Interventional Therapy for Pulmonary Embolism

Construction and Validation of a Benchtop Model for Testing of Mechanical Thrombectomy Devices for Pulmonary Embolism

PURPOSE

This study aims to define the process of designing and manufacturing 3D printed and glass models of the pulmonary artery (PA) and utilizing them in a test bed for evaluation of devices for mechanical thrombectomy of pulmonary embolism (PE).

MATERIALS AND METHODS

Patient derived computed tomography angiography (CTA) images of the PA were digitally converted into a hollowed-out structure and translated into clear 3D printed and glass models. A test bed was created using a peristaltic pump and silicone tubing connected to the models. Human clot analogs were then prepared and injected within the models. Thrombectomy testing was done using clinically used predicates and baseline characteristics of the models were evaluated by independent interventionalists.

RESULTS

The mean sizes of the main pulmonary artery (MPA) for the 3D printed model and glass model were 30.4 mm and 29.2 mm, mimicking those of the patient's PA obtained on CTA. Heterogeneous human clot analogs were created with fibrin composition ranging from 60 to 30%. Mechanical thrombectomy was successfully attempted by independent interventionalists. Both the 3D printed, and glass model were appraised as very good for multiple attributes.

CONCLUSION

A complete test bed using 3D printed and glass models of the PA with human clot analogs was created for testing of mechanical thrombectomy devices for PE.

Current Endovascular Treatment Options in Acute Pulmonary Embolism

Acute pulmonary embolism (PE) is a significant cause of mortality and morbidity across the globe. Over the last few decades, there have been major therapeutic advances in acute PE management, including catheter-based therapy. However, the effectiveness of catheter-based therapy in acute PE is not supported by Level I evidence, making the use of this promising treatment rather controversial and ambiguous. In this paper, we discuss the risk stratification of acute PE and review the medical and endovascular treatment options. We also summarize and review the data supporting the use of endovascular treatment options in acute PE and describe the potential role of the PE response team.

Technical efficiency, short-term clinical results and safety of a large-bore aspiration catheter in acute pulmonary embolism - A retrospective case study

BACKGROUND

Mechanical thrombectomy plays an important role in the management of acute pulmonary embolism (PE), either when rapid clot dissolution is needed or when thrombolytics are contraindicated. We describe our clinical and technical experience with the FlowTriever mechanical thrombectomy device in patients with acute PE.

MATERIALS AND METHODS

A retrospective analysis was performed on all cases of acute PE treated with the FlowTriever device at a single tertiary care hospital system during the trial period (November 2019-January 2020). Technical and clinical results, including complications, are reported.

RESULTS

Technical success was achieved in all eight successive cases (seven cases of submassive and 1 case of massive PE). Mean pulmonary artery pressure (MPAP) improved significantly after mechanical thrombectomy (27.8 ± 6.4 mmHg preprocedure; 20.5 ± 3.8 mmHg postprocedure; 7.3 ± 5.2 mmHg decrease after the procedure; P = 0.016). Hemoglobin levels did not change significantly after mechanical thrombectomy (11.8 g/dl ± 3.4 preprocedure; 9.9 g/dl ± 2.1 postprocedure; P = 0.20). Reduction in MPAP was achieved in 88% of cases (7/8) and hypoxia improved in all the nonintubated patients (7/7). Mortality observed in one patient with a massive central PE, was not related to the procedure. No mortality or procedural complications were observed in patients with submassive PE.

CONCLUSIONS

The positive initial clinical experience and safety profile using the FlowTriever in the treatment of acute PE suggests, it has the potential to fill the unmet needs of a good mechanical thrombectomy device to treat massive and submassive high-risk PE especially when thrombolytics are contraindicated.

Effect of Percutaneous Suction Thromboembolectomy on Improved Right Ventricular Function

Venous thromboembolism is a leading cause of cardiovascular death. Historically, surgical intervention has been associated with high morbidity rates. Pharmacologic therapy alone can be inadequate for patients with substantial hemodynamic compromise, so minimally invasive procedures are being developed to reduce clot burden. We describe our initial experience with using the AngioVac system to remove thromboemboli percutaneously. We reviewed all suction thromboembolectomy procedures performed at our institution from March 2013 through August 2015. The main indications for the procedure were failed catheter-directed therapy, contraindication to thrombolysis, bleeding-related complications, and clot-in-transit phenomena. We collected details on patient characteristics, procedural indications, thrombus location, hemodynamic values, cardiac function, pharmacologic support, and survival to discharge from the hospital. The Wilcoxon signed-rank test was used for statistical analysis. Thirteen patients (mean age, 56 ± 15 yr; 10 men) underwent suction thromboembolectomy; 10 (77%) survived to hospital discharge. The median follow-up time was 74 days (interquartile range [IQR], 23-221 d). Preprocedurally, 8 patients (62%) had severe right ventricular dysfunction; afterwards, 11 (85%) had normal function or mild-to-moderate dysfunction, and only 2 (17%) had severe dysfunction (P=0.031). Percutaneous suction thromboembolectomy, a promising therapeutic option for patients, appears to be safe, and we found it to be associated with improved right ventricular function.

Catheter-Directed Thrombolysis for Submassive Pulmonary Embolism

Acute pulmonary embolism (PE) is a leading cause of morbidity and mortality in the United States. PE associated with right ventricular strain, termed submassive or intermediate-risk PE, is associated with an increased rate of clinical deterioration and short-term mortality. Trials have demonstrated systemic thrombolytics may improve patient outcomes, but they carry a risk of major hemorrhage. Catheter-directed thrombolysis (CDT) may offer similar efficacy to and a lower risk of catastrophic hemorrhage than systemic thrombolysis. Three prospective trials have evaluated CDT for submassive PE; ULTIMA, SEATTLE II, and PERFECT. These trials provide evidence that CDT may improve radiographic efficacy endpoints in submassive PE with acceptable rates of major hemorrhage. However, the lack of clinical endpoints, long-term follow-up, and adequate sample size limit their generalizability. Future trials should be adequately powered and controlled so that the short- and long-term effectiveness and safety of CDT can be definitively determined.

Acute pulmonary embolism: endovascular therapy

Pulmonary embolism (PE) is a leading cause of morbidity and mortality worldwide. PE is a complex disease with a highly variable presentation and the available treatment options for PE are expanding rapidly. Anticoagulation (AC), systemic lysis, surgery, and catheter-directed thrombolysis (CDT) play important roles in treating patients with PE. Thus, a multidisciplinary approach to diagnosis, risk stratification, and therapy is required to determine which treatment option is best for a given patient with this complex disease.

Catheter-Based Embolectomy for Acute Pulmonary Embolism: Devices, Technical Considerations, Risks, and Benefits

A significant number of patients with high-risk pulmonary embolism have contraindications to thrombolytic therapy. Catheter-based therapy may be helpful and consists of a multitude of catheters and techniques, some old and some new. Although there are few data supporting the use of any of these techniques, there has been a recent rise in interest and use of catheter-based pulmonary embolectomy. This text describes the contemporary devices used in pulmonary embolism treatment, discusses their challenges, and proposes some future directions.