Interventional radiology treatment for pulmonary embolism

Intraoperative Embolization during Inferior Vena Cava Tumor Thrombectomy for Renal Cell Carcinoma

Intraoperative tumor thrombus embolization is a potentially lethal complication during inferior vena cava (IVC) thrombectomy for renal cell carcinoma (RCC). Intraoperative embolization is uncommonly encountered because IVC thrombectomy surgical technique is focused on avoiding this complication. Nonetheless, early recognition of embolization is essential so that emergent management can be instituted. When available, cardiopulmonary bypass (CPB) and embolectomy should be considered the gold standard for the management of intraoperative embolization. Several novel endovascular techniques are also available for selective use. We present the case of a 71-year-old female with a right renal mass and level II (retrohepatic) IVC tumor thrombus. During cytoreductive nephrectomy and IVC thrombectomy, tumor embolization was diagnosed during a period of hypotension based on transesophageal echocardiographic finding of new thrombus within the right atrium. This prompted sternotomy, CPB, and pulmonary artery embolectomy. The patient survived this embolization event and has a complete response to systemic therapy 9 months postoperatively. This case serves as the framework for a discussion on management considerations surrounding intraoperative embolization during IVC thrombectomy.

[Ultrasound-accelerated thrombolysis. Initial experience in patients with contraindications to systemic thrombolysis]

Background

acute pulmonary embolism (APE) is a complex and potentially deadly entity, with a variable clinical course, considered the third cardiovascular cause of death. Its management varies according to the stratified risk from anticoagulation to reperfusion therapy, suggesting systemic thrombolysis as a first-choice strategy; however, in a large group of patients their use will be contraindicated, discouraged or will have failed, thus recommending as options in such cases endovascular therapies or surgical embolectomy. With the presentation of 3 clinical cases and a review of the literature, we seek to communicate our initial experience in the use of ultrasound-accelerated thrombolysis with the EKOS system and to investigate key elements for its understanding and application.

Clinical cases

the cases of 3 patients with APE of high and intermediate risk with contraindications for systemic thrombolysis taken to accelerated thrombolysis therapy by ultrasound are discussed. They presented adequate clinical and hemodynamic evolution in the short term, achieving a rapid decrease in thrombolysis, systolic and mean pulmonary arterial pressure, improvement of right ventricular function and reduction of thrombotic burden.

Conclusion

Ultrasound-accelerated thrombolysis is a novel pharmaco-mechanical therapy that combines the emission of ultrasonic waves with the infusion of a local thrombolytic agent, a strategy that, according to different trials and clinical registries, has a high success rate and a good safety profile.

Interventional Reperfusion Strategies for Acute Pulmonary Embolism

Acute pulmonary embolism (APE) is a common, potentially life-threatening cardiovascular emergency, and represents the third leading cause of cardiovascular mortality after myocardial infarction and stroke. Risk stratification is important to guide the management of APE, as an early reperfusion strategy is associated with improved clinical outcomes in specific high-risk conditions. Pulmonary artery reperfusion is commonly achieved by systemic intravenous administration of thrombolytic drugs, but catheter-directed thrombolysis (CDThr) and interventional techniques of catheter-based embolectomy provide novel therapeutic approaches with an improved risk-benefit ratio. Future trials will help to determine when to use these different devices in massive or sub-massive APE, and which patient population is likely to benefit from interventional treatment.

Side-hole catheters have higher thrombus aspiration efficiency than regular end-hole catheters in an in vitro model

PURPOSE

We aimed to evaluate and compare thrombus aspiration efficiency between side-hole and end-hole thrombus-aspirating catheters.

METHODS

Using an in vitro model of acute thrombus occlusion, we performed thrombus aspiration with two catheter designs. Two end-hole and two side-hole catheters, 8 F and 10 F in diameter, were examined. Thrombus aspiration was performed with each catheter 30 times, and the amount of thrombotic material aspirated in each attempt was determined. The mean weight of the thrombotic material and the mean weight of the non-fluid thrombotic material extracted in all 30 attempts by each catheter were also determined.

RESULTS

The 10 F side-hole catheter aspirated more thrombotic material than did the 10 F end-hole catheter (44.76 g vs. 28.35 g). The 8 F side-hole catheter had higher thrombus aspiration capacity than did the 8 F end-hole catheter in terms of the mean weight of the aspirated thrombus at each aspiration attempt (1.41 g vs. 0.58 g; P < 0.001) and the mean volume of the aspirated thrombotic material at each aspiration attempt (1.79 mL vs. 1.01 mL; P < 0.001). The mean weight of the non-fluid thrombotic material aspirated with the side-hole catheters was higher than that aspirated by the end-hole catheters with the same diameter size (31.06 g vs. 22.41 g for the 10 F catheters; P < 0.001; and 4.54 g vs. 2.99 g for the 8 F catheters; P < 0.001).

CONCLUSION

Side-hole catheters are more effective in aspirating acute thrombi. The added benefit of the side-hole design is more remarkable in smaller-sized catheters. Animal models are needed to examine their aspiration capacity in a real elastic vascular conduit and in the presence of wall-adherent thrombi.

Vacuum-assisted mechanical thrombectomy in extensively occlusive thrombosis of dialysis arteriovenous grafts with indigo system

PURPOSE

To present a selected series of extensively occlusive thrombosis of arteriovenous graft treated with the Penumbra's Indigo System.

MATERIALS AND METHODS

Ten patients with acute (within 72 h) extensively occlusive thrombosis of arteriovenous graft (mean extension = 30.1 (range = 15-45) cm) were treated at our institution with the Indigo System. Of the 10 cases, thrombosis was extended to venous outflow in 7 cases and to both arterial inflow and venous outflow in 3 cases.

