Platelet Dynamics During Impella Use: A Time-Series Analysis by Model and Treatment Method

Mechanical circulatory support is the standard treatment for refractory cardiogenic shock. However, Impella-induced thrombocytopenia is an established complication, and data on its incidence and characteristics remain limited. This study compared thrombocytopenia progression between patients who received different Impella devices (2.5/CP and 5.0/5.5) using Impella-alone or ECpella strategies. ECpella was defined as Impella combined with venoarterial extracorporeal membrane oxygenation. Secondary analyses were conducted to evaluate factors influencing complications and mortality. Between April 2018 and December 2024, 35 patients received Impella 2.5/CP alone, 67 received ECpella (2.5/CP was used), six received Impella 5.0/5.5 alone, and 13 received ECpella (5.0/5.5 was used). Platelet counts decreased significantly over time in the Impella 2.5/CP subgroups, with a greater reduction observed in the ECpella subgroup. Significant platelet count reduction was observed in only the ECpella subgroup of the Impella 5.0/5.5 group. A haptoglobin level of <10 mg/dl was more commonly noted in the Impella-alone subgroup of the Impella 2.5/CP group and in the ECpella subgroup of the Impella 5.0/5.5 group. The platelet count on day 3 post-implantation was associated with 1 year survival in the Impella 2.5/CP group (hazard ratio: 1.174, 95% confidence interval: 1.033-1.333, p = 0.014). These findings warrant validation in larger prospective studies.