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

Catheter Directed Thrombolysis for Not Immediately Threatening Acute Limb Ischaemia: Systematic Review and Meta-Analysis

OBJECTIVE

This systematic review and meta-analysis reports the outcomes of catheter directed thrombolysis (CDT) in patients with not immediately threatening (Rutherford I) acute lower limb ischaemia (ALI).

DATA SOURCES

PubMed, Embase, and the Cochrane Library.

REVIEW METHODS

A systematic search of PubMed, Embase, and the Cochrane Library was performed to identify observational studies and trials published between 1990 and 2022 reporting on the results of CDT in patients with Rutherford I ALI. A meta-analysis was performed using a random effects model with 95% confidence intervals (CIs). The outcomes of interests were treatment duration, angiographic success, bleeding complications, amputation and mortality rates, primary and secondary patency, and functional outcome expressed as pain free walking distance.

RESULTS

Thirty-nine studies were included, comprising 1 861 patients who received CDT for not immediately threatening ALI. Funnel plots showed an indication of publication bias, and heterogeneity was substantial. Data from 5 to 13 studies were included in the meta-analysis. The pooled treatment duration was 2 days (95% CI 1 - 2), with an angiographic success rate of 80% (95% CI 73 - 86) and a 30 day freedom of amputation rate of 98% (95% CI 92 - 100). The major bleeding rate was 5% (95% CI 2 - 14), with a 30 day mortality rate of 3% (95% CI 1 - 5). The amputation free survival rate was 71% (95% CI 62 - 80) at the one year and 63% (95% CI 51 - 73) at the three year follow up. Long term patency rates were retrieved from four studies: 48% at one year (95% CI 27 - 70). No data could be retrieved on patient walking distance.

CONCLUSION

Although CDT in the treatment of not immediately threatening ALI showed high angiographic success, the long term outcomes were relatively poor, with low patency and a substantial risk of major amputation. Further research is required to interpret the outcome of CDT in the context of potential confounders such as age and comorbidities.

Skin necrosis following sclerotherapy. Part 2: Risk minimisation and management strategies

Tissue necrosis is a serious but rare complication of sclerotherapy. Early detection and targeted management are essential to prevent progression and minimise serious complications. In the first instalment of this paper, we reviewed the pathogenic mechanisms of post-sclerotherapy necrosis. Here, we describe risk minimisation and management strategies.

Risk factors must be addressed to reduce the chance of necrosis following sclerotherapy. These may be treatment-related including poor choice of sclerosant type, concentration, volume or format, poor injection technique, suboptimal ultrasound visualisation and treatment of vessels in high-risk anatomical areas. Risk factors specific to individual patients should be identified and optimised pre-operatively.

Tissue necrosis is more likely to occur with extravasation of irritant sclerosants such as absolute alcohol, sodium iodide, bleomycin and hypertonic saline, whereas extravasation of foam detergent sclerosants rarely results in tissue loss. Proposed treatments for extravasation of irritant sclerosants include infiltration of an isotonic fluid and hyaluronidase. Management of inadvertent intra-arterial injections may require admission for neurovascular observation and monitoring for ischaemia, intravenous systemic steroids, anticoagulation, thrombolysis and prostanoids infusion when required. Treatment of veno-arteriolar reflex vasospasm (VAR-VAS) necrosis follows the same protocol involving systemic steroids but rarely requires hospital admission and may not require anticoagulation.

In general, treatment of post-sclerotherapy necrosis is challenging and most proposed treatment measures are not evidence-based and only supported by anecdotal personal experience of clinicians. Despite all measures, once the necrosis has set in, it is very difficult to reverse the process and all measures described here may only be useful in prevention of progression and extension of the ulceration.

Mid to long-term measures include addressing exacerbating factors, management of medical and psychosocial comorbidities, treatment of secondary infections and referrals to relevant specialists. All ulcers should be managed with compression and prescribed dressing regimes in line with the healing stage of the ulcer.

Microbubbles and Ultrasound Accelerated Thrombolysis for Peripheral Arterial Occlusions: The Outcomes of a Single Arm Phase II Trial

OBJECTIVE

Acute peripheral arterial occlusions can be treated by catheter directed thrombolysis (CDT). However, CDT is time consuming and accompanied by the risk of bleeding complications. The addition of contrast enhanced ultrasound and microbubbles could improve thrombus susceptibility to thrombolytic agents and potentially shorten treatment time with a lowered risk of bleeding complications. This article reports the outcomes of the safety and feasibility of this novel technique.