RESULTS

Both anatomic and clinical success were achieved in 8 of the 10 procedures (80.0%). In the 2 cases of technical failure, the patients underwent surgical thrombectomy with the finding of arteriovenous graft exhaustion, which was then replaced. The 6-month primary patency, primary-assisted patency, and secondary patency rates were 37.5% (3/8), 50.0% (4/8), and 62.5% (5/8). We reported 2 complications (one minor and one major adverse event).

CONCLUSION

Percutaneous mechanical thrombectomy aspiration with Indigo System is a relatively safe and effective procedure and can be used even in extensively thrombosed arteriovenous graft.

Pulmonary embolism critical care update: prognosis, treatment, and research gaps

PURPOSE OF REVIEW

We provide a timely update on treatment care issues facing clinicians and patients with acute pulmonary embolism accompanied by either right ventricular strain (sub-massive pulmonary embolism) or shock (massive pulmonary embolism).

RECENT FINDINGS

Care and research changes over the last several years have resulted in four important trends: more consensus and accuracy in the way acute pulmonary embolism severity is described and communicated among acute care clinicians and researchers, increased availability and use of risk prediction scoring systems, increased use of advanced invasive therapy in the setting of severe right ventricular dysfunction, and emergence of multidisciplinary pulmonary embolism response teams to guide standard care decision-making.

SUMMARY

Pulmonary embolism with shock should be treated with either systemic or catheter-based thrombolytic therapy in the absence of contraindications. Patients with sub-massive pulmonary embolism accompanied by right heart dysfunction who are treated with thrombolytic therapy likely will experience more rapid improvement in RV function and are less likely to progress to hemodynamic decompensation. This comes, however, with an increased risk of major bleeding. Our recommendation is to consider catheter-based or systemic fibrinolytic therapy in sub-massive pulmonary embolism cases where patients demonstrate high-risk features such as: severe RV strain on echo or CT, and importantly worsening over time trends in pulse, SBP, and oxygenation despite anticoagulation. Understanding the impact of advanced therapy beyond standard anticoagulation on patient-centered outcomes, such as functional status and quality of life represent a research knowledge gap.

Safety and Efficacy of Acute Pulmonary Embolism Treated via Large-Bore Aspiration Mechanical Thrombectomy Using the Inari FlowTriever Device

PURPOSE

To report initial experience with safety and efficacy in the treatment of pulmonary embolism (PE) using the FlowTriever device.

MATERIALS AND METHODS

A single-center retrospective study was performed in all patients with acute central PE treated using the FlowTriever device between March 2018 and March 2019. A total of 46 patients were identified (massive = 8; submassive = 38), all with right ventricular (RV) strain and 26% with thrombolytic contraindications. Technical success (according to SIR reporting guidelines) and clinical success (defined as mean pulmonary artery pressure intraprocedural improvement) are reported, as are major device and procedure-related complications within 30 days after discharge.

RESULTS

Technical success was achieved in 100% of cases (n = 46). Average mean pulmonary artery pressure improved significantly from before to after the procedure for the total population (33.9 ± 8.9 mm Hg before, 27.0 ± 9.0 mm Hg after; P < .0001; 95% confidence interval [CI], 5.0-8.8), submassive cohort (34.7 ± 9.1 mm Hg before, 27.4 ± 9.2 mm Hg after; P < .0001; 95% CI, 5.2-9.5) and massive cohort (30.4 ± 6.9 mm Hg before, 25.4 ± 8.2 mm Hg after; P < .05; 95% CI:0.4-9.6). Intraprocedural reduction in mean pulmonary artery pressure was achieved in 88% (n = 37 of 42). A total of 100% of patients (n = 46 of 46) survived to hospital discharge. In total, 71% of patients (n = 27 of 38) experienced intraprocedural reduction in supplemental oxygen requirements. Two major adverse events (4.6%) included hemoptysis requiring intubation, and procedure-related blood loss requiring transfusion. No delayed procedure-related complications or deaths occurred within 30 days of hospital discharge.

CONCLUSIONS

Initial clinical experience using the FlowTriever to perform mechanical thrombectomy showed encouraging trends with respect to safety and efficacy for the treatment of acute central, massive, and submassive pulmonary embolism.

Imaging of suspected pulmonary embolism and deep venous thrombosis in obese patients

Obesity is a growing problem around the world, and radiology departments frequently encounter difficulties related to large patient size. Diagnosis and management of suspected venous thromboembolism, in particular deep venous thrombosis (DVT) and pulmonary embolism (PE), are challenging even in some lean patients, and can become even more complicated in the setting of obesity. Many obstacles must be overcome to obtain imaging examinations in obese patients with suspected PE and/or DVT, and to ensure that these examinations are of sufficient quality to diagnose or exclude thromboembolic disease, or to establish an alternative diagnosis. Equipment limitations and technical issues both need to be acknowledged and addressed. Table weight limits and scanner sizes that readily accommodate obese and even morbidly obese patients are not in place at many clinical sites. There are also issues with image quality, which can be substantially compromised. We discuss current understanding of the effects of patient size on imaging in general and, more specifically, on the imaging modalities used for the diagnosis and treatment of DVT and PE. Emphasis will be placed on the technical parameters and protocol nuances, including contrast dosing, which are necessary to refine and optimize images for the diagnosis of DVT and PE in obese patients, while remaining cognizant of radiation exposure. More research is necessary to develop consistent high-level evidence regarding protocols to guide radiologists, and to help them effectively utilize emerging technology.