Limitations of the Villalta scale in diagnosing post-thrombotic syndrome.

INTRODUCTION:The Villalta scale is currently the recommended tool for diagnosing post-thrombotic syndrome (PTS) in clinical studies, but there is concern that the sensitivity and specificity of the scale might be low. We aimed to evaluate the diagnostic accuracy of the Villata scale using criteria in line with clinical practice as a reference. MATERIAL AND METHODS:We invited patients with a history of proximal DVT during 2006-09 to participate in a cross-sectional follow-up study of long-term complications after DVT. PTS was diagnosed by the Villalta scale, and by the following four mandatory and predefined clinical criteria used as a reference for PTS: 1. Objectively verified DVT; 2. chronic complaints (>1 month) in the DVT leg; 3. complaints appeared after the DVT; and 4. an alternative diagnosis was unlikely. RESULTS:We included 88 of 170 eligible patients (52%). With our clinical criteria as a reference the sensitivity and specificity of the Villalta scale for diagnosing PTS were 75% (95% CI 60-87%) and 66% (95% CI 50-80%), respectively. Fifteen patients were diagnosed with PTS by the Villalta scale only. These patients more often experienced pain or had comorbidity that could explain their leg symptoms and signs. Eleven patients diagnosed with PTS by the clinical criteria only, had more fluctuating heaviness and edema. CONCLUSIONS:Our findings indicate that the diagnostic accuracy of the Villalta scale has limitations. Incorporating chronicity, whether the leg problems appeared following the DVT, fluctuations of heaviness and edema, and comorbidity in PTS assessment may improve the diagnostic accuracy.