METHODS

In this single arm phase II trial, 20 patients with acute lower limb ischaemia received CDT combined with an intravenous infusion of microbubbles and locally applied ultrasound during the first hour of standard intra-arterial thrombolytic therapy. The primary endpoint was safety, i.e., occurrence of serious adverse events (haemorrhagic complications and/or amputation) and death within one year. Secondary endpoints included angiographic and clinical success, thrombolysis duration, additional interventions, conversion, and quality of life.

RESULTS

The study included 20 patients (16 men; median age 68.0 years; range, 50.0 - 83.0; and 40% native artery and 60% bypass graft). In all patients, the use of microbubble contrast enhanced sonothrombolysis could be applied successfully. There were no serious adverse events related to the experimental treatment. Duplex examination showed flow distal from the occlusion after 23.1 hours (range 3.1 - 46.5) with a median thrombolysis time of 47.5 hours (range 6.0 - 81.0). The short term ABI and pain scores significantly improved; however, no changes were observed before or after thrombolysis in the microcirculation. Overall mortality and amputation rates were both 2% within one year. The one year patency rate was 55%.

CONCLUSION

Treatment of patients with acute peripheral arterial occlusions with contrast enhanced sonothrombolysis is feasible and safe to perform in patients. Further research is necessary to investigate the superiority of this new treatment over standard treatment.

Successful removal of an acute deep vein thrombosis by the INARI ClotTriever system

Pulmonary embolism is most feared sequela of a proximal deep vein thrombosis (DVT). Currently, first-line DVT treatment is anticoagulation to prevent post-thrombotic sequelae like pedal edema as well as a life threatening pulmonary embolism . Advanced therapy considerations for limb- or life-threatening DVT include catheter-directed thrombolysis and thrombectomy. Thrombectomy is necessary when thrombolytics are contraindicated secondary to increased bleeding risk. The authors present a DVT case treated with the mechanical thrombectomy device, ClotTriever (Inari Medical, Irvine, CA), resulting in the efficient and effective removal of thrombus with near-complete resolution of venous symptoms and prompt hospital discharge.

Evaluation of the Occlusive Arterial Disease and Diabetic Angiopathy Treatment Effects by Hyperbaric Oxygenation

Introduction:

One of the most severe complications of atherosclerosis is arterial occlusive disease (AOD) and with diabetic angiopathy (DA), is a common chronic problem in clinical practice worldwide. Hyperbaric oxygen (HBO) therapy is a therapeutic modality for solving all forms of hypoxia.

Aim:

To compare the treatment with HBO therapy in patients with AOD and DA ischemic symptomatology with standard treatment i.e. vasodilators, antibiotics, antiplatelets and statins, and to demonstrate the benefit of the therapeutic modality itself.

Methods:

We conducted a clinical prospective study and included a total of 80 patients, divided into two groups: 40 patients with the arterial occlusive disease and lower-extremity wounds, with sub-group (n=20) treated with HBO therapy on the top of the standard therapy and 40 patients with diabetic angiopathy and diabetic lower-extremity wounds, with sub-group (n=20) treated with HBO therapy on top of the standard therapy.

Results:

The efficacy of therapy in patients treated with HBO therapy on the top of standard therapy was significantly higher than in the group of HBO non-treated patients. There was a significant improvement in 9 patients treated with HBO therapy, while in HBO non-treated patients the significant improvement effect was observed only in one patient.

Conclusion:

HBO therapy is an effective therapeutic component in the healing of diabetic lower-extremity wounds in the patients with AOD and DA. In our patients HBO therapy on the top of standard therapeutic protocol has an effect of reducing the number of lower-limb amputations in patients with AOD and DA. These results support clinical use of HBO therapy for diabetic lower-extremity wound healing.

Catheter-directed thrombolysis is not limited to acute limb ischemia treatment: experience from a division of vascular surgery

BACKGROUND

Thrombolytic treatment has many potential indications in the era of modern vascular surgery. We aimed to analyze the contemporary experience in the catheter-directed, intraarterial thrombolysis in different clinical scenarios.

METHODS

The available data of 121 patients with different types (acute, subacute, complications of vascular procedures) of lower limb ischemia treated by means of the intraarterial, catheter-directed thrombolysis between November 2011 and December 2016 were retrospectively analyzed. The basic treatment protocol, utilized in 92% of patients, was a catheter-directed infusion of 40 mg of alteplase within 3.5 hours. Pre- and intraprocedural factors (indications, demographic details, comorbidities, the dose of alteplase utilized, underlying lesions procedures), as well as postoperative outcomes (lysis grade, death, complications, reinterventions, and limb loss after 1-month observation), were analyzed.

