Guidance for the use of thrombolytic therapy for the treatment of venous thromboembolism

Inferior vena cava filter use at a large community hospital: a retrospective cohort study

Inferior vena cava (IVC) filters are considered when patients with venous thromboembolism (VTE) develop a contraindication to anticoagulation. Use of IVC filters is increasing, despite associated complications and lack of data on efficacy in reducing VTE-related mortality. We characterized the pattern of IVC filter use at a large community hospital between 2018 and 2022. Specifically, we assessed the indications for IVC filter insertion, filter removal rates, and filter-associated complications. Indications for IVC filters were compared to those outlined by current clinical practice guidelines. We reviewed 120 consecutive filter placement events. The most common indications included recent VTE and active bleeding (40.0%) or need for anticoagulation interruption for surgery (25.8%). Approximately one-third (30.0%) of IVC filters were inserted for indications either not supported or addressed by guidelines. Half (50.0%) of patients had successful removal of their IVC filter. At least 13 patients (10.8%) experienced a filter-related complication. In a large community-based practice, nearly one-third of IVC filters were inserted for indications not universally supported by current practice guidelines. Moreover, most IVC filters were not removed, raising the risk of filter-associated complications, and supporting the need for development of comprehensive guidelines addressing use of IVC filters, and post-insertion monitoring practices.

Venous thromboembolism: diagnostic advances and unaddressed challenges in management

PURPOSE OF REVIEW

This review summarizes recent advances in developing targeted diagnostics for venous thromboembolism (VTE) and unaddressed knowledge gaps in patient management. Without addressing these critical data needs, the morbidity in VTE patients will persist.

RECENT FINDINGS

Recent studies investigating plasma protein profiles in VTE patients have identified key diagnostic targets to address the currently unmet need for low-cost, confirmatory, point-of-care VTE diagnostics. These studies and a growing body of evidence from animal model studies have revealed the importance of inflammatory and vascular pathology in driving VTE, which are currently unaddressed targets for VTE therapy. To enhance the translation of preclinical animal studies, clinical quantification of thrombus burden and comparative component analyses between modeled VTE and clinical VTE are necessary.

SUMMARY

Lead candidates from protein profiling of VTE patients' plasma offer a promising outlook in developing low cost, confirmatory, point-of-care testing for VTE. Additionally, addressing the critical knowledge gap of quantitatively measuring clinical thrombi will allow for an array of benefits in VTE management and informing the translatability of experimental therapeutics.

Comparative outcomes of catheter-directed thrombolysis versus AngioJet pharmacomechanical catheter-directed thrombolysis for treatment of acute iliofemoral deep vein thrombosis

OBJECTIVE

The objective of this study was to compare the outcomes of pharmacomechanical thrombolysis and thrombectomy (PCDT) plus catheter-directed thrombolysis (CDT) vs CDT alone for the treatment of acute iliofemoral deep vein thrombosis (DVT) and summarize the clinical experience, safety outcomes, and short- and long-term efficacy.

METHODS

We performed a 4-year retrospective, case-control study. A total of 95 consecutive patients with acute symptomatic iliofemoral deep vein thrombosis (DVT) with a symptom duration of ≤7 days involving the iliac and/or common femoral veins underwent endovascular interventions. The patients were divided into two groups according to their clinical indications: PCDT plus CDT vs CDT alone. Statistical analyses were used to compare the clinical characteristics and outcomes between the two groups. Additionally, the patients were followed up for 3 to 36 months after treatment, and the proportions of post-thrombotic syndrome (PTS) and moderate to severe PTS were analyzed using the Kaplan-Meier survival method.

RESULTS

A total of 95 consecutive patients were analyzed in this retrospective study, of whom, 51 underwent CDT alone and 44 underwent PCDT plus CDT. Between the two groups, in terms of immediate-term efficacy and safety, significant differences were found in the catheter retention time (60.64 ± 12.04 hours vs 19.42 ± 4.04 hours; P < .001), dosages of urokinase required (5.82 ± 0.81 million units vs 1.80 ± 0.64 million units; P < .001), the detumescence rate at 24 hours postoperatively (48.46% ± 8.62% vs 76.79% ± 7.98%; P = .026), the descent velocity of D-dimer per day (2266.28 ± 1358.26 μg/L/D vs 3842.34 ± 2048.02 μg/L/D; P = .018), total hospitalization stay (6.2 ± 1.40 days vs 3.8 ± 0.70 days; P = .024), number of postoperative angiograms (2.4 ± 0.80 vs 1.2 ± 0.30; P = .042), and grade III venous patency (>95% lysis: 54.5% vs 68.6%; P = .047). Furthermore, during the follow-up period, significant differences were found in the incidence of PTS (Villalta scale ≥5 or a venous ulcer: 47.0% vs 27.7%; P = .037), and the incidence proportion of moderate to severe PTS at 12 months (15.7% vs 4.5%; P = .024) and 24 months (35.3% vs 11.4%; P = .016).

CONCLUSIONS

Compared with CDT alone, in the iliofemoral DVT subgroup with a symptom duration of ≤7 days, PCDT plus CDT could significantly relieve early leg symptoms, shorten the hospitalization stay, reduce bleeding complications, promote long-term venous patency, and decrease the occurrence of PTS and the incidence proportion of moderate to severe PTS. Thus, the short- and long-term outcomes both support the superiority of PCDT plus CDT vs CDT in this subgroup.

Indigo® Aspiration System for thrombectomy in pulmonary embolism

Anticoagulation is mainstay therapy for patients with acute pulmonary embolism while systemic thrombolysis is reserved for those with hemodynamic instability. Over the last decade, percutaneous interventional options have entered the landscape aimed to achieve rapid pharmacomechanical pulmonary artery recanalization. The Penumbra Indigo® Aspiration System (Penumbra Inc., CA, USA) is a US FDA-approved large-bore aspiration thrombectomy device for the treatment of pulmonary embolism. Recent data has demonstrated improved radiographic end points with low rates of major adverse events in cases of intermediate-risk pulmonary embolism. In this review article, we outline device technology, applications, evidence and future directions.

Effect of Chandler loop shear and tubing size on thrombus architecture

Thrombosis can lead to a wide variety of life-threatening circumstances. As current thrombolytic drug screening models often poorly predict drug profiles, leading to failure of thrombolytic therapy or clinical translation, more representative clot substrates are necessary for drug evaluation. Utilizing a Chandler loop device to form clot analogs at high shear has gained popularity in stroke societies. However, shear-dependent clot microstructure has not been fully addressed and low shear conditions are often overlooked. We herein characterized the impact of wall shear rate (126 to 951 s^-1) on clot properties in the Chandler loop. Different revolutions (20-60) per minute and tubing sizes (3.2 to 7.9 mm) were employed to create different sized clots to mimic various thrombosis applications. Increased shear resulted in decreased RBC counts (76.9 ± 4.3% to 17.6 ± 0.9%) and increased fibrin (10 to 60%) based on clot histology. Increased fibrin sheet morphology and platelet aggregates were observed at higher shear under scanning electron microscope. These results show the significant impact of shear and tubing size on resulting clot properties and demonstrate the capability of forming a variety of reproducible in-vivo-like clot analogs in the Chandler loop device controlling for simple parameters to tune clot characteristics.

