Every year, pulmonary embolism kills up to 100,000 Americans, making it one of the most common preventable causes of hospital death, according to the CDC. A pulmonary embolism occurs when a blood clot — usually originating in the deep veins of the legs — breaks free and travels to the lungs, blocking blood flow. Despite its severity, many people have never heard of it until a diagnosis hits close to home. Recognizing the symptoms early and understanding who is most at risk can mean the difference between life and death. This guide covers everything you need to know about PE — from the first warning signs to long-term recovery — and belongs alongside our broader medical conditions guide.
What Is a Pulmonary Embolism?
A pulmonary embolism is a blockage in one or more arteries of the lungs. In most cases, the clot originates as a deep vein thrombosis (DVT) in the legs or pelvis and then travels through the bloodstream into the pulmonary vasculature. Once lodged in the lung arteries, the clot restricts blood flow, reduces oxygen levels, and places dangerous strain on the heart.
The severity of a PE depends on the size and number of clots, as well as the patient’s overall health. A small clot may cause only minor symptoms, while a large or “saddle” embolism — one that straddles the main pulmonary artery — can cause sudden cardiac arrest. The National Heart, Lung, and Blood Institute estimates that about 25% of PE cases present with sudden death as the first symptom, underscoring the importance of prevention and early detection.
Not all pulmonary emboli come from leg clots. In rare cases, fat from a broken bone, air bubbles, amniotic fluid during childbirth, or tumor fragments can cause the blockage. However, venous thromboembolism (VTE) — the umbrella term for DVT and PE — accounts for the vast majority of cases.
Symptoms and Warning Signs
The symptoms of pulmonary embolism can mimic many other conditions, which is one reason the diagnosis is frequently delayed. The most common symptom is sudden, unexplained shortness of breath. You may feel as though you cannot catch your breath even at rest, and the sensation typically worsens with exertion.
Sharp chest pain is another hallmark, often described as a stabbing sensation that gets worse when you breathe deeply, cough, or bend over. This pleuritic pain differs from the crushing pressure typically associated with a heart attack, though the two can sometimes be confused. A rapid or irregular heartbeat, coughing up blood (hemoptysis), lightheadedness, and excessive sweating are also common.
Some patients experience leg swelling, warmth, or tenderness before the PE occurs — signs of the underlying DVT. According to Mayo Clinic, about half of people with pulmonary embolism have no noticeable symptoms in their legs beforehand. This makes it critical to take respiratory symptoms seriously, especially if you have known risk factors.
When to seek emergency care: Call 911 or go to the nearest emergency room if you experience sudden shortness of breath, sharp chest pain, rapid heartbeat, coughing up blood, or fainting. Pulmonary embolism can be fatal within hours without treatment.
Risk Factors for Pulmonary Embolism
Understanding your risk profile is essential for prevention. The most significant risk factor is a history of deep vein thrombosis or a previous PE. Once you have had one venous clot, your lifetime risk of another increases substantially. Genetic clotting disorders — such as Factor V Leiden, prothrombin gene mutation, or deficiencies in protein C, protein S, or antithrombin — affect an estimated 5-8% of the population and significantly raise the likelihood of clot formation.
Prolonged immobility is another major contributor. Long-haul flights, extended bed rest after surgery, and sedentary lifestyles all slow blood flow in the deep veins, creating conditions favorable for clot formation. Research published in the PubMed database has consistently shown that major orthopedic surgeries — hip and knee replacements, in particular — carry some of the highest PE risk among surgical procedures.
Hormonal factors also play a role. Estrogen-containing birth control pills and hormone replacement therapy increase clotting risk, as does pregnancy. Cancer and its treatments are strongly linked to PE; patients with active malignancies face a four- to seven-fold increased risk compared to the general population. Obesity, smoking, and chronic conditions like heart failure and inflammatory bowel disease also contribute.
Age matters too. While PE can occur at any age, the risk rises significantly after 60. A combination of risk factors — say, an older adult recovering from hip surgery who also has a clotting disorder — can push the risk dramatically higher.
