Microplastics (MP) pose a significant environmental and health risk due to their pervasive presence and potential adverse effects. This study investigates the release of MP from cardiac invasive catheters, which are essential medical devices used in cardiovascular procedures. Twenty-one catheter samples from four diagnostic catheter and three guider catheter brands were analysed using a comprehensive experimental approach. MP were detected in all samples, with varying counts across brands and types. Statistical analysis revealed no significant difference in MP counts among catheter brands, while morphological and chemical characterization provided insights into types, sizes and compositions of leached MP. Our detailed discussion highlights patient safety and health implications, emphasizing the need for further research to address MP leaching in catheter materials and to promote design improvements for sustainable healthcare practices. © 2024 The Authors