (82%), vein graft (54%), supra-inguinal graft (54%) and thrombosed popliteal artery aneurysm (54%). When asked what their commonest usage for IAT was, the results again varied; acute limb ischaemia (40%), graft thrombosis (40%), embolism post radiological intervention (12%), other (8%).

CONCLUSION

there has been a significant decrease in IAT use. Concerns exist as to efficacy and complication rate. There is no clear consensus on indications.

Adjunctive techniques in percutaneous mechanical thrombectomy

Percutaneous mechanical thrombectomy is an established method in interventional radiology and refers to the removal of acute embolic or thrombotic occlusive material in arteries, veins, or vascular grafts using percutaneous transluminal methods. However, initial complete removal of occlusive material can be achieved only in a minority of patients. The amount of removed material varies with the age and composition of the occlusive material. To achieve sufficient revascularization, adjunctive use of a variety of percutaneous endovascular recanalization techniques is necessitated. Additional treatment with local intra-arterial fibrinolysis, balloon angioplasty, stent implantation, endoluminal atherectomy, and other measures results in primary technical success rates of 70% to 100% for revascularization of acutely occluded vessels. The above-mentioned different techniques should not be viewed as competitive treatment modalities, rather a synergistic approach should be offered. The aim of this report is to review different adjunctive techniques in percutaneous mechanical thrombectomy with emphasis on techniques, mechanisms of action, experimental and clinical results, potential complications, and their potential role in view of clinical pathways to treat acute limb ischemia.

Approach to the patient with acute limb ischemia: diagnosis and therapeutic modalities

Good patient outcomes depend on the rapidity and completeness with which re-establishment of arterial blood flow to the limbs occurs. Patients with a greater magnitude of ischemic tissue--such as with an acute aortic occlusion--have worse outcomes than patients with a segmental artery occlusion such as a popliteal arterial thrombosis. Limb loss is high in any situation in which a delay in diagnosis occurs. It is unclear whether or not endovascular therapy will supercede traditional surgery because the etiologies of ALI are too broad to make sweeping conclusions at this time. The author and others [14,15], including those who have promulgated the use of thrombolytic therapy, have come to reasonable conclusions regarding how to deal with ALI: The diagnosis of ALI should be established rapidly. Determine its classification based on the patient's history and physical examination, and promptly institute anticoagulant therapy. Determine whether or not the patient should be taken emergently for surgical thromboembolectomy or a revascularization procedure versus arteriogram and possible thrombolysis. Adjunctive therapy such as antiplatelet agents (e.g., GIIb/IIIa antagonists) and other anticoagulant agents must be better investigated before recommendations can be made. Save life over limb. Emergent guillotine amputation is sometimes required to save a patient's life.

Acute leg ischaemia from thrombosed popliteal artery aneurysms: role of preoperative thrombolysis

OBJECTIVE

to evaluate early and long term results of thrombolysis and surgery in acutely thrombosed popliteal artery aneurysms.

SETTING

retrospective study; teaching hospital.

MATERIALS

between 1990 and 2000, 109 popliteal artery aneurysms were operated on. In 24 patients acute leg ischaemia due to thrombosis of aneurysm was present.

METHODS

ten patients underwent urgent surgical intervention (group 1); and 14 thrombolysis with urokinase, until patency of popliteal and tibial vessels was achieved or for a maximum of 3 days (group 2). Ultrasonographic follow-up was performed at 1, 3, 6 and 12 months and then annually. Early results and follow-up data were analysed by chi-square test and life-table analysis (Kaplan-Meier curve) and late results were compared by mean of log rank test.

RESULTS

in group 1 early limb salvage was 70%; in group 2 it was 86% (p=n.s.). When thrombolysis was successful, patency and limb salvage were 100%. There was no local or systemic complications during thrombolysis nor worsening of ischaemia. Follow-up was completed in 91 cases, with a mean duration of 26 months. Forty-eight months primary patency rate was better, even if not statistically significant, in group 2 than in group 1.

CONCLUSIONS

in patients with acute leg ischaemia due to thrombosis of popliteal artery aneurysms, preoperative thrombolysis can be considered a safe and effective alternative to urgent surgery.

Recombinant tissue plasminogen activator versus urokinase for local thrombolysis of femoropopliteal occlusions: a prospective, randomized multicenter trial

PURPOSE

To report the outcome of a prospective, randomized, open multicenter trial comparing (1) the effects of local thrombolysis with recombinant tissue plasminogen activator (rtPA) or urokinase (UK) and (2) 2 administration techniques.

METHODS

Two hundred thirty-four patients with thromboembolic occlusions in 223 native femoral or popliteal arteries (95%) and 11 bypass grafts (5%) were randomized to rtPA (n = 124) or UK (n = 110) administered either through an endhole catheter (Hess technique) in 81 patients or a microporous balloon catheter (Schneider technique) in 153 patients. When lysis was incomplete, additional catheter interventions were applied to achieve patency. Results were analyzed by fluoroscopy during intervention and by angiography evaluated by independent experts blinded to the methods applied.

RESULTS

The only significant difference between rtPA and UK was found at the end of lysis using the Hess technique. Complete reperfusion (TIMI grade 3) was produced in 60% of patients by rtPA versus 37% by UK (p = 0.045). By both techniques TIMI grade 3 was achieved in 62% with rtPA and in 50% with UK (p = 0.18). Independent of delivery technique, thrombolytic agent, or additional catheter interventions, TIMI grade 3 was achieved in 81% and angiographic patency in 88%. Primary patency at 6 months was 66%, which was increased by secondary interventions to 75%. Major amputations were performed in 6%, all in patients with initial Fontaine stage III/IV ischemia.

CONCLUSIONS

With local thrombolysis alone, rtPA appears to be more effective than UK; however, additional catheter interventions further improved patency, abolishing the difference between the lytic agents.

Patency following successful thrombolysis of occluded vascular grafts

AIM

to determine patency after successful lysis of occluded bypass grafts.

METHODS

data were collected from four centres with a wide experience of thrombolysis. Outcome following successful lysis was determined from prospectively collected data or case notes. Data from 75 patients, 53 men, were analysed.

RESULTS

median age at time of lysis was 68 years (range 33-88). Median age of graft was 12 months (range 1-120). Patency at 12 months was 33% (95% conf. interval: 21-44%). There were no differences in patency depending on whether the graft was above or below the inguinal ligament or whether an additional procedure eg. percutaneous or vein patch angioplasty was carried out. However in those 48 cases when lysis was deemed complete, i.e. there was restoration of graft patency and at least one vessel run off patency at 12 months was 39% compared with 17% if lysis was incomplete (p=0.04).

CONCLUSIONS

at the present time it is difficult to justify routine thrombolysis of occluded grafts when patency, based on intention to treat, is approximately 20% at one year. Following successful graft lysis the role of anticoagulation and careful graft surveillance require further investigation.