RESULTS

Successful thrombolysis was achieved in 76.1% (92 of 121) patients. The success rate was similar for acute, subacute limb ischemia and thrombotic complications of vascular procedures. Around 67.8% of patients (N.=82) had procedures to correct underlying lesions performed. Overall complication rate was 28.1%, but the major bleeding was observed in only 5% (6 patients). Neither intracranial bleeding nor gastrointestinal bleeding occurred. No mortality, 1.7% reintervention rate and 10.7% amputation rate were recorded during one-month follow-up.

CONCLUSIONS

Accelerated intraarterial thrombolysis is an effective measure in the treatment of acute, sub-acute limb ischemia as well as thromboembolic complications of vascular procedures. It carries a low risk of major bleeding. The location of thrombus in the crural arteries adversely affects the treatment results. Atrial fibrillation increases the risk of amputation while complete thrombus lysis is protective.

A History of Thrombolytic Therapy

Thrombolytic therapy has been available for the last 5 decades, but the modern era of thrombolysis began in the early 1990s, with the execution of 3 multicenter trials designed to compare this potentially less invasive therapy to the then standard of care for acute limb ischemia, open surgical revascularization. Even with the development of several bioengineered lytic agents, the major risk of thrombolytic therapy continues to be bleeding complications. Nevertheless, data exist to suggest that thrombolysis should be considered as an adjunct to open surgery, percutaneous interventions, or, occasionally, as sole therapy for acute vascular occlusion. This review summarizes the developmental milestones in the history of thrombolysis and reviews data supporting its use in acute arterial occlusions.

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.

Safety of Intra-arterial Catheter Directed Thrombolysis: Does Level of Care Matter?

OBJECTIVES

The aim was to assess whether the level of care influenced the safety related outcomes of catheter directed thrombolysis (CDT) for patients presenting with limb ischaemia and dialysis access thrombosis.

METHODS

This was a retrospective cohort study. All consecutive patients at two tertiary referral centres for vascular surgery undergoing CDT for limb ischaemia and dialysis access thrombosis (N = 252) between 2012 and 2014 were included. Patients at Centre 1 were cared for on a general vascular ward and patients at Centre 2 were kept on a post-operative recovery unit with an increased level of care including invasive haemodynamic monitoring. Patient medical records were retrospectively scrutinised and data collected on comorbidities, anti-thrombotic medication, indications for CDT, technical success of CDT, bleeding and non-bleeding related complications, and transfer to a higher level of care.

RESULTS

There were no differences in the frequency of non-bleeding related complications between Centre 1 and Centre 2. Patients on the vascular ward had a higher frequency of minor bleeding (p = .002) but there was no difference in major bleeding (p = .12). Eleven patients on the ward required an increased level of care for medical reasons and six were moved for a lack of resources. The presence of cardiac disease was an independent risk factor for patient transfer (OR 3.2; 95% CI 1.04-9.8, p = .04).

CONCLUSIONS

CDT may be undertaken outside of a high dependency setting without a significantly increased risk of complications. Pre-existing cardiac disease was an independent risk factor for transfer to a higher level of care. These findings could have an implication for the clinical cost-effectiveness of CDT.

Clinical outcomes and cost-effectiveness of initial treatment strategies for nonembolic acute limb ischemia in real-life clinical settings

OBJECTIVE

The optimal initial treatment for patients with acute limb ischemia (ALI) remains undefined. Although clinical outcome data are inconsistent, catheter-directed thrombolysis (CDT) with tissue plasminogen activator is increasingly used. Patient-level analysis combining clinical and economic data in a real-life setting is lacking. This study compared clinical outcomes and cost-effectiveness of initial treatment strategies for nonembolic ALI using real-life patient-level data.

METHODS

Medical records and data for hospital costs were analyzed for nonembolic ALI patients treated in four hospitals over 3 years. A cost-effectiveness analysis was performed using a decision tree analytic model. All costs were valued based on cost-to-charge ratios.

RESULTS

In 205 patients, initial treatments were CDT alone in 68 or with angioplasty in 16, open surgery in 60, endovascular in 33, and hybrid in 28. Although clinical outcomes did not differ significantly among the groups, reintervention rates during hospital stay, readmission rates, and costs were highest in the CDT group. Reintervention was required in 62% of patients after CDT compared with 7% after open surgery, and 16% of the CDT patients needed more than one reintervention. The mean total hospital cost was $34,800 per patient in CDT group compared with $10,677 in open surgery group.