How Pulmonary Embolism Is Diagnosed
Diagnosing PE requires clinical suspicion backed by imaging. Emergency physicians often begin with a clinical probability score, such as the Wells criteria, which assigns points based on symptoms, heart rate, recent surgery, and other factors. A D-dimer blood test can help rule out PE in low-risk patients — if D-dimer levels are normal, a clot is unlikely. However, D-dimer is elevated in many conditions, including infection and pregnancy, so a positive result requires further investigation.
The gold standard for diagnosing pulmonary embolism is CT pulmonary angiography (CTPA). This specialized CT scan uses contrast dye to visualize blood flow in the lung arteries and can detect clots with high accuracy. When CTPA is unavailable or contraindicated (for example, in patients with severe kidney disease or contrast allergy), a ventilation-perfusion (V/Q) scan is an alternative. This nuclear medicine test compares airflow and blood flow patterns in the lungs to identify mismatches suggestive of clots.
Additional tests often performed include echocardiography to assess heart strain, troponin levels to detect heart muscle damage, and compression ultrasound of the legs to look for DVT. The American College of Radiology recommends CTPA as the first-line imaging study for most suspected PE cases.
Emergency and Acute Treatment
Treatment for pulmonary embolism depends on its severity. The cornerstone of therapy is anticoagulation — blood thinners that prevent existing clots from growing and new clots from forming. For most patients, treatment begins with an injectable anticoagulant like heparin or low-molecular-weight heparin, followed by an oral anticoagulant. Direct oral anticoagulants (DOACs) such as rivaroxaban and apixaban have largely replaced warfarin as first-line options for many patients because they require less monitoring and have fewer food interactions.
In massive PE — defined as a PE causing sustained low blood pressure (systolic below 90 mmHg) — thrombolytic therapy may be necessary. Thrombolytics like alteplase (tPA) dissolve clots rapidly but carry a significant risk of major bleeding. According to the American Heart Association, thrombolysis is recommended when the PE is life-threatening and the bleeding risk is acceptable.
For patients who cannot receive anticoagulation or thrombolytics, surgical or catheter-based interventions may be considered. Catheter-directed therapy can deliver clot-busting drugs directly to the blockage or physically break up the clot. Surgical embolectomy — open-heart surgery to remove the clot — is reserved for the most critical cases. An inferior vena cava (IVC) filter may be placed to trap future clots before they reach the lungs, though filters are generally considered a temporary measure rather than a long-term solution.
Submassive and Chronic Pulmonary Embolism
Between the extremes of small PE and massive PE lies submassive PE — a clot that causes right heart strain without causing systemic hypotension. Managing submassive PE is one of the most debated topics in emergency and pulmonary medicine. Some patients improve with anticoagulation alone, while others deteriorate and need escalation to thrombolytics or catheter-based intervention. Multidisciplinary pulmonary embolism response teams (PERTs) have emerged at many hospitals to guide these complex decisions in real time.
A small percentage of patients develop chronic thromboembolic pulmonary hypertension (CTEPH) after a PE. In CTEPH, residual clot material organizes and scars in the pulmonary arteries, leading to persistently elevated lung pressures. Symptoms include progressive shortness of breath and exercise intolerance that persist for months after the acute event. The New England Journal of Medicine has reported that CTEPH affects roughly 2-4% of PE survivors. Pulmonary thromboendarterectomy (PTE) surgery is the definitive treatment, with cure rates exceeding 90% in experienced centers. For patients who are not surgical candidates, balloon pulmonary angioplasty and medications like riociguat may help.
Prevention Strategies
Preventing a first or recurrent PE centers on reducing clot risk. After surgery, hospitals routinely prescribe blood thinners and encourage early ambulation. Compression stockings and intermittent pneumatic compression devices help maintain blood flow during periods of immobility. If you are scheduled for major surgery, ask your care team about their VTE prophylaxis protocol — research published in The Lancet has shown that appropriate prophylaxis can reduce postoperative VTE by more than 50%.
For people with inherited clotting disorders or a history of recurrent VTE, long-term or even lifelong anticoagulation may be recommended. The decision involves balancing the risk of another clot against the risk of bleeding. Your hematologist will consider factors like the severity of your clotting disorder, your bleeding history, and your lifestyle.
