Feasibility of continuous, catheter-directed thrombolysis using low-dose urokinase in combination with low molecular-weight heparin for acute iliofemoral venous thrombosis in patients at risk of bleeding

Catheter-Directed Thrombolysis Protocols for Deep Venous Thrombosis of the Lower Extremities-A Systematic Review and Meta-analysis

OBJECTIVE

 To summarize characteristics, complications, and success rates of different catheter-directed thrombolysis (CDT) protocols for the treatment of lower extremity deep venous thrombosis (LE-DVT).

METHODS

 A systematic review using electronic databases (MEDLINE, Scopus, and Web of Science) was performed to identify randomized controlled trials and observational studies related to LE-DVT treated with CDT. A random-effects model meta-analysis was performed to obtain the pooled proportions of early complications, postthrombotic syndrome (PTS), and venous patency.

RESULTS

 Forty-six studies met the inclusion criteria reporting 49 protocols (n = 3,028 participants). In studies that addressed the thrombus location (n = 37), LE-DVT had iliofemoral involvement in 90 ± 23% of the cases. Only four series described CDT as the sole intervention for LE-DVT, while 47% received additional thrombectomy (manual, surgical, aspiration, or pharmacomechanical), and 89% used stenting.Definition of venogram success was highly variable, being the Venous Registry Index the most used method (n = 19). Among those, the minimal thrombolysis rate (<50% lysed thrombus) was 0 to 53%, partial thrombolysis (50-90% lysis) was 10 to 71%, and complete thrombolysis (90-100%) was 0 to 88%. Pooled outcomes were 8.7% (95% confidence interval [CI]: 6.6-10.7) for minor bleeding, 1.2% (95% CI: 0.8-1.7%) for major bleeding, 1.1% (95% CI: 0.6-1.6) for pulmonary embolism, and 0.6% (95% CI: 0.3-0.9) for death. Pooled incidences of PTS and of venous patency at up to 1 year of follow-up were 17.6% (95% CI: 11.8-23.4) and 77.5% (95% CI: 68.1-86.9), respectively.

CONCLUSION

 Assessment of the evidence is hampered by the heterogeneity of protocols, which may be reflected in the variation of PTS rates. Despite this, CDT is a low-risk treatment for LE-DVT.

Circle or semi-circle hyper-intensity on T1 high-resolution isovolumetric examination (THRIVE) indicates the young age of experimentally induced caval thrombus

To evaluate the age of caval thrombus that experimentally induced in swine by use of magnetic resonance imaging (MRI). Caval thrombus was experimentally created in 15 swine by autologous clot injection assisted with caval net knitting. Serial high-resolution MR images were obtained using magnetic resonance venography (MRV) and T1 high-resolution isotropic volume examination (THRIVE) sequences in a 3.0-T MR system at 1, 7, 14, 21, and 28 days post model creation. At each time point, three pigs were sacrificed and the thrombotic vena cava was processed for histopathological examinations respectively. Caval thrombus was successfully induced in 15 pigs in group A. The signal intensity (SI) change of caval thrombus on THRIVE was age-dependent, with a typical sign of circle or semi-circle hyper-intensity at 7-day-old model while SI of thrombus was lower than that of muscle from day 14 throughout day 28. The histo-pathological findings revealed that RBCs-rich thrombus at day 1 without blue-stained particles, RBCs layers with infiltration of inflammatory cells and sporadically distributed blue-stained particles at 7-day-old thrombus. At day 14, 21 and 28, blue-stained particles became richer, coupled with formation of granulation tissue and fibrous tissue. The swine model in the study is good for age evaluation of venous thrombosis. The peripheral circle or semi-circle hyperintensity on THRIVE indicates the young age of caval thrombus in swine.

