​Difficulty breathing? It may be due to a blood clot, or pulmonary embolism

What’s more serious than a heart attack? It depends on whom you ask. But one answer might be a pulmonary embolism (PE).

To get a full overview of PE, we spoke to Jonathan D. Paul, MD, assistant professor of medicine at the University of Chicago Medicine and director of the pulmonary embolism response team (PERT), about the best way to treat this frightening and life-threatening condition that affects more than 500,000 Americans a year.

What is a pulmonary embolism?

PE is a blood clot that originates in a large vein, typically in the leg, that then travels (also known as embolizes) into the lungs. Symptoms can vary from mild to severe. They include, but are not limited to, significant shortness of breath, difficulty breathing, low blood pressure, shock or cardiac arrest.

Patients may also have more than one PE at a time, caused by a blood clot that breaks up into smaller pieces.

“We do see patients that have blood clots throughout both lungs, in more than seven or eight different branches,” Paul said. “Sometimes it’s just a very large clot that gets stuck in one of the main large branches of the lung arteries.”

How PE starts

There are multiple reasons why a person can suffer from a PE. But what’s most surprising is a perfectly healthy person can suffer from a PE as well. The most common causes of PE are:

• Genetic predisposition – Genetic defects make some people more prone to clotting.
• Injury to the legs or prolonged immobility – Blood is not circulating sufficiently throughout the vascular system.
• Other illnesses, such as cancer – Certain illnesses put the body into what’s called a hypercoagulable state, which means a blood clot is more likely to form.
• Increased tendency for venous blood clotting due to other factors – Medications such as birth control pills may increase the chance that a blood clot may form.

No matter the cause, a clot starting in a large vein and travelling to the lungs is the result.

UChicago Medicine’s approach

“We make PE a priority and treat it in a very efficient and aggressive way,” said Paul. “That’s why we developed the pulmonary embolism response team (PERT).”

PERT allows any practitioner – whether they’re in the emergency department or anywhere else in the hospital – to quickly notify available experts when a patient is diagnosed with a PE.

Then experts from cardiology, pulmonary critical care medicine, radiology, hematology and cardiac surgery discuss the case and determine what treatment is the best, safest and most effective for each patient.

Treating a pulmonary embolism

Treatments for PE can range from blood thinners alone, all the way up to more invasive approaches such as the use of catheters or even surgery to dissolve or directly remove the clots.

“The standard of care for any PE usually starts with blood thinners. These are available as pills or via intravenous infusion,” said Paul.

Paul said that a subset of patients suffer from a submassive PE, which means the clot is big enough to cause low blood pressure, significant shortness of breath and low oxygen levels, but not severe enough to cause a complete collapse of the cardiovascular system.

“Depending on the severity of the PE, we increase the aggressiveness to more invasive therapies,” Paul continued. “We can do minimally invasive procedures and remove some of the clot. We can also place catheters within the clot and deliver very strong blood thinners called thrombolytic drugs that dissolve the clot more slowly.”

In the past, large dosages of thrombolytic drugs were delivered through an IV in the arm to treat large PEs. So-called “systemic” thrombolytics, however, may lead to higher rates of serious complications such as bleeding – even in the brain, which is very dangerous. So the minimally invasive approach is often preferred.

“The minimally invasive route allows us to lower the dose of the drug over a longer period of time, minimizing bleeding complications. It also allows us to inject the drugs directly into the spot where it needs to work,” said Paul. This procedure is called catheter directed thrombolytic therapy.

In extreme cases, such as when someone is suffering from cardiopulmonary collapse, which is a sudden loss of blood flow caused by the heart not effectively pumping blood, surgery is also available. In those cases, the clot is directly removed by opening the patient’s chest during a procedure known as pulmonary thrombectomy surgery.

Follow-up program

Patients begin a follow-up program once their PE is successfully treated by seeing cardiologists and pulmonarycritical care doctors in UChicago Medicine’s Chronic Thromboembolic Disease (CTED) Clinic. There, staff will screen patients for potential reoccurrences and long term problems related to PEs, and monitor any preexisting issues.

“We’re working together to make sure a patient stays healthy and clot-free,” said Paul. “That’s why we’re really aggressive about screening and seeing patients on a regular basis to make sure they’re on the appropriate medications for the long term.”

On the flip side, some patients come to the clinic already on blood thinners when they no longer need them. Blood thinners can cause excess bleeding and may not be necessary for the long term in certain cases.

Other times, there are issues with IVC filters.

“Sometimes filters are placed in the inferior vena cava, a large vein that goes up to the heart, to try to trap clots. These filters don’t usually need to be in for an extended period of time.” Paul continued. “So, when it’s appropriate, we take these filters out to try and avoid complications.

What to do if you think you have PE

Concerned you may have developed a pulmonary embolism? Paul’s best advice is to call your doctor, or if you’re struggling to breathe and feel lightheaded, call 911 or go to the emergency room. Just like a heart attack, time is of the essence, and an untreated PE can be deadly.

Shortness of breath and difficulty breathing are common symptoms related to a number of issues. But it is important to recognize that although a symptom may seem minor, it could be the tip of the iceberg.