Percutaneous thrombectomy in patients with intermediate- and high-risk pulmonary embolism and contraindications to thrombolytics: a systematic review and meta-analysis

Catheter-directed interventions have slowly been gaining ground in the treatment of pulmonary embolism (PE), especially in patients with increased risk of bleeding. The goal of this study is to summarize the evidence for the efficacy and safety of percutaneous thrombectomy (PT) in patients with contraindications to systemic and local thrombolysis. We performed a systematic review and meta-analysis using MEDLINE, Cochrane, Scopus and the Web of Science databases for studies from inception to March 2022. We included patients with intermediate- and high-risk PE with contraindications to thrombolysis; patients who received systematic or local thrombolysis were excluded. Primary endpoint was in-hospital and 30-day mortality, with secondary outcomes based on hemodynamic and radiographic changes. Major bleeding events were assessed as a safety endpoint. Seventeen studies enrolled 455 patients, with a mean age of 58.6 years and encompassing 50.4% females. In-hospital and 30-day mortality rates were 4% (95% CI 3-6%) and 5% (95% CI 3-9%) for all-comers, respectively. We found a post-procedural reduction in systolic and mean pulmonary arterial pressures by 15.4 mmHg (95% CI 7-23.7) and 10.3 mmHg (95% CI 3.1-17.5) respectively. The RV/LV ratio and Miller Index were reduced by 0.42 (95% CI 0.38-46) and 7.8 (95% CI 5.2-10.5). Major bleeding events occurred in 4% (95% CI 3-6%). This is the first meta-analysis to report pooled outcomes on PT in intermediate- and high-risk PE patients without the use of systemic or local thrombolytics. The overall mortality rate is comparable to other contemporary treatments, and is an important modality particularly in those with contraindications for adjunctive thrombolytic therapy. Further studies are needed to understand the interplay of anticoagulation with PT and catheter-directed thrombolysis.

Catheter-Directed Interventions for the Treatment of Lower Extremity Deep Vein Thrombosis

Lower extremity deep vein thrombosis (DVT) leads to significant morbidity including pain, swelling, and difficulty walking in the affected limb. If left untreated, DVT increases the risk of pulmonary embolism (PE), recurrent venous thromboembolism (VTE), and post thrombotic syndrome (PTS). The objective of this review was to identify catheter-directed interventions and their success rates for the treatment of lower extremity DVT. A comprehensive search of current and emerging catheter-directed interventions for lower extremity DVT treatment was conducted in PubMed and Google Scholar. Clinical trials, retrospective and prospective observational studies, and case reports were identified to classify percutaneous mechanical thrombectomy (PMT), catheter-directed thrombolysis (CDT), and pharmacomechanical CDT (PCDT) devices based on their mechanism of action and indication of use. Catheter-directed interventions such as PMT, CDT, and PCDT offer an alternative therapeutic strategy for DVT management, particularly in patients with limb-threatening conditions and absolute contraindications to anticoagulants. Currently, there are limited guidelines for the use of mechanical and pharmacomechanical devices because of the lack of clinical evidence available for their use in treatment. Future studies are required to determine the short and long-term effects of using catheter-directed interventions as well as their effectiveness in treating acute versus subacute and chronic DVT.

A unique case of acute bilateral internal iliac deep vein thrombosis leading to right iliofemoral venous outflow obstruction

Venous thromboembolism has been associated with high morbidity and mortality, with a cost burden for the U.S. health care system owing to secondary complications such as pulmonary embolism and post-thrombotic syndrome. The current standard of therapy for acute deep vein thrombosis (DVT) is anticoagulation. For patients with venous outflow obstruction of the iliac vein system, several minimally invasive recanalization techniques are now available. In the present report, we have described a case of bilateral internal iliac DVT that had progressed to right-sided iliofemoral DVT in a young athletic adult, in the absence of anatomic abnormalities, that was treated with thrombolysis-free mechanical thrombectomy.

Design and Haemodynamic Analysis of a Novel Anchoring System for Central Venous Pressure Measurement

BACKGROUND/OBJECTIVE

In recent years, treatment of heart failure patients has proved to benefit from implantation of pressure sensors in the pulmonary artery (PA). While longitudinal measurement of PA pressure profoundly improves a clinician's ability to manage HF, the full potential of central venous pressure as a clinical tool has yet to be unlocked. Central venous pressure serves as a surrogate for the right atrial pressure, and thus could potentially predict a wider range of heart failure conditions. However, it is unclear if current sensor anchoring methods, designed for the PA, are suitable to hold pressure sensors safely in the inferior vena cava. The purpose of this study was to design an anchoring system for accurate apposition in inferior vena cava and evaluate whether it is a potential site for central venous pressure measurement.

MATERIALS AND METHODS

A location inferior to the renal veins was selected as an optimal site based on a CT scan analysis. Three anchor designs, a 10-strut anchor, and 5-struts with and without loops, were tested on a custom-made silicone bench model of Vena Cava targeting the infra-renal vena cava. The model was connected to a pulsatile pump system and a heated water bath that constituted an in-vitro simulation unit. Delivery of the inferior vena cava implant was accomplished using a preloaded introducer and a dilator as a push rod to deploy the device at the target area. The anchors were subjected to manual compression tests to evaluate their stability against dislodgement. Computational Fluid Dynamics (CFD) analysis was completed to characterize blood flow in the anchor's environment using pressure-based transient solver. Any potential recirculation zones or disturbances in the blood flow caused by the struts were identified.

RESULTS

We demonstrated successful anchorage and deployment of the 10-strut anchor in the Vena Cava bench model. The 10-strut anchor remained stable during several compression attempts as compared with the other two 5-strut anchor designs. The 10-strut design provided the maximum number of contact points with the vessel in a circular layout and was less susceptible to movement or dislodgement during compression tests. Furthermore, the CFD simulation provided haemodynamic analysis of the optimum 10-strut anchor design.

CONCLUSIONS

This study successfully demonstrated the design and deployment of an inferior vena cava anchoring system in a bench test model. The 10-strut anchor is an optimal design as compared with the two other 5-strut designs; however, substantial in-vivo experiments are required to validate the safety and accuracy of such implants. The CFD simulation enabled better understanding of the haemodynamic parameters and any disturbances in the blood flow due to the presence of the anchor. The ability to place a sensor technology in the vena cava could provide a simple and minimally invasive approach for heart failure patients.

Factor XI, a potential target for anticoagulation therapy for venous thromboembolism

Venous thromboembolism (VTE) is a common cause of mortality and disability in hospitalized patients, and anticoagulation is an essential therapeutic option. Despite the increasing use of direct oral anticoagulants, complications and adverse drug reactions still occur in patients with VTE. Within 5 years, 20% of patients with VTE experience recurrence, and 50% of patients with deep vein thrombosis develop post-thrombotic syndrome. Furthermore, bleeding due to anticoagulants is a side effect that must be addressed. Therefore, safer and more effective anticoagulant strategies with higher patient compliance are urgently needed. Available epidemiological evidence and animal studies have shown that factor XI (FXI) inhibitors can reduce thrombus size and loosen the thrombus structure with a relatively low risk of bleeding, suggesting that FXI has an important role in thrombus stabilization and is a safer target for anticoagulation. Recent clinical trial data have also shown that FXI inhibitors are as effective as enoxaparin and apixaban in preventing VTE, but with a significantly lower incidence of bleeding. Furthermore, FXI inhibitors can be administered daily or monthly; therefore, the monitoring interval can be longer. Additionally, FXI inhibitors can prolong the activated partial thromboplastin time without affecting prothrombin time, which is an easy and common test used in clinical testing, providing a cost-effective monitoring routine for patients. Consequently, the inhibition of FXI may be an effective strategy for the prevention and treatment of VTE. Enormous progress has been made in the research strategies for FXI inhibitors, with abelacimab already in phase III clinical trials and most other inhibitors in phase I or II trials. In this review, we discuss the challenges of VTE therapy, briefly describe the structure and function of FXI, summarize the latest FXI/activated FXI (FXIa) inhibitor strategies, and summarize the latest developments in clinical trials of FXI/FXIa inhibitors.

A unique case of hypoplastic inferior vena cava leading to bilateral iliofemoral venous outflow obstruction and review of literature

Venous thromboembolism (VTE) is a common cardiovascular disease associated with high rates of morbidity and mortality whereas it induces substantial health care costs and increased use of resources. The current standard of treatment for acute deep vein thrombosis (DVT) is anticoagulation, although revascularization can be considered in younger patients with severe symptoms and extensive thrombus burden to prevent long-term sequalae of VTE (eg, recurrent DVTs, post-thrombotic syndrome post-pulmonary embolism syndrome, and chronic thromboembolic pulmonary hypertension). A rare cause of VTE is anomalous development of the inferior vena cava (IVC) and can challenge endovascular revascularization. This case report describes a case of hypoplastic supra hepatic IVC, associated with distal IVC occlusion and bilateral lower extremity DVTs treated successfully with suction thrombectomy and on table only thrombolysis, avoiding the higher risk for major bleeding, intensive care unit admission and prolonged hospitalization associated with prolonged tissue plasminogen activator infusion.

