Authors

Rogers, Frederick B. MD; Cipolle, Mark D. MD, PhD; Velmahos, George MD, PhD; Rozycki, Grace MD; Luchette, Fred A. MD

Author Information

From the University of Vermont, Department of Surgery, Fletcher Allen Health Care (F.B.R.), Burlington, Vermont, Department of Surgery, Lehigh Valley Hospital (M.D.C.), Allentown, Pennsylvania, Department of Surgery, Division of Trauma and Critical Care, University of Southern California (G.V.), Los Angeles, California, Department of Surgery, Emory University School of Medicine, Atlanta, Georgia, and Department of Surgery, Division of Trauma, Critical Care, and Burns, Loyola University Medical Center (F.A.L.), Maywood, Illinois.

Submitted for publication September 1, 2001.

Accepted for publication March 15, 2002.

Any reference in this guideline to a specific commercial product, process, or service by trade name, trademark, or manufacturer does not constitute or imply an endorsement, recommendation, or any favoritism by the authors or EAST. The views and opinions of the authors do not necessarily state or reflect those of EAST and shall not be used for advertising or product endorsement purposes.

Address for reprints: Frederick B. Rogers, MD, University of Vermont Department of Surgery, Fletcher Allen Health Care, 111 Colchester Avenue, Burlington, VT 05401; email: frederick.rogers@vtmednet.org.

Statement of the Problem

All invasive or noninvasive diagnostic modalities for DVT are compared with venography, often referred to as the gold standard for the diagnosis of DVT in trauma patients. The problem with venography is that it is not feasible as a screening study because it is time-consuming, invasive, and has inherent risks and complications associated with its use. As such, it is rarely used clinically and is used more as a research modality.

Process

A MEDLINE search from 1966 to the present identified 3,520 articles related to venography in the diagnosis of DVT. Only eight articles were specifically related to the use of venography to diagnose DVT in the trauma patient. These articles, as well as some seminal review articles, were reviewed (Table 9).

Recommendations

A. Level I: A Level I recommendation on this topic cannot be supported because of insufficient data.

B. Level II:

C. 1. Ascending venography should be used as a confirmatory study in those trauma patients who have an equivocal IPG or Doppler ultrasound examination for DVT.^[82][98][99]

D. 2. Ascending venography should not be used to screen asymptomatic trauma patients at high risk for DVT. A role for ascending venography may exist in research studies on the incidence of DVT in trauma patients.^[4][11][100]

E. Level III:

F. 1. Magnetic resonance venography may have a role in diagnosing acute DVT in the trauma patient, especially with clots in the calf and pelvis (areas where venography and ultrasound are less reliable).^[101]

Scientific Foundation

Ascending contrast venography as a diagnostic modality has been around since the 1920s but was considered unreliable or even dangerous until Rabinov and Paulin^[102] standardized the technique in 1972. When this proper technique is used by a skilled radiologist, the entire lower extremity venous system should be visualized in a normal patient. Rabinov and Paulin^[102] described the four cardinal signs of DVT: (1) constant filling defects, (2) abrupt termination of the dye column, (3) nonfilling of the entire deep venous system or portions thereof, and (4) diversion of flow. Despite improvements in technique, several logistical problems remain for venography. A venogram requires patient transport to the radiology suite, which is often difficult for critically ill trauma patients. Venography requires a cooperative patient who can be examined in a semierect position on a tilting fluoroscopy table. Venous access is not always possible, especially in those with massive leg swelling. Usually 150 to 300 mL of contrast material is required for adequate visualization of the deep venous system. With the use of nonionic contrast agents, the risk of allergic reactions and nephrotoxicity is very uncommon. Although the possibility of contrast-induced DVT exists,^[103] the risks of this complication are unknown but are likely to be low. Injection of the contrast media may result in local discomfort and, if significant extravasation of contrast occurs, skin necrosis may result. Despite its common label as the gold standard in DVT diagnostic imaging, up to 30% of venograms will fail to visualize some segment of the venous system.^[82]Because of problems visualizing the entire venous system, a review of consecutive series of venograms by independent radiologists has resulted in only a 90% accuracy for venography.^[98] As a result, most radiologists now believe that accurate, noninvasive imaging procedures such as duplex ultrasound are the imaging procedure of choice for suspected DVT above the knee. However, the accuracy of venography in the calf appears to exceed noninvasive tests in most centers.^[99] Accordingly, it can be considered the gold standard for the diagnosis of calf DVT.

The most notable study in which venography was used as a screening technique in high-risk trauma patients was that of Geerts et al.^[11] In this study, all patients admitted with an ISS > 9 were assessed with contrast venography for evidence of DVT. No patient received any DVT prophylaxis. In 349 patients, DVT was found in 201 (58%) and proximal DVT was found in 63 (18%). Multivariate analysis identified five independent risk factors for DVT: increasing age, blood transfusion, surgery, fracture of the femur or tibia, and spinal cord injury. Most of these thrombi were asymptomatic. The authors did not articulate on the nature of the thrombi, such as how many were nonocclusive or were small and confined to single venous segments below the knee. A criticism of venography is that it may detect small isolated thrombi such as those on valve cusps that are clinically insignificant.^[82] It can be difficult to predict which ones will emerge as one of the 5% to 30%^104] that go on to propagate an extensive, proximal (dangerous) thrombus. A decision to treat these patients is important, as anticoagulant treatment can be associated with substantial morbidity in the trauma patient. Brathwaite et al.,^[105] in a cohort of 70 trauma patients treated with full anticoagulation, found a 36% complication rate requiring termination of anticoagulation.

Magnetic resonance venography (MRV) has been used to diagnose proximal and acute pelvic vein DVT preoperatively in patients undergoing complex pelvic or acetabular fixation. Montgomery et al.^[101] used MRV in 45 consecutive patients with displaced acetabular fracture and diagnosed 24 asymptomatic DVTs, 7 of which were in the internal iliac vein, an area that could not have been seen with contrast venography or ultrasound. Nevertheless, it is an expensive examination that requires transport to the magnetic resonance suite and a dedicated radiologist with an interest in this technique. Many of these patients have recently placed external fixators or implants that prohibit the use of MRV in these patients. No study to date has compared that accuracy of MRV to any other diagnostic modality in trauma patients.

Summary

Although venography traditionally has been the diagnostic modality for DVT with which all other diagnostic modalities have been compared, logistical problems and complications associated with the procedure make it less appealing than other noninvasive diagnostic measures. Nevertheless, it still has a role in confirming DVT in trauma patients when diagnostic studies are equivocal or, possibly, as an outcome measure in clinical trials of thromboprophylaxis efficacy.

Future Investigation

Future studies may want to look at the role MRV has as a screening modality in diagnosing DVT in trauma patients.

Acknowledgment

We thank Jody Ciano for her help in the preparation of this article.

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