Mitigation effect of cell exclusion on blood damage in spiral groove bearings.

Cell exclusion in spiral groove bearing (SGB) excludes red blood cells from high shear regions in the bearing gaps and potentially reduce haemolysis in rotary blood pumps. However, this mechanobiological phenomenon has been observed in ultra-low blood haematocrit only, whether it can mitigate blood damage in a clinically-relevant blood haematocrit remains unknown. This study examined whether cell exclusion in a SGB alters haemolysis and/or high-molecular-weight von Willebrand factor (HMW vWF) multimer degradation.

Extracorporeal Membrane Oxygenation-Induced Hemolysis: An In Vitro Study to Appraise Causative Factors.

In vitro hemolysis testing is commonly used to determine hemocompatibility of ExtraCorporeal Membrane Oxygenation (ECMO). However, poor reproducibility remains a challenging problem, due to several unidentified influencing factors. The present study investigated potential factors, such as flow rates, the use of anticoagulants, and gender of blood donors, which could play a role in hemolysis.

Ex vivo assessment of erythrocyte tolerance to the HeartWare ventricular assist device operated in three discrete configurations.

Despite technological advances in ventricular assist devices (VADs) to treat end-stage heart failure, hemocompatibility remains a constant concern, with supraphysiological shear stresses an unavoidable reality with clinical use. Given that impeller rotational speed is related to the instantaneous shear within the pump housing, it is plausible that the modulation of pump speed may regulate peak mechanical shear stresses and thus ameliorate blood damage. The present study investigated the hemocompatibility of the HeartWare HVAD in three configurations typical of clinical applications: standard systemic support left VAD (LVAD), pediatric support LVAD, and pulmonary support right VAD (RVAD) conditions.

Shear-dependent platelet aggregation size.

Nonsurgical bleeding is the most frequent complication of left ventricular assist device (LVAD) support. Supraphysiologic shear rates generated in LVAD causes impaired platelet aggregation, which increases the risk of bleeding. The effect of shear rate on the formation size of platelet aggregates has never been reported experimentally, although platelet aggregation size can be considered to be directly relevant to bleeding complications.

Effect of ex vivo extracorporeal membrane oxygenation flow dynamics on immune response.

Background: Extracorporeal membrane oxygenation is a life-saving support for heart and/or lung failure patients. Despite technological advancement, abnormal physiology persists and has been associated with subsequent adverse events. These include thrombosis, bleeding, systemic inflammatory response syndrome and infection.

In Vitro Hemocompatibility Evaluation of Ventricular Assist Devices in Pediatric Flow Conditions: A Benchmark Study.

Development of pediatric ventricular assist devices (VADs) has significantly lagged behind that of adult devices. This frustrating reality is reflected by the fact that the Berlin Heart EXCOR VAD is currently the only approved pediatric-specific device in the USA. An alternative option is an off-label use of adult continuous-flow VADs, such as HeartMate II (HMII), which inevitably causes patient-device size mismatch in small children.

The effect of shear stress on the size, structure, and function of human von Willebrand factor.

Clinical outcomes from ventricular assist devices (VADs) have improved significantly during recent decades, but bleeding episodes remain a common complication of long-term VAD usage. Greater understanding of the effect of the shear stress in the VAD on platelet aggregation, which is influenced by the functional activity of high molecular weight (HMW) von Willebrand factor (vWF), could provide insight into these bleeding complications. However, because VAD shear rates are difficult to assess, there is a need for a model that enables controlled shear rates to first establish the relationship between shear rates and vWF damage.