Hemocompatibility of Mechanical Circulatory Support Devices: An Integrated Review of Platelet Function Assessment in In-Vitro Blood Experiments.

Abstract

Despite persistent bleeding and thrombotic adverse events in patients supported with blood pumps, standardized preclinical assessment of hemocompatibility remains largely restricted to hemolysis testing. To advance the field, robust and comparable in vitro platelet function testing within mock-loop mechanical circulatory support (MCS) studies is needed. This review systematically summarizes current methodologies for platelet function assessment in MCS devices and critically examines their advantages and limitations to inform the development of a unified, evidence-based testing framework. A systematic literature search was conducted in PubMed, Web of Science, Embase, and Scopus using Medical Subject Headings (MeSH) and free-text terms in accordance with PRISMA guidelines. Articles were screened according to predefined inclusion and exclusion criteria. Thirty-nine studies met the eligibility criteria. Study designs varied substantially with respect to experiment duration, sampling strategies, mock-circulation loop configurations, and pump types. Human whole blood was the predominant test medium (n = 27). Anticoagulation strategies differed widely, with citrate-based formulations (n = 22) and heparin (n = 15) most frequently employed. Flow cytometry was the predominant analytical method (n = 25), primarily assessing platelet function through changes in surface receptor expression or shedding. Flow cytometry offers a highly informative and direct approach for assessing platelet state in MCS research compared to other methods. However, substantial methodological heterogeneity continues to hinder data interpretation and cross-study comparability. Beyond standardizing experimental setups and protocols, future investigations should incorporate multiple complementary biomarkers and clarify their relationships to clinically relevant outcomes to more comprehensively characterize shear-induced platelet responses.