Ultrasound-Accelerated versus Standard Catheter-Directed Thrombolysis in 102 Patients with Acute and Subacute Limb Ischemia

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Percutaneous thrombectomy or ultrasound-accelerated thrombolysis for initial management of acute limb ischaemia

BACKGROUND

Acute limb ischaemia (ALI), the sudden and significant reduction of blood flow to the limb, is considered a vascular emergency. In the general population, the incidence is estimated as 14 per 100,000. Prognosis depends on the time it takes to diagnose the condition and begin appropriate treatment. Standard initial interventional treatments include conventional open surgery and endovascular interventions such as catheter-directed thrombolysis (CDT). Percutaneous interventions, such as percutaneous thrombectomy (PT, including mechanical thrombectomy or pharmomechanical thrombectomy) and ultrasound-accelerated thrombolysis (USAT), are also performed as alternative endovascular techniques. The proposed advantages of PT and USAT include reduced time to revascularisation and when combined with catheter-directed thrombolysis, a reduction in dose of thrombolytic agents and infusion time. The benefits of PT or USAT versus open surgery or thrombolysis alone are still uncertain. In this review, we compared PT or USAT against standard treatment for ALI, in an attempt to determine if any technique is comparatively safer and more effective.

OBJECTIVES

To assess the safety and effectiveness of percutaneous thrombectomy or ultrasound-accelerated thrombolysis for the initial management of acute limb ischaemia in adults.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL, the World Health Organization (WHO) International Clinical Trials Registry Platform, and ClinicalTrials.gov to 3 March 2021. We searched reference lists of relevant studies and papers.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared PT (any modality, including mechanical thrombectomy (aspiration, rheolysis, rotation) or pharmomechanical thrombectomy) or USAT with open surgery, thrombolysis alone, no treatment, or another PT modality for the treatment of ALI.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected the studies, assessed risk of bias, extracted data, performed data analysis, and assessed the certainty of evidence according to GRADE. Outcomes of interest were primary patency, amputation rate, major bleeding, clinical success, secondary patency, and adverse effects.

MAIN RESULTS

We included one RCT in this review. This study had a total of 60 participants and compared USAT with standard treatment (CDT). The study included 32 participants in the CDT group and 28 participants in the USAT group. We found no evidence of a difference between USAT and CDT alone for the following evaluated outcomes: amputation rate (risk ratio (RR) 1.14, 95% confidence interval (CI) 0.17 to 7.59); major bleeding (RR 1.71, 95% CI 0.31 to 9.53); clinical success (RR 1.00, 95% CI 0.94 to 1.07); and adverse effects (RR 5.69, 95% CI 0.28 to 113.72). We rated the certainty of the evidence as very low for these outcomes. We downgraded the certainty of the evidence for amputation rate, major bleeding, clinical success, and adverse effects by two levels due to serious limitations in the design (there was a high risk of bias in critical domains) and by two further levels due to imprecision (a small number of participants and only one study included). The study authors reported 30-day patency, but did not report primary and secondary patency separately. The patency rate in the successfully lysed participants was 71% (15/21) in the USAT group and 82% (22/27) in the CDT group. The study authors did not directly report secondary patency, which is patency after secondary procedures, but they did report on secondary procedures. Secondary procedures were subdivided into embolectomy and bypass grafting. Embolectomy was performed on 14% (4/28) of participants in the USAT group versus 3% (1/32) of participants in the CDT group. Bypass grafting was performed on 4% (1/28) of participants in the USAT group versus 0% in the CDT group. As we did not have access to the specific participant data, it was not possible to assess these outcomes further. We did not identify studies comparing the other planned interventions.

AUTHORS' CONCLUSIONS

There is insufficient evidence to assess the safety and effectiveness of USAT versus CDT alone for ALI for our evaluated outcomes: amputation rate, major bleeding, clinical success, and adverse effects. Primary and secondary patency were not reported separately. There was no RCT evidence for PT. Limitations of this systematic review derive from the single included study, small sample size, short clinical follow-up period, and high risk of bias in critical domains. For this reason, the applicability of the results is limited. There is a need for high-quality studies to compare PT or USAT against open surgery, thrombolysis alone, no treatment, or other PT modalities for ALI. Future trials should assess outcomes, such as primary patency, amputation rate, major bleeding, clinical success, secondary patency, and adverse effects.

Endovascular Versus Surgical Revascularization for Acute Limb Ischemia: A Propensity-Score Matched Analysis

BACKGROUND

The optimal revascularization strategy for acute limb ischemia (ALI) remains unclear, and contemporary comparative effectiveness data on endovascular versus surgical revascularization are lacking.

METHODS

We used the 2010 to 2014 National Inpatient Sample databases to identify hospitalizations with a primary diagnosis of ALI. Patients were propensity-score matched on the likelihood of undergoing endovascular versus surgical revascularization using a logistic regression model. The primary outcome was in-hospital mortality. Secondary outcomes included myocardial infarction, stroke, composite of death/myocardial infarction/stroke, any amputation, fasciotomy, acute kidney injury, major bleeding, transfusion, vascular complications, length of stay, and hospital costs.

