The Effect of Impeller Position on CFD Calculations of Blood Flow in Magnetically Levitated Centrifugal Blood Pumps

2010 ◽  
Author(s):  
Katharine H. Fraser ◽  
M. Ertan Taskin ◽  
Tao Zhang ◽  
J. Scott Richardson ◽  
Barry Gellman ◽  
...  
Keyword(s):  
Cardiovascular Disease ◽  
The United States ◽  
Lifestyle Changes ◽  
Circulatory Support ◽  
Ventricular Assist ◽  
Bridge To Transplant ◽  
Mechanical Circulatory Support Devices ◽  
The Right ◽  
End Stage ◽  
Transcatheter Interventions

Cardiovascular disease is the leading cause of mortality globally. Among various forms of cardiovascular disease, heart failure (HF) affects 5.7 million patients in the United States with about 670,000 new patients diagnosed for the first time annually (1). The fatality rate for HF is high, with one in five people dying within 1 year (1). The number of deaths has increased (1) despite advances in surgical treatment and new pharmaceutical therapies. Many therapies are available to treat patients with HF, including lifestyle changes, medications, transcatheter interventions and surgery. However, despite optimal medical and surgical therapies, some patients still do not improve and the available therapies fail to control their symptoms; for them, cardiac transplantation may be the only treatment option. However, only approximately 2300 donor hearts become available each year resulting in around 2200 transplants (1), or only about 6% of the estimated 35,000 US patients who would benefit from a heart actually receiving a transplant. To address the need to support the circulation in patients with end-stage HF a wide variety of mechanical circulatory support devices (MCSDs) have been developed over the past four decades. These MCSDs have been developed as a bridge to transplant, a bridge to recovery, and as an end stage treatment. They can be implanted as a ventricular assist device (VAD) to support the left ventricle (LVAD) or the right ventricle (RVAD) or two devices are used to support both left and right ventricles (Bi-VAD).

Differences in Shear Stress, Residence Time and Estimates of Hemolysis Between Different Ventricular Assist Devices

2011 ◽  
Author(s):  
Katharine H. Fraser ◽  
Tao Zhang ◽  
Bartley P. Griffith ◽  
Zhongjun J. Wu
Keyword(s):  
Cardiovascular Disease ◽  
Mechanical Circulatory Support ◽  
Ventricular Assist Devices ◽  
Circulatory Support ◽  
Ventricular Assist ◽  
The Past ◽  
The Us ◽  
Mechanical Circulatory Support Devices ◽  
End Stage ◽  
Support Devices

Cardiovascular disease is the leading cause of mortality globally. Among various forms of cardiovascular disease, heart failure (HF) affects 5.7 million patients in the United States1. Despite optimal treatment, some patients still do not improve and the available therapies fail to control their symptoms; for them, cardiac transplantation may be the only option. However, only around 2200 transplants are performed in the US each year1, or only about 6% of the estimated 35,000 US patients who would benefit actually receive a heart. To address the need to support the circulation in patients with end-stage HF a wide variety of mechanical circulatory support devices (MCSDs) have been developed over the past four decades.

Comparative Studies of Axial Ventricular Assist Devices (VAD) and the Effect of Outflow Cannulation

2013 ◽  
Author(s):  
Wei-Che Chiu ◽  
Yared Alemu ◽  
Bryan Lynch ◽  
Shmuel Einav ◽  
Marvin Slepian ◽  
...  
Keyword(s):  
Heart Failure ◽  
The United States ◽  
Ventricular Assist Devices ◽  
Circulatory Support ◽  
Ventricular Assist ◽  
Assist Devices ◽  
High Incidence ◽  
Mechanical Circulatory Support Devices ◽  
Compact Design ◽  
Blood Flow Patterns

