#35 Pulmonary Embolism: Part III
AUDIO
VIDEO
On this week's release, Cyrus and Nick revisit one of their favorite topics: Pulmonary Embolism! In this episode - a follow up to our two-parter from season 1 - we sit down with Dr. Rick Channick of UCLA to talk about his approach to PE management with a focus on catheter directed therapies & PE response teams. This episode is packed full of expert insights and practical clinical pearls. Give it a listen and let us know what you think!
Show notes by Shane McMahon, DO
PE Risk Stratification Methodologies
What is the landscape of risk stratification in Pulmonary Embolism (PE)?
Broadly, what interventions does each risk category group warrant?
Rule of Thumb: The greater the risk to the patient, the more likely aggressive interventions will be considered.
Most patients with PE are low risk:
Typically treated with systemic anticoagulation
Excellent prognosis
High risk PE patients typically have hemodynamic involvement and can present in shock requiring emergent management :
No contraindications + shock due to PE systemic thrombolysis
Absolute contraindications:
Prior history of ICH
Known cerebrovascular lesion
Known malignant intracranial neoplasm
Non-acute ischemic stroke, within the last 3 months
Suspect aortic dissection
Intermediate risk patients:
Management options exist and are tailored to each specific patient.
Most, but not all, patients with PE deemed to be at intermediate risk will do well with systemic anticoagulation.
Some patients are good candidates for catheter directed therapies such as thrombectomy or thrombolysis.
Who? We don’t really know with a high degree of certainty. Considerations should be made for those with numerous risk factors for poor PE-related outcomes OR those with significant cardiopulmonary reserve / excellent functional status who theoretically could benefit from more brisk reversal of their acute pulmonary hypertension.
How to stratify the risk?
Several ways exist to risk stratify patients with PE:
Many attempt to predict likelihood of progression to right heart failure and obstructive shock.
Data points include:
Markers of cardiac stress: Troponins and RV enlargement seen on imaging such as bedside echocardiography and CT scans.
Existing risk scoring systems are good for categorization at the extremes however sometimes fail to discriminate which patients will require more invasive management when a patient is intermediate risk.
Does PE size and burden matter?
There is no data that a larger/saddle PE gives a worse diagnosis.
Larger clot burden does not correlate to worse outcomes per se. Rather, RV function assessment can reveal more clinically relevant data regarding the patient's ability to compensate for a given PE burden.
What is the role of assessing RV:LV ratios in PE patients?
There is a relatively high false positive rate on RV: LV size comparisons using CT.
This is because CT PE studies are not gated to make this assessment, meaning they don’t record what cardiac cycle they are in at the time of scanning and contrast injection.
This can be evaluated using echocardiography which allows size comparison between the RV:LV.
For patients with clinical discrepancy despite having a CT indicating a enlarged RV:LV ratio it can be helpful to obtain echocardiography for more accurate RV assessment.
What about CT Findings during PE traditionally associated with PE risk?
Findings of CT contrast reflux into the hepatic vasculature is nonspecific and may be overcalled on CT scan. Risk stratification of these patients requires additional testing, a thorough case and history review along with careful bedside evaluation.
Current guidelines on risk stratification of a patient with PE vary according to region and professional organization.
European guidelines are simpler and evaluate using:
Troponin
RV: LV ratio (CT/POCUS US)
Scores are generated as
Both positive = high intermediate risk
One positive = low intermediate risk
BOVA score: For use in hemodynamically stable patients with acute PE
Presence of concurrent DVT
Attempts to further stratify risk of progression of and/or repeat incidence of PE by using presence of DVT on presentation
Heart Rate
Tachycardia may indicate heart strain and is a compensatory mechanism possibly indicating impending/ongoing shock
Ultimately the role of a provider in these patients is to look at patients holistically using physical exam, risk stratification tools and clinical experience rather than relying on arbitrary data point cut offs.
This process is relatively similar irrespective of your operational environment or background: The approach is essentially the same whether you are an intensivist, ER clinician, internist, etc.
Why does risk stratification in these patients matter?
Risk stratification attempts to predict which patients will clinically deteriorate which provides guidance on if further, invasive management is needed. This is important especially considering that many of these patients present to smaller community hospitals and will require possible transfer to a tertiary care center which will take precious time.
High-Intermediate risk patients (so called per the ESC guidelines) have a 10-25% chance to clinically deteriorate over the next 24-48 hours.
