Update on Thrombolytic Therapy in Acute Pulmonary Thromboembolism

Recurrent High-Risk Pulmonary Thromboembolism Treated with Repeated Thrombolytic Therapy Could be Helpful for Certain Patients: A Case Report and Review of the Literature

Acute pulmonary thromboembolism (PTE) is considered the third most frequent acute cardiovascular syndrome behind myocardial infarction and stroke, with annual incidence rates ranging from 39 to 115 per 100,000 people and ranking high among the causes of cardiovascular mortality. High-risk PTE is characterised by haemodynamic instability and encompasses clinical manifestations such as cardiac arrest, obstructive shock and persistent hypotension. The European Society of Cardiology (ESC) recommends a reperfusion strategy with systemic thrombolytic therapy for high-risk PTE under class I, level B if there are no contraindications. Overall, unsuccessful thrombolytic therapy and recurrent PTE have been reported in 8% of patients with high-risk PTE. The guidelines recommend surgical pulmonary embolectomy if thrombolysis is contraindicated or has failed. The position of repeated thrombolytic therapy as a treatment option in patients with recurrent high-risk PTE, especially in situations with a lack of surgical expertise or resources, was not mentioned in the guidelines. We report the case of a patient who suffered a recurrent high-risk PTE and was treated with repeated thrombolytic therapy that was effective and resulted in excellent outcomes.

LEARNING POINTS

Acute pulmonary thromboembolism (PTE) is a serious medical condition and widespread disease with well-recognised morbidity and mortality.Systemic thrombolytic therapy should be the first choice in patients with high-risk PTE without contraindication.Repeated thrombolytic therapy in recurrent high-risk PTE might be effective in patients with low risk of bleeding as an alternative to surgical embolectomy or catheter-directed therapy.

[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.

Plant-Derived Compounds and Extracts as Modulators of Plasmin Activity-A Review

Functionality of the fibrinolytic system is based on activity of its central enzyme, plasmin, responsible for the removal of fibrin clots. Besides the hemostasis, fibrinolytic proteins are also involved in many other physiological and pathological processes, including immune response, extracellular matrix degradation, cell migration, and tissue remodeling. Both the impaired and enhanced activity of fibrinolytic proteins may result in serious physiological consequences: prothrombotic state or excessive bleeding, respectively. However, current medicine offers very few options for treating fibrinolytic disorders, particularly in the case of plasmin inhibition. Although numerous attempts have been undertaken to identify natural or to develop engineered fibrinolytic system modulators, structural similarities within serine proteases of the hemostatic system and pleiotropic activity of fibrinolytic proteins constitute a serious problem in discovering anti- or profibrinolytic agents that could precisely affect the target molecules and reduce the risk of side effects. Therefore, this review aims to present a current knowledge of various classes of natural inhibitors and stimulators of the fibrinolytic system being well-defined low-molecular plant secondary metabolites or constituents of plant extracts as well as plant peptides. This work also discusses obstacles caused by low specificity of most of natural compounds and, hence, outlines recent trends in studies aimed at finding more efficient modulators of plasmin activity, including investigation of modifications of natural pharmacophore templates.

Current Diagnosis and Management of Acute Pulmonary Embolism: A Strategy for General Practitioners in Emergency Department

Pulmonary embolism (PE) is a disease with a relatively good prognosis when diagnosed and treated properly. This review aims to analyse available data and combine them into algorithms that physicians can use in the emergency department for quick decision-making in diagnosing and treating PE. The available data show that PE can be excluded through highly sensitive clinical decision rules, i.e. Pulmonary Embolism Rule-Out Criteria (PERC), Wells criteria, and Revised Geneva criteria, combined with D-dimer assessment. In cases where PE could not be excluded through the mentioned strategies, imaging modalities, such as compression ultrasonography (CUS), computed tomographic pulmonary angiography (CTPA), and planar ventilation/perfusion (V/Q) scan, are indicated for a definite diagnosis. Once a diagnosis has been made, treatment of PE depends on its mortality risk as patients are divided into low-, intermediate-, and high-risk cases. High-risk cases are treated for their hemodynamic instability, given parenteral or oral anticoagulant therapy, and are indicated for reperfusion therapy. Intermediate-risk PE is only given parenteral or oral anticoagulants and reperfusion is indicated when anticoagulants fail. Low-risk cases are given oral anticoagulants and based on the Hestia criteria, patients may be discharged and treated as outpatients.

