Standard vs Ultrasound-assisted Catheter Thrombolysis for Submassive Pulmonary Embolism

Computed tomography angiography (CTA) will be performed before and after treatment. An independent radiologist will quantify the degree of obstruction from the thrombus by determining the vascular obstruction index. For determining the CT obstruction index, the arterial tree of each lung will be considered to have 10 segmental arteries (three to the upper lobes, two to both the middle lobe and the lingula, and five to the lower lobes).

Mortality during hospitalization will be compared between the two study arms.

Mortality until 90 days post procedure will be compared between the two study arms.

Cardiac decompensation, defined as hypotension (<90 millimeters of mercury (mmHg)) and use of catecholamines, will be compared between the two study arms.

Major bleeding is defined as overt bleeding associated with a hemoglobin level reduction of at least 2.0 grams per deciliter (g/dL), or with transfusion of two or more units of red blood cells, or involvement of a critical site (intracranial, intraspinal, intraocular, retroperitoneal, intraarticular or pericardial, or intramuscular with compartment syndrome).

Clinically overt bleeding not fulfilling the criteria of major bleeding is classified as a minor bleeding complication.

Recurrent venous thromboembolism (VTE) will be diagnosed if symptoms or signs of deep vein thrombosis or acute pulmonary embolism (PE) are confirmed by an imaging test. There will be no routine surveillance for asymptomatic recurrent VTE.

Treatment will be considered successful if pulmonary embolism related decompensation is prevented, without the participant experiencing a major adverse event or death.

The number of days participants were admitted to the ICU will be compared between study arms.

Under normal circumstances, the right ventricle appears smaller than the left ventricle when measured by an echocardiogram (RV/LV ratio<1). An increased RV/LV ratio may be a predictor of poor clinical outcomes following pulmonary embolism.

Tricuspid annular plane systolic excursion (TAPSE) is an echocardiographic of measuring right ventricular function. TAPSE measurements can be categorized as normal (1.5-2.0cm), mildly abnormal (1.3-1.5cm), moderately abnormal (1.0-1.2cm) or severely abnormal (<1.0cm).

Right ventricular systolic pressure (RVSP) measured by echocardiogram provides an estimate the pressure inside the artery supplying blood to the lungs. Dysfunction in the right ventricle is assessed to predict clinical outcomes following pulmonary embolism.

New York Heart Association (NYHA) Functional Classification of heart failure classifies heart failure with a combination of two methods: patient symptoms and objective assessment by a healthcare provider. Patient symptoms are classified as I-IV, where I = "no limitation of physical activity" and IV = "unable to carry on any physical activity without discomfort". An objective assessment by a healthcare provider is classified as A through D where A = "objective evidence of cardiovascular disease" and D = "objective evidence of severe cardiovascular disease".

The 6-minute walk test (6MWT) measures the distance that can be quickly walked by the study participant in 6 minutes. A 30 meter long walking course is created using cones on a hard, flat surface and the participant will walk the course as many times as they can in 6 minutes while a study team member counts the number of laps completed. Specific test guidelines from the American Thoracic Society will be followed.

The SF-36 is a 36 item survey assessing the quality of life across the 8 domains of physical functioning, limitations due to physical health, limitations due to emotional health, energy, emotional well-being, social functioning, pain, and general health. Each item is scored between 0 and 100 where 0 represents the worst possible quality of life and 100 corresponds with a healthy state of being. The numbers analyzed below represent the average score obtained with 0 being the bottom 25% of the quality of life (score 0-25), 1 is 26-50, 2 is 51-75, and 4 is 76-100.

Quality of life after pulmonary embolism (PEmb QoL) questionnaire is a 40 item survey asking respondents about their lung symptoms after having a pulmonary embolism. Participants report on 6 dimensions which cover the frequency and intensity of lung symptoms, physical and social limitations due to symptoms, pain, and emotional distress following having a pulmonary embolism. Scoring the responses involves specific instructions to reverse the scores for several dimensions, resulting in a score between 0 and 100 where 0 corresponds with "no complaints" and 100 is "worst possible" outcome.

The University of California San Diego (UCSD) Medical Center Shortness of Breath Questionnaire is a 24 item survey asking respondents how much shortness of breath they experience doing particular activities. Breathlessness is rated on a scale of 0 (not at all breathless) to 5 (maximally breathless or unable to do an activity become of breathlessness). Total scores range from 0 to 120, with higher scores indicating increased shortness of breath.

A Markov state-transition, cost effectiveness model will be created to simulate patient oriented outcomes assuming a societal perspective with a 12-month time horizon. All point estimates for model parameters will be determined from the prospectively collected data. Quality adjusted life years will be determined for each therapy based on survival, freedom from major adverse events, discharge status, functional status, and quality of life measures. Costs will be calculated for each therapy based on in-hospital resource utilization (i.e., length of stay in the ICU, operating room and procedure costs, and associated adverse event costs) and out-of-hospital costs (outpatient nursing care, loss of work, outpatient testing and follow-up).