Abstract Number: PB2201
Meeting: ISTH 2020 Congress
Theme: Venous Thromboembolism and Cardioembolism » Post-thrombotic Syndrome
Background: There is a lack of consistency in how the Villalta scale (VS) is used to denote the post-thrombotic syndrome (PTS).
Aims: Within the ATTRACT Trial database, we aimed to compare 8 approaches of using the VS to define PTS, in terms of their ability to discriminate between DVT patients with poorer vs. better venous disease-specific QOL over follow-up.
Methods: At baseline, 1, 6, 12, 18 and 24 months, we assessed the VS in both legs and measured venous disease-specific quality of life (VEINES-QOL). We compared 8 approaches to classify patients as having vs. not having PTS during 24 months follow-up. For each approach, we calculated the proportion of patients that would be classified as having PTS, and compared the fitted average area under the curve (AUC) of VEINES-QOL scores between the 6 and 24 month visits for patients classified with vs. without PTS. Finally, we explored if results of the ATTRACT Trial would have differed if approaches 2-8 had been used as the primary outcome instead of
approach 1.
Results:
Approach | How defined | Construct |
1 | Ipsi-VS ≥ 5 at least once from 6 to 24 months follow-up (ATTRACT primary outcome) | PTS |
2 | Ipsi-VS ≥ 5 on two or more consecutive assessments from 6 to 24 months follow-up | PTS |
3 | Ipsi-VS ≥ 5 on any two or more assessments (not necessarily consecutive) from 6 to 24 months follow-up | PTS |
4 | Ipsi-VS ≥ 10 at least once from 6 to 24 months follow-up (ATTRACT secondary outcome) | Moderate/severe PTS |
5 | Ipsi-VS ≥ 10 on two or more consecutive assessments from 6 to 24 months follow-up | Moderate/severe PTS |
6 | Ipsi-VS ≥ 10 on any two or more consecutive assessments (not necessarily consecutive) from 6 to 24 months follow-up | Moderate/severe PTS |
7 | Ipsi-VS minus contra-VS ≥ 5 at least once from 6 to 24 months follow-up | PTS, adjusted for contra CVI |
8 | Ipsi-VS ≥ 5 at least once from 6 to 24 months follow-up, only assessed in patients with VS < 5 in the contralateral leg at baseline | PTS, only assessed in patients without baseline CVI |
ipsi ipsilateral; contra contralateral; CVI chronic venous insufficiency |
[Approach, definition, construct captured]
Approach | N (%) classified with PTS | Difference (SE) in average fitted AUC of VEINES-QOL scores * | P value for difference in AUC, PTS vs. No PTS | Comparison of PCDT vs. No PCDT Adjusted# RR (95% CI) |
1 | 328/691 (47%) | -21.2 (1.5) | <.0001 | 0.96 (0.82 to 1.11) |
2 | 159/691 (23%) | -23.7 (1.7) | <.0001 | 0.95 (0.72 to 1.26) |
3 | 200/691 (29%) | -22.0 (1.6) | <.0001 | 0.94 (0.74 to 1.18) |
4 | 144/691 (21%) | -25.5 (1.8) | <.0001 | 0.73 (0.54 to 0.98) |
5 | 58/691 (8%) | -31.7 (2.6) | <.0001 | 0.87 (0.52 to 1.45) |
6 | 73/691 (11%) | -31.0 (2.3) | <.0001 | 0.97 (0.62 to 1.51) |
7 | 189/691 (27%) | -13.6 (1.8) | <.0001 | 0.86 (0.68 to 1.09) |
8 | 265/607 (44%) | -19.9 (1.5) | <.0001 | 0.98 (0.82 to 1.18) |
* Adjusted for age, sex, BMI, treatment (PCDT vs. No PCDT), extent of DVT and baseline VS; # Adjusted for extent of DVT and center; AUC area under curve; PCDT pharmacomechnical catheter-directed lysis |
[Results for each approach]
Conclusions: For the outcome any PTS, approach 1, 2, and 3 had similar ΔAUC; thus, approach 1 is preferred due to greater convenience (only 1 positive assessment needed). For moderate/ severe PTS, approach 5 and 6 had similar and greater ΔAUC than approach 4; thus, approach 6 is preferred due to greater convenience (any 2 positive assessments). Attempting to “adjust” the VS for contralateral CVI or restrict the population to patients without baseline CVI (i.e “pure” PTS rather than preexisting CVI) did not improve ΔAUC, hence approach 1 is preferred to 7 or 8. Finally, results of the ATTRACT trial (used approach 1 for any PTS and approach 4 for moderate/severe PTS) were substantively unchanged if reanalysed using the other approaches.
To cite this abstract in AMA style:
Kahn SR, Gu C-, Galanaud J-, Kearon C, Vedantham S, for the ATTRACT Trial . Exploring Alternative Approaches of Using the Villalta Scale to Capture the Post-Thrombotic Syndrome: A Sub-analysis of the ATTRACT Trial [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/exploring-alternative-approaches-of-using-the-villalta-scale-to-capture-the-post-thrombotic-syndrome-a-sub-analysis-of-the-attract-trial/. Accessed April 18, 2024.« Back to ISTH 2020 Congress
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