High-frequency ultrasound measurement for assessing post-thrombotic syndrome and monitoring compression therapy in chronic venous disease.

BACKGROUND

The purpose of this study was to validate high-frequency ultrasound (HFU) measurement of dermal thickness for quantification of edema in patients with different severities of chronic venous disease.

METHODS

HFU measurements of dermal thickness were made with a 17-MHz probe (Philips iU22 Ultrasound scanner, Bothell, Wash) or a 20-MHz medium-focus probe (DermaScan-C, Cortex Technology, Denmark), 7.5 cm above the medial malleolus. For validation, 20 patients with venous leg ulcers who were not receiving compression therapy, 20 patients with previous deep vein thrombosis (DVT) and symptoms of post-thrombotic syndrome (PTS) without ulceration, and 31 age-matched healthy controls were measured on a single occasion. To investigate the effect of compression on dermal thickness, the leg ulcer patients from the validation study were treated with compression therapy for 7 weeks and measured after 1, 3, 5, and 7 weeks. The association between dermal thickness and the clinical (C) component of the CEAP classification was examined in a cross-sectional analysis of 157 patients with a confirmed history of DVT >or=3 years ago.

RESULTS

Dermal thickness in patients with venous leg ulcers before compression therapy (median, 2.56 mm; interquartile range [IQR], 2.31-2.82 mm) was significantly greater (P = .002) than that in patients with symptoms of PTS without ulceration (median, 2.16 mm; IQR, 1.90-2.36 mm). Dermal thickness in both groups was significantly greater (P < .0001) than the control group (median, 1.34 mm; IQR, 1.29-1.44 mm). Compression therapy caused a steady and significant decrease in dermal thickness during the first 5 weeks until normal control levels were achieved. Dermal thickness increased with increasing CEAP category. In 121 patients with a positive diagnosis of DVT >or=3 years ago from Radiology Department records, a hypothetical test cutoff of 1.985 mm for the prediction of severe PTS noted as C(4b), C(5), and C(6) (lipodermatosclerosis or leg ulceration) had a positive predictive value of 46.9% and a negative predictive value of 90.3%.

CONCLUSION

HFU measurement of dermal thickness enables the monitoring of edema reduction by compression therapy. A prospective study is required to determine the temporal dynamics of dermal thickness changes after DVT and the relationship to the development of PTS. This test has the potential to be beneficial in the follow-up of patients after a DVT and provide clinical evidence for using graduated elastic compression stockings to control edema and prevent the development of more advanced skin changes.