Updated:
by
Eddie A. Fernandez, MD, RPVI
Medically reviewed by Eddie A. Fernandez, MD, RPVI
A blood clot in the lung usually doesn't start there. It usually starts in a leg. That's the part many people misunderstand.
Here's the sequence: A clot forms in one of the deep veins in your leg. That's called a deep vein thrombosis (DVT). A fragment can break off and travel through your bloodstream to your lungs, where it blocks an artery. That's a pulmonary embolism (PE). The National Heart, Lung, and Blood Institute (NHLBI) groups the two under one name, venous thromboembolism (VTE).
Here’s how they differ: A DVT is a blood clot that forms in a deep vein, usually in the leg. A PE happens when part of that clot breaks loose and travels to the lungs. Both are medical emergencies, and both require prompt treatment. A DVT needs urgent medical care to keep the clot from reaching your lungs and becoming a PE.
Center for Vein Restoration (CVR) doesn't treat pulmonary embolism. Again, that's an emergency best treated in the hospital. CVR treats the leg veins where these clots begin and is the nation's largest physician-led vein center, with 130+ locations across 23 states.
Your veins carry blood back toward your heart. A clot fragment passes through the heart easily, then meets the arteries of the lungs, which branch into steadily narrower vessels until the fragment can go no further and wedges in place. The American Society of Hematology describes what follows in plain terms: during a PE, blood flow to that part of the lung is blocked.
MedlinePlus notes that the clot most often begins in a deep vein of the thigh or the pelvis. Air bubbles, fat droplets, and amniotic fluid can also cause a blockage, but a leg clot is the usual source.
How serious it gets depends on the size of the clot and where it lands. A small one may cause little more than breathlessness. A large one can be fatal in minutes to hours. Left untreated, NHLBI notes, a pulmonary embolism can lead right heart strain, shock, cardiac arrest, or death.
Blood clot symptoms can appear within seconds or build slowly over days. In the lungs, watch for:
Call 911 if you have these symptoms.
Johns Hopkins Medicine is direct about it: a PE is an emergency that can cause death, and anyone with signs of a blood clot in the lungs should call 911 or get emergency help. Don't drive yourself. Don't wait to see whether it passes.
A sense of unease or anxiety can arrive alongside the physical symptoms, which sometimes leads people to write the whole episode off as a panic attack. Get evaluated anyway.
Most people who develop a clot have more than one risk factor in play at once. NHLBI groups them roughly this way:
The American Society of Hematology adds pregnancy, smoking, estrogen-containing contraceptives, trauma, and catheter placement, and makes one point worth holding onto: blood clots are among the most preventable blood conditions there are.
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This part happens in a hospital, not a vein clinic.
Diagnosis usually begins with a CT pulmonary angiogram, which NHLBI identifies as the main test for PE. A D-dimer blood test may come first in otherwise healthy patients, to decide whether imaging is needed at all.
Most clots are then treated with blood thinners, and patients take them at home rather than as an inpatient. More serious cases may call for clot-dissolving medication, catheter-based clot removal, or a filter placed in the vena cava. Your treating physician decides which applies.
If you're reading this during an emergency, stop reading and call 911.
Here's where professional vein care comes in.
DVT is a clot in one of the deep veins of the leg. A pulmonary embolism is what happens when part of that clot breaks off and travels through the heart to the lungs.
The Society for Vascular Surgery calls DVT a medical emergency in its own right and lists the signs: swelling in the calf or thigh, pain or tenderness that worsens when you stand or walk, warmth and redness over the area, a bluish or reddish tint to the skin, and a heavy or fatigued feeling in the leg. It can also show up with no warning signs at all.
The test itself is straightforward. A duplex ultrasound is the most common test for DVT: gel on the leg, a handheld probe, a live picture of blood flow on a screen. No needles, no radiation, no recovery time.
And a clot isn't the only thing worth ruling out. The American Venous Forum reports that up to one-third of people who have a DVT go on to develop post-thrombotic syndrome, a long-term condition marked by leg swelling, heaviness, changes in skin color, and in some cases open sores. It happens when scarring in the vein or damage to the valves inside it leaves the leg unable to move blood properly afterward.
📞 Questions about leg health? Speak with a Patient Representative directly. Call 240-249-8250
Johns Hopkins Medicine and the American Venous Forum both list varicose veins as a risk factor for DVT. That doesn't mean bulging veins send clots to your lungs, and it isn't a reason to panic about the veins you can see.
Here's what it does mean: Varicose veins are a sign that the small valves inside your leg veins have stopped closing properly. Blood pools instead of moving, and still blood is more likely to clot.
You didn't cause your varicose veins. Genetics, age, occupation, weight, and pregnancies are some of the main risk factors. Left untreated, that same valve failure can progress to chronic venous insufficiency (CVI), a more advanced form of the problem. With CVI, aching and swelling build throughout the day, and skin near the ankle can thicken, discolor, or break down into a sore that won't heal, called a venous ulcer.
CVR treats the venous side of this: varicose veins, CVI, and the valve failure underneath both. Vein treatments are minimally invasive and outpatient, and most patients drive themselves home and return to a normal routine the same day.
If you have leg symptoms and want a clot ruled out quickly, CVR offers same-day DVT rule-out scanning. Call 877-SCAN-DVT (877-722-6388).
A CVR physician uses duplex ultrasound to identify what’s driving your leg symptoms. If it's vein disease, CVR treats it in a comfortable office setting. If it isn't vein disease, we'll refer you to the right medical professional. Insurance is accepted, including Medicare and Medicaid.
Either way, you leave with an answer, not a guess.
Q: Can a blood clot in the lung go away on its own?
A: A pulmonary embolism needs prompt medical treatment, and left untreated, it can lead to right heart strain, shock, cardiac arrest, or death. Most people are treated with blood thinners, most times at home, but that's a decision for the physician treating you, not a wait-and-see.
Q: What's the difference between a DVT and a pulmonary embolism?
A: A DVT is a blood clot in a deep vein, usually in the leg. A pulmonary embolism is what happens when a piece of that clot breaks off and blocks an artery in the lung. Together they're called venous thromboembolism, because they're two stages of the same problem.
Q: Do varicose veins mean I'm going to get a blood clot?
A: No, BUT Varicose veins are a DVT risk factor, but most people with varicose veins never have a clot. They're a sign of vein disease that's worth evaluating on its own terms.
Q: How do doctors check my legs for a blood clot?
A: With a duplex ultrasound, the most common test for DVT. A technician moves a handheld probe over the leg, and blood flow appears on a monitor. It takes minutes, involves no needles or radiation, and you go home right afterward.
Q: Can compression stockings prevent a blood clot?
A: Compression help decrease the risk by helping move blood out of your legs instead of letting it pool, and it's commonly recommended for long flights and drives. It isn't a substitute for evaluation if you already have symptoms, and anyone at higher risk should ask a physician what's most appropriate for them.
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