Pulmonary embolism (PE) is a blockage or obstruction in the pulmonary arteries in the lungs. It is most commonly caused by blood clots that travel to the lungs from the venous system. Most often, the clots form in the leg veins or pelvic veins (a condition known as deep vein thrombosis or DVT). Because pulmonary emboli can lead to acute and significant strain on the heart, this condition can be potentially life threatening.
Types of Pulmonary Embolism
Pulmonary emboli can present as acute PE or chronic PE. Acute PE is a new obstruction causing acute onset heart strain. Acute PE often needs immediate treatment with clot busters and blood thinning medications. Chronic PE is a more insidious presentation that includes heart failure with gradual progressive symptoms. Chronic PE is caused by an older residual obstruction resulting from an undissolved clot in the pulmonary circulation left over from previous acute pulmonary emboli. In addition, in a small percentage of patients, chronic PE can lead to elevated blood pressure in the pulmonary arteries over time, developing into a rare type of pulmonary hypertension called chronic thromboembolic pulmonary hypertension (CTEPH).
Acute Pulmonary Embolism
An acute pulmonary embolism is a sudden blockage in the arteries of the lung. The blockage begins as a clot in a vein somewhere in the body that travels to the lung. Acute pulmonary embolism is the third most common cause of death from cardiovascular disease after heart attack and stroke. Approximately 25-30 percent of patients will die without immediate treatment.
Clinical Presentation of Acute PE
The clinical presentation of acute pulmonary embolism is:
- Shortness of breath
- Chest pain
- Rapid or irregular heartbeat
- Fainting episodes
Chronic Pulmonary Embolism and CTEPH
A chronic pulmonary embolism is a blockage of the pulmonary arteries that occurs when prior clots in these vessels don’t dissolve over time despite treatment of an acute PE, or the result of an undetected or untreated acute PE.
Chronic blood clot accumulation can lead to scar tissue formation in the blood vessels of the lungs, which blocks normal blood flow and makes the right side of the heart work harder. The result is a rare but often treatable type of severe pulmonary hypertension (high blood pressure in the blood vessels of the lungs) known as chronic thromboembolic pulmonary hypertension (CTEPH). While pulmonary emboli are common, CTEPH affects only 2-4 percent of chronic PE patients.
Clinical Presentation of Chronic PE and CTEPH
The clinical presentation of chronic pulmonary embolism is:
- Progressively worsening shortness of breath
- Rapid or irregular heartbeat
- Fainting episodes
- Cough that may produce bloody sputum
If you have unexplained shortness of breath, ask your doctor about getting evaluated for CTEPH. A ventilation perfusion scan is a quick, non-invasive screening tool to look for CTEPH.
Pulmonary Embolism Risk Factors
Any blood clot increases the risk of a pulmonary embolism. Risk factors for blood clot formation include:
- Genetic blood clotting disorders
- Inactivity for long periods of time; for example, during lengthy automobile or airplane travel or long bed rest
- Pregnancy and childbirth
- Taking birth control pills
- Chronic medical illness
A pulmonary embolism can be diagnosed in several ways, including:
- Computed tomography (CT): Scan of the chest with Doppler ultrasound of the legs (the most common method of diagnosing a PE and DVT)
- Chest X-ray: Provides a picture of the lungs and chest and helps rule out other possible conditions
- Electrocardiogram (ECG): Helps differentiate a PE from a heart attack
- Ventilation perfusion scan: A quick, non-invasive screening tool to look for CTEPH
- Echocardiogram: Helps diagnose heart dysfunction noted in CTEPH and Pulmonary Embolism
Patients with a pulmonary embolism can be treated with blood thinners, also known as anticoagulants. These medications can be given intravenously or by mouth. Blood thinners help our body to break down existing blood clots and prevent new clots from forming.
Advanced Therapies: Non-Surgical Treatments
Catheter-directed thrombolysis is a minimally invasive treatment to dissolve vascular blood clots and improve blood flow to prevent damage to tissues and organs. During this procedure, which is performed in a catheterization laboratory, a clot-dissolving medication called thrombolytic is delivered in the pulmonary blood clot through a thin plastic tube, or catheter, placed in the pulmonary arteries typically from the groin, neck or behind the knee vein. The catheter is guided using X-ray imaging.
Catheter-Based Thrombus Removal
Catheter-based thrombus removal, or thrombectomy, involves a novel thin tube, or catheter, used to remove large blood clots from an artery. Michigan Medicine offers all of the current approved non-surgical catheter-based technologies as well as numerous investigational studies.
Inferior Vena Cava Filter
This procedure involves a vein filter implanted via a thin wire into the vena cava, the main vein leading from the legs to the right side of the heart. The vein filter prevents clots from traveling to the heart or lungs. These devices prevent future clot migration from legs to lungs and are placed temporarily if a patient’s bleeding risk with conventional blood thinners is very high.
Balloon Pulmonary Angioplasty (BPA)
In patients with more chronic and well organized clot, Balloon Pulmonary Angioplasty (BPA) is performed to relieve obstruction using special catheter-based balloons delivered over a thin wire in the lung arteries. Currently, this procedure is investigational and reserved for patients who are not candidates for open heart surgery. During the procedure, a deflated balloon is directed to the diseased lung vessels and inflated to break up blood clots and restore blood flow to the lungs. Currently, we are the only hospital in Michigan performing BPA in patients with chronic PE and one of the top five medical centers nationwide.
Advanced Therapies: Surgical Treatment with Pulmonary Thromboendarterectomy (PTE)
When medications are not working to break up the clot, especially in cases of severe or long-lasting chronic blockages, open heart surgery may be required. The University of Michigan Frankel Cardiovascular Center has the most advanced surgical program in the region for the treatment of acute and chronic PE and CTEPH. We are the only hospital in Michigan currently performing pulmonary endarterectomy (PTE) in patients with chronic PE and one of the top five medical centers nationwide.
Not all CTEPH patients are eligible for this surgery. Balloon Pulmonary Angioplasty and medications are also available for CTEPH patients if a patient is not a candidate for the PTE surgery or if PH remains after the surgery.
Pulmonary rehabilitation helps patients regain strength and endurance following treatment for a pulmonary embolism. Patients exercise under the guidance of respiratory therapists and attend education sessions to learn about breathing techniques, medications, oxygen therapy, etc.
Pulmonary Embolism Treatment at the University of Michigan
At the University of Michigan, pulmonary embolism patients are treated with a specialized multidisciplinary team based approach. Our team includes specialists from cardiology, vascular medicine, hematology, pulmonary hypertension, interventional cardiology, interventional radiology and cardiothoracic surgery. The Frankel Cardiovascular Center has dedicated specialized pulmonary embolism and pulmonary hypertension clinics where specialists from various disciplines work in sync to deliver high quality personalized advanced care to these patients.
In the hospital, we have a dedicated 24 hour on call pulmonary embolism response team (PERT). Every PERT consultation is provided after an extensive evaluation and discussion between various subspecialists. Michigan Medicine PE and CTEPH patients have access to all available and upcoming novel investigations for the entire spectrum of pulmonary embolic disease including acute, chronic and CTEPH. Our ability to work in a multidisciplinary fashion differentiates our program and allows patients access to various specialists and therapies.
Make an Appointment
To make an appointment to discuss treatment for pulmonary embolism or CTEPH, call the University of Michigan Cardiovascular Call Center at 888-287-1082 or visit our Make a Cardiovascular Appointment page, where you can earn what to expect when you call us.