Congestive heart failure has reached epidemic proportions in the United States with more than 5.7 million patients suffering from it annually ( 1). Due to the limited availability of donor hearts, patients in their late stage heart failure who may require cardiac transplantation are dying while waiting for a matched heart. Mechanical circulatory support devices (MCS), such as ventricular assist devices (VAD), are utilized as a bridge to transplantation, and recently as destination therapy for extending the life of these patients. Continuous-flow VAD offer a surgical advantage over older generation pulsatile-flow VAD due to their compact design; however, due to the high RPM these VADs are operated with and the non-physiological blood flow patterns they generates, VADs are burdened with high incidence of thromboembolic events, and antiplatelet/anticoagulation regimens are mandated for the device recipients.

scholarly journals Hybrid membranes for the production of blood contacting surfaces: physicochemical, structural and biomechanical characterization

2021 ◽  
Vol 25 (1) ◽  
Author(s):  
Martina Todesco ◽  
Carlo Zardin ◽  
Laura Iop ◽  
Tiziana Palmosi ◽  
Pietro Capaldo ◽  
...  
Keyword(s):  
Artificial Heart ◽  
Point Of View ◽  
Total Artificial Heart ◽  
Circulatory Support ◽  
Hybrid Membranes ◽  
Ventricular Assist ◽  
Actuation System ◽  
Mechanical Circulatory Support Devices ◽  
End Stage ◽  
Porcine Pericardium

Abstract Background Due to the shortage of organs’ donors that limits biological heart transplantations, mechanical circulatory supports can be implanted in case of refractory end-stage heart failure to replace partially (Ventricular Assist Device, VAD) or completely (Total Artificial Heart, TAH) the cardiac function. The hemocompatibility of mechanical circulatory supports is a fundamental issue that has not yet been fully matched; it mostly depends on the nature of blood-contacting surfaces. Methods In order to obtain hemocompatible materials, a pool of hybrid membranes was fabricated by coupling a synthetic polymer (polycarbonate urethane, commercially available in two formulations) with a decellularized biological tissue (porcine pericardium). To test their potential suitability as candidate materials for realizing the blood-contacting surfaces of a novel artificial heart, hybrid membranes have been preliminarily characterized in terms of physicochemical, structural and mechanical properties. Results Our results ascertained that the hybrid membranes are properly stratified, thus allowing to expose their biological side to blood and their polymeric surface to the actuation system of the intended device. From the biomechanical point of view, the hybrid membranes can withstand deformations up to more than 70 % and stresses up to around 8 MPa. Conclusions The hybrid membranes are suitable for the construction of the ventricular chambers of innovative mechanical circulatory support devices.

scholarly journals In Full Flow: Left Ventricular Assist Device Infections in the Modern Era

2020 ◽  
Vol 7 (5) ◽  
Author(s):  
Radoslav Zinoviev ◽  
Christopher K Lippincott ◽  
Sara C Keller ◽  
Nisha A Gilotra
Keyword(s):  
The United States ◽  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
Circulatory Support ◽  
Left Ventricular Assist Devices ◽  
Ventricular Assist ◽  
External Power Source ◽  
Left Ventricular Assist ◽  
Improved Design ◽  
End Stage

Abstract With the rising prevalence of heart disease in the United States, there is increasing reliance on durable mechanical circulatory support (MCS) to treat patients with end-stage heart failure. Left ventricular assist devices (LVADs), the most common form of durable MCS, are implanted mechanical pumps that connect to an external power source through a transcutaneous driveline. First-generation LVADs were bulky, pulsatile pumps that were frequently complicated by infection. Second-generation LVADs have an improved design, though infection remains a common and serious complication due to the inherent nature of implanted MCS. Infections can affect any component of the LVAD, with driveline infections being the most common. LVAD infections carry significant morbidity and mortality for LVAD patients. Therefore, it is paramount for the multidisciplinary team of clinicians caring for these patients to be familiar with this complication. We review the epidemiology, prevention, diagnosis, treatment, and outcomes of LVAD infections.

