Enhanced Hemocompatibility via Bivalirudin and Bicarbonate as Alternative to Heparin in a Catheter‐Based Axial‐Flow System

Figures

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  Figure 1. Circulatory loop design with Impella 5.5. Porcine whole blood was loaded into circulatory loop and circulated with Impella 5.5 for 4 h. Blood temperature was maintained at 37°C in a water bath and pressure across pump maintained at 60 mmHg via clamps and pressure sensors at syringe ports. [Color figure can be viewed at wileyonlinelibrary.com]

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  Figure 2. Plasma free hemoglobin and particle count. Porcine whole blood was collected from noncirculating (“Rest”) samples and from samples circulated with Impella5.5 using sodium bicarbonate (25 mEq/L in D5W) or heparin (25 IU/mL in D5W) purge solution. Pigs were anticoagulated with either heparin (100 IU/kg; “Heparin−Sodium Bicarb”) or bivalirudin (0.75 mg/kg; “Bivalirudin−Sodium Bicarb”) before blood collection and circulation. Blood samples were collected and analyzed for (A) plasma‐free hemoglobin and processed for (B) platelet‐sized (2–4 µm) particle count. All data are offset from t = 5 min measurements to better compare between experiment conditions at each time point. Values are reported as mean ± standard deviation. Data were collected and pooled from N = 10 pigs; *p < 0.05 between “Rest” and “Heparin−Heparin”; #p < 0.05 between “Rest” and “Heparin−Sodium Bicarb.” [Color figure can be viewed at wileyonlinelibrary.com]

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  Figure 3. Platelet surface P‐selectin and phosphatidylserine exposure and plasma β‐thromboglobulin. Porcine blood samples were collected and processed into fixed platelet rich plasma for flow cytometry with fluorescent labeled (A) P‐selectin (CD62P) and (B) phosphatidylserine exposure via Annexin V binding. Platelet poor plasma samples were simultaneously collected and measured for (C) free β‐thromboglobulin using ELISA. All data are offset from t = 5 min measurements to better compare between experiment conditions at each time point. Values are reported as mean ± standard error. Data were collected and pooled from N = 10 pigs. [Color figure can be viewed at wileyonlinelibrary.com]

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  Figure 4. Platelet‐derived microparticle (PDMP) quantification and surface P‐selectin and phosphatidylserine exposure. Porcine blood samples were collected and processed into fixed platelet‐rich plasma for flow cytometry. Forward and back scatter gates were placed to distinguish platelets from microparticles as a percentage of total particles counted (A). Particles and PDMPs were stained with fluorescent‐labeled (B) P‐selectin (CD62P) and (B) phosphatidylserine exposure via Annexin V binding. All data were offset from t = 5 min measurements to better compare between experiment conditions at each time point. Values are reported as mean ± standard deviation. Data were collected and pooled from N = 10 pigs; *p < 0.05 between “Rest” and “Heparin−Heparin.” [Color figure can be viewed at wileyonlinelibrary.com]

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  Figure 5. Von Willebrand factor collagen binding activity. Porcine blood samples were collected and processed into platelet poor plasma. Plasma was measured in modified ELISA to quantify (A) collagen binding activity (CBA). Samples were further analyzed via immunoturbidometric assay to quantify vWF antigen (Ag). Collagen binding activity was quantitatively adjusted by vWF antigen concentration and reported as (B) vWF:AG/CBA Ratio. All data are offset from t = 5 min measurements to better compare between experiment conditions at each time point. Values are reported as mean ± standard deviation. Data were collected and pooled from N = 10 pigs; *p < 0.05 between “Rest” and “Heparin−Heparin”; #p < 0.05 between “Rest” and “Heparin−Sodium Bicarb; °p < 0.05 between “Rest” and “Bivalirudin−Sodium Bicarb.” [Color figure can be viewed at wileyonlinelibrary.com]