## 1 Introduction  
Heart failure is a constantly increasing health problem (e.g., 6.5 million people in the U.S. alone [1]) that is associated with high morbidity and mortality. Despite advances in medicine and surgical treatment, it is estimated that more than 40% of patients diagnosed with heart failure will die within five years [1; 2; 3; 4]. Importantly, heart transplantation is considered the best treatment option in patients with advanced heart failure [5]. However, transplantation raises some difficulties, which are related to the lack of donors (e.g., 5500 in 2020 [6]). Further problems are the high costs (e.g., estimated USD 69.8 billion in 2030 [7]) and the large number of patients waiting for heart transplantation [8; 9; 10; 11]. Additional problems include organ rejection and mortality rates [12], where it is estimated that the one-year survival rate is around 50% [13] for stage D heart failure. It should also be mentioned that stage D refers to patients with end-stage heart failure in the ABCD classification according to the American College of Cardiology [14]. If, for the above reasons, heart transplantation is not possible and other conservative treatments are unsuccessful to prevent further deterioration, mechanical circulatory support in the form of artificial blood pumps should be considered. Such devices in the form of left ventricular assist devices (LVADs) are used for both short-term and destination therapy. Moreover, LVAD is considered to be an effective therapeutic approach as a bridge to heart transplantation [15; 16] even for patients with stage D (end-stage) heart failure. It is important that LVADs are also being used for destination therapy [17]. Among the many well-known solutions are, for example, intra-aortic balloon pumps, IMPELLA\({}^{\text{\text{\textregistered}}}\)[18], VA ECMO (e.g., [19; 20]), POLVAD [21], Levitronix [22], CentriMag\({}^{\text{\text{\textregistered}}}\)[23], TandemHearart\({}^{\text{\text{\textregistered}}}\)[24], HeartMate 3\({}^{\text{\text{\textregistered}}}\)[23], and HeartWare\({}^{\text{\text{\textregistered}}}\)[25]. However, it should be noted that the devices currently available are used for temporary support of the ailing heart. This means that they are intended for patients during hospitalization and not for outpatient applications. Exceptions include HeartMate 3\({}^{\text{\text{\textregistered}}}\) and HeartWare\({}^{\text{\text{\textregistered}}}\), which allow patients to return home as long as close monitoring and batteries are not an issue. Artificial blood pumps have been steadily developed over the past few decades, beginning in the 1960s, replacing cardiopulmonary bypass circuits [26]. This has led to increased survival rates for patients with advanced heart failure [27]. For instance, patients receiving HeartMate 2\({}^{\text{\text{\textregistered}}}\) demonstrated an 85% survival rate at one year [28]. In general, we can distinguish two main types of LVAD: pulsatile and continuous flow devices. Until 2009, the former pumps were common, whereas since 2010, the latter devices have been used almost exclusively [29; 30; 31]. Furthermore, the first pulsatile pumps mimicked the cyclic action of the heart by means of artificial heart valves and diaphragms, resulting in their large size and weight, as well as noise. On the other hand, continuous flow devices are smaller, less noisy, and permit patient mobility. These pumps can be divided into axial [32; 33] and centrifugal, where axial pumps are much smaller. In order to achieve the required pressure increments, axial pumps require significant angular velocities [34], which leads to unfavorable phenomena, i.e., thrombosis (blood clot formation at the blood-pump contact surface) [2; 35] and hemolysis [36; 37] phenomena. What is more, thrombosis may occur in any component of the pump and may lead, for instance, to higher power consumption.