Increased Plasma‐Free Hemoglobin Levels Identify Hemolysis in Patients With Cardiogenic Shock and a Trans valvular Micro‐Axial Flow Pump

Abstract

Hemolysis is a potential limitation of percutaneously delivered left-sided mechanical circulatory support pumps, including trans valvular micro-axial flow pumps (TVP). Hemolytic biomarkers among durable left ventricular assist devices include lactate dehydrogenase (LDH) >2.5 times the upper limit of normal (ULN) and plasma-free hemoglobin (pf-Hb) >20 mg/dL. We examined the predictive value of these markers among patients with cardiogenic shock (CS) receiving a TVP. We retrospectively studied records of 116 consecutive patients receiving an Impella TVP at our institution between 2012 and 2017 for CS. Twenty-three met inclusion/exclusion criteria, and had sufficient pf-Hb data for analysis. Area under receiver-operator characteristic (ROC) curve for diagnosing hemolysis were calculated. Mean age was 62 ± 14 years and ejection fraction was 15 ± 5%. Mean duration of support was 5.4 ± 3.5 days. Pre-device LDH levels were >2.5x ULN in 71% (n = 5/7) of 5.0 and 29% of CP patients, while pre-device pf-Hb levels were >20 mg/dL in 14% (n = 1/7) of 5.0 and 25% (n = 4/16) of CP patients. Given elevated baseline LDH and pf-Hb levels, we defined hemolysis as a pf-Hb level >40 mg/dL within 72 h post-implant plus clinical evidence of device-related hemolysis. We identified that 30% (n = 7/23) had device-related hemolysis. Using ROC curve-derived cut-points, an increase in delta pf-Hb by >27mg/dL, not delta LDH, within 24 h after TVP implant (delta pf-Hb: C-statistic = 0.79, sensitivity: 57%, specificity: 93%, p <0.05) was highly predictive of hemolysis. In conclusion, we identified a change in pf-Hb, not LDH, levels is highly sensitive and specific for hemolysis in patients treated with a TVP for CS.

Direct bridging to cardiac transplantation with the surgically implanted Impella 5.0 device

“…The complications that are encountered with ongoing Impella 5.0 support are well documented and include peripheral or central arterial injury, limb ischemia, injury to the aortic valve, left ventricle or mitral subvalvular apparatus, functional mitral regurgitation, bleeding, cerebrovascular accidents (CVA), hemolytic anemia, and device failure or thrombosis . While some of these complications such as hemolysis can be attenuated by optimizing the patient's volume status and device parameters, others may be more challenging to modify and negatively impact quality of life, survival, and ability to bridge to OHT . Although reflective of nationwide practice, the current reported experience with utilizing the Impella 5.0 device as a bridge to OHT is modest in numbers with many reports limited to case reports or small cohorts, even in studies that compile multicenter data …”

Cardiac prostheses‐related hemolytic anemia

“…In the Interagency for Mechanically Assisted Circulatory Support registry, hemolysis is diagnosed when pFH exceeds 40 mg/dL. 46 The utility of pFH in diagnosing and monitoring hemolysis in patients with pLVAD and in those with PVL has also been suggested in several studies . Indeed, pFH was superior to LDH in detecting hemolysis in patients with cardiogenic shock treated with the Impella micro‐axial pump .…”

“…46 The utility of pFH in diagnosing and monitoring hemolysis in patients with pLVAD and in those with PVL has also been suggested in several studies . Indeed, pFH was superior to LDH in detecting hemolysis in patients with cardiogenic shock treated with the Impella micro‐axial pump . However, pFH is not widely used in this setting due to the dearth of supportive data and the frequent need to send out to a reference lab.…”

“…44 Mild hemolysis occurs in 10% to 30% of patients who receive short-term percutaneous LVAD support with the Impella device (Abiomed Inc., Danvers, Massachusetts). [47][48][49] However, the incidence increases to 60% with device indwelling times >6 hours. 6 In a study of patients undergoing veno-arterial extracorporeal membrane oxygenation, concomitant Impella use was associated with higher incidence of hemolysis (76% vs 33%, P = .004).…”

Transaxillary Impella support: Bridging the gap of powerful left ventricular support

“…Of the major technological advancements during this time, the improved design and applicability of mechanical circulatory support and the expanding clinical knowledge of these devices have had a direct impact on patient care . Among these devices, the Impella axial flow pump (Abiomed, Danvers, MA, USA) is unique because it is inserted into the left ventricle (LV) and expels blood into the aorta, thereby unloading the LV . Impella devices include the Impella 2.5, Impella CP, and Impella 5.0.…”