CONCLUSIONS

In this real-life study, initial treatment of nonembolic ALI with currently available CDT options was associated with greater health care resource consumption and cost compared with other initial treatment options.

Use of duplex guided stent graft placement to prevent bleeding from previously thrombosed pseudo-aneurysms during thrombolytic therapy for acute popliteal artery occlusion

We present a 68-year-old female who developed multiple pseudo-aneurysms (PSAs) following cardiac catheterization via the right groin. During subsequent thrombin injection of PSAs, the patient developed acute occlusion of the popliteal artery. A covered stent was placed to obliterate the PSAs and allow for successful endovascular treatment of the occlusion without hemorrhage from the previous arteriotomy sites. This report demonstrates a safe and successful method to treating high surgical risk patients with recent PSA's and a necessity for thrombolysis.

Local thrombolysis: a newer approach to treating inflammatory bowel disease-related thromboembolism

GOALS

To review the experience with a relatively novel treatment, local thrombolysis, in patients with inflammatory bowel disease (IBD)-related thromboembolism (TE).

BACKGROUND

TE is an extraintestinal complication of IBD for which there are no clear treatment guidelines. Systemic treatment with anticoagulants or thrombolytics often raises fear of hemorrhagic complications, particularly hematochezia.

STUDY

Cases of IBD-related and non-IBD-related TE treated with local thrombolysis were searched for in PubMed, reviewed, and grouped into anatomic areas. Outcomes in each anatomic area were compared between IBD and non-IBD patients. Due to the small number of IBD-related TE cases, a descriptive, not statistical, analysis was performed.

RESULTS

There were 17 cases of IBD-related TE treated with local thrombolysis grouped as follows: 7 of cerebral venous thrombosis, 3 of lower extremity arterial TE, 1 of deep vein thrombosis, 1 of upper extremity deep vein thrombosis, 3 of abdominal vein thrombosis, and 2 of inferior vena cava TE. Mean age was 32 (range, 14 to 50) years, and 13 of 17 patients were female. Twelve had ulcerative colitis, 3 had Crohn's disease, and 1 was indeterminate. Four of the 7 patients with active IBD had pretreatment hematochezia, 2 of whom had worsening of hematochezia secondary to treatment. The rates of radiologic resolution, clinical resolution, and hemorrhagic complications in the IBD patients were favorable in all the anatomic areas and were very similar to non-IBD patients.

CONCLUSIONS

Local thrombolysis may be considered a viable therapeutic option for IBD-related TE. As more cases of local thrombolysis for IBD-related TE accumulate, further recommendations can be made as to the indications for its use.

Treatment for peripheral arterial obstructive disease: An appraisal of the economic outcome of complications

OBJECTIVE

This study determined the average estimated total costs after treatment for peripheral arterial occlusive disease (PAOD) and evaluated the effect of postoperative complications and their consequences for the total costs.

METHODS

Cost data on all admissions involving treatment for PAOD from January 2007 until July 2007 were collected. A prospective analysis was made using the patient-related risk factor and comorbidity (Society for Vascular Surgery/International Society of Cardiovascular Surgeons) classification, primary and secondary treatment, and prospectively registered complications. At admission, patients without complications were placed in group A, and those with complications were in group B. Prospectively registered complications were divided into patient management (I), surgical technique (II), patient's disease (III), and outside surgical department (IV). The consequences of these were divided into minor complication, no long-term consequence (1A), additional medication or transfusion (1B), surgical reoperation (2A), prolonged hospital stay (2B), irreversible physical damage (3), and death (4). The main outcome measures were total costs of patients and costs per patient (PP), with or without the presence of complications, cost of complications and costs per complication (PC), and the costs of their consequences calculated in euros (euro).

RESULTS

Ninety patients (mean age, 71.4 years; 59% men) were included. Group B patients had a significantly higher American Society of Anesthesiologists (4) and Fontaine (3) classification and more secondary procedures. Total costs were euro 1,716,852: group A, euro 512,811 (PP euro 12,820); and group B, euro 1,204,042 (PP euro 24,081). The costs of the 115 complications were euro 568,500 (PC euro 4943). Split by the cause of the complication, costs were I, euro 95,924 (PC euro 2998); II, euro 163,137 (PC euro 8157); III, euro 289,578 (PC euro 5171); and IV, euro 19,861 (PC euro 2837). The increase of costs in group B was mainly caused by additional medication or transfusion (1B) euro 348,293 (61.3%), a surgical reoperation (2A) euro 118,054 (20.8%), or prolonged hospital stay (2B) euro 60,451 (10.6%). Patients who died caused 23% of the total costs.