Clinical Effect of Digital Subtraction Angiography Combined with Neurointerventional Thrombolysis for Acute Ischemic Cerebrovascular Disease and Its Influence on Vascular Endothelial Function and Oxidative Stress

Objective

Ischemic cerebrovascular disease is a commonly seen vascular disorder in clinical practice. Given the difficulty of drug therapy to achieve ideal curative effects, interventional therapy has gradually become the preferred treatment for the disease. This research primarily discusses the short-term efficacy of digital subtraction angiography- (DSA-) guided neurointerventional thrombolysis for acute ischemic cerebrovascular disease (AICVD) and its influence on vascular endothelial function (VEF) and oxidative stress (OS).

Methods

All the clinical data of 162 patients diagnosed with AICVD and treated between June 2019 and December 2021 were collected and analyzed retrospectively. They were assigned to two cohorts according to the difference in interventional methods: a conventional group (CG) given recombinant tissue plasminogen activator (rt-PA) therapy and an observation group (OG) intervened by DSA-guided neurointerventional thrombolysis. The two groups were compared with respect to short-term treatment efficacy, the National Institutes of Health Stroke Scale (NIHSS) score, cerebral hemodynamics, and VEF and OS indexes.

Results

The short-term efficacy was better in OG (93.98%) than in CG (82.28%). After treatment, the NIHSS score decreased in both cohorts with obvious differences within the group at different time points, and the posttreatment NIHSS score was lower in OG as compared to CG. OG had higher Q m and V m while lower W v, Z cv, and R v than CG. Higher endothelial-dependent flow-mediated dilatation (FMD) was observed in OG, as well as lower ankle-brachial index (ABI) and pulse wave velocity (PWV). And the posttreatment MDA was lower while SOD, GSH-Px, and TAC were higher in OG compared with those on CG. All the above differences were of statistical significance (P < 0.05).

Conclusions

DSA-guided neurointerventional thrombolysis is highly effective in the treatment of AICVD, which can not only effectively improve patients' neurological function and cerebral hemodynamics but also mitigate VEF injury and help to alleviate patients' OS.

A Brief Review of Thrombolytics for Venous Interventions

Anticoagulation continues to be the mainstay of therapy for the management of venous thromboembolism. However, anticoagulation does not lead to the breakdown or dissolving of the thrombus. In an acute pulmonary embolism, extensive thrombus burden can be associated with a high risk for early decompensation, and in acute deep venous thrombosis, it can be associated with an increased risk for phlegmasia. In addition, residual thrombosis can be associated with chronic thromboembolic pulmonary hypertension and postthrombotic syndrome in a chronic setting. Thrombolytic therapy is a crucial therapeutic choice in treating venous thromboembolism for thrombus resolution. Historically, it was administered systemically and was associated with high bleeding rates, particularly major bleeding, including intracranial bleeding. In the last two decades, there has been a significant increase in catheter-based therapies with and without ultrasound, where lower doses of thrombolytic agents are utilized, potentially reducing the risk for major bleeding events and improving the odds of reducing the thrombus burden. In this article, we provide an overview of several thrombolytic therapies, including delivery methods, doses, and outcomes.

Post-thrombolytic coagulopathy and complications in patients with pulmonary embolism treated with fixed-dose systemic alteplase

BACKGROUND

Alteplase treatment can cause a systemic coagulopathy although the incidence and contributory factors are unknown in pulmonary embolism (PE). Fixed-dosing of alteplase for PE may lead to interpatient variability in drug exposure and influence post-thrombolytic coagulopathy (PTC). While changes in fibrinogen and INR have been used to describe PTC, no universal PTC definition is available.

OBJECTIVES

Evaluate the incidence of PTC after alteplase treatment for PE, the effect of patient weight and blood/plasma volume and the association with bleeding complications.

METHODS

We conducted a retrospective cohort study of patients treated with alteplase for massive or high-risk submassive PE. Demographics, alteplase dosing, laboratory assessment of coagulopathy, and bleeding events were collected. The primary endpoint was incidence of PTC defined as an international normalized ratio (INR) > 1.5 or fibrinogen < 170 mg/dL. Secondary outcomes included correlation between coagulopathies and alteplase dose normalized to actual body weight (ABW), ideal body weight (IBW), plasma volume (PV), and estimated blood volume (EBV). Bleeding events in patients with and without PTC were compared.

RESULTS

125 patients met criteria for inclusion in the study. PTC occurred in 35.3% of patients, with INR >1.5 in 21.8% and fibrinogen <170 mg/dL in 26%. Alteplase dose >50 mg was associated with increased odds of PTC (OR 6.5, CI 2.1-19.9). Dose normalized to ABW and EBV correlated weakly with absolute increase in post-alteplase INR (r =0.20, p =0.06 and r =0.21, p =0.057 respectively) and to percent change in INR (r =0.20, p = 0.058 and r =0.21, p =0.048 respectively). Dose/ABW, dose/PV, and dose/EBV each correlated moderately with absolute decrease in fibrinogen (r =-0.53, -0.49, and -0.47 respectively, p <0.001 for each) and percent change in fibrinogen (r = -0.55, -0.49, and -0.49 respectively, p < 0.001 for each). Dose/IBW correlated weakly with absolute and percent decrease in fibrinogen (r = -0.32, p =0.013 and r =-0.33, p =0.011). Patients with bleeding were more likely to have PTC (58.3% vs. 28.6%, p= 0.05) and a bleeding event was predictive of PTC (OR 5.33, 1.32-23.99).

CONCLUSIONS

PTC is prevalent in patients with PE. PTC is influenced by alteplase dose and exposure parameters (ABW, IBW, PV, EBV) and may contribute to the bleeding risk.

A Comparative Analysis of Catheter Directed Thrombolysis with Anticoagulation Alone or Systemic tPA in Acute Pulmonary Embolism with Cor Pulmonale

Background

Pulmonary embolism (PE) with cor pulmonale causes considerable mortality and morbidity. Randomized trials have failed to show a mortality difference between treatment modalities including anticoagulation (AC), Catheter directed thrombolysis (CDT) and systemic tPA (tissue plasminogen activator).

Methods

This is a cross-sectional retrospective case-control study utilizing the 2017 National Inpatient Sample (NIS). Patients admitted with acute PE with cor pulmonale were divided into groups based on whether they received anticoagulation, CDT or systemic tPA based on appropriate ICD-10 PCS codes. The AC group and CDT group were compared using univariate and multivariate analyses after adjusting for age, gender, race, comorbidities, insurance status and Charlson comorbidity index (CCI). Secondary outcomes included factors influencing length of stay (LOS) and total charges incurred. Similar analyses were done to compare the CDT group with the tPA group.

Results

In 2017, 13240 patients were admitted with acute PE and cor pulmonale, of whom 18% underwent CDT, 10% underwent systemic tPA and 72% underwent AC alone. Patients who received CDT over AC alone were significantly younger (61.5 vs. 65.5, p = 0.00). Mortality rate overall was 4.8% with tPA group, CDT group and AC alone group having a 11.2%, 3.0% and 4.4% mortality rate respectively. On multivariate analyses, there was no significant mortality difference between the CDT and AC groups (aOR 0.61, 0.34-1.1 95%CI, p = 0.103). Patients with liver disease had significantly higher mortality while obese patients had a significantly lower mortality after adjusting for treatment strategy and confounders. Length of stay (LOS) was not significantly different between the groups however, compared to AC alone, patients who underwent CDT or tPA incurred significantly higher total hospital charges.

Conclusions

CDT offers an attractive alternative to tPA therapy; however, our study does not show an in-hospital mortality benefit. More studies are required to guide patient selection prior to establishing treatment protocols.

