Blood clots in the lung (pulmonary embolism, PE) often completely dissolve within a few weeks or months and a patient’s symptoms of shortness and breath and chest pain disappear. Many people return to their normal self and have no physical limitations thereafter. Other people have some residual symptoms of shortness of breath or chest discomfort, but adjust to it well. However, in a few patients, clots do not completely dissolve and significant chronic damage to the lung results.If severe, then this is called pulmonary hypertension. It has also been given the name CTEPH, which stands for Chronic Thromboembolic Pulmonary Hypertension. Persistent or worsening shortness of breath, particularly with exercise, is the most common symptom. As pulmonary hypertension can eventually lead to right heart failure and death, the condition is to be taken seriously and patients with previous PE should be evaluated for it.
What is pulmonary hypertension? How is it defined?
When blood clots do not completely dissolve, they develop into scar tissue. This obstructs some of the blood vessels (the pulmonary arteries) in the lung. The right side of the heart, which has to pump blood into the vessels of the lung, now has to pump chronically against this resistance. As a consequence, the right heart is under chronic stress and eventually tires out, resulting in right heart failure.
Physicians define pulmonary hypertension by pressure measurements they take at the time of a heart echo examination (cardiac echo) and, if that is abnormal, a subsequent right heart catheterization and pulmonary angiogram (= pulmonary arteriogram). In medical terms, pulmonary hypertension is defined as “a mean pulmonary artery pressure of ≥ 25 mm Hg by right heart catheterization, with normal left atrial pressure and left ventricular capillary wedge pressure”. There are many causes of pulmonary hypertension other than blood clots. If pulmonary hypertension is due to previous PE or due to asymptomatic recurrent clots, the term Chronic Thrombo-Embolic Pulmonary Hypertension (CTEPH) is used.
How common is it? Who develops it?
Pulmonary hypertension typically occurs within the first 2 years after a PE. It affects up to 4 % of PE patients, i.e. 1 out of 25 PE patients develops it. A patient is at higher risk if (a) the PE was fairly large, and (b) a person has recurrent clots. Also, for unclear reasons, women and younger people are at somewhat higher risk.
What are the symptoms?
Worsening shortness of breath with exercise is the classic presentation. Some patients report that their shortness of breath after a PE never resolved or only partially improved. As the lung disease worsens, additional symptoms may be present: generalized fatigue, chest pain, light-headedness, near-fainting and fainting, and eventually symptoms of right heart failure: swelling of both ankles and whole leg, abdominal distension, feeling full easily.
Who should be screened for it?
The following patients should be evaluated for pulmonary hypertension after they had a PE: the patient with (a) history of large PE, (b) shortness of breath, limited recovery of exercise tolerance after the PE episode and, (c) symptoms or signs of right heart failure after a PE (swelling of both ankles, calves, and whole leg, abdominal distension, near fainting). Typically, patients improve from their PE in the weeks to months following the acute PE, and within 6, 9 or 12 months a steady state is reached. Certainly, there is some variability from patient to patient. However, if there has been no significant improvement at 6-9 months, or improvement has reached a plateau at an impaired functional level, then evaluation for pulmonary HTN is appropriate.
How to screen for it?
The following medical tests are appropriate:
- Pulse oximetry (finger clip device) in clinic at rest and after climbing stairs (or formal 6 minute walk test in a pulmonary function laboratory);
- Heart echo with focus on the right heart and estimation of pulmonary artery pressure;
- VQ lung scan (nuclear medicine perfusion-ventilation scan) to look for chronic/previous/old PE. A CTA (CT angiogram) of the chest is NOT a useful test to detect chronic PE – it is often normal. In medical terms: it is not sensitive enough to detect chronic PE.
- If any of the these screening test raises the suspicion that the patient may have pulmonary hypertension, then appropriate next steps are:
- Referral to a lung specialist (= pulmonologist) with expertise and interest in pulmonary hypertension, and
- Right heart catheterization with pulmonary artery pressure measurements and pulmonary arteriography (contrast injection into the lung vessesl).
- The patient with pulmonary hypertension should be treated with long-term blood thinners (most commonly warfarin), unless the patient has a significant bleeding risk [ref 1].
- Surgical removal of the chronic scar tissue in the lung vessels (= pulmonary endarterectomy) in a specialized center should be considered. This is a major surgery.
- Medications (Bosentan, etc) may be considered by the pulmonologist for patients with pulmonary hypertension who are not surgical candidates or who have residual pulmonary hypertension after endarterectomy surgery [ref 1].
- American Heart Association (AHA) Scientific Statement [ref 1]
- AHA, ACCP (American College of Chest Physicians) and PHA (Pulmonary Hypertension Association) Consensus Document 2009 [ref 2]
- European Guideline [ref 3]
Support for Patients
For health care professionals: This same information, written for health care professionals, is available here.
- Jaff MR et al. Management of massive and submassive pulmonary embolism, iliofemoral deep vein thrombosis, and chronic pulmonary hypertension. Circulation 2011;123:1788-1830.
- McLaughlin VV et al. ACCF/AHA 2009 expert consensus document on pulmonary hypertension. J Am Coll Cardiol. 2009 Apr 28;53(17):1573-619.
- Galie N et al. Guidelines for the diagnosis and treatment of pulmonary hypertension: the Task Force for the Diagnosis and Treatment of Pulmonary Hypertension of the European Society of Cardiology (ESC) and the European Respiratory Society (ERS), endorsed by the International Society of Heart and Lung Transplantation (ISHLT). Eur Heart J. 2009 Oct;30(20):2493-537. Epub 2009 Aug 27.
Acknowledgement: This blog entry was written in collaboration with Dr. Hubert (Jimmy) Ford, Assistant Professor, Division of Pulmonary, Critical Care and Sleep Medicine, UNC School of Medicine, Chapel Hill, NC. Dr. Ford directs the UNC Pulmonary Hypertension Clinic.
Disclosure: The authors have no financial conflict of interest relevant to this educational post.
Last updated: June 29th, 2011
Disclaimer: ClotConnect.org, its contributors, authors, advisors, members and affiliate organizations do not assume any liability for the content of the website, blog and educational materials. Medical information changes rapidly. While information is believed to be correct, no representation is made and no responsibility is assumed for the accuracy of information contained on or available through this web site and blog. Information is subject to change without notice.