CONCLUSION

Complications cause an increase of the average estimated total costs in the treatment for peripheral arterial occlusive disease and are responsible for 33% of these total costs. The most expensive complications were errors in surgical technique and patient's disease, resulting in surgical reoperation or additional medication, or both, or transfusion, the two most expensive consequences.

Outcomes of Intra-arterial Thrombolysis for Acute Limb Ischemia

Intra-arterial thrombolysis is an alternative treatment to surgery for acute limb ischemia. We report our own experiences by retrospectively assessing initial and long-term outcomes using this strategy. Patients (n = 48; 50 events) underwent thrombolysis according to our protocol (64.6% male, median age 68.5 years). Using thrombolysis as an initial treatment strategy, overall limb survival on index admission was 84%. Of this group who had successful limb salvage, 76% was attributable to thrombolysis alone, and 24% had limb salvage attributable to subsequent surgery after failed thrombolysis or anticoagulation. Significant complications occurred in 8% of cases, and no deaths were attributed to thrombolysis. Patients alive at 6 and 24 months after index admission who had limb salvage attributable to thrombolysis alone had limb survival rates of 89% and 82%, respectively. The majority of these patients had not required subsequent secondary procedures to maintain limb survival. Thrombolysis is an acceptable and less invasive treatment of acute limb ischemia, with many patients not needing subsequent surgery.

Rheolytic thrombectomy, angioplasty, and selective stenting for subacute isolated popliteal artery occlusions

OBJECTIVE

We have observed that some patients with isolated popliteal artery occlusions (PAOs) harbor varying degrees of organized clot, as suggested by the rapidity with which these occlusions are traversed with the Glidewire. We hypothesized that debulking such PAOs by using rheolytic thrombectomy without adjunctive thrombolysis before percutaneous transluminal angioplasty and selective stenting (PTA/S) is safe and enables single-session treatment with minimal risk of embolization.

METHODS

Between February 2004 and January 2007, 16 male patients (mean age, 68.9 +/- 11.1 years; range, 54-84 years) presenting with disabling claudication (n = 1), rest pain (n = 5), and tissue loss (n = 10; mean duration, 11 +/- 8 weeks; range, 4-26 weeks) were prospectively followed up after rheolytic thrombectomy and angioplasty and selective stenting of their PAO.

RESULTS

The mean occlusion length was 11.6 +/- 4.5 cm. After rheolytic thrombectomy, the occlusions were converted to long stenoses (mean length of 7.6 +/- 3.6 cm). Self-expanding stents were used in 10 of 16 (mean length of 8.3 +/- 4.4 cm). Additional recanalizations of occlusions of the iliac artery and proximal superficial femoral artery were performed before popliteal artery recanalizations in two patients. Ankle-brachial indexes increased from 0.27 +/- 0.22 to 0.94 +/- 0.13. No case of distal embolization was observed. Adjuvant thrombolysis was used in only one case to improve runoff. Inline flow to the foot was achieved in 15 of 16 cases. Three occlusions occurred at 3, 6, and 20 months after surgery (mean follow-up, 15.7 +/- 10.0 months), and two patients underwent successful thrombolysis. The third patient refused further intervention and remains a claudicant. One-year primary and secondary patency rates were 84% and 92%, respectively. Two limb losses occurred at 7 and 9 months as a result of recurrent foot infection in patients with diabetes, both with patent popliteal arteries (1-year limb salvage rate, 83%).

CONCLUSIONS

We advocate debulking isolated subacute PAOs with rheolytic thrombectomy when they are easily crossed, because this enables recanalization of these lesions in a single setting, thus obviating the additional need for thrombolysis in most cases, with seemingly minimal risk of distal embolization. This simple approach is effective and widely available.

Endovascular Therapies for Noncoronary Atherosclerosis in the Elderly: Aortoiliac and Femorotibial Lesions

Many interventional cardiologists are becoming interested in the interventional treatment of noncoronary atherosclerotic disease. The elderly may be especially benefited by the application of many new techniques for the treatment of lower limb atherosclerosis, such as protection and thromboaspiration devices, new atherectomy devices, and cryoplasty. In this review the authors offer geriatric cardiologists an overview and an update of the most recent advances in techniques and results in the field of interventional treatment of aortoiliac and femorotibial artery atherosclerosis in the elderly.