Phytochemical analysis and thrombolytic profiling of Costus afer stem fractions

Background

The most commonly occurring mechanism driving ischemic heart disease, ischemic stroke, and myocardial infarction is thrombosis. It is normally characterized by platelet activation and aggregation. Thrombolytics have been used in the treatment of several forms of thrombosis, but their adverse effects have limited their usefulness. Thus, there is a need to develop alternatives from medicinal plants known to possess antithrombotic activity such as Costus afer.

Results

The phytochemical evaluations indicated the presence of flavonoids, alkaloids, cardiac glycosides, tannins, terpenoids, and saponins. The antithrombotic profiling showed that streptokinase had the highest percentage clot lysis, followed by ethylacetate fraction of the extract, which was higher than aspirin and other fractions of the extract.

Conclusion

The present findings show that C. afer stem extract and various fractions possess antithrombotic activities. However, further studies are needed to characterize the antithrombotic bioactive compounds present in the different fractions that are responsible for the activities.

(More than) doubling down: Effective fibrinolysis at a reduced rt-PA dose for catheter-directed thrombolysis combined with histotripsy

Deep vein thrombosis is a major source of morbidity and mortality worldwide. For acute proximal deep vein thrombosis, catheter-directed thrombolytic therapy is an accepted method for vessel recanalization. Thrombolytic therapy is not without risk, including the potential for hemorrhagic bleeding that increases with lytic dose. Histotripsy is a focused ultrasound therapy that generates bubble clouds spontaneously in tissue at depth. The mechanical activity of histotripsy increases the efficacy of thrombolytic therapy at doses consistent with current pharmacomechanical treatments for venous thrombosis. The objective of this study was to determine the influence of lytic dose on histotripsy-enhanced fibrinolysis. Human whole blood clots formed in vitro were exposed to histotripsy and a thrombolytic agent (recombinant tissue plasminogen activator, rt-PA) in a venous flow model perfused with plasma. Lytic was administered into the clot via an infusion catheter at concentrations ranging from 0 (control) to 4.54 μg/mL (a common clinical dose for catheter-directed thrombolysis). Following treatment, perfusate samples were assayed for markers of fibrinolysis, hemolysis, and intact red blood cells and platelets. Fibrinolysis was equivalent between the common clinical dose of rt-PA (4.54 μg/mL) and rt-PA at a reduction to one-twentieth of the common clinical dose (0.23 μg/mL) when combined with histotripsy. Minimal changes were observed in hemolysis for treatment arms with or without histotripsy, potentially due to clot damage from insertion of the infusion catheter. Likewise, histotripsy did not increase the concentration of red blood cells or platelets in the perfusate following treatment compared to rt-PA alone. At the highest lytic dose, a refined histotripsy exposure scheme was implemented to cover larger areas of the clot. The updated exposure scheme improved clot mass loss and fibrinolysis relative to administration of lytic alone. Overall, the data collected in this study indicate the rt-PA dose can be reduced by more than a factor of ten and still promote fibrinolysis when combined with histotripsy.

Prevention, treatment, and risk factors of deep vein thrombosis in critically ill patients in Zhejiang province, China: a multicenter, prospective, observational study

PURPOSE

The aim of this study is to investigate the prevention and treatment patterns of deep vein thrombosis (DVT) in critically ill patients and to explore the risk factors for DVT in people from Zhejiang Province, China.

MATERIALS AND METHODS

This study prospectively enrolled patients admitted in intensive care units (ICUs) of 54 hospitals from 09/16/2019 to 01/16/2020. The risk of developing DVT and subsequent prophylaxis was evaluated. The primary outcome was DVT occurrence during ICU hospitalisation. Univariate and multivariate logistic regression were performed to determine the risk factors for DVT.

RESULTS

A total of 940 patients were included in the study. Among 847 patients who received prophylaxis, 635 (75.0%) patients received physical prophylaxis and 199 (23.5%) patients received drug prophylaxis. Fifty-eight (6.2%) patients were diagnosed with DVT after admission to the ICU, and 36 patients were treated with anticoagulants (all patients received low molecular weight heparin [LMWH]). D-dimer levels (OR = 1.256, 95% CI: 1.132-1.990), basic prophylaxis (OR = 0.092, 95% CI: 0.016-0.536), and physical prophylaxis (OR = 0.159, 95% CI: 0.038-0.674) were independently associated with DVT in ICU patients. The short-term survival was similar between DVT and non-DVT patients.

CONCLUSIONS

DVT prophylaxis is widely performed in ICU patients. Prophylaxis is an independent protective factor for DVT occurrence. The most common treatment of DVT patients is LMWH, although it might increase the rate of bleeding.Key messagesThis is the only multicenter and prospective study of DVT in ICUs in China.d-dimer levels were independently associated with DVT in ICU patients.Prophylaxis was an independent protective factor for DVT occurrence in ICU.

Assessment of histological characteristics, imaging markers, and rt-PA susceptibility of ex vivo venous thrombi

Venous thromboembolism is a significant source of morbidity and mortality worldwide. Catheter-directed thrombolytics is the primary treatment used to relieve critical obstructions, though its efficacy varies based on the thrombus composition. Non-responsive portions of the specimen often remain in situ, which prohibits mechanistic investigation of lytic resistance or the development of diagnostic indicators for treatment outcomes. In this study, thrombus samples extracted from venous thromboembolism patients were analyzed ex vivo to determine their histological properties, susceptibility to lytic therapy, and imaging characteristics. A wide range of thrombus morphologies were observed, with a dependence on age and etymology of the specimen. Fibrinolytic inhibitors including PAI-1, alpha 2-antiplasmin, and TAFI were present in samples, which may contribute to the response venous thrombi to catheter-directed thrombolytics. Finally, a weak but significant correlation was observed between the response of the sample to lytic drug and its magnetic microstructure assessed with a quantitative MRI sequence. These findings highlight the myriad of changes in venous thrombi that may promote lytic resistance, and imaging metrics that correlate with treatment outcomes.

Neurological Complications of Pulmonary Embolism: a Literature Review

PURPOSE OF REVIEW

The present review discusses in-depth about neurological complications following acute venous thromboembolism (VTE).

RECENT FINDINGS

Intracranial hemorrhage, acute ischemic cerebrovascular events, and VTE in brain tumors are described as central nervous system (CNS) complications of PE, while peripheral neuropathy and neuropathic pain are reported as peripheral nervous system (PNS) sequelae of PE. Syncope and seizure are illustrated as atypical neurological presentations of PE. Mounting evidence suggests higher risk of venous thromboembolism (VTE) in patients with neurological diseases, but data on reverse, i.e., neurological sequelae following VTE, is underexplored. The present review is an attempt to explore some of the latter issues categorized into CNS, PNS, and atypical complications following VTE.

Catheter-directed thrombolysis for deep vein thrombosis: 2021 update

Catheter-directed thrombolysis (CDT) has been utilized as an adjunct to anticoagulant therapy in selected patients with deep vein thrombosis (DVT) for approximately 30 years. CDT used to be limited to patients with DVT causing acute limb threat and those exhibiting failure of initial anticoagulation, but has expanded over time. Randomized trials evaluating the first-line use of CDT for proximal DVT have demonstrated that CDT does not produce a major reduction in the occurrence of post-thrombotic syndrome (PTS) and that it is poorly suited for elderly patients and those with limited thrombus extent or major risk factors for bleeding. However, CDT does offer selected patients with acute iliofemoral DVT improvement in reducing early DVT symptoms, in achieving reduction in PTS severity, and in producing an improvement in health-related quality of life (QOL). Clinical practice guidelines from medical and surgical societies are now largely aligned with the randomized trial results. This review offers the reader an update on the results of recently completed clinical trials, and additional guidance on appropriate selection of patients with DVT for catheter-directed thrombolytic therapy.

