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- Otherwise unexplained dyspnea, tachypnea, or chest pain.
- Clinical, electrocardiogram, or echocardiographic evidence of acute cor pulmonale.
- Positive chest computed tomography angiography scan with contrast.
- High-probability ventilation-perfusion lung scan or high-probability perfusion lung scan with a normal chest radiograph.
- Positive venous ultrasound of the legs with a convincing clinical history and suggestive lung scan.
- Diagnostic contrast pulmonary angiogram.
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The term “venous thromboembolism” (VTE) encompasses both pulmonary embolism (PE) and deep venous thrombosis (DVT) and accounts for more than 250,000 hospitalizations per year in the United States. VTE constitutes one of the most common causes of cardiovascular and cardiopulmonary illnesses in Western civilization. PE causes or contributes to at least 50,000 deaths per year in the United States, a rate that has probably remained constant for the past three decades. However, a significant proportion of cases of PE remain undiagnosed, partly due to the variable nature of its clinical presentation and partly due to the lack of access of appropriate diagnostic testing modalities at the point of initial care. With the increasing use of computed tomographic pulmonary angiography (CT-PA) in mainstream clinical practice, a larger proportion of PE cases are now being diagnosed. In fact, the estimated incidence of PE has approximately doubled after the introduction of CT-PA in routine clinical practice, from 62.1 to 112.3 cases per 100,000 individuals. For those who survive PE, further disability includes the potential development of chronic pulmonary hypertension or chronic venous insufficiency. After a VTE event, patients and their physicians are concerned about the presence of an occult carcinoma, the risk of a recurrent PE after anticoagulation therapy has been discontinued, and whether the patients' family members are at risk for VTE.
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“Primary” PE occurs in the absence of surgery or trauma. Patients with this condition often have an underlying hypercoagulable state, although a specific thrombophilic condition may not be identified. A common scenario is a clinically silent tendency toward thrombosis, which is precipitated by a stressor such as prolonged immobilization, oral contraceptives, pregnancy, or hormone replacement therapy. Recently, there has been an increased appreciation of the risks of VTE among patients with medical illnesses, including cancer (which itself may be associated with a hypercoagulable state), congestive heart failure, and chronic obstructive pulmonary disease.
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The prevalence of “secondary” PE is high among patients undergoing certain types of surgery, especially orthopedic surgery of the hip and knee, gynecologic cancer surgery, major trauma, and craniotomy for brain tumor. PE in these patients may occur as late as a month after discharge from the hospital.
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A thorough history should be obtained, including history of prior VTE, family history of VTE, history of frequent miscarriages, past history of cancer, recent history of heparin use (suggestive of heparin-induced thrombocytopenia), and history of prothrombotic conditions (myeloproliferative disease, nephrotic syndrome, collagen-vascular disease, and congestive heart failure). An acquired or inheritable risk factor is found in 50% of patients who present with ...