Case Presentation #1:
HPI: 38M with no past medical history or contraindications to systemic anticoagulation presenting with shortness of breath following a long flight. Pulmonary artery CT shows a thrombus in the right main pulmonary artery with an elevated RV:LV ratio noted as well. Blood test is positive for elevated troponins.
Vital Signs: HR 110 bpm, BP 122/84 mmHg, SpO2 > 95% on 3L O2 per Nasal Cannula
Physical Exam: Patient is awake, comfortable in no acute distress. He feels well and is making jokes. Overall appears very stable on bedside evaluation.
How should this patient be evaluated and dispositioned? What treatments should be considered?
Initial Evaluation:
This patient traditionally is considered high-intermediate risk based on elevated RV:LV size ratio, positive troponins. As mentioned, prior patient is tachycardic which may indicate higher risk for progression of disease.
Evaluation of these patients is best performed by a dedicated, multi-disciplinary, team similar to that of a rapid response.
Treatment Options:
Options include conservative systemic anticoagulation and monitoring in the ICU vs invasive management via catheter directed thrombolysis and catheter directed thrombectomy.
Data has shown that conservative management with close observation in the ICU allows for patient’s condition to “declare itself” without worse outcomes versus patients who received invasive management immediately. This means for overnight presentations, watchful waiting with systemic anticoagulation and ICU monitoring is a viable treatment option.
Clinical Case #1 Continued:
In summary, because this patient is high-intermediate risk it is appropriate to start patient on anticoagulation and admit to the ICU for further monitoring, as long as, an invasive management/catheter team is available for thrombolysis/thrombectomy should his clinical state decompensate.
Systemic Anticoagulation
Generally, when treating PE what options and levels of anticoagulation exist?
Anticoagulation has good data to show that when given within the first 24 hours of symptom onset there is a decreased risk of clot progression and recurrence and clinical deterioration.
The first 24 hours of presentation are the highest risk time for recurrent PE!
Options include:
Low Molecular Weight Heparin: Weight-based and provides predictable anticoagulation
Generally safe even in patients with planned procedures however exceptions exist for those with recent neurosurgery.
Unfractionated Heparin (UFH): Data suggests that a large percentage of patients are not adequately anticoagulation within 24 hours of use.
Perhaps fewer than 25% achieve a therapeutic dose when on UFH!
How should risks associated with t-Pa/thrombolytics be assessed relative to that of a PE?
Most studies show a 2-3% range of intracerebral hemorrhage with systemic t-PA
Elevated rates in those who are older i.e. > 70 years old
Catheter Directed Thrombolysis (CDT) has lower rates of bleeding complications and should be preferred to systemic thrombolysis for intermediate risk patients if capabilities for CDT exist at your facility
Consider the RIETE score or similar calculators to further characterize risk for a given patient.
What are important considerations of continued evaluation of a known PE patients?
Heart rate: Persistent tachycardia should be taken seriously and may indicate impending shock and persistent RV dysfunction.
Lactate: Persistent lactate elevation also may indicate decreased organ perfusion relative to impending/present shock.
Hypoxia and tachycardia with very mild movements such as eating breakfast.
These evaluations are best performed with a dedicated pulmonary embolism team (PERT).
Clinical Case #1 Progression:
Update: Our 38 year old male was deemed high-intermediate risk and was started on systemic anticoagulation, likely via weight based low-molecular weight heparin. He was then placed in the ICU for further observation with plan to consider catheter-based intervention in the AM.
In the morning the patient presents with persistent tachycardia, fatigue, persistent hypoxia requiring 3L NC still. Serum lactate is > 3.
How should this patient be re-evaluated?
As above, if possible this patient’s case should likely be discussed with a dedicated PE care team. This patient would probably be a strong candidate for catheter-based interventions his clinical deterioration and evidence of ongoing obstructive shock.
Catheter Based Therapies, What is available?
Within the last 10 years there has been growth in the availability of commercially available and FDA approved catheter-based devices for PE. This includes:
Catheter Directed Thrombolysis (CDT):
Thrombolytics are injected into the embolism.
Theoretically, this provides the same thrombolytic mechanism as systemic t-Pa with use of much lower doses of thrombolytics and less bleeding complications as a result.
An Ultrasound Enhanced Thrombolysis device was specifically approved which used therapeutic ultrasound to disrupt Fibrin cross leaks and then t-Pa can be infused.