Clot Degradation Under the Action of Histotripsy Bubble Activity and a Lytic Drug

Deep vein thrombosis is a major source of morbidity worldwide. For critical obstructions, catheter-directed thrombolytics are the frontline therapy to achieve vessel recanalization. Techniques that aid lytic therapy are under development to improve treatment efficacy and reduce procedure-related complications. Histotripsy is one such adjuvant under development that relies on focused ultrasound for in situ nucleation of bubble clouds. Prior studies have demonstrated synergistic effects for clot dissolution when histotripsy is combined with lytic therapy. The success of this combination approach is hypothesized to promote thrombolytic efficacy via two mechanisms: erythrocyte fractionation (hemolysis) and increased lytic activity (fibrinolysis). In this study, the contributions of hemolysis and fibrinolysis to clot degradation under histotripsy and a lytic were quantified with measurements of hemoglobin and D-dimer, respectively. A linear regression analysis was used to determine the relationship between hemoglobin, D-dimer, and the overall treatment efficacy (clot mass loss). A similar analysis was conducted to gauge the role of bubble activity, which was assessed with passive cavitation imaging, on hemolysis and fibrinolysis. Tabulation of these data demonstrated hemolysis and fibrinolysis contributed equally to clot mass loss. Furthermore, bubble cloud activity promoted the generation of hemoglobin and D-dimer in equal proportion. These studies indicate a multifactorial process for clot degradation under the action of histotripsy and a lytic therapy.

Antithrombotic Therapy for VTE Disease: Second Update of the CHEST Guideline and Expert Panel Report - Executive Summary

BACKGROUND

This is the second update to the 9^th edition of these guidelines. We provide recommendations on 17 PICO (Patients, Interventions, Comparators, Outcomes) questions, four of which have not been addressed previously.

METHODS

We generate strong and weak recommendations based on high, moderate, and low-certainty evidence, using GRADE methodology.

RESULTS

The panel generated 29 guidance statements, 13 of which are graded as strong recommendations, covering aspects of antithrombotic management of venous thromboembolism from initial management through secondary prevention and risk reduction of post-thrombotic syndrome. Four new guidance statements are added that did not appear in the 9^th edition (2012) or first update (2016). Eight statements have been substantially modified from the first update.

CONCLUSION

New evidence has emerged since 2016 which further informs the standard of care for patients with venous thromboembolism. Substantial uncertainty remains regarding important management questions, particularly in limited disease and special patient populations.

First-in-Human Study to Assess the Safety and Feasibility of the Bashir Endovascular Catheter for the Treatment of Acute Intermediate-Risk Pulmonary Embolism

BACKGROUND

The Bashir Endovascular Catheter (BEC) is a novel pharmaco-mechanical device designed to enhance thrombolysis by increasing the exposure of thrombus to endogenous and exogenous thrombolytics. The aim of this prospective, multicenter, single-arm study was to evaluate the feasibility and initial safety of the BEC in patients with acute intermediate-risk pulmonary embolism (PE).

METHODS

Patients with symptomatic PE and right ventricular to left ventricular diameter ratio ≥0.9 as documented by computer tomography angiography were eligible for enrollment. The primary safety end points were device related death or adverse events, and major bleeding within 72 hours after BEC directed therapy.

RESULTS

Nine patients were enrolled across 4 US sites. The total dose of r-tPA (recombinant tissue-type plasminogen activator) was 14 mgs in bilateral PE and 12 mgs in unilateral PE over 8 hours delivered via the expanded BEC. At 30-day follow-up, there were no deaths or device-related adverse events. At 48 hours post-BEC therapy, the right ventricular to left ventricular diameter ratio decreased from 1.52±0.26 to 0.97±0.06 (P=0.0009 [95% CI, 0.33-0.82]; 37.0% reduction). Thrombus burden as measured by the Modified Miller Index decreased from 25.4±5.3 to 16.0±4.0 (P=0.0005; [95% CI, 5.5-13.4]; 37.1% reduction).

CONCLUSIONS

In this early feasibility study of the BEC for intermediate-risk PE, there were no deaths or device-related adverse events and a significant reduction in right ventricular to left ventricular diameter ratio and thrombus burden. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT03927508.

Insights from experimental post-thrombotic syndrome and potential for novel therapies

Post-thrombotic syndrome (PTS) is an end stage manifestation of deep vein thrombosis. This is an inherently inflammatory process, with consequent fibrosis. Multiple cellular types are involved, and are likely driven by leukocytes. Herein, we review the current gaps in therapy, and insights from rodent models of venous thrombosis that suggest possible targets to treat and prevent PTS.

Return of spontaneous circulation in patients with out-of-hospital cardiac arrest caused by pulmonary embolism using early point-of-care ultrasound and timely thrombolytic agent application: Two case reports

Introduction:

Acute pulmonary embolism is a confirmed cause of up to 5% of out-of-hospital cardiac arrest and 5%–13% of unexplained cardiac arrest in patients. However, the true incidence may be much higher, as pulmonary embolism is often clinically underdiagnosed. Thrombolytic therapy is a recognized therapy for pulmonary embolism–associated cardiac arrest but is not routinely recommended during cardiopulmonary resuscitation. Therefore, clinicians should attempt to identify patients with suspected pulmonary embolism. Many point-of care ultrasound protocols suggest diagnosis of pulmonary embolism for cardiac arrest patients.

Case presentation:

We describe two male patients (60 years and 66 years, respectively) who presented to the emergency department with cardiac arrest within a period of 1 week. With administration of point-of care ultrasound during the ongoing cardiopulmonary resuscitation in both patients, fibrinolytic therapy was initiated under suspicion of cardiac arrest caused by pulmonary embolism. Both patients had return of spontaneous circulation; however, only the second patient, who received fibrinolytic therapy relatively early, was discharged with a good outcome. In this report, we discussed how to diagnose and manage patients with cardiac arrest–associated pulmonary embolism with the help of point-of care ultrasound. We also discuss the different clinical outcomes of the two patients based on the experience of the clinicians and the timing of thrombolytic agent application.

Conclusions:

If acute pulmonary embolism is suspected in patients with out-of-hospital cardiac arrest, we recommend prompt point-of care ultrasound examination. Point-of care ultrasound may help identify patients with pulmonary embolism during cardiopulmonary resuscitation, leading to immediate treatment, although the clinical outcomes may vary.

Thrombolytic therapy in preterm infants: Fifteen-year experience

OBJECTIVE

To report a single-center experience with thrombolytic therapy using recombinant tissue plasminogen activator (rt-PA) in preterm neonates with severe thrombotic events, in terms of thrombus resolution and bleeding complications.

STUDY DESIGN

This retrospective study included 21 preterm neonates with severe venous thrombotic events admitted to the neonatal intensive care unit, identified in our pharmacy database from January 2001 to December 2016, and treated with rt-PA until complete or partial clot lysis, no-response or bleeding complications. Our primary outcome was thrombus resolution.

RESULTS

Twenty-one preterm neonates were treated with rt-PA for an average of 2.9 cycles. Seventeen patients (80.9%) had superior vena cava thrombosis and superior vena cava syndrome. All patients had a central venous catheter, parenteral nutrition, mechanical ventilation, and sepsis. Fifteen patients (71.4%) were extremely preterm, 11 (52.4%) were extremely low birth weight, and seven (33.3%) were very low birth weight. The patency rate was 85.7%, complete lysis occurred in 11 (52.4%) patients, and partial lysis in seven (33.3%). Minor bleeding occurred in five (23.8%) patients, three patients (14.2%) had clinically relevant nonmajor bleeding events, and major bleeding occurred in six (28%) patients.

CONCLUSION

In this study, the rate of thrombus resolution in preterm neonates treated with rt-PA were similar to the percentages reported in children and adolescents, with a high rate of bleeding. Therefore, rt-PA thrombolytic therapy should only be considered as a treatment option for severe life-threatening thrombosis in premature neonates for whom the benefits of the thrombolytic treatment outweigh the risks of bleeding.

