Risk Stratification of Patients With Pulmonary Embolism

Alice Goodman

November 21, 2011

November 21, 2011 (New York, New York) — Editor's note: It is now possible to risk-stratify patients with pulmonary embolism (PE), and to initiate aggressive therapy for massive PE and submassive PE when indicated.

Here at the 38th Annual VEITH Symposium, Victor F. Tapson, MD, discussed the need for risk stratification and the need to recognize submassive PE, which can be fatal. Echocardiography is key to risk stratification.

Dr. Tapson is professor of medicine and director of the Center for Pulmonary Vascular Disease at Duke University Medical Center in Durham, North Carolina.

In an interview with Medscape Medical News, Dr. Tapson discussed the need for risk stratification and aggressive treatment of patients with PE.

Medscape: Can you quantify the problem of acute PE?

Dr. Tapson: It is estimated that as many as 200,000 to 300,000 deaths occur in the United States every year from PE. Interestingly, autopsy studies suggest that if a patient dies from acute PE, usually PE is not suspected until the patient is dead.

Medscape: How can patients who will die of PE be identified?

Dr. Tapson: In many patients, we do have a window of opportunity, and it is becoming increasingly recognized that we should risk-stratify these patients. Our general therapy is anticoagulation therapy. If we can't anticoagulate because of contraindications, then we put in an intravascular vena cava filter. Some patients have massive PE (massive PE causing extensive hemodynamic instability and right ventricular enlargement, regardless of how big the clot is), and there is agreement that these patients should be treated as aggressively as possible, or consider embolectomy if there are contraindications to thrombolytic therapy.

Nonrandomized studies have provided compelling evidence that if the right ventricle is enlarged on echocardiography, mortality is higher. Also, elevated troponin levels confer a much higher mortality rate.

Medscape: How do you risk-stratify patients?

Dr. Tapson: First, you have to prove they have PE. Echocardiography gives us the best idea of right ventricular function. If the right ventricular size is more than 0.9 times the left ventricle size, we would call that submassive PE, and that would be concerning. CT scan can also show an enlarged right ventricle.

The next steps are to order troponin level and use ultrasound to see if there is any residual deep vein thrombosis (DVT).

Medscape: Is risk stratification being done on a widespread basis for patients with suspected PE?

Dr. Tapson: A lot of physicians do not order these tests. There are patients with normal blood pressure but with right ventricular enlargement and/or elevated troponin who we believe should be considered for more aggressive therapy. We have to individualize therapy.

We would like to risk-stratify everyone. If someone has a severe right ventricular enlargement and/or elevated troponin and extensive DVT in the legs after a diagnosis of PE, they would need more aggressive therapy. If a patient has a mildly enlarged right ventricular, normal troponin, and no evidence of DVT in the leg, some physicians would think they could be handled less aggressively, but based on right ventricular enlargement alone, they are still at risk for higher mortality.

Medscape: Why isn't risk stratification routinely done?

Dr. Tapson: Previously, when we saw massive PE, we would consider systemic thrombolytic therapy. Physicians are now concerned about risk of bleeding with thrombolytic therapy. In view of that, there has been increasing interest in catheter-based therapy. Some smaller hospitals may not have an interventional radiology suite or sufficient radiology staff to care for these kinds of patients, but in most hospitals, this can be done.

This requires a team approach — interventional radiologists, thoracic surgeons, pulmonary critical care doctors, hematologists, radiologists, use of echocardiography. It is prudent for these specialties to come to a consensus as to how to approach patients with massive or submassive PE. If the hospital does not have an interventional radiology suite, strong consideration should be given for referral to a larger institution. However, physicians must be careful about any potential delays in therapy. With massive PE, you often don't have time to transfer patients who are at risk of dying.

Medscape: What is your main message to physicians who see these patients?

Dr. Tapson: Consider echocardiography as key in stratifying patients. All PE is not the same. We need to risk-stratify patients into massive PE, submassive PE, or neither, and aggressively manage massive PE, consider being aggressive with submassive PE, and consider a catheter-based therapy.

Dr. Tapson reports receiving research funding from Bayer and sanofi-aventis; and receiving consultant and lecture fees from Bayer, sanofi-aventis, Biolex, Genentech, Merck, Daiichi, Boehringer-Ingelheim, and Covidien.

38th Annual VEITH Symposium. Presented November 18, 2011.

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