Doses of approximately 12 mg of t-Pa vs typical 100 mg doses in traditional systemic thrombolysis.
Catheter Directed Thrombectomy/Thrombo-aspiration/Hybrid devices:
FDA has several approved devices (FlowTriever, Penumbra, etc.)
Hybrid options both extract clot and allow use of thrombolysis
What does the data say in terms of thrombolysis outside the context of massive PE and clinical outcomes of patients treated with CDT for PE?
The PEITHO trial (Pulmonary Embolism Thrombolysis) was a large, randomized controlled trial that evaluated the efficacy and safety of systemic thrombolysis with tenecteplase plus anticoagulation versus anticoagulation alone in patients with intermediate-risk (submassive) pulmonary embolism (PE). Here are the key findings:
Reduced Risk of Hemodynamic Collapse: Systemic thrombolysis with tenecteplase significantly reduced the risk of hemodynamic decompensation or collapse (i.e., shock or the need for resuscitation) compared to anticoagulation alone (2.6% vs. 5.6%).
Increased Risk of Major Bleeding: Thrombolysis was associated with a significantly higher rate of major bleeding events (11.5% vs. 2.4%), including a notable increase in intracranial hemorrhage (2.0% vs. 0.2%).
No Significant Difference in Mortality: There was no statistically significant difference in all-cause mortality between the thrombolysis group and the anticoagulation-only group (2.4% vs. 3.2%).
Improved Short-Term Hemodynamic Outcomes: Thrombolysis resulted in quicker improvements in right ventricular dysfunction and overall hemodynamic stability compared to anticoagulation alone.
Risk-Benefit Balance for Certain Patients: The trial highlighted the need to carefully weigh the benefits of reducing hemodynamic collapse against the increased risk of bleeding, particularly intracranial hemorrhage, when considering thrombolysis for intermediate-risk PE patients.
Potential for Selective Use: Based on these findings, thrombolysis may be considered for select intermediate-risk PE patients who are at high risk for hemodynamic deterioration but must be used cautiously due to the significant bleeding risks.
The ULTIMA trial (Ultrasound-Assisted Catheter-Directed Thrombolysis for Acute Intermediate-Risk Pulmonary Embolism) was a randomized controlled trial that compared ultrasound-assisted catheter-directed thrombolysis (USCDT) using the EKOS system with standard anticoagulation alone for the treatment of intermediate-risk pulmonary embolism (PE). Here are the key findings:
Significant Reduction in RV/LV Ratio: The primary endpoint, reduction in the right ventricular to left ventricular (RV/LV) ratio at 24 hours, was significantly greater in the USCDT group compared to the anticoagulation-only group (18% vs. 3%).
Is this significant / clinically relevant?
No Increase in Major Bleeding: There were no major bleeding events reported in either group, highlighting the safety of USCDT with low-dose thrombolytics in intermediate-risk PE patients.
Rapid Hemodynamic Improvement: Patients treated with USCDT experienced faster improvement in right ventricular function, leading to quicker relief from the hemodynamic burden associated with PE.
Does not comment on long-term benefits. Would these patients “be fine” otherwise?
Low rtPA Dosage: The trial used a relatively low dose of rtPA (total of 10-20 mg over 15 hours), which effectively reduced clot burden without the higher risk of bleeding associated with full-dose systemic thrombolysis.
No Deaths in Either Group: There were no deaths in either the USCDT group or the standard anticoagulation group, indicating that both approaches were safe in the context of intermediate-risk PE.
Potential for Broader Application: The success of USCDT in rapidly improving right ventricular function and reducing clot burden without increasing major bleeding suggests it could be a useful alternative to anticoagulation alone in certain intermediate-risk PE patients.
The OPTALYSE PE trial (Optimal Duration and Dose of R-tPA With the EKOS Endovascular System for PE) investigated the optimal dose and duration of thrombolytic therapy using ultrasound-facilitated catheter-directed thrombolysis (USCDT) for the treatment of PE. Their findings:
Lower Doses of TPA were Effective: The trial demonstrated that lower doses of recombinant tissue plasminogen activator (rtPA), ranging from 8 to 24 mg, delivered over 2 to 6 hours were effective in reducing right ventricular (RV) dilation in patients with intermediate-risk PE.
Shorter Infusion Duration Was Safe: Shorter infusion times of 2 to 6 hours were associated with significant improvements in right ventricular function without increasing major bleeding complications compared to longer durations.
