How long will I need to be on blood thinners after a pulmonary embolism?

Usually at least three months, and often longer. A PE triggered by a temporary event such as surgery may need a shorter course, while an unprovoked PE or one linked to ongoing risk such as cancer often calls for extended or indefinite treatment. The duration balances clotting risk against bleeding risk.

Why did I get a pulmonary embolism when I am otherwise healthy?

Between a third and a half of pulmonary embolisms happen with no obvious trigger. Sometimes there is a subtle contributor found later, such as an inherited clotting tendency, and sometimes there is no clear reason. An unprovoked PE is real and worth treating fully.

I still feel short of breath months after my PE. Is that normal?

Lingering breathlessness in the year after a PE is common and often part of post-PE syndrome, which improves with a gradual return to activity. Persistent shortness of breath should still be checked, because a small number of people develop chronic thromboembolic pulmonary hypertension (CTEPH), a treatable condition where old clots keep lung pressures high.

A patient's guide to pulmonary embolism

Pulmonary EmbolismA Cardiologist's Guide to a Blood Clot in the Lungs

What a blood clot in the lung is, how it feels, how it's found and treated, what recovery looks like, and when to call 911.

Dr. Damian Rasch, D.O.

Medically Reviewed & Edited

Board-Certified Invasive Cardiologist
Encinitas and La Jolla, CA

Developed with digital research and writing assistance, then medically reviewed and edited by Dr. Rasch to ensure clinical accuracy and adherence to current evidence-based guidelines.

Last reviewed and updated on October 24, 2026

Printable patient handoutPDF, 1 sheet

60 to 120

people per 100,000 each year are affected by a pulmonary embolism

About 80%

of people with a PE have shortness of breath that appears out of nowhere, the most common symptom

Up to half

of pulmonary embolisms, somewhere between a third and a half, happen with no identifiable trigger at all

3 months

is the usual minimum time on blood thinners, and often it's longer

A pulmonary embolism is one of those diagnoses that can range from "we caught it early, here's your prescription, you'll be fine" to a true life-threatening emergency, sometimes in the same afternoon. It's common, it's treatable, and it's also one of the more commonly missed serious diagnoses, because the symptoms overlap with so many ordinary things.

This is the explanation I give patients and families who want to understand what a pulmonary embolism is, how we find it, how we treat it, and what recovery really looks like.

Pulmonary embolism in 30 seconds

Quick facts, for anyone who reads nothing else.

What it isA pulmonary embolism (PE) is a blood clot that lodges in the arteries of the lungs. Most of the time the clot forms in a deep vein of the leg or pelvis, breaks loose, and travels up through the heart into the lungs.
How it feelsThe most common symptoms are sudden shortness of breath, sharp chest pain that's worse with a deep breath, a fast heartbeat, and low oxygen. Some people cough up a little blood. The symptoms are easy to mistake for other things, which is why testing comes first.
Who's at riskRecent surgery, a long period of immobility, major injury, active cancer, pregnancy and the weeks after delivery, estrogen-containing birth control, obesity, older age, and inherited clotting tendencies. About a third to a half happen with no obvious trigger.
How it's treatedBlood thinners are the foundation, and most people are treated with a once- or twice-daily pill. Large, dangerous clots may need clot-busting drugs or a catheter procedure.
How it's foundA stepwise approach. A doctor first estimates how likely a PE is, then a D-dimer blood test or a CT pulmonary angiogram, the scan that shows a clot directly.
When to call 911Sudden shortness of breath, sharp chest pain that's worse when you breathe in, a racing heart, coughing up blood, or feeling faint. The full list is just below.
RecoveryAbout half of people have lingering breathlessness and lower stamina in the year after. A smaller group develops CTEPH, which is treatable.
The outlookMost people who are diagnosed and treated promptly recover well. The danger is a clot large enough to strain the heart, which is why a sudden, severe presentation is an emergency. Call 911.

Emergency

When to call 911

A sudden, severe presentation is an emergency. Don't wait to see whether it passes.

Call 911 or go to the nearest emergency room right away

If you have any of these, especially with a swollen, painful leg or a risk factor such as recent surgery, a long trip, active cancer or recent childbirth.

Sudden breathlessness: Sudden shortness of breath.
Sharp chest pain: Sharp chest pain that's worse when you breathe in.
A racing heart: Your heart is racing.
Coughing up blood: You cough up blood.
Faint or passing out: You feel faint or you pass out.

