The second issue of this series of supplements on venous thromboembolic disease is centered on diagnostic approaches to patients with venous thromboembolism (VTE). VTE includes the related disorders of deep venous thrombosis (DVT) and pulmonary embolism (PE). VTE is prevalent, sometimes lethal in the short run and is a potential source of disability in the long run. Diagnosis of VTE with sufficiently high sensitivity and specificity is not possible using the clinical history and physical examination alone, so objective methods of diagnosis are required. In the past, plythesmographic and radionuclide-based techniques were commonly employed for diagnosis of VTE. Currently, however, diagnosis of DVT in most institutions is made on the basis of ultrasound evaluation of the lower extremity veins and the most common initial direct test for PE is contrast-enhanced computerized tomography (CT scan).
Reliance on ultrasound for diagnosis of DVT has resulted in a literal explosion in the demand for urgent testing for screening for possible DVT in patients with suggestive symptoms, and this has become the most frequent type of examination performed in most vascular laboratories. Not all patients are suited to technically satisfactory examinations, and only about 15% of such studies are positive for DVT. For these reasons, it is important to select patients for immediate ultrasound examination, to exclude DVT on the basis of reasonable criteria, and to have other options in mind when ultrasound evaluation is not adequate. Similar considerations apply for patients with possible PE. It is important for clinicians to understand the diagnostic accuracy and limitations of CT scanning for identification of PE and to recognize when pulmonary angiography is indicated.
Just how patients with possible VTE should be evaluated in 2004 is the subject of this monograph. This supplement contains four chapters authored by experts in the various techniques used to evaluate patients with suspected VTE. In preparing this material, it was assumed that readers would have a basic knowledge of the available tests, so the authors were asked not only to describe techniques of diagnosis but also to indicate how they can be integrated into a reasonable overall approach to evaluating patients with possible VTE. By studying this supplement, the physician will have a better appreciation of the relative advantages and limitations of each method and be able to develop an evidence-based approach to diagnosis that includes ultrasound, CT, MR, and serological tests.
Limiting the mortality and morbidity of VTE begins with making the correct diagnosis in a timely fashion. The goal of this supplement is to help the physician employ and prioritize appropriate diagnostic techniques with VTE. If this saves a single life or prevents only one venous stasis ulcer, it will have been well worth the effort.