Feasibility of anticoagulation using low molecular-weight heparin during catheter-directed thrombolysis for lower extremity deep venous thrombosis

Background

The optimal anticoagulant scheme during catheter-directed thrombolysis (CDT) for deep venous thrombosis (DVT) remains unknown. This study was performed to evaluate the feasibility of anticoagulation therapy using low molecular-weight heparin (LMWH) during CDT for DVT.

Methods

The clinical data of DVT patients who underwent CDT during the past six years was retrospectively collected and reviewed. Patients were divided into therapeutic-dose anticoagulation (TPDA) and sub therapeutic-dose anticoagulation (sub-TPDA) groups according to LMWH dosage.

Results

A total of 61 patients involving 61 limbs were comprised. Acute and subacute DVT were identified in 39 (63.9%) and 22 (36.1%) patients, respectively. Thrombosis involving the iliac vein was identified in 34 (55.7%) patients. Inferior vena cava filter placement was performed in 38 (62.3%) patients. Intraoperatively, adjunctive balloons, stents, and thrombectomy were provided for nine (14.8%), four (6.6%), and one (1.6%) patients, respectively. Twenty (32.8%) patients accepted TPDA therapy, while 41 (67.2%) patients were administrated with sub-TPDA therapy. Median urokinase infusion rate was 2.5 (0.83 to 5) × 10⁴ U/h. Median infusion duration time was 4 (2 to 14) days, and median urokinase dose infused was 2.4 (0.6 to 10.80) × 10⁶ U. During CDT, five (8.2%) cases of minor bleeding were observed, and blood transfusion was not required. No major bleeding, symptomatic pulmonary embolisms, or death occurred. Complete (> 90%) and partial thrombolysis (50 ~ 90%) were achieved in 56 (91.8%) patients. In comparison with sub-TPDA group, TPDA group exhibited no significant differences in baseline characteristics, clinical improvement, thrombolysis results, and complications.

Conclusions

Anticoagulation therapy using low molecular-weight heparin during CDT with low infusion rate for DVT is likely to be feasible and safe. Sub-therapeutic-dose anticoagulation and therapeutic-dose could be used for CDT with similar clinical outcome and bleeding complications.

The perplexity of catheter-directed thrombolysis for deep venous thrombosis: the approaches play an important role

The recent adjunctive catheter-directed thrombolysis (ATTRACT) trial rose a controversy about the treatment effect of catheter-directed thrombolysis (CDT) in deep venous thrombosis (DVT). In fact, most studies including the ATTRACT trial did not perform subgroup analysis of catheterization approaches. Different approaches would confound the conclusions. Therefore, a single-center retrospective analysis was performed to compare the differences between the antegrade (AGA) and retrograde (RGA) approaches. Total 217 DVT patients treated with CDT were enrolled from January 2010 to December 2017, with mean age of 55.3 years (67 received antegrade approach, 150 received retrograde approach). The clot burden reduction by segment was evaluated. The mean access establishment time and thrombolytic time were compared. The patency of the iliofemoral vein at 6 months was evaluated. The rate of PTS, quality of life and venous insufficiency were assessed at 1 year. AGA group showed better thrombolytic effect in popliteal and femoral vein than RGA group. The rate of iliofemoral clot burden reduction in RGA group was mostly at Grade II, while most were at Grade III in AGA group. The retrograde approach showed better thrombolysis effect in iliofemoral DVT than popliteal to iliac DVT. The RGA group reported longer mean access establishment time (5.4 ± 1.8 vs 27.0 ± 7.5 min, p < 0.001) and thrombolytic time (6.9 ± 1.5 days vs 6.8 ± 1.5 days, p = 0.586). At 6 months, RGA group had a lower rate of femoral vein patency (52.0% vs 89.6%, p < 0.001) and a higher rate of venous insufficiency (52.0% vs 29.9%, p < 0.001), compared with AGA group. Although there was no difference in the rate of PTS, the RGA group showed higher Villalta scores in the free and mild PTS. The antegrade approach was preferably recommended over the retrograde approach for CDT treatment.