A pulmonary embolism can be diagnosed and treated quickly, but only if you get evaluated.

As with chest pain, the cost of coming in and being told you're fine is small, and the cost of staying home with a growing clot can be enormous.

What it is

What a pulmonary embolism is

Your lungs are where blood picks up oxygen. Blood flows from the right side of your heart into the pulmonary arteries, the vessels that carry it into the lungs, and returns freshly oxygenated. A pulmonary embolism is a blockage in one of those pulmonary arteries, almost always caused by a blood clot.

Here's the part that surprises people. The clot usually doesn't form in the lung at all. Tap through the four steps to follow it.

Step 1 of 4

A clot forms in a deep vein of the leg or pelvis

Most of the time the clot doesn't start in the lung at all. It forms in a deep vein, most often in the leg or pelvis, a problem called a deep vein thrombosis, or DVT.

A clot forms in a deep vein of the leg or pelvis. Most of the time the clot doesn't start in the lung at all. It forms in a deep vein, most often in the leg or pelvis, a problem called a deep vein thrombosis, or DVT.

A piece of the clot breaks loose. A piece of that clot breaks off and rides the bloodstream up toward the heart.

It passes through the right side of the heart. The piece travels up through the right side of the heart, which pumps blood into the pulmonary arteries, the vessels that carry blood into the lungs.

It gets stuck in a lung artery, the pulmonary embolism. The clot lodges where the arteries branch into smaller and smaller vessels, and blocks that artery. That blockage is the pulmonary embolism.

The DVT and the PE are really two ends of the same disease, which is why doctors group them together under the term venous thromboembolism.

60 to 120

people per 100,000 each year are affected by a pulmonary embolism.

60,000 to 100,000

deaths a year in the United States are linked to it.

This is not a rare event. Those numbers are part of why we take a suspicion of PE seriously and test for it rather than waiting to see what happens.

Symptoms

What it feels like, and why it's easy to miss

The classic pulmonary embolism comes on suddenly. Most people also have a fast heart rate.

Out of every 100 people with a confirmed PE, about how many have it

Shortness of breath that appears out of nowhereabout 80
Low oxygen level when we check itabout 70
Sharp chest pain, worse with a deep breath, a cough or moving60 to 70
Dangerously low blood pressure, fainting, or shock10 to 20
Coughing up a small amount of blood5 to 13

Chest pain that gets worse when you breathe in is what doctors call pleuritic pain. The people with very low blood pressure, fainting or shock need emergency treatment within minutes rather than hours.

Why a PE gets missed

None of these symptoms belong only to a pulmonary embolism. Sudden breathlessness and chest pain describe a heart attack, a panic attack, pneumonia, a flare of asthma, and a dozen other things.

About 40%

of people with a confirmed PE also have a clot in a deep leg vein.

Only half

of them have any leg swelling or pain to hint at it.

Testing is the only dependable way to know

Because the signs are so nonspecific, we can't reliably diagnose or rule out a PE by exam alone. Objective testing is the only dependable way to know. That limit comes from the nature of the disease, and it applies to every doctor.

Who is at risk

Blood clots form when something tips the balance toward clotting, and pulmonary embolism usually comes from a mix of a person's background risk and a specific trigger.

Short-term triggers

The strongest ones. Together these account for about a fifth of all cases.

Major surgery: Recent major surgery is one of the strongest short-term triggers.
A long stretch of immobility: Anything that keeps blood sitting still in the legs raises the risk, whether that's a hospital stay, a cast, or a very long flight or car ride.
Serious injury or trauma: A major injury is another.

Risk factors that stick around

Active cancer: The single most common, responsible for roughly a fifth of cases. Cancer makes the blood more prone to clotting, and some treatments add to that.
Hormones and pregnancy: Estrogen-containing birth control, pregnancy, and the postpartum weeks.
Age and weight: Older age and obesity.
Inherited clotting conditions: Conditions that make the blood clot too easily, which doctors call thrombophilias.

A third to a half have no trigger at all

One point I want patients to hear clearly. Somewhere between a third and a half of pulmonary embolisms are what we call unprovoked, meaning they happen with no identifiable trigger at all. So the absence of an obvious cause does not make a PE less real or less dangerous. It sometimes just means we look a little harder afterward for an underlying reason.

Tests

How we diagnose it

Because the symptoms are nonspecific, we use a stepwise approach that the 2026 national guidelines lay out clearly. It's designed to confirm a PE quickly in the people who have one while sparing everyone else an unnecessary scan.

