Elsevier

Mayo Clinic Proceedings

Volume 70, Issue 1, February 1995, Pages 45-49
Mayo Clinic Proceedings

Concise Review for Primary-Care Physicians
Venous and Pulmonary Thromboembolism: An Algorithmic Approach to Diagnosis and Management

https://doi.org/10.4065/70.1.45Get rights and content

The frequently encountered disorder of venous thromboembolism (VTE) can cause serious morbidity and even death. Nevertheless, in more than 70% of patients who die of pulmonary embolism (PE), the diagnosis is not considered before death. Thus, clinicians should have a high index of suspicion for VTE, especially in high-risk patients. Some risk factors for VTE are a recent surgical procedure and general anesthesia, immobilization, congestive heart failure, previous PE, pregnancy, and oral contraceptive use. Before therapy can be initiated, a definitive diagnosis of VTE must be established. An algorithm for assessing patients with possible VTE is presented; decisions about proceeding with various studies are based primarily on the clinician's degree of suspicion for the presence of PE and the findings on a ventilation-perfusion scan. Elevation of the patient's legs before, during, and after a surgical procedure is a simple measure that may substantially decrease the occurrence of PE.

Section snippets

CLINICAL SUSPICION

The importance of the clinician's degree of suspicion for PE was a major feature of the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED)7 and is incorporated in the proposed algorithm. This factor becomes important in decisions about further testing. If the clinical suspicion is low to intermediate, Dalen8 suggested that anticoagulation therapy could be withheld in patients suspected of having PE but with nondiagnostic ventilation/perfusion (V/Q) scans and normal findings on

DIAGNOSIS

Before definitive long-term treatment can be initiated, the diagnosis of VTE must be confirmed by pulmonary angiography, a “high-probability” V/Q lung scan in the appropriate clinical setting, or study of the lower extremity venous system, including impedance plethysmography, duplex ultrasonography, or venography. Anything less than substantiation by one of these techniques is nonconfirmatory of the diagnosis of VTE and diminishes the likelihood that the patient has this disorder. If any of

HEPARIN ANTICOAGULATION

If the clinical suspicion for PE is intermediate to high, immediately consider beginning empiric intravenous heparin therapy (if no absolute contraindications are present) before further diagnostic studies are pursued. Confirmatory testing often takes hours to complete, and the next embolic event could prove fatal. Several studies have shown that up to 80% of patients receive inappropriate treatment—for example, an incorrect dose of heparin or no monitoring of the activated partial

PREVENTION

Preventive measures must be emphasized in managing highrisk patients. Nevertheless, preventive steps are used in only a third (ranging from 9% in a community hospital to 56% in a major teaching hospital) of all patients with moderate to high risk of developing VTE.11 A detailed discussion of prevention of VTE is beyond the scope of this article, but increased awareness about a simple preventive measure is important. An inexpensive, no-risk, highly patient-acceptable procedure of elevating the

ALGORITHMIC APPROACH

The PIOPED study showed that a physician's clinical suspicion for PE in certain situations can be highly correlated with the actual presence of the disorder. In patients in whom the clinical suspicion for PE was low and the V/Q scan also showed low probability of PE, only 4% were ultimately proved to have PE; thus, the clinician could usually withhold treatment in such circumstances. Conversely, in patients in whom the clinical suspicion of PE was high and the V/Q scans exhibited a high

ACKNOWLEDGMENT

Jay H. Ryu, M.D., provided a useful review and suggestions for the design of the algorithm.

Questions About Venous Thromboembolism

(See article, pages 45 to 49)

  • 1.

    On the fifth day after repair of an abdominal aortic aneurysm in a 66-year-old man who had never smoked, swelling and tenderness developed in his right calf. During the next day, he coughed up some bloody sputum and experienced dyspnea and pleuritic right chest pain. His vital signs were as follows: body temperature, 39°C; blood pressure, 110/60 mm Hg; and pulse, 120 beats/min. A chest roentgenogram disclosed only an elevated right hemidiaphragm. An

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