RESULTS

Of 10 484 (weighted national estimate=51 914) hospitalizations for ALI, endovascular revascularization was performed in 5008 (47.8%) and surgical revascularization in 5476 (52.2%). In the propensity-score matched cohort (n=7746; 3873 per group), patients who underwent endovascular revascularization had significantly lower in-hospital mortality (2.8% versus 4.0%; P=0.002), myocardial infarction (1.9% versus 2.7%; P=0.022), composite of death/myocardial infarction/stroke (5.2% versus 7.5%; P<0.001), acute kidney injury (10.5% versus 11.9%; P=0.043), fasciotomy (1.9% versus 8.9%; P<0.001), major bleeding (16.7% versus 21.0%; P<0.001), and transfusion (10.3% versus 18.5%; P<0.001), but higher vascular complications (1.4% versus 0.7%; P=0.002), compared with those undergoing surgical revascularization. Rates of any amputation were similar between the 2 groups (4.7% versus 5.1%; P=0.43). Median length of stay was shorter and hospital costs higher with endovascular versus surgical revascularization.

CONCLUSIONS

In patients with ALI, endovascular revascularization was associated with better in-hospital clinical outcomes compared with surgical revascularization. Contemporary randomized controlled trials are needed to determine the optimal revascularization strategy for ALI.

Real-World Outcomes of EKOS Ultrasound-Enhanced Catheter-Directed Thrombolysis for Acute Limb Ischemia

BACKGROUND

Ultrasound-enhanced catheter-directed thrombolysis (UET) using the Ekosonic® Endovascular System device for acute, peripheral arterial ischemia has been purported in clinical trials to accelerate the fibrinolytic process to reduce treatment time and lytic dosage. We aim to describe outcomes of UET in a real-world clinical setting.

METHODS

We performed a retrospective review of all patients undergoing UET for acute limb ischemia at a single institution. Data collected included patient demographics, procedural details, and 30-day and 1-year outcomes. The primary endpoints for analysis were major adverse limb events (MALEs; reintervention and/or amputation) and mortality within 30-days and 1-year. Secondary endpoints included technical success, use of adjunctive therapies, and postoperative complications.

RESULTS

A total of 32 patients (mean age 67.4 ± 14.9 years; 25% women) underwent UET for acute limb ischemia between 2014 and 2018. The Rutherford Acute Limb Ischemia Classification was Rutherford (R) 1 in 56.3%, R2a in 31.3%, and R2b in 12.5%. Etiology was thrombosis of native artery in 12.5% of patients, prosthetic bypass in 31.3%, autogenous bypass in 6.3%, and stented native vessel in 50.0%. Mean duration of thrombolytic therapy was 22.2 ± 11.3 hr, and mean tissue plasminogen activator dose was 24.5 ± 15.3 mg. MALEs occurred in 16.7% of patients within the first 30 days and 38.9% experienced a MALE by 1 year. Limb salvage at 30 days and 1 year was 93.8% and 87.5%, respectively. Ipsilateral reintervention was required in 12.5% of patients within 30 days and 37.5% of patients within 1 year. Overall mortality was 6.2% at 30 days and 13.5% at 1 year. In-line flow to the foot was re-established in 90.6% of patients, with a significant improvement in preoperative to postoperative ankle-brachial index (0.31 ± 0.29 vs. 0.78 ± 0.34, P < 0.001) and number of patent tibial runoff vessels (1.31 ± 1.20 vs. 1.96 ± 0.86, P < 0.001). There was no significant difference in revascularization success between occluded vessel types. All but one patient required adjunctive therapy such as further thromboaspiration, stenting, or balloon angioplasty. Major bleeding complications occurred in 3 patients (9.4%), including 1 intracranial hemorrhage (3.1%).

CONCLUSIONS

UET with the EKOS device demonstrates acceptable real-world outcomes in the treatment of acute limb ischemia. UET is generally safe and effective at re-establishing in-line flow to yield high limb salvage rates. However, UET is associated with a high rate of reintervention. Further investigation is needed into specific predictors of limb salvage and need for reintervention, as well as cost-efficacy of this technology compared with that of traditional methods.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Current Status of Distal Embolization in Femoropopliteal Endovascular Interventions

The application of advanced endovascular techniques in very complex femoropopliteal atherosclerotic lesions has shown to expose patients to a higher risk of distal embolization (DE). This complication can affect both the short- and long-term outcomes, leading to worsening ischemia, early minor/major amputation, and longer hospital stay. Recently, there has been an increasing body of evidence on pathophysiology and clinical–radiological management of DE that however has not been systematically addressed by guidelines. The aim of this review was to analyze the current evidence outlining definition and classification, risk assessment, prevention, and management strategies of DE in femoropopliteal endovascular interventions.