Goodman, Daniel

AbstractOver the last half‐century, left ventricular assist device (LVAD) technology has progressed from conceptual therapy for failed cardiopulmonary bypass weaning to an accepted destination therapy for advanced heart failure. The history of LVAD engineering is defined by an initial development phase, which demonstrated the feasibility of such an approach, to the more recent three major generations of commercial devices. In this review, we explore the engineering challenges of LVADs, how they were addressed over time, and the clinical outcomes that resulted from each major technological development. The first generation of commercial LVADs were pulsatile devices, which lacked the appropriate durability due to their number of moving components and hemocompatibility. The second generation of LVADs was defined by replacement of complex, pulsatile pumps with primarily axial, continuous‐flow systems with an impeller in the blood passageway. These devices experienced significant commercial success, but the presence of excessive trauma to the blood and in‐situ bearing resulted in an unacceptable burden of adverse events. Third generation centrifugal‐flow pumps use magnetically suspended rotors within the pump chamber. Superior outcomes with this newest generation of devices have been observed, particularly with respect to hemocompatibility‐related adverse events including pump thrombosis, with fully magnetically levitated devices. The future of LVAD engineering includes wireless charging foregoing percutaneous drivelines and more advanced pump control mechanisms, including synchronization of the pump flow with the native cardiac cycle, and varying pump output based on degree of physical exertion using sensor or advanced device‐level data triggers.

Abstract Background Lactate hydrogenase (LDH) is a common biomarker utilized in the detection and monitoring of left ventricular assist device (LVAD) hemolysis and thrombosis. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) are common laboratory tests that can be used to calculate the De Ritis ratio and the De Ritis adjusted AST. Methods A retrospective review of LVAD patients was performed to identify three cohorts of patients: those with confirmed pump thrombosis after device exchange, those with LVAD‐related hemolysis who were medically managed without pump exchange, and those who did not meet these criteria and served as the control cohort. Evaluation of AST, AST/ALT ratio (referred to as the De Ritis ratio) as well as AST x (AST/ALT) or the De Ritis‐adjusted AST (DRA) was performed. Results There were 29 patients who underwent device exchange for thrombosis, 25 patients who were diagnosed with hemolysis and treated medically (clopidogrel ( N = 6), heparin ( N = 13), tirofiban ( N = 8), eptifibatide ( N = 2), and some received more than one of these treatments), and 425 control patients. A qualitatively comparable relative and absolute rise in DRA and LDH were found in both surgically managed pump thrombosis and suspected device‐related hemolysis. Conclusions Both AST and LDH as well DRA are significantly associated with pump thrombosis ( p < 0.0001 for each). DRA is a potential screening biomarker for hemolysis and device thrombosis in stable left ventricular assist device patients.