The first step is estimating how likely a PE is before any imaging, using a scoring tool such as the Wells or Geneva score, or experienced clinical judgment. That probability decides what comes next.

Pick how likely a PE is before any scan. The box shows the next step the guidelines lay out for that group.

A simple checklist can close the door

For people at very low probability, a simple checklist called the PERC rule can safely rule out a PE without even drawing the D-dimer blood test.

Your doctor estimates this probability from your history and exam, and decides which test comes next.

The scans

CT pulmonary angiogram (CTPA)

The test of choice. It's a CT scan with contrast dye that lights up the pulmonary arteries and shows a clot directly. It's accurate, finding about 94 percent of PEs, and it's fast.

Ventilation-perfusion (V/Q) scan

A good alternative when the dye can't be used, for example in someone with a contrast allergy or poor kidney function. It looks at airflow and blood flow through the lungs instead.

Treatment

How we treat it

The foundation of treatment is anticoagulation, which means blood thinners.

Blood thinners don't dissolve the clot that's already there. They stop it from growing and stop new clots from forming, and your body's own systems gradually break down the existing clot over the following weeks. For most people, that's enough.

The preferred pills: DOACs

The direct oral anticoagulants, or DOACs, a group that includes apixaban (Eliquis), rivaroxaban, edoxaban, and dabigatran. We reach for these over the older drug warfarin because they work just as well, cause less serious bleeding, including a lower risk of bleeding into the brain, and are far more convenient, since they don't require the routine blood monitoring warfarin needs.

When a shot comes first

When someone needs a fast-acting injectable blood thinner first, we usually use low-molecular-weight heparin, which causes fewer recurrent clots and fewer platelet problems than the older unfractionated heparin.

When the clot is large and dangerous

Not every PE is treated the same way. The 2026 guidelines introduced a system that sorts patients into categories based on how much the clot is straining the heart. That's the central question. A small clot in a stable patient is a very different situation from a large clot that's overwhelming the right side of the heart.

For patients whose blood pressure has dropped dangerously low, usually a top number under 90, we consider clot-busting drugs given through the vein, called systemic thrombolysis. These powerful medications dissolve the clot quickly and lower the risk of death in this high-risk group. The trade-off is real, though, so we reserve it for people sick enough to need it.

3.9% to 2.3%

Thrombolysis lowers 30-day death rates by a bit under 2 percent in absolute terms, from about 3.9 to 2.3 percent.

About 1.4%

more people have a serious bleed or a bleed in the brain.

Catheter-based options

For patients in between, or those who can't safely receive full-dose clot busters, catheter-based options deliver clot-dissolving drugs right at the clot or physically remove it. Surgery and heart-lung support machines are there for the most severe cases.

A PE response team

Many hospitals now assemble a pulmonary embolism response team, or PERT, that brings several specialists together quickly to choose the best approach for a complicated case.

Outlook

How serious it is

It depends almost entirely on how much strain the clot puts on your heart, and we have good tools to measure that.

Pick a group to see its risk of dying within 30 days.

Under 1 in 100

For low-risk patients, identified with a score called the sPESI, the risk of dying within 30 days is under 1 percent. Blood thinners are the foundation of treatment.

This is not a calculator. Your doctor places you in a group from your exam, tests and scores such as the sPESI, and sets the treatment plan.

One number that needs context

One number can sound alarming out of context, so let me put it in perspective. Nearly 20 percent of people treated for PE die within 90 days, but in many of those cases the PE isn't the actual cause of death. These are often people who already had serious illnesses like advanced cancer, and the PE was a marker of how sick they were rather than what took their life. For an otherwise healthy person who gets diagnosed and treated promptly, the outlook is much better than that headline figure suggests.

Recovery

Recovery and the long haul

Most people recover from a pulmonary embolism, but recovery isn't always a straight line, and I think it helps to know that in advance.

Post-PE syndrome

About half of patients, in the year after the event

What it is: A lingering combination of reduced exercise tolerance, breathlessness on exertion, and a dip in quality of life.
What helps: It's common, it's real, and it tends to improve with time and a gradual return to activity, often guided by cardiac rehabilitation.

A man in his fifties with dark hair and a day pack walks a sandy coastal trail above the ocean, smiling.