Reduced Risk of Bleeding: The study found that by using lower doses of thrombolytics, there was a lower risk of major bleeding, particularly intracranial hemorrhage, which is a significant concern in thrombolysis.
Improved RV/LV Ratios: The primary efficacy outcome, the reduction in right ventricular to left ventricular (RV/LV) ratio, showed similar improvement across all dosing regimens, confirming the efficacy of the reduced-dose protocols.
Again… is this clinically significant?
Comparable Outcomes Across Regimens: All four dosing regimens demonstrated similar clinical outcomes in terms of RV function improvement and safety, suggesting flexibility in treatment approaches depending on the patient’s needs.
Shorter Hospital Stays: The patients treated with the shorter, lower-dose regimens also had shorter hospital stays, which could lead to reduced healthcare costs and improved patient convenience.
EKOS System Use Validated: The trial supported the efficacy and safety of the EKOS catheter system for ultrasound-facilitated thrombolysis, which uses ultrasound energy to help disperse the thrombolytic agent and reduce clot burden.
The SEATTLE II trial (A Prospective, Single-Arm, Multi-Center Trial of EkoSonic® Endovascular System and r-tPA for Treatment of Acute Pulmonary Embolism) evaluated the efficacy and safety of ultrasound-facilitated catheter-directed thrombolysis (USCDT) using the EKOS system for treating acute massive and submassive pulmonary embolism (PE). Here are the key findings:
Significant Reduction in RV/LV Ratio: The trial showed a significant reduction in the right ventricular to left ventricular (RV/LV) ratio by approximately 23% within 48 hours after treatment, indicating a rapid improvement in right ventricular function.
Are we sensing a theme here?!
Low Doses of rtPA Effective: The use of low doses of recombinant tissue plasminogen activator (rtPA), typically 24 mg over 12-24 hours, was effective in significantly reducing clot burden in both massive and submassive PE patients.
Minimal Major Bleeding: Major bleeding occurred in 10% of patients, but no cases of intracranial hemorrhage were reported. This demonstrated a favorable safety profile compared to traditional systemic thrombolysis.
Improved Pulmonary Artery Pressure: Pulmonary artery systolic pressure decreased by 30% from baseline, which is associated with relief from the hemodynamic strain caused by the PE.
If you remove the space occupying lesion, the pressure within the space improves. Cool!
Rapid Symptom Relief: Patients experienced rapid relief of symptoms such as shortness of breath and chest pain, correlating with the improvement in RV function and decreased pulmonary artery pressures.
Okay – THIS is clinically relevant / patient centered!
EKOS System Efficiency: The trial validated the use of the EKOS catheter system for delivering rtPA, confirming its role in improving clot dissolution with ultrasound energy, leading to better clot penetration.
Shorter Infusion Times than Systemic Thrombolysis: USCDT allowed for shorter infusion times compared to systemic thrombolysis, leading to reduced hospitalization times without compromising efficacy.
Good Tolerability Across a Broad Range of Patients: The treatment was well tolerated in both massive and submassive PE patients, supporting its broader application for high-risk individuals.
At least 4 ongoing clinical trials with Catheter Directed Therapies exist
Given the heterogenous nature of this patient population and the nature of “crossover” where patients get multiple interventions it is difficult to assess mortality in a truly blinded manner.
Though data for catheter-based interventions is still being gathered, initial signals are positive and these high-intermediate risk PE patients should be considered for transfer to a care facility where catheter based interventions can be provided.
How does the approach to using Catheter Based Therapies change in patients who have lower Cardiopulmonary reserve?
When looking at a patient with PE it is appropriate to ask: “What would happen to this patient is they developed another PE?”
Patients with lower cardiopulmonary reserve have higher risk of developing shock and higher mortality.
In patients with higher cardiopulmonary reserve and no residual DVT seen on imaging systemic anticoagulation may be adequate to allow patient to dissolve current PE with lower risk of recurrent PE.
In patients with lower cardiopulmonary reserve and/or residual DVT seen on duplex extremity ultrasound it may be more appropriate to pursue more aggressive catheter based interventions in a attempt to preventing further decompensation from recurrent PE.
Note: Intermediate-High Risk patients should have a lower extremity duplex ultrasound to help in the risk-stratification process.