Surgical Treatment in a High-Risk Pulmonary Embolism: Case Report

We present the case of a 35-year-old woman who had a high-risk pulmonary embolism (according to ESC risk stratification for pulmonary embolism) after she had undergone a Caesarion section. Postoperatively, she presented with acute left lower limb pain, swelling and erythema. A diagnosis was made of deep vein thrombosis (DVT) of the ilio-femoral and popliteal veins. She was started on anticoagulant therapy, which proved to be inefficient, the patient developing a left calf and thigh oedema and shortness of breath. A CT scan revealed high-risk embolus located in the right atrium and through the tricuspid valve. The decision was made to refer her to a cardiovascular surgeon. During her preoperative evaluation, the patient became hemodynamically unstable and was rushed into the operating room, severely desaturated, bradycardic, without consciousness, with severe hypotension. On the basis of the severe state of the patient and the CT scan findings we performed an emergency pulmonary embolectomy, with the patient on cardio-pulmonary by-pass, without cross-clamping the aorta, using a modified Trendelenburg procedure. This case supports using open pulmonary embolectomy for patients with hemodynamic instability on the basis of clinical diagnosis.

Thrombolytic Therapy in Treatment in Patients with Pulmonary Embolism not High-risk: SIRENA Registry Data

Aim. To study the features of the use of thrombolytic therapy (TLT) in normotensive patients with pulmonary embolism (PE) in real clinical practice in Russian hospitals.

Material and Methods. From 04/1 5/2018 to 04/15/2019 patients hospitalized with a diagnosis of PE consistently were included in the Russian multicenter observational prospective register "SIRENA” (RusSIan REgistry of pulmoNAry embolism).

Results. For 12 months in the registry was included 609 patients with a lifetime confirmed diagnosis of PE. TLT was performed in 152 patients with PE (25.0%), of which only 51 (33.8%) were indicated as "high risk" (shock or hypotension). In 101 not high risk patients, the indications for TLT were: severe shortness of breath/respiratory failure - 19 (18.8%), massive venous thrombosis - 7 (6.9%), signs of massive/submassive PE - 10 (9.9%), intermediate-high risk - 14 (13.9%), suspicion of acute coronary syndrome with ST segment elevation - 3 (2.9%), high pulmonary hypertension -2 (2.0%). The other 46 (45.5%) non-high-risk patients had no clear indication of the reasons for TLT in their medical history. To study the features of management of patients with not high-risk PE who received TLT (group 1), a selection of pairs of patients from the "SIRENA” registry, comparable in gender and age, in a ratio of 1:1 of patients with not high-risk PE who did not perform TLT (group 2). Hospital mortality was 4 (4%) patients in the TLT group and 6 (5.9%) patients in group 2 (р=0,748). Logistic regression analysis showed that floating blood clot in the veins of the lower extremities, syncopes in the debut of PE, respiratory rate over 22 per minute were independent clinical factors that significantly influence the doctor's decision to perform thrombolysis, and probability of completion TLT decreased in the presence of a history of bleeding, chronic kidney disease, surgery in the previous 12 months, increase in the size of the right atrium on EchoCG (statistical significance of the model x2=51.574; p<0.001). The development of bleeding during hospitalization was recorded only in 10 (9.9%) patients of group 1, including severe (3 stage on the BARC scale) in 2 patients. Patients without TLT more often developed an acute heart failure (25.9% vs. 8.5%, p=0.043).

Conclusion. In real clinical practice, there is a high frequency of TLT in patients with not high-risk PE. Floating blood clot in the veins of the lower extremities, syncope in the debut of PE, respiratory rate over 22 per minute were independent clinical factors that significantly influence the doctor's decision to perform thrombolysis.