CTEPH: the less common, more serious problem

Chronic thromboembolic pulmonary hypertension

What happens: Old clots don't fully clear and the lung arteries stay narrowed, raising the pressure the heart has to pump against.
How common: It affects roughly 1 to 4 percent of PE patients and is dangerous if left untreated, with a 25 to 30 percent risk of death within three years.
Who is most at risk: People with a prior PE, younger patients, those who had large clots, and those whose PE had no clear cause.
Why I mention it: CTEPH is treatable, and often curable, with a specialized operation called pulmonary thromboendarterectomy that removes the old scarred clot.

Still breathless months later?

If you have ongoing breathlessness months after a PE, that deserves a closer look rather than being written off as deconditioning.

Your questions

Common patient questions

Is a pulmonary embolism the same as a heart attack?

No, though they can feel similar. A heart attack is a blockage in the arteries that feed the heart muscle. A pulmonary embolism is a blockage in the arteries that carry blood into the lungs, and the clot usually starts in a leg vein. They're different problems with different treatments, which is one reason the emergency room tests carefully rather than assuming.

How long will I need to be on blood thinners?

Usually at least three months, and often longer. The right duration depends on why the clot happened. A PE triggered by a temporary event like surgery may need a shorter course, while an unprovoked PE or one linked to an ongoing risk like cancer often calls for extended or indefinite treatment. This is a decision you and your doctor make together by weighing your clotting risk against your bleeding risk.

Can a pulmonary embolism go away on its own?

Your body does gradually break down clots, but a PE should never be left untreated on the assumption it will resolve. Without blood thinners, the clot can grow, more clots can form, and the risk of a life-threatening event is much higher. Treatment is what makes the natural healing safe.

Why did I get a PE when I'm otherwise healthy?

Between a third and a half of pulmonary embolisms happen with no obvious trigger. Sometimes there's a subtle contributor we uncover later, such as an inherited clotting tendency, and sometimes there simply isn't a clear reason. An unprovoked PE in an otherwise healthy person is real and worth treating fully, and it sometimes prompts a look for an underlying cause.

Will flying or long car trips be dangerous now?

Long periods of sitting still are a risk factor, so take simple precautions on trips over about four hours, such as moving your legs, walking when you can, and staying hydrated. If you're on blood thinners, you're already substantially protected. Ask your doctor about your specific situation before a long trip, especially soon after a PE.

I still feel short of breath months later. Is that normal?

Lingering breathlessness in the year after a PE is common and often part of post-PE syndrome, which tends to improve with a gradual, guided return to activity. But persistent shortness of breath should always be checked, because a small number of people develop CTEPH, a treatable condition where old clots keep the lung pressures high. Don't just push through it without telling your doctor.

Get checked, then get moving

A pulmonary embolism can be diagnosed and treated quickly, but only if you get evaluated. Most people who are diagnosed and treated promptly recover well.

A woman with shoulder-length auburn hair stretches one leg on a seaside walkway, the ocean and a coastal bluff behind her.

References

Freund, Yonathan, Fleur Cohen-Aubart, and Ben Bloom. "Acute Pulmonary Embolism: A Review." JAMA 328, no. 13 (2022): 1336-1345.
Khan, Faizan, Tobias Tritschler, Susan R. Kahn, and Marc A. Rodger. "Venous Thromboembolism." Lancet 398, no. 10294 (2021): 64-77.
Di Nisio, Marcello, Nick van Es, and Harry R. Büller. "Deep Vein Thrombosis and Pulmonary Embolism." Lancet 388, no. 10063 (2016): 3060-3073.
Gregson, John, Stephen Kaptoge, Thomas Bolton, et al. "Cardiovascular Risk Factors Associated With Venous Thromboembolism." JAMA Cardiology 4, no. 2 (2019): 163-173.
Kahn, Susan R., and Kerstin de Wit. "Pulmonary Embolism." New England Journal of Medicine 387, no. 1 (2022): 45-57.
Creager, Mark A., Geoffrey D. Barnes, Jay Giri, et al. "2026 AHA/ACC/ACCP/ACEP/CHEST/SCAI/SHM/SIR/SVM/SVN Guideline for the Evaluation and Management of Acute Pulmonary Embolism in Adults." Journal of the American College of Cardiology (2026).
Zuin, Marco, and Walter Ageno. "Precision Diagnosis of Acute Pulmonary Embolism: Decision Rules, Biomarkers, and Imaging." Journal of the American College of Cardiology (2026).

Published on damianrasch.com. The above information was composed by Dr. Damian Rasch, drawing on individual insight and bolstered by digital research and writing assistance. The information is for educational purposes only and does not constitute medical advice.