Emerging drugs in peripheral arterial disease

Peripheral arterial disease (PAD) is the manifestation of atherosclerotic occlusion within a peripheral vascular bed. This can occur in any noncoronary arterial bed, but PAD most commonly refers to atherosclerosis in the aorto-iliac system and infrainguinal vessels that lead to symptoms in the lower extremities. The disease most often becomes clinically apparent in elderly individuals, commonly presenting as intermittent claudication. More advanced, or multisegmental disease, may present with ischaemic rest pain or tissue loss. Although the limb manifestations of PAD can be disabling, PAD is also a marker of coronary or cerebrovascular atherosclerosis. In fact, approximately 80% of mortality in PAD patients is secondary to a cardiovascular event. In accordance with this, initial medical management of this disease focuses on preventative and risk reduction strategies to minimise the risk of cardiovascular morbidity and mortality. At present, the majority of recommendations with respect to risk reduction therapy in PAD patients are extrapolated from the coronary and cerebrovascular literature. Limb-directed therapy in PAD intends to minimise symptoms and serve as an adjunct to surgical intervention. However, existing data on the efficacy of these agents suggests that they are only partially effective. In addition, the effect of existing nonoperative intervention on the progression of disease has not been completely elucidated. As such, new therapies are under development, which target various goals, including minimising local progression of disease, minimising disability, reducing systemic cardiovascular morbidity/mortality and augmenting the durability of surgical intervention.

Thrombolysis and mechanical thrombectomy for arterial disease

Thrombolytic therapy has been around for close to 30 years now,but its exact role in the treatment of acute and chronic arterial occlusive disease continues to be debated. Studies have produced varying and contradictory results. We are still not sure if thrombolysis has any true advantages over surgical thromboembolectomy,or which lytic agent is the best. Nonetheless, the technique still plays an important role in the treatment of arterial occlusions.

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.

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

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

Reteplase Monotherapy and Reteplase/Abciximab Combination Therapy in Peripheral Arterial Occlusive Disease: Results from the RELAX Trial

PURPOSE

The safety and efficacy of increasing doses of intraarterial reteplase monotherapy and reteplase/abciximab combination therapy were examined in patients with acute peripheral arterial occlusive disease (PAOD). The primary endpoint of this analysis was major bleeding as defined by the Thrombolysis in Myocardial Infarction (TIMI) investigators.

MATERIALS AND METHODS

The RELAX trial was a prospective, dose-escalating safety trial of reteplase monotherapy (0.1, 0.2, 0.5, or 1.0 U/h) and reteplase/abciximab combination therapy (0.25-mg/kg bolus and 0.125 micro g/kg/min abciximab in addition to each reteplase regimen) for patients with acute or subacute clinical deterioration of PAOD. Reteplase was administered intraarterially to 74 patients; 38 patients were also administered intravenous abciximab for the duration of reteplase infusion. Protocol-specified angiograms were obtained at 6 and 20 hours or for clinical need. Each angiogram was assessed for volume of thrombus dissolved and for arterial patency. The primary safety endpoint (TIMI major bleeding) was assessed at discharge and at day 7. Clinical endpoints were assessed at discharge and at days 30 and 90.

RESULTS

Major bleeding occurred with similar frequency in patients treated with and without abciximab (15% of the pooled patients receiving reteplase monotherapy and 20% of patients receiving reteplase/abciximab combination therapy). There were no intracranial hemorrhagic events in the 74 patients. Reteplase doses of at least 0.2 U/hour were effective at dissolving thrombus and restoring patency. There was no clear dose-response relationship for reteplase. However, the addition of abciximab reduced the occurrence of distal embolic events requiring intervention (5% vs. 31%; P =.014).

CONCLUSIONS

Over the range of reteplase doses studied for peripheral arterial thrombolysis, there were no significant differences in safety or efficacy. However, the addition of intravenous abciximab to reteplase was associated with a decreased rate of distal embolic events without a significant increase in the risk of hemorrhagic complications. Further investigation is needed to define the role of abciximab in catheter-directed thrombolysis with reteplase for PAOD.

Clinical and economic evaluation of the trellis thrombectomy device for arterial occlusions: preliminary analysis

OBJECTIVES

This preliminary study examined the technical efficacy, safety, and cost of treating arterial occlusions with a single device that combines pharmacologic and mechanical thrombolysis.