A Case of Failure of EkoSonic™ Endovascular System in the Treatment of Submassive Pulmonary Embolism

Submassive pulmonary embolism (SPE) is characterized by the presence of right ventricular (RV) strain as visualized on echocardiogram or CT scan with brain natriuretic peptide (BNP) and/or troponin elevation. The condition accounts for 20-25% of all pulmonary embolism (PE) cases. In cases of SPE, catheter-directed thrombolysis (CDT) is generally considered in the presence of severe hypoxemia, worsening RV dysfunction, patients with increasing tachycardia and elevated troponins, free-floating thrombus in the right atrium or RV, and presence of extensive clot burden. EkoSonic™ Endovascular System (EKOS; Boston Scientific, Marlborough, MA) has been successfully used to treat cases of PE even where systemic thrombolytic therapy has failed. However, in this article, we describe a unique case of the failure of EKOS in treating a 71-year-old African American man who presented to the hospital with progressively worsening chest pain, shortness of breath, and fatigue. He was suspected to have SPE; however, a CT pulmonary angiogram could not be performed to estimate the clot burden due to an acute kidney injury. He was diagnosed with coronavirus disease 2019 (COVID-19) pneumonia during the hospitalization and had a delayed EKOS procedure with minimal improvement in oxygenation and clot burden. He subsequently underwent half-dose systemic thrombolytic therapy with complete resolution of his symptoms. Given our success with half-dose systemic therapy, we propose that it may be considered as a "rescue therapy" in cases where EKOS fails to deliver results.

Thrombolytic Therapy in Normotensive Patients with Pulmonary Embolism (Data from the Retrospective Study)

Background. The thrombolytic therapy is absolutely recommended for patients in shock or hypotension because the benefits are clearly outweighing the risks. However, in hemodynamically stable patients, including those with acute right ventricular dysfunction and/or myocardial damage, thrombolysis has a significantly lower evidence level.

Aim. To study the criteria based on which doctors decide to conduct thrombolytic therapy in normotensive patients in real clinical practice according to the retrospective data.

Material and methods. A single-center retrospective cohort study analyzed medical records of patients hospitalized in 2006-2017 with a verified diagnosis of pulmonary embolism (PE) and who had a systolic blood pressure >90 mm Hg at the time of admission.

Results. The present study population included 299 patients with a verified diagnosis of PE from 2006 to 2017 years. Patients were divided into two groups: with thrombolysis (group 1) and without thrombolysis (group 2). Logistic regression analysis showed that age younger than 60 years, the presence of varicose veins of the lower extremities, skin cyanosis, syncope in the debut of PE were independent clinical factors that significantly influence the doctor's decision to perform thrombolysis. Increased troponin I, right ventricular dysfunction, and the severity of PE according to the PESI score showed no significant impact on this decision. In-hospital mortality in the group 2 was 1.9% (5 patients), while there were no deaths in the group 1. But the analysis of the association of thrombolysis with survival was difficult to perform due to the low incidence of deaths and the small number of patients in the group with thrombolysis (odds ratio 0.34; 95% confidence interval 0.03-8.18; р=0.856). No major bleeding was registered in any group.

Conclusion. We were not able to clearly identify independent clinical or instrumental factors that influence the decision to perform thrombolysis in patients with PE outside the framework of evidence-based medicine. Further research is needed.

Surgical pulmonary embolectomy in a multi-trauma patient: One-center experience in the resource-limited setting

Pulmonary embolism, a serious complication after trauma, may cause sudden death. We discuss an unusual case of 65-year-old woman who had traffic accident with liver injury and open fracture of both tibia and fibula on the right side. She was diagnosed with massive pulmonary embolism on the second day after accident and successfully underwent emergency surgical embolectomy from bilateral pulmonary arteries. There were no postoperative complications. The patient's good state of health was recorded after 13 months of surgery. Surgical pulmonary embolectomy for such a multi-trauma patient provides valuable experience not only for our institution but also for the countries having similar resource-limited conditions.

The Role of EkoSonic Endovascular System or EKOS® in Pulmonary Embolism

Pulmonary embolism has become a cause of great concern to health care professionals. Despite strides in research and availability of sensitive diagnostic tests, the mortality and morbidity related to this entity continues to cause tremendous economic burden. Patients present with an array of symptoms ranging from mild dyspnea to hemodynamic instability and even death. Prompt recognition of symptoms along with early risk stratification can be lifesaving. Management focuses on achieving hemodynamic stability and reducing clot burden. Approved treatment modalities include anticoagulation, systemic or catheter directed thrombolytic therapy and surgical embolectomy. In this article we will review catheter-directed thrombolytic therapy, specifically the EKOS® or the EkoSonic endovascular system. EKOS® uses ultrasound-facilitated catheter-directed thrombolysis. The rationale behind this therapy is using shorter infusion times and lower dosage of the thrombolytic therapy, thereby reducing the complications associated with their use.