Reassessing the Villalta score’s use of signs and symptoms Open Access

TO THE EDITOR:

We read with interest the study by Iding et al titled “Untangling profiles of post-thrombotic syndrome using unsupervised machine learning.”¹ The authors identified 4 distinct clusters exhibiting changes in symptom and sign profiles over a 6-month follow-up period. However, our review of the Villalta score for postthrombotic syndrome reveals an inherent weakness in the classification of signs and symptoms, which may influence the interpretation of their findings.² 

A sign is typically defined as an observable feature that conveys information or supports an inference about an underlying pathological process.³ In contrast, a symptom refers to a subjective deviation from normal function, as reported by the patient, although it may also be observed objectively in some cases. Objectively noted symptoms, however, are more accurately termed physical findings. Importantly, a symptom should be reclassified as a sign only if it supports a specific diagnostic inference.³ 

Although we support Villalta’s inclusion of clinical symptoms, we question the categorization of several elements listed as signs. For example, features such as pretibial edema, skin induration, hyperpigmentation, redness, venous ectasia, and ulceration are more appropriately classified as physical findings. Among the included criteria, pain elicited by calf compression is arguably the only true sign. Notably, the Villalta scale provides no standardized guidance on how this maneuver should be performed.

The maneuver can be executed either by applying forward pressure to the gastrocnemius muscle against the posterior aspect of the tibia or by grasping the calf between its lower and middle thirds and pressing anteriorly against the tibia.⁴ Understanding how this physical manipulation elicits pain is essential to ensure consistency in clinical assessment and reproducibility across raters.

The Villalta score demonstrates good to excellent interrater reliability, particularly in more severe cases, and is regarded as externally valid and clinically useful.⁵ However, significant limitations remain, most notably the lack of data regarding intrarater and test-retest reliability.⁵ Despite these concerns, the score remains a valuable tool for assessing disease severity across multiple dimensions. Improved classification of its 12 components, clearly distinguishing signs, symptoms, and physical findings, together with standardization of the calf compression technique, could enhance its utility in risk stratification and support more individualized treatment strategies.¹ 

Contribution: All authors were all involved in conceptualization, drafting, editing, and reviewing the manuscript.

Conflict-of-interest disclosure: The authors declare no competing financial interests.

Correspondence: Steven H. Yale, Department of Medicine, University of Central Florida College of Medicine, 6850 Lake Nona Blvd, Orlando, FL 32827; email: steven.yale.md@gmail.com.