Comparison of catheter-directed thrombolysis with and without percutaneous mechanical thrombectomy for subacute iliofemoral deep vein thrombosis

OBJECTIVE

To evaluate and compare the treatment efficacy and safety between catheter-directed thrombolysis monotherapy and catheter-directed thrombolysis combined with percutaneous mechanical thrombectomy for patients with subacute iliofemoral deep vein thrombosis.

METHODS

We conducted a retrospective analysis of a total of 74 subacute iliofemoral deep vein thrombosis patients who underwent catheter-directed thrombolysis with and without percutaneous mechanical thrombectomy. Patients treated with catheter-directed thrombolysis combined with percutaneous mechanical thrombectomy (percutaneous mechanical thrombectomy group, n = 30) or catheter-directed thrombolysis monotherapy (catheter-directed thrombolysis group, n = 44) were included. The primary endpoints were the clinical efficacy rate of thrombolysis, primary patency, and the incidence of post-thrombotic syndrome (at 12 months diagnosed according to the original Villalta score criteria. Secondary endpoints were the total urokinase dose, the thrombolysis time, the detumescence rate and complications.

RESULTS

The percentage of successful thrombolysis for percutaneous mechanical thrombectomy group was higher than that for catheter-directed thrombolysis group (P = 0.045). At the 12-month follow-up, there was no difference in the primary patency (P > 0.05) or the incidence of post-thrombotic syndrome (P = 0.36). Percutaneous mechanical thrombectomy group had significant advantages in reducing urokinase doses and thrombolysis times compared with catheter-directed thrombolysis group for patients with thrombus clearance levels II and III (P < 0.05).

CONCLUSION

Catheter-directed thrombolysis combined with percutaneous mechanical thrombectomy performs better in removing vein thrombi, reducing urokinase doses, and shortening thrombolysis times.

Feasibility of low-dose infusion of alteplase for unsuccessful thrombolysis with urokinase in deep venous thrombosis

The aim of the present study was to investigate whether the rescue of thrombolysis with the recombinant tissue plasminogen activator (rt-PA) alteplase was an effective and safe therapeutic option in patients who did not respond to urokinase. Between February 2016 and February 2017, 26 patients with deep venous thrombosis (DVT) underwent rescue thrombolysis with alteplase. Unsuccessful thrombolysis with urokinase was defined as a lack of improvement in the degree of thrombotic removal with a lysis rate <50% under one of the following three conditions: Two consecutive venography procedures, administration of >3 million units of total urokinase, or >7 days infusion duration. The thrombus score, lysis rate and post-thrombolysis safety of alteplase, following unsuccessful urokinase thrombolysis were all evaluated. At the end of the unsuccessful urokinase thrombolytic therapy, the mean duration of the perfusion was 6.09±1.60 days, and the mean total dose was (362.5±90.0) ×10⁴ units. No significant difference was detected in the total thrombus score before (7.85±2.40) and at the completion (6.19±2.33) of urokinase thrombolysis (P>0.05). The mean duration of perfusion was 3.36±1.69 days, and the mean total infusion dose was 44.8±22.6 mg for the rescue thrombolysis with alteplase. The mean thrombus score decreased to 1.19±2.10 at the completion of rescue thrombolysis. The alteplase post-thrombolysis scores were significantly decreased compared with those of urokinase thrombolysis (P<0.05). There were 23 (88.5%) patients who achieved a successful lysis rate (grade II/III) following rescue thrombolysis with alteplase, and symptoms of swelling and pain in the affected limbs were significantly improved. Successful thrombolysis rates in patients in the acute (<14 days) and subacute (14-28 days) phases were high (93.3 and 81.8%, respectively; P>0.05). No symptomatic pulmonary embolism or major bleeding occurred during rescue thrombolysis, but minor bleeding complications occurred in 4 cases (15.4%). In conclusion, rescue thrombolysis with alteplase led to an effective and safe outcome in patients with DVT who did not respond to initial thrombolysis with urokinase, and may be a valid and easy alternative treatment option.

