Comparison of Thrombosis Risk in Patients Undergoing Purified and Non-Purified Islet Cell Transplantation.

OBJECTIVES:To investigate the thrombosis risk and adverse bleeding events in patients who received purified vs. non-purified islet cell autotransplants (IAT). METHODS:We performed a retrospective cohort study evaluating the rate of portal vein thrombosis (PVT), adverse bleeding events, and premature heparin discontinuation in purified and non-purified IAT patients at our center between 2013 and 2022. RESULTS:The incidence of PVT formation was 0 % in the purified group (23 patients) and 4.2 % in the non-purified group (48 patients). Patients in the purified islet group received lower intra-operative heparin dosing compared to patients in the non-purified group (3157units vs 2657units, p = 0.03), but both groups received similar post-operative heparin dosing (505units vs. 437units, p = 0.55). Non-purified patients were on heparin for significantly fewer days than purified patients (1.6 days vs. 3.2 days, p < 0.01). There was no difference in adverse bleeding events that resulted in premature heparin discontinuation (39.1 % vs. 62.5 %, p = 0.08) nor blood transfusion requirements (34.8 % vs. 41.7 %, p = 0.58) between the purified and non-purified groups. However, patients in the purified group had higher rates of reoperation due to rebleeding compared with the non-purified group (17.4 % vs 0 %, p < 0.01). CONCLUSIONS:While PVT is a relatively rare event in both purified and non-purified IAT when peri-operative and post-operative full-dose heparinization is administered, there remains a clinical difference in PVT formation between purified and non-purified IATs. Although bleeding risk may potentially be mitigated by a reduction in the duration of full dose heparinization without a corresponding risk in PVT rate, further investigation is warranted.