Bleeding and Thrombotic Events in Patients Undergoing Mechanical Circulatory Support: A Review of Literature

Abstract

Bleeding and thrombotic events are among the most common complications detected in patients with mechanical circulatory support (MCS). Herein, we reviewed the available evidence on the prevalence, etiology, and management of bleeding and thrombotic events in patients following MCS procedures, such as implantation of both intra- and paracorporeal devices that generate either pulsatile or nonpulsatile flow. Extracorporeal life support procedures providing support to the failing heart and lungs were also reviewed. Most bleeding and thromboembolic events occur despite appropriate hemostatic and anticoagulation management based on conventional coagulation laboratory parameters. Prevalence of bleeding events in this population ranges between 5 and 81%. Wide range in prevalence of bleeding reported in literature may be explained by different devices with different anticoagulation protocols being used, as well as different definitions of bleeding outcomes. Although bleeding events are more common than thromboembolic events, the consequences of thrombotic events are often detrimental. Management of bleeding events remains challenging and measures to prevent and treat bleeding events are often followed by thromboembolic events. Therefore, a personalized approach based on point-of-care hemostatic tests and adjusted to device type and patient comorbidities is therefore warranted. To provide advanced understanding of hemostatic disturbances during MCS, prospective trials focused on bleeding and thromboembolic events as primary endpoints should be conducted. Better understanding of the underlying pathophysiology and a shift towards a personalized approach based on functional point-of-care hemostatic properties assessment may provide more favorable clinical outcomes. This should, however, be coupled with further technological improvements providing better device surface hemocompatibility as interaction between blood and device surface affects the hemostatic equilibrium.

Impella 5.5 Versus Centrimag: A Head-to-Head Comparison of Device Hemocompatibility

“…MCS and ECMO systems are associated with a decrease of platelet count not related to heparin administration. 33 , 34 Thrombocytopenia requiring platelet transfusion was also noted in patients supported with Impella systems. 35 , 36 Therefore, we examined whether Impella 5.5 and Centrimag induce alteration of platelet number and generation of MPs; in addition, the surface marker phenotype of generated MPs was analyzed.…”

“…Along with the shear-compromised platelet count and function, acquired deficiency of vWF is another well-recognized contributor to the etiology of MCS-related bleeding complications. 21 , 22 , 34 Therefore, we have analyzed the effect of shear stress generated by the Impella 5.5 and Centrimag on plasma levels of vWF:Ag and its collagen binding as indicators of intact vWF structure and function. We observed no significant decrease of vWF antigen concentration over the shear exposure time, rather a slight increase of vWF was noted at 180 minutes of recirculation for Centrimag.…”

Complications of Temporary Percutaneous Mechanical Circulatory Support for Cardiogenic Shock: An Appraisal of Contemporary Literature

“…This may be linked to the need for trans-septal puncture, as well as higher index of comorbidity in patients receiving TandemHeart. Rates of major bleeding in VA-ECMO have the most variability, ranging from 5 to 81% [67]. In a meta-analysis of nearly 1900 patients receiving VA-ECMO, Cheng et al noted major bleeding in 41% (95% confidence interval 27–57%) and the need for re-thoracotomy for major bleeding or tamponade in 42% of all recipients [25].…”

“…The mechanisms for bleeding include blood loss in the device circuit, need for anticoagulation, access-site issues, hemolysis due to mechanical strain, thrombocytopenia, acquired von Willebrand syndrome and high shear stress on the circulating blood [25, 67]. Typical sites for hemorrhage (beside access site) include the pulmonary and neurological systems [68, 69].…”

Multivariate Analysis of Risk Factor for Mortality and Feasibility of Extracorporeal Membrane Oxygenation in High-Risk Thoracic Surgery

“… 22) Second, newer circulatory systems utilizing heparin-bonded catheters, low-pressure oxygenators, and centrifugal pumps allow for the use of less anticoagulant during ECMO without circuit thrombotic complications. 23) Third, most thromboses occur at sites of stasis or turbulent flow in the circuit, that is, on the venous (pre-oxygenator) side of the circuit rather than on the arterial (post-oxygenator) side. 24 , 25) We performed ECMO intraoperatively without heparin except a loading dose during elective ECMO insertion to reduce bleeding due to anticoagulation use.…”