Catheter-Directed Thrombolysis With a Continuous Infusion of Low-Dose Alteplase for Subacute Proximal Venous Thrombosis: Efficacy and Safety Compared to Urokinase

The purpose of this study was to compare the efficacy and safety associated with catheter-directed thrombolysis (CDT) using either recombinant tissue plasminogen activator (rt-PA) or urokinase (UK) for subacute deep venous thrombosis (DVT). From January 2014 to December 2016, we conducted a retrospective analysis on a total of 49 patients who underwent consistent CDT with either rt-PA (rt-PA-CDT group) or UK (UK-CDT group) treatment. The thrombolytic rate of the rt-PA-CDT group was significantly higher than that of the UK-CDT group (87.5% vs 60%, respectively; χ2 = 4.751; P = .029). The rt-PA-CDT group exhibited an improved grade III thrombolytic rate (9 patients vs 3 patients; χ2 = 5.144; P = .023). The time for the rt-PA-CDT group to achieve a grade III thrombolytic rate was shorter than that of the UK-CDT group (5.01 ± 1.09 days vs 6.43 ± 1.69 days, respectively; t = -2.187; P = .044). No severe complications were seen in either group and mild complications rates were 16.7% and 20.0% (χ2 = .091; P = .763). The clinical efficacy rates at discharge were 91.7% and 76.0%, respectively (χ2 = 2.200; P = .138). In conclusion, CDT with a continuous infusion of low-dose rt-PA resulted in safe and effective thrombolysis in the great majority of patients with proximal DVT in the subacute phase. Furthermore, rt-PA was significantly better than UK in terms of the thrombolytic rate. In our study, rt-PA-CDT improved the thrombolytic rate of grade III thrombus and achieved a grade III thrombolytic rate in a shorter time than UK-CDT.

Consensus among Chinese experts on standard interventional therapy for deep venous thrombosis of lower extremity (second edition)

This is an update on the first edition of the expert consensus. This document discusses the indications and contraindications of interventional treatment methods for deep venous thrombosis such as anticoagulation, catheter-directed thrombolysis, percutaneous mechanical thrombectomy, percutaneous transluminal angioplasty and stent implantation. The operational procedures, considerations, preoperative management, and prevention of complications were also updated, supplemented, and revised. Emphasis is placed on the interventional treatment of acute and subacute deep venous thrombosis to effectively reduce the incidence of post-thrombosis syndrome.

The Efficacy and Safety of Intermittent Low-Dose Urokinase Thrombolysis for the Treatment of Senile Acute Intermediate-High-Risk Pulmonary Embolism: A Pilot Trial

Thrombolysis and anticoagulation were the main treatment methods for acute pulmonary embolism. However, the use of thrombolysis drugs may lead to bleeding complications. We compared intermittent low-dose urokinase (UK) and alteplase (recombinant tissue plasminogen activator [rt-PA]) in normotensive patients with intermediate-high-risk pulmonary embolism. The UK group was treated with intravenous UK 10 000 U/kg once a day for 7 days. The rt-PA group was given alteplase 50 mg by intravenous injection within 2 hours of admission. After thrombolytic therapy, 48 patients were included in this trial. Compared with before treatment, right and left ventricular diastolic diameter ratio, systolic pulmonary artery pressure, and cardiac troponin I of the 2 groups all significantly decreased 8 and 14 days after treatment, which indicated that right heart function improved. Total efficacy rates for the UK group 8 and 14 days after treatment (79.2%, 87.5%) and the rt-PA group (75.0%, 91.67%) were not significantly different. Adverse bleeding reactions were higher in the rt-PA group (20.8%) than in the UK group (8.3%). This pilot study indicates that intermittent low-dose UK thrombolysis is equally effective as rt-PA. However, future large-scale studies must also determine whether small doses of UK thrombolysis reduce the risk of bleeding.