Does Red Blood Cell Fragility Predict the Degree of Post-LVAD Hemolysis?

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• 作者：J.L. Madden¹ ; S.G. Drakos² ; J. Stehlik² ; S.H. McKellar¹ ; M.T. Rondina³ ; A.S. Weyrich⁴ ; C.H. Selzman¹
• 刊名：The Journal of Heart and Lung Transplantation
• 出版年：2013
• 出版时间：April, 2013
• 年：2013
• 卷：32
• 期：4_supp_S
• 页码：S273
• 全文大小：115 K

文摘

Purpose

Continuous-flow LVADs subject elements of the blood to significant shear stress. The balance between hemostasis and thrombosis that challenge all LVAD patients is potentially impacted by the development and high-prevalence of both sub-clinical and clinical hemolysis. Lactate dehydrogenase (LDH) is a readily available marker of hemolysis and can vary significantly between supported patients. While different types of pumps (centrifugal versus rotary) might affect rates of hemolysis, we sought to determine if a patient¡¯s baseline red cell fragility influences their hemolytic response to LVAD support.

Methods and Materials

Osmotic fragility assesses the degree of red blood cell hemolysis under varying degrees of osmotic stress. Assays were prospectively obtained on 50 consecutive patients prior to placement of continuous flow LVADs. Five patients were excluded as they were already on circulatory support. LDH was obtained post-operatively at 3-5 weeks or at discharge.

Results

The mean age was 60.2 yrs, 86.6 % were male, and 46.6 % were nonischemic. Patients were supported with the Jarvik 2000 (n=5), HeartWare (n=6), and HeartMate II (n=34). The mean LDH was 714 (¡À324) and there was no difference among devices. A scatter plot did not reveal any relationship between pre-op osmotic fragility and post-op LDH. Mean hemolysis was 15.68 ¡À 12.96 % at 0.45 % NaCL (the inflection point of the osmotic fragility hemolysis curve). Linear regression confirmed no predictive relationship (p=0.71).

Conclusions

Pre-op variations in osmotic fragility do not appear to account for differences in hemolysis following VAD placement. Shear forces across existing LVADs create similar levels of biochemical hemolysis, as assessed by LDH, despite baseline differences in a patient¡¯s red cell fragility.