Rescue catheter-based therapies for the treatment of acute massive pulmonary embolism after unsuccessful systemic thrombolysis

The management of acute massive pulmonary embolism (PE) patients who did not respond to systemic thrombolysis (ST) has not been well established. The present study aimed to investigate the safety and effectiveness of catheter-based therapies (CDT) in this condition. We conducted a retrospective study of PE patients after unsuccessful ST (UST) between January 2012 and January 2018. Massive PE was identified in 408 patients and treated with full-dose ST therapy. Thrombolysis at 36 h was judged to be unsuccessful in 52 patients. Four ineligible patients were excluded, and the remaining 48 patients underwent rescue CDT: 30 patients underwent thrombus fragmentation with a rotating pigtail catheter; 8 patients underwent Straub rotational thrombectomy; and 10 patients underwent AngioJet rheolytic thrombectomy. In total, 42 patients subsequently underwent CDT relative to reduced-dose thrombolysis. Pooled clinical success was achieved in 45 patients, and the time-to-clinical instability relief for CDT was short (i.e., 48 h). Clinical findings significantly improved with oxygen saturation and the shock index (p < 0.01). CDT resulted in a significant decrease in the right ventricular (RV)/left ventricular end-diastolic diameter ratio and the average number of patients with pulmonary hypertension (p < 0.01). None of the patients suffered major complications or procedure-related adverse events, and two patients experienced minor complications. During follow-up, RV function symptoms were uneventful. The present study found that CDT is a safe and effective modality for rescue management of massive PE in patients with clinical instability and RV dysfunction after UST, leading to improved clinical outcomes and RV function with a low complication rate.

Single arm access venous sinus stenting (SAVeS) technique: Technical note

Intracranial venous sinus stenting is gaining acceptance as an effective treatment for idiopathic intracranial hypertension (IIH). The typical approach is via femoral venous and arterial access for transvenous stenting with simultaneous angiography. These patients are at an above average risk for groin complications considering obesity is typically associated with IIH and the need for heparinization and dual antiplatelet therapy. Here, we describe cerebral venography, angiography, and venous sinus stenting via a single upper extremity. We utilize a transradial approach for angiography and a venous access via the brachial or basilic vein. Over a series of 28 consecutive procedures, we were able to successfully access the intracranial venous sinuses via the arm without access site complications. This method offers the advantages of immediate patient mobilization after the procedure and more easily monitored and compressible access sites for easier post-procedural care.

Factors influencing recanalization of thrombotic venous occlusions

Summary. The outcome of a thrombotic vessel occlusion is related to the resolution of thrombus and restitution of blood flow. Thrombus formation simultaneously activates an enzymatic process that mediates endogenous fibrinolysis to maintain vessel patency. The balance between coagulation and fibrinolysis determines the extent of thrombus formation, its resolution, and clinical outcome. Endogenic fibrinolysis is frequently unable to overcome coagulation and to resolve the thrombus. Therefore, for a complete resolution of thrombus in an acute phase, exogenic fibrinolytic agents are needed. Currently, tissue plasminogen activator (tPA) is most frequently used for therapeutic thrombolysis. Also, heparins, particularly low-molecular-weight heparins and direct oral anticoagulants which are known as anticoagulant drugs, have some pro-fibrinolytic properties. Besides the extent and age of a clot, different other factors influence the lysis of thrombus. Thrombus structure is one of the most important determinants of thrombus lysis. The concentration of thrombolytic agent (tPA) around and inside of thrombus importantly determines clot lysis velocity. Further, flow-induced mechanical forces which stimulate the transport of thrombolytic agent into the clot influence thrombolysis. Inflammation most probably represents a basic pathogenetic mechanism of activation of coagulation and influences the activity of the fibrinolytic system. Inflammation increases tissue factor release, platelet activity, fibrinogen concentration and inhibits fibrinolysis by increasing plasminogen activator inhibitor 1. Therefore, recanalization of a thrombotic vessel occlusion is inversely related to levels of some circulating inflammatory agents. Consequently, inhibition of inflammation with anti-inflammatory drugs may improve the efficacy of prevention of thromboembolic events and stimulate recanalization of thrombotic occlusions of veins.

Assessment of the value of 3D-DSA combined with neurointerventional thrombolysis in the treatment of senile cerebrovascular occlusion

Assessment of the value of three-dimensional digital subtraction angiography (3D-DSA) combined with neurointerventional thrombolysis in the treatment of senile cerebrovascular occlusion was investigated. A total of 129 patients with senile cerebrovascular occlusion admitted to the Affiliated Hospital of Zunyi Medical University from August 2015 to September 2017 were collected. Among them, 69 patients who underwent neurointerventional catheter thrombolysis under 3D-DSA were included in the study group, and 60 patients treated with neurointerventional thrombolysis were the control group. The levels of inflammatory cytokines IL-6, IL-1β and IL-8 in the two groups were measured by enzyme linked immunosorbent assay (ELISA) before treatment (T0), 7 days (7d) after treatment (T1) and 14 days (14d) after treatment (T2). The score of the National Institute of Health Stroke Scale and the clinical efficacy of patients in the two groups were compared before and after treatment, and Barthel index (BI) was used for investigation before and after treatment. The recurrence rate of disease in the two groups within 1 year was recorded. At T1, IL-6, IL-1β and IL-8 in the study group were significantly lower than those in the control group (P<0.05). The NIHSS score in the study group was lower than that in the control group after treatment (P<0.05). The BI score in the study group was significantly higher than that in the control group after treatment (P<0.05). After the prognostic follow-up, the disease recurrence rate of the study group was significantly lower than that of the control group (P<0.05). In conclusion, 3D-DSA combined with neurointerventional thrombolysis can significantly reduce the expression of inflammatory cytokines and improve the quality of life in patients with cerebrovascular occlusion, which has a high clinical value.

Discretionary Thrombophilia Test Acquisition and Outcomes in Patients With Venous Thromboembolism in a Real-World Clinical Setting

Background The value of thrombophilia test acquisition in improving risk prediction beyond clinical presentation remains unknown. We investigated the effect of thrombophilia test acquisition on venous thromboembolism (VTE) outcomes. Methods and Results We performed a retrospective cohort study of adult patients over a 15-year period (September 2001 and May 2016) with first diagnosis of VTE in a single academic medical center. Participants were identified by International Classification of Diseases, Ninth Revision (ICD-9), Current Procedural Terminology (CPT) codes and medication history. Participants with thrombophilia testing were matched to control participants without thrombophilia testing using a propensity model. Primary outcomes included recurrent VTE, anticoagulant use 12 months after the index VTE event, bleeding-related hospitalization, and death. From 3590 unique patients who met the inclusion criteria, 747 participants with VTE who underwent thrombophilia testing were matched to a control participant without testing. Tested participants were more likely to have a recurrent event (46.1% versus 28.5%; P<0.001) and an anticoagulant prescription 12 months from the index event (53.9% versus 37.1%; P<0.001) but had no significant difference in bleeding-related hospitalization (11.4% versus 11.8%; P=0.81) compared with untested participants. An abnormal thrombophilia test result, per se, did not predict recurrent VTE (47.8% versus 44.1%; P=0.13), longer duration anticoagulation (53.2% versus 54.8%; P=0.51), bleeding (11.5% versus 11.3%; P=0.70), or mortality (12.2% versus 16.1%; P=0.18) compared with participants who had normal test results. Conclusions The decision to perform thrombophilia testing, but not the test result, is associated with a high risk of recurrent VTE despite a greater likelihood of long-duration anticoagulation.

Acute Thrombolysis-Resistant Occlusive Left Femoral and Iliac Venous Thrombosis Treated with Mechanical Thrombectomy via the ClotTriever Device

BACKGROUND

Deep vein thrombosis (DVT) is frequently treated by anticoagulation, which helps to prevent new thrombus formation, but to restore venous flow, additional efforts might be needed. Thrombolytic agents can help clear acute thrombus, but increased bleeding risk is a concern; frequent contraindications are another. One lesser discussed potential limitation is thrombus age, which can affect efficiency of treatment.

CASE

A 62-year-old female patient with extensive DVT affecting the inferior vena cava (IVC) through the left femoral vein was initially treated with EKOS catheter directed thrombolysis (CDT) for 24 hr. Subsequent venogram revealed persistent, occlusive femoral and iliac thrombus. We decided on mechanical thrombectomy via the ClotTriever catheter (Inari Medical, Irvine, California), a nitinol coring element with an attached collection bag that can remove wall-adherent thrombus. We performed three passes with the device and removed large amounts of organized thrombus. Subsequent venography showed complete resolution of the occlusion. Finally, an underlying compression was treated via stenting.

