Hemolysis and Kidney Injury in Patients Receiving Mechanical Circulatory Support: A Mechanistic Review

Temporary mechanical circulatory support (MCS) devices have emerged as a viable treatment strategy for patients with cardiogenic shock (CS). MCS devices improve systemic perfusion, ameliorate shock, and improve patient survival. However, the improvement in systemic perfusion with MCS comes with complications. The most common complication is hemolysis, with a reported incidence of up to 60%. Despite decades of design innovation, hemolysis is inevitably caused by shear forces induced by MCS devices on red blood cells, leading to the release of hemoglobin. Hemolysis due to MCS significantly worsens patient prognosis, morbidity, and mortality and is amajor contributor to MCS-associated acute kidney injury (MAKI). The lack of standardized diagnostic criteria in addition to variance in reporting has complicated detection and treatment of hemolysis in MCS. Another challenge in understanding the role of hemolysis-associated pigment nephropathy (HAPN) in MAKI is the confounding effect of shock on kidney injury. Importantly, there is broad consensus on MCS-related factors leading to hemolysis and their mitigation. Understanding the respective roles of device type, position, and power in generation of hemolysis has the potential to reduce complications and the incidence of HAPN. Therefore, this article provides a contemporary overview of the pathophysiology and mechanism of hemolysis amongst the most widely employed types of MCS devices. Practical approaches addressing clinical factors associated with hemolysis across different devices will also be highlighted.