Post-thrombotic syndrome in children with symptomatic deep vein thrombosis

Deep vein thrombosis (DVT) is an increasingly common diagnosis in pediatric inpatients. Approximately 85% of DVTs of extremities are associated with the use of a central venous catheter (CVC). CVC-related thrombosis and non-CVC-related thrombosis differ in their pathophysiology and patient characteristics. We thought it worthwhile to try and analyze whether there was an association between these parameters and further development of complications, namely, post-thrombotic syndrome (PTS). Thus, we aimed to evaluate differences in patient characteristics as well as in the frequency and severity of PTS in children with symptomatic CVC-related and non-CVC-related thrombosis. The study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology of Ministry of Healthcare of the Russian Federation. We retrospectively analyzed medical records of patients aged 0 to 18 years (at the time of thrombosis) who had undergone treatment at the Center between 2013 and 2023 and selected patients with verified symptomatic DVT of the upper or lower extremity. The patients were divided into 2 groups: patients with CVC-related thrombosis (group 1) and patients with non-CVC-related thrombosis (group 2). Then we analyzed data on PTS in these patients collected during consultations with a hematologist at the Center or via a phone interview. PTS was evaluated using the Russian versions of the Manco–Johnson Instrument (MJI), the Modified Villalta Scale (MVS) and the Clinical Assessment of PTS (CAPTSure) (see the supplementary materials). The statistical significance of differences between the groups was assessed using Chi-square test or, if the expected values in a table were less than 5, using Fisher’s exact test. The study included 47 patients with symptomatic DVT: 17 patients with CVC-related DVT and 30 patients with non-CVCrelated DVT. The patients with CVC-related DVT were found to be younger at the time of thrombosis (median age: 4.1 years (range: 0–17 years) in group 1 versus 15.5 years (range: 3–17 years) in group 2; р < 0.001) and were followed up for longer periods of time (median follow-up time: 5 years (range: 0.5–15 years) in group 1 versus 1 year (range: 0.5–7.5 years) in group 2; р = 0.001). Recanalization at 3 months after DVT was better in the patients with non-CVC-related DVT (50% of the patients in group 1 versus 93% of the patients in group 2; р = 0.002). The overall frequency of PTS was 87% in accordance with MVS/ MJI and 68% as per CAPTSure. The frequency of PTS in the groups was comparable: there were 13 (76%) patients with PTS in the CVC-related thrombosis group and 28 (93%) patients in the non-CVC-related thrombosis group; р = 0.2). The patients with non-CVC-related DVT were found to have more severe PTS more often: 44% of the patients with moderate PTS in the non-CVCrelated DVT group versus 23% of the patients with moderate PTS and CVC-related DVT; р = 0.2. However, these differences did not turn out to be statistically significant. Thus, there were no statistically significant differences in either the frequency or severity of PTS between the two groups. In this study, the overall frequency of PTS in the patients with symptomatic DVT was rather high but the majority of the children in both groups had mild PTS. Still, since PTS is a late complication, it is important to continue patient follow-up to monitor symptoms and severity of chronic venous insufficiency over time.