CONCLUSIONS

ClotTriever was effective in removing subacute and chronic thrombus, as demonstrated in this case with persistent extensive thrombus after 24 h of CDT. The ClotTriever System adds a valuable option for vascular interventionalists to treat DVT.

Global guidelines trends and controversies in lower limb venous and lymphatic disease: Narrative literature revision and experts' opinions following the vWINter international meeting in Phlebology, Lymphology & Aesthetics, 23-25 January 2019

Guidelines are fundamental in addressing everyday clinical indications and in reporting the current evidence-based data of related scientific investigations. At the same time, a spatial and temporal issue can limit their value. Indeed, variability in the recommendations can be found both among the same nation different scientific societies and among different nations/continents. On the other side, Garcia already published in 2014 data showing how, after three years in average, one out of five recommendations gets outdated (Martinez Garcia LM, Sanabria AJ, Garcia Alvarez E, et al. The validity of recommendations from clinical guidelines: a survival analysis. CMAJ 2014;186(16):1211–1219). The present document reports a narrative literature revision on the major international recommendations in lower limb venous and lymphatic disease management, focusing on the different countries’ guidelines, trends and controversies from all the continents, while identifying new evidence-based data potentially influencing future guidelines. World renowned experts’ opinions are also provided. The document has been written following the recorded round tables scientific discussions held at the vWINter international meeting (22–26 January 2019; Cortina d’Ampezzo, Italy) and the pre- and post-meeting literature search performed by the leading experts.

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.

Systemic Thrombolysis for Pulmonary Embolism: Evidence, Patient Selection, and Protocols for Management

Acute pulmonary embolism presents a clinical challenge for optimal risk stratification. Although associated with significant morbidity and mortality at the population level, the spectrum of presentation in an individual patient varies from mild symptoms to cardiac arrest. Treatment options include anticoagulation, systemic thrombolysis, catheter-based interventions, and surgical embolectomy. In this article, an attempt is made to optimally identify patients who, based on available evidence, may benefit from systemic thrombolytic therapy. The clinical efficacy of systemic thrombolysis must be balanced against increased risks of major bleeding and intracranial hemorrhage.

Long-term results of low-dose tissue plasminogen activator therapy in acute pulmonary embolism

Recombinant tissue plasminogen activator (rt-PA) is the most commonly used thrombolytic agent in patients with high risk and intermediate to high mortality risk acute pulmonary embolism (PE). Clinical trials have shown early efficacy and safety of low-dose rt-PA. This study investigated the effects of low-dose rt-PA treatment on acute PE in long-term prognosis, recurrence of pulmonary thromboembolism, or the development of late complications. In this study, 48 patients undergoing low-dose rt-PA for the relative contraindications of thrombolytic therapy and 48 patients undergoing standard-dose therapy were evaluated retrospectively. Long-term follow-up investigated the chronic PE, recurrence, and causes of morbidity and mortality.

In both treatment groups, embolism-induced mortality and overall mortality rates were similar in the first 30 days (p=1.000, p=0.714, respectively). Overall mortality rates in long-term follow-up were 41.7% in the low-dose treatment group and 16.7% in the standard-dose treatment group (p=0.013). The mortality rate at the first year was higher in the low-dose-treated group (p=0.011) and most of the deaths were due to accompanying comorbidities. There was no difference in PE recurrence and duration of recurrence between the groups (p=0.598, p=0.073, respectively). Intracranial hemorrhage due to therapy developed in one patient in both groups.

Low-dose thrombolytic therapy in acute PE reduces PE-related mortality in the early period. Long-term follow-up showed that thrombolytic therapy did not affect mortality rates independently of the dose and PE recurrence.

Safety, procedural success and outcome of the Aspirex®S endovascular thrombectomy system in the treatment of iliofemoral deep vein thrombosis – data from the Arnsberg Aspirex registry

Summary. Background: Percutaneous mechanical thrombectomy (PMT) represents a treatment option in addition to conventional therapy for patients with iliofemoral deep vein thrombosis (DVT). We sought to determine the safety, patency and short-term outcome of the Aspirex®S catheter as a rotational mechanical thrombectomy device in the endovascular treatment of iliofemoral DVT. Patients and methods: 56 patients (66 % female, median age 51 years) undergoing mechanical thrombectomy with the Aspirex®S catheter for endovascular treatment of iliofemoral DVT were included in the analysis. Device- and procedure-related complications, prevention of post-thrombotic syndrome (PTS) and patency rates were determined at baseline and at 1, 6 and 12 months after intervention. Results: No device-related complications or malfunction occurred. Procedure-related complications (rehospitalization, re-occlusion of target vein, prolonged hospitalization resulting from access site complication) were seen in 14 % of patients. PMT was followed by implantation of a dedicated venous stent in all patients. Low PTS reflected by a revised venous clinical severity score (rVCSS) of < 3 and a clinical, etiologic, anatomic and pathophysiologic (CEAP) score of < 3 were achieved in 64 % of the patients at 12 months. Patency was 95 % after 1 month, 94 % after 6 months and 87 % after 12 months. Conclusions: Even though long-term studies are missing, PMT of iliofemoral DVT using the Aspirex®S rotational thrombectomy device as a standalone approach exhibited an excellent patency at short term associated with substantial prevention of moderate to severe PTS and low device-related complications including bleeding.

Platelet-derived growth factor-beta as a new marker of deep venous thrombosis

Background:

Deep venous thrombosis (DVT) is associated with significant morbidity and mortality. Thus, there is a great need to demonstrate a more efficient biomarker that would confirm the diagnosis of DVT. Our work aimed to evaluate the role of platelet-derived growth factor-beta (PDGF-B) as a new marker of DVT and its correlation with other radiological and laboratory tools used for the diagnosis.

Materials and Methods:

A case–control study enrolled forty patients selected from our university hospital between April 2018 and August 2018, who divided into two groups: Group I (n = 20) consisted of patients diagnosed with acute venous thrombosis and Group II (n = 20) consisted of patients diagnosed with chronic venous thrombosis. Twenty samples were collected from age- and gender-matched apparently healthy controls to be used as a control. Venous duplex ultrasonography, routine laboratory investigations, D-dimer (DD), and protein expression of PDGF-B were performed on all patients.

Results:

There was a highly significant increase in a protein expression of PDFG-B in all cases of acute and chronic venous thrombosis compared to the control group with P < 0.001; furthermore, it was more specific than DD for the detection of DVT (specificity 95% and 90%, respectively).

Conclusion:

Our study submits a novel association of PDGF-B plasma levels with DVT, and PDGF-B is considered to be a more specific indicator for DVT than is DD.

Catheter-directed therapy for acute pulmonary embolism in children

BACKGROUND

Acute pulmonary embolism is a life-threatening condition and rarely occurs in children. In adults, catheter-directed therapy emerges as a potentially safer and effective therapeutic option. However, there is a paucity of data on the safety and efficacy of catheter-directed therapy for pulmonary embolism in children. We report a single-centred experience of catheter-directed therapy for acute pulmonary embolism in children.

METHODS

This is a retrospective study of children who had no CHD and underwent catheter-directed therapy at Detroit Medical Center during a 12-year period from 2005 to 2017. Demographic and clinical data associated with pulmonary embolism were collected along with the outcome.

RESULTS

A total of nine patients of median age 16 years with the range from 12 to 20 received catheter-directed therapy for sub-massive (n = 6) and massive pulmonary embolism (n = 3). Among nine patients, one patient received Angiojet thrombectomy and balloon angioplasty, whereas eight patients received catheter-directed thrombolysis using tissue plasminogen activator through infusion catheters (n = 3) or EkoSonic ultrasound-accelerated thrombolysis system (n = 5). In four out of five patients treated with EkoSonic, significant clinical improvement was noticed within 24 hours. Among seven patients who survived, two patients had minor gastrointestinal bleeding with median hospital stay of 8 days with the range from 5 to 24 days, and two patients with massive pulmonary embolism died possibly due to delayed institution of catheter-directed therapy.