METHODS

The technical success, bleeding complications, and costs for the first 26 consecutive patients in whom lower extremity ischemia was treated with the Trellis infusion catheter (TIC) were analyzed. Procedure time, thrombolytic infusion time, technical success, bleeding complications (major and intracranial hemorrhage), interventional suite time, and 30-day amputation-free survival were evaluated.

RESULTS

15 of 26 patients (58%) who received treatment with the TIC had acute arterial occlusions, and 11 of 26 patients (42%) had nonacute arterial occlusions. Nineteen of 26 patients (73.1%) received treatment of an infrainguinal occlusion, and 7 of 26 patients (26.9%) received treatment of a suprainguinal occlusion. Lower extremity native arteries were treated in 18 of 26 patients (69%), and lower extremity bypass grafts in 8 of 26 patients (31%). The technical success rate with TIC treatment was 92%, and the 30-day amputation-free survival rate was 96%. There was no difference in technical success or amputation-free survival rate between acute versus nonacute arterial occlusions, native artery versus bypass grafts, and suprainguinal versus infrainguinal arterial occlusions. Procedure time was 2.1 +/- 0.9 hours, and infusion time was 0.3 +/- 0.2 hours. There were no bleeding complications; however, 3 of 26 patients (11.5%) required further intervention to treat distal embolization. The overall mean cost for patients with TIC treatment was $3216 +/- $1740.

CONCLUSIONS

Early results of TIC treatment in patients with arterial occlusions suggest that it is as effective as traditional catheter-directed thrombolysis. Furthermore, there were no bleeding complications, likely the result of TIC requiring shorter procedure and infusion times.

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.

Endovascular techniques in the treatment of acute limb ischemia: thrombolytic agents, trials, and percutaneous mechanical thrombectomy techniques

Acute peripheral arterial occlusion is associated with great risk to the patient's limb and life. Failure to restore adequate arterial flow in a timely fashion can result in the development of irreversible tissue infarction and the opportunity for limb salvage is lost. On the other hand, patients with acute limb ischemia are often elderly and frail, and early invasive open surgical procedures without adequate preoperative stabilization and preparation result in an unacceptably high risk of perioperative cardiopulmonary complications and death. Percutaneous methods designed to remove the intraluminal thrombus offer an alternative to immediate open surgical revascularization. These less invasive techniques constitute an option that is better tolerated in medically compromised patients. The causative lesion can be precisely identified and the patency of outflow vessels can be restored. The lesion can then be addressed on an elective basis in a well-prepared patient, using percutaneous or open surgical techniques to effect a durable long-term solution. The treatment options include primary surgical revascularization, thrombolytic therapy, percutaneous mechanical thrombectomy, or a combination of any of the three. Clinicians who themselves have the skills to perform a wide assortment of interventions ranging from percutaneous therapies through open surgical revascularization are best able to arrive at the most rational option for treating a specific clinical scenario. This article is directed at providing the practicing surgeon with a basic fund of knowledge on the diagnostic and therapeutic strategies useful in treating patients with peripheral arterial occlusion. Only in this manner can we expect to reduce the high rate of morbidity and mortality that remains associated with these events.

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.

Surgical thrombectomy: current role in thromboembolic occlusions

Thromboembolic disease occurs in a heterogeneous group of patients with significant co-morbidities and variable presentations, resulting in high morbidity and mortality rates. To decrease these complications, multiple different endovascular modalities have been developed and used to treat this challenging problem. Physicians are now left with a broad array of endovascular and surgical options. Unfortunately, there are little data that accurately compare these modalities. Therefore, an individual approach to each patient with acute ischemia from thromboembolic disease must be employed. In order to tailor the treatment to the needs of each patient, the physician must be familiar with the techniques, complications, technology, and relative strengths and weaknesses of each treatment modality. This article will first outline the main technical considerations for performing surgical thromboembolectomy. The complications of operative thromboembolectomy will then be discussed followed by the data comparing operative and nonoperative therapy. Finally, clinical scenarios that are best treated by surgical intervention will be described.

Microtibial embolectomy

BACKGROUND

microtibial embolectomy is an important technique in cases of limb threatening acute arterial occlusion affecting native crural and pedal vessels. It is particularly useful when thrombolysis is contraindicated or ineffective as in "trash foot".