Lifestyle modifications also matter. Staying physically active, maintaining a healthy weight, staying hydrated during travel, and avoiding prolonged immobility all reduce risk. During long flights or car rides, get up and walk every one to two hours, perform calf exercises while seated, and consider wearing compression socks. If you are on estrogen-containing contraceptives and have additional risk factors, discuss alternative options with your provider. Understanding the healthcare costs of long-term anticoagulation therapy can also help you plan ahead financially.
Recovery and Long-Term Outlook
Most patients with properly treated PE recover fully, but the timeline varies. Anticoagulation therapy typically lasts at least three months for a first-time PE provoked by a temporary risk factor (like surgery). An unprovoked PE — one without an identifiable trigger — may warrant extended or indefinite treatment, as the recurrence risk is higher.
Post-PE syndrome is a recognized condition in which patients experience persistent shortness of breath, reduced exercise capacity, and fatigue for months or even years. Studies suggest that up to 50% of PE survivors report some degree of functional limitation at one year, even without CTEPH. Cardiac rehabilitation and structured exercise programs have shown promise in improving outcomes for these patients.
Psychological effects should not be overlooked. Anxiety, depression, and post-traumatic stress symptoms are common after a life-threatening PE. Many patients report fear of recurrence, difficulty sleeping, and reluctance to travel. Addressing these concerns with your healthcare provider — and connecting with support groups — can significantly improve quality of life during recovery.
Frequently Asked Questions
Can a pulmonary embolism happen without DVT symptoms?
Yes. According to Mayo Clinic, approximately half of patients with PE have no noticeable leg symptoms. The clot may form in a deep vein and break free without causing obvious swelling or pain in the leg. This is why sudden shortness of breath or chest pain should always be evaluated promptly, even in the absence of leg complaints.
How long do you stay on blood thinners after a PE?
Treatment duration depends on the circumstances. A PE triggered by a known, temporary risk factor (such as surgery or a long flight) typically requires three to six months of anticoagulation. An unprovoked PE or one linked to an ongoing risk factor may require indefinite treatment. Your doctor will weigh the recurrence risk against the bleeding risk to make a recommendation tailored to your situation.
Is pulmonary embolism the same as a heart attack?
No. A heart attack occurs when blood flow to the heart muscle is blocked, usually by a cholesterol plaque rupture in a coronary artery. A pulmonary embolism involves a clot blocking blood flow in the lung arteries. Both are medical emergencies with overlapping symptoms like chest pain and shortness of breath, but they have different causes and treatments.
Can you fly after having a pulmonary embolism?
Many doctors advise waiting at least two to four weeks after starting anticoagulation before flying, and some recommend waiting longer depending on the severity of the PE. When you do fly, stay hydrated, move around the cabin regularly, wear compression stockings, and take your anticoagulant as prescribed. Discuss specific travel plans with your healthcare provider before booking.
What is the survival rate for pulmonary embolism?
With prompt diagnosis and treatment, the short-term survival rate for PE exceeds 95%. However, massive PE with cardiovascular collapse carries a mortality rate of 25-50% even with aggressive treatment. Early recognition and prevention remain the most effective ways to reduce PE-related deaths.
Living With and After Pulmonary Embolism
Surviving a pulmonary embolism is just the beginning of a longer journey. Work closely with your healthcare team to determine the right duration for anticoagulation, monitor for signs of CTEPH, and gradually return to physical activity. Many people find that a structured exercise program — even starting with simple walking — helps rebuild confidence and cardiovascular fitness.
Stay vigilant about new symptoms. If you develop worsening shortness of breath, leg swelling, or chest pain while on treatment, contact your provider immediately. Keep all follow-up appointments, especially if you are taking warfarin, which requires regular INR monitoring. If you are on a DOAC, adherence is critical because these medications have short half-lives — missing doses can leave you unprotected.
Finally, become your own advocate. Know your risk factors, inform every new healthcare provider about your PE history, and do not hesitate to ask about preventive measures before surgery, hospitalization, or extended travel. Pulmonary embolism is serious, but with proper awareness and management, most people go on to live full, active lives.