Development of Mechanical Circulatory Support Devices: 55 Years and Counting

Heart failure is a leading cause of morbidity and mortality in the United States. Treatment of this condition increasingly involves mechanical circulatory support devices. Even with optimal medical therapy and use of simple cardiac devices, heart failure often leads to reduced quality of life and a shortened life span, prompting exploration of more advanced treatment approaches. Left ventricular assist devices constitute an effective alternative to cardiac transplantation. These devices are not without complications, however, and their use requires careful cooperative management by the patient’s cardiology team and primary care provider. Left ventricular assist devices have undergone many technological advancements since they were first introduced, and they will continue to evolve. This article reviews the history of different types of left ventricular assist devices, appropriate patient selection, and common complications in order to increase health professionals’ familiarity with these treatment options.

The influence of surface roughness on the damage of von Willebrand Factor under shear flow condition

Despite technological advances in mechanical circulatory support devices to treat end-stage heart failure, blood damage induced by non-physiological shear stress in operation often triggered clinical hemocompatibility complications. The loss of high molecular weight von Willebrand Factor (HMW-VWF) has been considered as an essential cause of gastrointestinal bleeding. In addition to the mechanics factors, interface factors may also affect blood damage, especially the surface characteristics. In this study, the effect of surface roughness on VWF damage under flow condition was investigated. A roller pump circulation experimental platform with a roughness embedded sample chamber was constructed to provide blood shearing flow condition. VWF molecular weight analysis, VWF antigen (VWF-Ag) concentration assay, and VWF ristocetin cofactor activity (VWF-Rico) assay were performed on the sheared blood samples. These variables are the main functional indicators of VWF. It was found that the surface roughness induced VWF damage is mainly caused by the loss of HMW-VWF rather than reducing the total amount of VWF. The threshold value of surface roughness for a rapid increase in the degradation of HMW-VWF under low flow rate was obtained between Ra 0.4 and 0.6 μm, which was smaller than the threshold for hemolysis. Our findings indicated that VWF is more sensitive to the interface factor of surface roughness than red blood cells, thus has a higher requirement for blood pump design. It could provide reference for the material design and processing in developing mechanical circulatory support devices.

Current Landscape of Temporary Percutaneous Mechanical Circulatory Support Technology

Mechanical circulatory support devices provide hemodynamic support to patients who present with cardiogenic shock. These devices work using different mechanisms to provide univentricular or biventricular support. There is a growing body of evidence supporting use of these devices as a goal for cardiac recovery or as a bridge to definitive therapy, but definitive, well-powered studies are still needed. Mechanical circulatory support devices are increasingly used using shock team and protocols, which can help clinicians in decision making, balancing operator and institutional experience and expertise. The aim of this article is to review commercially available mechanical circulatory support devices, their profiles and mechanisms of action, and the evidence available regarding their use.

Racial disparities in the use of mechanical circulatory support devices in cardiogenic shock

Background Racial bias has always been a concern for healthcare. Lack of guideline directed utilization of mechanical circulatory support (MCS) devices in cardiogenic shock (CS) may lead to implicit and racial bias. Purpose To identify the racial differences in the use of mechanical circulatory support in cardiogenic shock and its association with outcomes. Methods National Inpatient Database from 2015–2018 using ICD 10 codes was used. Patients >18 years of age admitted for cariogenic shock were included. Results Among 1,021,274 patients hospitalized for cardiogenic shock, overall MCS was utilized in 11.4% (N=116,539). Use of MCS for patients stratified by race was 12.2% white (N=85543), 8% Blacks (N=14688), 11.3% Hispanics (N=11067), 13.8% Asian (N=4417), 12.3% Native American (N=825). IABP was the most commonly used MCS device, followed by Impella, ECMO and LVAD. Overall odds of MCS insertion was significantly higher in white population [1.18 (1.13–1.23) <0.001] and significantly lower in Blacks [0.65 (0.61–0.69) <0.001] and Hispanics [0.89 (0.83–0.97) 0.004]. Among black patients with CS requiring MCS, odds of LVAD insertion were similar compared to other races [1.03 (0.89–1.19) 0.714], while odds of all other types of MCS devices including ECMO [0.83 (0.72–0.95) 0.009], IABP [0.63 (0.59–0.68) <0.001] and Impella [0.61 (0.54–0.70) <0.001] were significantly lower compared to other races. This trend also holds true for patients with CS associated with acute myocardial infarction. Among all patients with CS, the odds of mortality were significantly lower among white patients [0.92 (0.90–0.95) <0.001], on the contrary, odds of mortality were significantly higher in Blacks [1.06 (1.02–1.10) 0.001] and Asians [1.11 (1.02–1.20) 0.012]. Interestingly, when only comparing patients who underwent MCS utilization for CS, odds of mortality were similar in black population compared to other races. [1.03 (0.91–1.17) 0.636]. Conclusion(s) There still exist significant racial differences in the use of mechanical circulatory devices for cardiogenic shock potentially leading to significantly higher mortality in black population compared to whites. This difference in mortality is mitigated with equal use of MCS devices in cardiogenic shock among all races. FUNDunding Acknowledgement Type of funding sources: None.

Lingua Franca of Cardiogenic Shock: Speaking the Same Language

Cardiogenic shock has remained a vexing clinical problem over the last 20 years despite progressive development of increasingly capable percutaneous mechanical circulatory support devices. It is increasingly clear that the published trials of various percutaneous mechanical circulatory support devices have compared heterogenous populations of cardiogenic shock patients, and therefore have not yielded a single result where one approach improved survival. To classify patients, various risk scores such as the CARDSHOCK and IABP-Shock-II scores have been developed and validated but they have not been broadly applied. The Society for Cardiac Angiography and Intervention Expert Consensus on Classification of Cardiogenic Shock has been widely studied since its publication in 2019, and is reviewed at length. In particular, there have been numerous validation studies done and these are reviewed. Finally, the directions for future research are reviewed.