Is it safe to withhold anticoagulation based on a single negative color duplex examination in patients with suspected deep venous thrombosis? A prospective 3-month follow-up study

Complete compression ultrasound for the diagnosis of venous thromboembolism

PURPOSE OF REVIEW

Since its first appearance in the 1980s, venous ultrasound has increasingly gained interest of both clinicians and researchers. However, a majority of authors currently are convinced that venous ultrasound has inherent limitations that preclude it from safely ruling out distal deep vein thrombosis (DVT) in symptomatic patients and from detecting proximal and distal DVT accurately in asymptomatic patients. The aim of this review is to present recent lines of evidence indicating that venous ultrasound has developed beyond these limitations.

RECENT FINDINGS

The major development does not arise from technical progress of imaging but from standardizing the examination procedure. The most efficient protocols now focus on B-mode sonography only but extend the examination to the paired deep calf veins and the calf muscle veins. For such an examination protocol, the term complete compression ultrasound (CCUS) has been coined. Interobserver variability of CCUS resembles that of venography, as do the technical failure rates. By means of a CCUS protocol, the diagnostic work-up of patients with suspected DVT can be simplified significantly. Studies in asymptomatic patients indicate that CCUS has the potential to generate valid data in prevalence and incidence studies and in intervention trials.

SUMMARY

Complete compression ultrasound protocols are ready for implementation into clinical practice for diagnosing patients with symptomatic DVT. Research has already benefited from CCUS and benefits further with an increasing number of CCUS-driven trial designs. However, the value of a CCUS protocol critically depends on sound training and on strict compliance with all its details.

Venous protocols, techniques, and interpretations of the upper and lower extremities

Deep venous thrombosis and pulmonary embolism are common problems and frequently included in the differential diagnosis of patients presenting to the emergency department and in the acute care setting. Clinical signs and symptoms of these entities are nonspecific and it is important to perform objective testing to confirm the diagnosis and initiate proper therapy. Compression ultrasonography is the diagnostic procedure of choice for the investigation of patients with suspected deep venous thrombosis. This article reviews the clinical indications, diagnostic techniques, and interpretation of compression ultrasound to assess deep venous thrombosis in the upper and lower extremities and to evaluate the role of compression ultrasonography in the assessment of patients with suspected pulmonary embolism.

A detailed analysis of equivocal duplex findings in patients with suspected deep venous thrombosis

OBJECTIVE

To analyze equivocal duplex findings in patients with clinically suspected deep venous thrombosis and thus to increase the diagnostic utility of color duplex sonography in this category of patients.

METHODS

Phlebography was requested in a series of 102 consecutive patients with inconclusive duplex findings. These patients were, according to the duplex findings only, subdivided into having low, intermediate, and high probability of deep venous thrombosis.

RESULTS

Phlebographywas attempted in 71 cases and successfully performed in 49. The remaining 53 patients were prospectively followed clinically for 6 months. Phlebography showed deep venous thrombosis in 1 of 63 patients in the group with low probability, 3 of 31 in the intermediate group, and all of the 8 patients with high probability. Twenty-two (31%) of the 71 attempted phlebographic examinations were nondiagnostic. None of the patients in the follow-up group had any thromboembolic complications.

CONCLUSIONS

Even if a duplex examination is equivocal, it is still possible to extract clinically useful information by categorizing the duplex results into subgroups with low, intermediate, and high probability of deep venous thrombosis. This can have implications for the diagnostic or therapeutic handling of these patients and thus can increase the utility of sonography in patients with inconclusive duplex findings.