Dr. Albert Rizzo: Welcome back to Lungcast, the monthly respiratory health podcast series from the American Lung Association and HCP Live. I'm your host, Dr. Albert Rizzo, chief medical officer of the American Lung Association. Before we jump into today's interview, here's a reminder you can subscribe to Lungcast on YouTube to get new and archived episodes, as well as interview segments and highlights throughout the month. If you prefer a podcast, you can subscribe on Spotify, Apple Podcasts, or your favorite platform. You can also register for more respiratory news and insights at lung.org and hcplive.com. Today's guest is Dr. Parth Rali, associate professor of thoracic medicine and surgery at Temple University's Lewis Katz School of Medicine, an expert in pulmonary embolism. He joins us for a review of every stage in the pulmonary embolism care process—from screening and imaging to optimal intervention and long-term outpatient management.
Dr. Albert Rizzo: PE, or pulmonary embolism, is generally described as an obstruction of the pulmonary artery due to a blood clot, tumor, air, or fat. Today we're focusing on blood clots. Pulmonary embolism is currently the third most common cause of death among hospitalized patients. Older age, comorbid cardiopulmonary diseases, and thrombolytic treatment used in this population are associated with increased healthcare costs and, at times, worse outcomes. Even with therapy, patients can have mild to moderate functional impairment up to 18 months after the initial event.
Dr. Albert Rizzo: Dr. Rali, your expertise lies in pulmonary vascular disease, particularly pulmonary embolism. You're a co-author of "Submassive Pulmonary Embolism" published in the American Journal of Respiratory and Critical Care Medicine and of "Diagnosis, Treatment, and Follow-up of Acute Pulmonary Embolism: A Consensus Practice from the PERT Consortium" in Clinical and Applied Thrombosis/Hemostasis. Thank you for joining us. Before we discuss submassive PE, can you define terms like acute, chronic, sub-acute, saddle, segmental, massive, and submassive embolism? I've also noticed newer classifications like low risk, intermediate low, intermediate high, and high risk.
Dr. Parth Rali: Thank you, Dr. Rizzo. This is a perfect question because confusion starts with terminology. For example, "saddle pulmonary embolism" is purely a radiological term describing a clot at the bifurcation of the main pulmonary artery; it doesn't necessarily reflect clinical severity. Likewise, terms like lobar, segmental, and subsegmental are radiological and describe clot location relative to the lung anatomy—they don't indicate clinical behavior.
Dr. Parth Rali: Clinically, there are three key guideline classifications: American Heart Association (AHA), American College of Chest Physicians (ACCP), and European Society of Cardiology (ESC). AHA and ACCP use low risk, submassive, and massive. ESC classification mirrors these but further stratifies intermediate-risk PE into intermediate-low and intermediate-high based on clinical presentation. This allows us to anticipate which patients may deteriorate.
Dr. Albert Rizzo: That certainly clarifies the terminology.
Dr. Parth Rali: Diagnosis and treatment are aided by tools like the Pulmonary Embolism Severity Index (PESI) and the simplified PESI score, which predict 30-day mortality. CTPA is the mainstay for diagnosis and also provides prognostic information about right ventricular (RV) dysfunction. Echocardiogram is valuable for dynamic monitoring, especially if the patient deteriorates or has a free-floating clot or patent foramen ovale.
Dr. Parth Rali: Other markers include lactic acid, troponins, BNP, and subtle lab abnormalities like mild acute kidney injury or liver function changes, which indicate hypoperfusion and RV dysfunction. These, along with clinical scoring systems, help classify patients and guide management.
Dr. Albert Rizzo: How does D-dimer fit in?
Dr. Parth Rali: D-dimer is valuable for initial diagnosis in the ER and can help guide post-PE management, especially for isolated subsegmental PE. If serial D-dimers trend downward and there’s no clot in the leg, anticoagulation may not be necessary in high bleeding-risk patients.
Dr. Albert Rizzo: Once PE is diagnosed, therapeutic anticoagulation is indicated unless contraindicated. Can you describe current anticoagulation options?
Dr. Parth Rali: Anticoagulation should begin promptly. At Temple, we've moved from unfractionated heparin to low-molecular-weight heparin for most patients because it achieves therapeutic anticoagulation faster and reduces adverse outcomes. Choice of anticoagulation depends on patient risk, presence of DVT, and bleeding risk.
Dr. Albert Rizzo: Beyond anticoagulation, what about other interventions?
Dr. Parth Rali: Additional options include IVC filters, catheter-directed thrombolysis, percutaneous thrombectomy, surgical embolectomy, and sometimes ECMO as supportive therapy. These require rapid, coordinated decisions, often through a multidisciplinary Pulmonary Embolism Response Team (PERT). Temple’s PERT has grown nationally, involving over 150 members to optimize individualized care.
Dr. Albert Rizzo: What about long-term outcomes and chronic thromboembolic disease?
Dr. Parth Rali: Chronic thromboembolic pulmonary hypertension (CTEPH) affects 4–6% of PE patients. Some patients have residual clots (chronic thromboembolic disease, CTED) without pulmonary hypertension. Post-PE syndrome is a benign category where patients are short of breath despite radiologic clearance; other causes like sleep apnea, COPD, or anxiety should be optimized first.
Dr. Albert Rizzo: How do you follow up with patients regarding anticoagulation?
Dr. Parth Rali: We see intermediate-risk PE patients in a pulmonary clinic within three months of discharge to review anticoagulation, screen for hypercoagulable states if indicated, and assess for RV dysfunction. Imaging and echocardiography are repeated at three to six months, and long-term anticoagulation decisions are individualized based on recurrence risk, bleeding risk, and patient preference. Low-dose prophylaxis can reduce recurrence from 10–15% to less than 3%.
Dr. Albert Rizzo: Where do you see the field going?
Dr. Parth Rali: AI software can now diagnose PE and calculate RV/LV ratios instantly, speeding treatment. Randomized controlled trials are ongoing comparing advanced catheter-based interventions. Guidelines for post-PE management are also expected to evolve, emphasizing long-term follow-up and evidence-based decision-making.
Dr. Albert Rizzo: Thank you, Dr. Rali, for this comprehensive discussion. Pulmonary embolism is complex but increasingly well-managed with multidisciplinary approaches. For more conversations, visit lung.org or hcplive.com. If you can't breathe, nothing else matters.