However: Despite all this discussion, there are schools of thought where by clinicians will argue for more aggressive interventions in intermediate risk patients with very high functional statuses / significant reserve due to a perception of preserving function. There is no data to really support this practice but… that is admittedly true for a lot of critical care!
Is there data to for low dose thrombolytic regimens as opposed to CDT?
100% of blood flow goes through the pulmonary arteries… much less goes through the coronaries or the intracranial vessels and yet PE doses for TPA are based on those other interventions. So… what does the data suggest for lower-dosed interventions:
Efficacy Comparable to Full-Dose Thrombolysis: Studies have shown that half-dose thrombolysis can provide similar efficacy in improving right ventricular (RV) function and reducing clot burden compared to full-dose thrombolysis. For example, half-dose regimens have been effective in reducing RV dilation and improving the right ventricular to left ventricular (RV/LV) ratio, a key marker of PE severity.
Reduced Risk of Major Bleeding: One of the primary benefits of half-dose thrombolysis is a lower risk of major bleeding, particularly intracranial hemorrhage, compared to full-dose thrombolysis. This has been demonstrated in several studies, which found that the incidence of major bleeding events, including life-threatening intracranial bleeding, was significantly reduced in patients receiving half-dose thrombolysis.
Safe for Intermediate-Risk PE Patients: Half-dose thrombolysis has been most commonly studied in intermediate-risk (submassive) PE patients, where it has been shown to improve clinical outcomes with fewer complications. This patient group benefits from clot resolution and hemodynamic improvement without the higher bleeding risks seen with full-dose regimens.
Comparable Short-Term Outcomes: Short-term outcomes such as improvement in RV function and reduction in pulmonary artery pressures have been similar between patients treated with half-dose and full-dose thrombolysis. These improvements often lead to faster recovery and shorter hospital stays.
Favorable Long-Term Outcomes: Some studies suggest that half-dose thrombolysis also leads to favorable long-term outcomes, including reduced risk of chronic thromboembolic pulmonary hypertension (CTEPH), a serious long-term complication of PE.
Potential for Tailoring Treatment: The success of half-dose thrombolysis opens the possibility for more individualized treatment approaches, where thrombolytic dosing can be adjusted based on patient factors such as age, comorbidities, and bleeding risk, rather than applying a one-size-fits-all approach.
Where does this come from?
MOPETT Trial (Moderate Pulmonary Embolism Treated With Thrombolysis):
This landmark study compared half-dose thrombolysis with standard anticoagulation in patients with moderate (intermediate-risk) PE. It found that half-dose thrombolysis was effective in reducing the risk of recurrent PE and improving long-term outcomes, such as preventing the development of pulmonary hypertension, with a low rate of major bleeding events.
Key finding: Half-dose thrombolysis resulted in improved outcomes with fewer bleeding complications compared to full-dose thrombolysis.
Zhang et al. (Meta-analysis, 2019):
A meta-analysis of several studies assessing low-dose thrombolysis in acute PE patients. The study concluded that half-dose thrombolysis provided similar efficacy in terms of clot resolution and RV function improvement compared to full-dose regimens, with a significantly reduced risk of major bleeding, particularly intracranial hemorrhage.
Key finding: Half-dose thrombolysis was associated with fewer bleeding complications, especially in intermediate-risk PE patients.
Chatterjee et al. (Systematic Review and Meta-analysis, 2014):
This meta-analysis reviewed outcomes from both full-dose and lower-dose thrombolysis trials and found that reduced-dose thrombolysis could be as effective as full-dose therapy in treating PE, with fewer bleeding events.
Key finding: Lower-dose thrombolysis may offer a more favorable safety profile while maintaining efficacy in certain PE patients.
PEITHO Study Subgroup Analyses:
Although the PEITHO trial primarily assessed full-dose thrombolysis, post-hoc analyses and subgroup data have informed clinicians about the potential risks and benefits of alternative dosing strategies, particularly for intermediate-risk patients where the risk of bleeding is of concern.
Key finding: Full-dose thrombolysis showed efficacy in preventing hemodynamic collapse but was associated with significant bleeding risks, prompting interest in half-dose approaches.
Local Retrospective and Prospective Studies:
Several smaller retrospective and prospective studies have evaluated half-dose thrombolysis in specific clinical settings, such as elderly patients or those with higher bleeding risks. These studies have generally supported the use of lower-dose regimens for balancing efficacy with reduced risk of bleeding.
