External validation of Villalta score in high-middle income country patients with deep vein thrombosis

Post-thrombotic syndrome (PTS) is a late complication that does not have a cure yet, with a prevalence estimated between 20 to 75%, associated with previous deep vein thrombosis event. Although the Villalta score (VS) is the gold-standard clinical tool for diagnostic and prognostic evaluation of PTS, there are currently no VS intra-rater agreement established and no validation studies for VS’ application into Brazilian Portuguese. We sought to translate and validate VS reliability systematically; and, secondarily, to compare the ultrasound findings with the severity of PTS. We systematically translated the original VS into Brazilian Portuguese (BP). Fifty participants who underwent two outpatient visits were evaluated using the translated VS. We assessed its intra-rater and inter-rater agreement and compared BP VS versus CEAP clinical component (CEAP C), and the clinical PTS severity versus the duplex ultrasound (DUS) findings. The study and its report followed the Guidelines for Reporting Reliability and Agreement Studies. The intra-rater evaluation of VS grades had a simple Kappa coefficient of 0.73, and the simple Kappa coefficient inter-rater for VS grades was 0.67. When VS was compared to CEAP C, it established a remarkably high correlation over 0.9. There was difference among VS values compared to DUS initial deep vein thrombosis territory, with femoropopliteal showing higher values than distal veins. Higher VS values were correlated to DUS venous recanalization and reflux. There was a substantial inter-rater and intra-rater agreement when the BP VS was applied; and when compared to CEAP C, VS showed a high correlation. When VS grading was compared to DUS characteristics, there were significant statistical and clinical correlation, with presence of reflux and recanalization showing higher VS values. This external VS validation also changes the clinical practice allowing the VS use in a different population and establishes the VS intra-rater agreement.