CONCLUSION

Catheter-directed therapy with/without EkoSonic is an emerging alternative therapy for sub-massive and massive pulmonary embolism in children. A timely institution of catheter-directed therapy appeared important to improve the outcome.

Repeated Thrombolytic Treatment for Recurrent Pulmonary Thromboembolism: A Report of 2 Cases and a Literature Review

We present 2 cases of pulmonary thromboembolism (PTE). The first case, a 50-year-old man, was admitted to the emergency department because of sudden onset dyspnea and left side chest pain. He was diagnosed with intermediate-risk (submassive) PTE, and thrombolytic treatment was commenced. The patient fully recovered, but 5 days later, he was diagnosed with a new, high-risk PTE. The second patient, a 23-year-old woman, presented with syncope, dyspnea, and chest pain for 2 days. She was diagnosed with high-risk (massive) PTE. Thrombolytic treatment was commenced, and the patient fully recovered, too. But the later patient was also diagnosed with a new PTE 4 days later. We applied repeated thrombolytic treatment in the patients due to repeated PTE. The first patient fully recovered and was discharged from the hospital, but the second patient died because of gastrointestinal bleeding and renal insufficiency. A repeated thrombolytic treatment could be an alternative treatment for these patients, considering treatment's risks.

Use of reteplase for thrombolysis in patients with massive pulmonary embolism diagnosed by bedside transthoracic echocardiography: A retrospective study of safety and efficacy

Background:

Pulmonary embolism (PE) is a lethal clinical condition requiring immediate systemic thrombolysis to decrease mortality. Reteplase has been extensively used in acute myocardial infarction but studies in massive PE are rare. We have presented here efficacy and safety of reteplase in patients with high risk PE diagnosed on basis of bedside transthoracic echocardiography.

Methods:

This was retrospective study including 20 patients of massive PE undergoing thrombolysis with reteplase. Bedside TTE was used to evaluate presence of RV dysfunction and thrombi in these patients with hemodynamic compromise. Safety and efficacy outcomes were analysed till three months of follow up.

Results:

12 patients (60%) included in the study were males and mean age was 41 ± 19 years. The dyspnoea, chest pain and haemoptysis improved in all patients after thrombolysis. At discharge, RV dilatation normalised, systolic pulmonary artery pressure decreased, systolic blood pressure significantly increased and hypoxemia had completely corrected. Two patients had minor self-limiting bleeding episodes in form of mild haematuria and oral bleeding. During the follow up period of 3 months all patients were clinically stable and there were no bleeding episodes or death. Moreover, there was no recurrence of PE and/or DVT.

Conclusion:

Reteplase is highly efficacious in massive pulmonary embolism and results in rapid clinical improvement. Moreover, it can be safely used without increased risk of significant bleeding or mortality. Although limited by retrospective nature, reteplase appears to be an attractive option for massive PE but large prospective studies are further required.

Direct-Thrombin Inhibitor Utilization in Patients With Heparin-Induced Thrombocytopenia and Undergoing Catheter-Directed Thrombolysis: A Summary of Published Case Reports

BACKGROUND

Catheter-directed thrombolysis (CDT) is one of the emerging venous thromboembolism management modalities. There are fairly limited data regarding the use of direct-thrombin inhibitors (DTIs) in patients with heparin-induced thrombocytopenia and undergoing CDT.

OBJECTIVES

The aim of this study was to provide a summary of the available evidence supporting the use of DTIs in patients undergoing CDT.

METHODS AND RESULTS

We included 6 case reports in our analysis after searching for peer-reviewed articles and case reports in multiple research engines. Four of the 6 cases used argatroban, and 2 cases used bivalirudin. Alteplase was used in all of the 6 cases. All cases used lower activated partial thromboplastin time target. The average initial dose of alteplase ranged from 0.5 to 3 mg/h. The average duration of CDT was 26 hours (SD, 13 hours). Five patients (83%) survived after the procedure, and no complications were reported.

CONCLUSIONS

The use of DTIs might be safe and effective in selected patients with heparin-induced thrombocytopenia and undergoing CDT.

Comparison of clear effect and the complications, and short and mid-term effects between ultrasound-guided and non-guided catheter-directed thrombolysis in the treatment of deep venous thrombosis of lower extremity

Objective

To compare the therapeutic effects of ultrasound-guided and non-guided catheter-directed thrombolysis in the treatment of deep venous thrombosis of lower extremity.

Methods

From August 2015 to April 2016, 60 patients with lower extremity deep venous thrombosis were randomly divided into two groups ( n = 30 for each) to receive catheter-directed thrombolysis. Group A was treated under the ultrasound guidance, while Group B was treated without guidance.

Results

Catheter-directed thrombolysis was successfully performed by only one intubate in Group A but by 5.9 intubates in Group B. It took 15.4 ± 3.2 min in Group A, significantly less than that in Group B (30.8 ± 6.6 min, p < 0.05). The incidences of hematoma were also remarkably different between the two groups (3.33% vs. 26.67%, p = 0.026). No pseudoaneurysm or arteriovenous fistula was found in Group A, but there were two cases of pseudoaneurysm and two cases of arteriovenous fistula in Group B (both 6.67%, p = 0.492). The circumference differences of the affected limb between before and after thrombolysis were 49.47 ± 2.484 mm in Group A, significantly higher than that in Group B (28.40 ± 2.856 mm, p < 0.001). After treatment, the venous unobstructed improvement rates and deep vein patency rate were both better than those in Group B (77 + 2.603% vs. 57.23 + 1.828% and 80% vs. 46.67%, respectively; p < 0.001). There were only three cases of PTS in Group A (10%, 3/30), but there were 11 cases in Group B (36.67%, 11/30).

Conclusion

Ultrasound-guided catheter-directed thrombolysis has advantages, with improvement of venous patency and decrease of the incidence of PTS.

May-Thurner syndrome and the risk of pulmonary embolism in patients with acute deep venous thrombosis. J Vasc Surg Venous Lymphat Disord. 2018;6:433-440.e1. [PMID: 29909851 DOI: 10.1016/j.jvsv.2018.01.007]

OBJECTIVE

Pulmonary embolism (PE) is the most common complication of deep venous thrombosis (DVT). May-Thurner syndrome (MTS) is known to increase the risk of DVT, but an association between MTS and PE has not been established. This study investigated an association between MTS and the risk of PE in patients with acute lower extremity DVT.

METHODS

Between June 2014 and September 2016, there were 112 patients with DVT at our hospital who underwent venous angiography and computed tomography pulmonary angiography. Data related to the patients' demographics, risk factors, disease onset time, side of DVT, D-dimer level, Doppler ultrasound, venous angiography, and computed tomography pulmonary angiography were collected. Associations between MTS and PE were analyzed.

RESULTS

The 112 DVT patients included 79 with MTS. The rate of DVT in the left lower extremity was higher in the MTS group (98.7%) than in the non-MTS group (48.5%; P < .001). PE was less common in the MTS group (50.6%) than in the non-MTS group (78.8%; P = .006). The multinomial logistic analysis revealed a significant negative correlation between MTS and PE. The correlation remained after applying adjustment models I, II, and III. Model I adjusted for risk factors, DVT side, and D-dimer tertile (odds ratio [OR], 0.17; 95% confidence interval [CI], 0.04-0.68; P = .0125); model II adjusted for sex, age, risk factors, onset time, DVT side, D-dimer level, and D-dimer tertile (OR, 0.15; 95% CI, 0.03-0.71; P = .0162); and model III adjusted for sex, age, risk factors, onset time, DVT side, D-dimer level, D-dimer tertile, iliofemoral DVT, mixed (both iliofemoral and femoropopliteal) DVT, and femoropopliteal DVT (OR, 0.35; 95% CI, 0.06-2.08; P = .2501).

CONCLUSIONS

DVT patients with concomitant MTS have a decreased risk of PE compared with those without MTS. This finding extends previous reports of increased PE risk after DVT and calls for better understanding of shared risk factors and underlying mechanisms.