PEITHO3 is an ongoing clinical trial looking at systemic half-dose thrombolysis which will help answer this question.
Case Presentation #2
HPI: 55 year old female with NSCLC with multiple brain mets receiving brain radiation who presents with sudden hypoxemia.
Vitals: HR 120, BP 90/55, RR 30, SpO2 90-92% on 5L per nasal cannula.
CT shows large Saddle PE with evidence of RV strain.
En-rout to ER the Emergency provider is starting vasopressors for worsening hypotension and shock.
Case Discussion:
This patient has multiple confounders not seen in the prior patient
Her intracranial metastasis indicate a < 6 month survival most likely
Rapid evaluation of this patient should still be performed with a dedicated PE care team
Her clinical options include:
Push systemic TPA – Given current brain metastasis she is at HIGH risk for developing a significant intracranial bleed – intracranial metastasis are widely considered to be a contraindication to systemic thrombolysis.
Start patient on ECMO – Given her stage IV lung cancer this is contraindicated…
ECMO is becoming a leading treatment of massive PE!
Surgical embolectomy
Emergency catheter embolectomy – Possible though data at this time for these patients consists of testimonials and other uncontrolled data
What is a current role of ECMO in management of PE?
ECMO has become more standardized via use of cannula insertion teams.
ECMO supports patients with massive PE by “offloading” the patients RV and oxygenating their blood.
Case series have shown support for use of ECMO during massive PE especially in the context of buying time for patients so that other advanced techniques i.e. CDT/surgical thrombectomy can be performed.
How does the use of lytics prior to patient arrival to a hospital capable of CDT affect the decision to invasive management in PE patients?
One way to “measure” a patient’s bleeding risk on arrival after receiving thrombolytics is to check Fibrinogen levels.
Levels 150-200 can be reassuring
The half-life of thrombolytics is only a few minutes and will generally degrade rapidly after use… however that is long enough for a bleed to occur!
Case Presentation # 3
HPI: Internal Medicine Ward team calls regarding a decompensating patient presenting with hypoxia, visible respiratory distress, tachycardia, chest pain.
Bedside ultrasound is performed and shows a visible clot in the right atrium.
What are the next steps in the evaluation and management of this patient with confirmed intracardiac thrombus?
As with other suspected PE patients, this patient should undergo CT to assess total clot burden in the lungs.
There is data suggesting that patients with intracardiac thrombus in-transit have worse outcomes than patients without a visible clot in transit.
But, every PE starts as a clot in transit!
Management can include mechanical aspiration catheters with a larger bore which can directly remove intracardiac thrombus
Retrospective and case-series data also support use of thrombolytics to break up a larger thrombus which does not seem to lead to worse outcomes.
What is the role of the IVC filter today?
The data is a little confusing and suggests higher rates of DVT with lower rates of PE.
Current use is typically used for patients that:
Failed systemic anticoagulation (Recurrent PE while on anticoagulation)
Have contraindications to anticoagulation
Can’t tolerate another PE due to poor reserve, emboli-in-transit or residual clot in legs
IVC filters should be removed
IVC placement can be limited to facilities with interventional Radiology support though capabilities differ at different facilities
What - or who - is a PE response team (PERT) composed of?
First developing in early 2010’s in Boston, MA in an effort to streamline the admission and management of PE patients.
Typically within a hour of patient presentation a Code PE is called which prompts a interdisciplinary team to evaluate the patients online and come to management/disposition decisions rapidly.
This approach is becoming the standard-of-care and PE teams even have annual meetings dedicated to improvement.
What Clinical Trials are on-going and available for patients to enroll in?
Inari device trial (PEERLESS I, II)
Prenumbra Device trial (STORM-PE)
HI-PEITHO trial – CDT vs anticoagulation alone
PE-TRACT– NIH funded study – looking at any catheter based treatment vs anticoagulation alone
In the next few years these studies should give answers to how these devices affect patient outcomes however they will likely not elucidate which patients need these invasive treatments. That decision will likely remain with medical providers.
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PEITHO trial (Pulmonary Embolism Thrombolysis)
MOPETT Trial (Moderate pulmonary embolism treated with thrombolysis)
ULTIMA trial (Ultrasound-Assisted Catheter-Directed
Thrombolysis for Acute Intermediate-Risk Pulmonary Embolism)OPTALYSE PE trial(Optimal Duration and Dose of R-tPA With
the EKOS Endovascular System for PE) -