CO065 | THROMBOTIC RISK IS NOT UNIFORM ACROSS APHERESIS SETTINGS: INSIGHTS FROM CAR-T LYMPHOCYTAPHERESIS AND AUTOLOGOUS STEM CELL COLLECTION

I. Pansini^1|2, G. Brizzi², E. Galli¹, A. Corrente², P. Rea², N. Piccirillo^1|2, M. Viscovo^1|2, S. Hohaus^1|2, P. Chiusolo^1|2, F. Sorà^1|2, S. Sica^1|2 | ¹Fondazione Policlinico Universitario A. Gemelli, Italy; ²Università Cattolica del Sacro Cuore, Italy

Background. Pericatheter thrombosis (PCT) is a recognized complication of large-bore venous catheters used for cell collection. An incidence of approximately 1.8% has been reported for Mahurkar catheters in peripheral blood stem cell collection. Data in patients undergoing lymphocytapheresis for CAR-T therapy are limited. This study evaluates PCT in this setting and compares thrombotic events with those observed in autologous stem cell collection.
Methods. A retrospective single-centre analysis included 62 patients undergoing CAR-T lymphocytapheresis with a Mahurkar catheter (September 2019–October 2025). During the same period, 127 patients underwent autologous stem cell collection; 62 required a Mahurkar catheter, and a subset of 21 with comparable diseases was analyzed. Within the CAR-T cohort, analyses compared (1) PCT vs non-PCT and (2) any thrombosis vs no thrombosis. A third analysis compared CAR-T and autologous cohorts. Continuous variables were analyzed with Student’s t-test and categorical variables with chi-square or Fisher’s exact test.
Results. In the CAR-T cohort, PCT occurred in 5/62 patients (8%) and 13/62 (21%) developed overall thrombosis. No variable was significantly associated with PCT, although platelet count showed a borderline trend (p = 0.061). Procedural difficulty was more frequent in PCT cases (66% vs 18%), without statistical significance. In the autologous cohort, no PCT was observed (0/21), while 2 patients (9.5%) developed thrombosis at non-catheter sites. Compared to the autologous cohort, CAR-T patients showed lower platelet count (p < 0.0001), hemoglobin (p = 0.0276), and differences in white blood cell count (p = 0.045). Disease status also differed significantly, with all autologous patients in partial or complete response (p < 0.001).
Conclusions. PCT was more frequent in CAR-T lymphocytapheresis than in autologous stem cell collection. This difference appears to reflect underlying patient characteristics rather than procedural factors. CAR-T patients represent a distinct population with more advanced disease and altered hematological profiles. Thrombotic risk should not be considered uniform across apheresis settings, supporting tailored risk assessment and preventive strategies.