METHODS

in order to evaluate the efficacy of this technique, a retrospective case note review was carried out for patients undergoing microtibial embolectomy from 1990 to 1999. Data collected included the causes and degree of ischaemia, additional procedures required, vessel patency, limb salvage and complications encountered.

RESULTS

twenty-two limbs underwent exploration of the crural/pedal vessels with ankle level arteriotomies under local anaesthetic in 12 cases, general anaesthetic in nine and epidural in one. The causes of ischaemia were cardiac emboli (8), "trash foot" (7), emboli from aortic and popliteal aneurysms (3) and thrombotic occlusion of crural vessels (4). The vessel patency rate was 69% and limb salvage rate 62% (13/21) up to 5-years follow-up. Six of the seven cases with "trash foot" were salvaged while one required an amputation at 3-months post-operatively. The 30-day mortality was 22% (5/22).

CONCLUSIONS

microtibial embolectomy is effective in acute occlusion of the crural/pedal arteries including cases of "trash foot", offering limb salvage to a worthwhile proportion of cases.

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.

Current status of thrombolysis for peripheral arterial occlusive disease

Acute peripheral arterial occlusion occurs as a result of thrombosis or embolism. A reduction in the prevalence of rheumatic heart disease accounts for a shift in the frequency of embolic to thrombotic occlusions. Also, a dramatic increase in the number of lower extremity arterial bypass graft procedures explains the predominance of graft occlusions in most recent series of patients with acute limb ischemia. While open surgical procedures remain the gold standard in the treatment of peripheral arterial occlusion, thrombolytic agents have been employed as an alternative to primary surgical revascularization in patients with acute limb ischemia. Systemic administration of thrombolytic agents, while effective for small coronary artery clots, fails to achieve dissolution of the large peripheral arterial thrombi. Catheter-directed administration of the agents directly into the occlusive thrombus is the only means of effecting early recanalization. Prior to 1999, urokinase was the sole agent used in North America for peripheral arterial indications, but the loss of the agent from the marketplace forced clinicians to turn to alternate agents, specifically alteplase and reteplase. Interest in the use of platelet glycoprotein inhibitors and mechanical thrombectomy devices also rose, coincident with the loss of urokinase from the marketplace. Most clinicians welcome the predicted return of urokinase to the marketplace. New investigative trials should be organized and executed to answer some of the remaining questions related to thrombolytic treatment of peripheral arterial disease. Foremost in this regard remains the question of which patients are best treated with percutaneous thrombolytic techniques and which are best treated with primary operative intervention. Ultimately, however, the thrombolytic agents are but one tool in the armamentarium of the vascular practitioner. This review is directed at providing the practicing clinician with the basic fund of knowledge necessary when determining the most appropriate intervention in a particular patient with peripheral arterial occlusion, be it thrombolytic therapy, percutaneous mechanical thrombectomy, primary surgical revascularization, or a combination of the three.

Acute lower limb ischaemia

Salvage of the acutely ischaemic lower limb represents a large proportion of the emergency workload for the vascular surgeon. A successful outcome is dependent upon a careful clinical assessment and a prompt multidisciplinary approach to revascularization.

Treatment of acute occlusion of peripheral arteries

Acute lower-extremity peripheral arterial occlusion is responsible for a wide variety of complications culminating in limb loss or death. The real incidence of acute limb ischemia (ALI) in the general population is not well known even though recent epidemiological data estimated that it occurs in 14 out of a population of 100,000 and that it accounts for 10-16% of the vascular workload. The two main causes of acute occlusion of peripheral arteries are: (i) embolism and (ii) thrombosis, which usually occurs in cases of severe atherosclerotic stenoses. Arterial flow can be restored through operative revascularization or pharmacological dissolution of thrombus. Immediate surgical revascularization is indicated in the profoundly ischemic limb. Catheter embolectomy is also usually preferred for emboli to a non-atherosclerotic limb. Catheter-directed thrombolysis has become a commonly employed technique in the treatment of ALI. It may offer definitive treatment without the need of major surgery in a significant subset of patients with acute occlusion of a native leg artery or a bypass graft. A number or reports from individual centers and three large prospective studies, which compared intra-arterial thrombolysis to surgical intervention, suggest that thrombolytic therapy may be an appropriate initial treatment of ALI, provided that the limb is not immediately or irreversibly threatened. Using this approach, the underlying lesions can be further defined by angiography, and the percutaneous or surgical revascularization procedure can be performed. However, severe bleeding is still a non-rare complication of intra-arterial thrombolysis and the risk of intracranial hemorrhage is 1-2%.