In Vitro Evaluation of Shear-Induced Platelet Activation in the MicroMed DeBakey Ventricular Assist Device With Antiplatelet Therapy

2013 ◽  
Author(s):  
Jawaad Sheriff ◽  
Gaurav Girdhar ◽  
Sheela George ◽  
Wei-Che Chiu ◽  
Bryan E. Lynch ◽  
...  
Keyword(s):  
Platelet Activation ◽  
Thrombus Formation ◽  
Optimization Techniques ◽  
Ventricular Assist Devices ◽  
Circulatory Support ◽  
Ventricular Assist ◽  
Bridge To Transplant ◽  
Thrombotic Complications ◽  
End Stage

Mechanical circulatory support (MCS) devices, which include ventricular assist devices (VADs), offer an attractive solution to approximately 35,000 end-stage heart failure patients eligible for transplants, of which only 2,000–2,300 are performed annually [1]. These devices are employed to augment the function of the ailing left and/or right ventricle and serve as bridge-to-transplant or destination therapy, but are often accompanied by thrombotic complications. Pathologic flow patterns are characteristic of VADs and increase susceptibility to shear-induced platelet activation, which leads to thrombus formation [2]. Patients implanted with such devices are routinely prescribed antiplatelets to tackle these complications. Despite this concurrent therapy, thromboembolic incident rates of 0.9–13% are reported for the widely-implanted Thoratec HeartMate II and MicroMed DeBakey VADs [3, 4]. This has spurred the development of design optimization techniques to lower or eliminate the incidence of thrombosis and reduce the dependence on pharmacotherapy management.

Development of Mechanical Circulatory Support Devices: 55 Years and Counting

2021 ◽  
Vol 32 (4) ◽  
pp. 424-433
Author(s):  
Emalie Petersen
Keyword(s):  
Mechanical Circulatory Support ◽  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
Circulatory Support ◽  
Left Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Assist Devices ◽  
Left Ventricular Assist ◽  
Mechanical Circulatory Support Devices ◽  
Support Devices

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.

Design Optimization of a Mechanical Heart Valve for Reducing Valve Thrombogenicity: A Case Study With ATS Valve

2010 ◽  
Author(s):  
Gaurav Girdhar ◽  
Yared Alemu ◽  
Michalis Xenos ◽  
Jawaad Sheriff ◽  
Jolyon Jesty ◽  
...  
Keyword(s):  
Heart Valves ◽  
Thrombus Formation ◽  
Anticoagulation Therapy ◽  
Mechanical Heart Valve ◽  
Ventricular Assist Devices ◽  
Circulatory Support ◽  
Ventricular Assist ◽  
Mechanical Circulatory Support Devices ◽  
Artificial Hearts

Flow past mechanical heart valves (MHV) in mechanical circulatory support devices including total artificial hearts and ventricular assist devices, is primarily implicated in thromboembolism due to non-physiological flow conditions where the elevated stresses and exposure times are sufficiently high to cause platelet activation and thrombus formation. Mitigation of this risk requires lifelong anticoagulation therapy and less thrombogenic MHV designs should therefore be developed by device manufacturers [1].

Abstract 15253: A Paradoxical Rise in Serum Copeptin After Non-Pulsatile LVAD: a New SIADH?

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Cara M Statz ◽  
Aleksandra M Ras ◽  
Kevin D Ballard ◽  
Jason A Gluck ◽  
Detlef Wencker
Keyword(s):  
Surrogate Marker ◽  
Left Ventricular ◽  
Serum Samples ◽  
Ventricular Assist ◽  
Bridge To Transplant ◽  
Left Ventricular Assist ◽  
End Stage ◽  
A Prospective Study

Introduction: Hyponatremia (Na< 136 mmol/L) is prevalent (~28%) among hospitalized heart failure (HF) patients and a marker of advanced/end-stage HF(AHF) with increased mortality. Treatment of hyponatremia has no survival benefit in this population. In a prospective study of AHF patients, we sought to define the prevalence, pathophysiology and role of V2 vasoreceptor activity in the development of hyponatremia. Serum copeptin (S-COP), a surrogate marker for AVP activity, was assessed during AHF therapies (AHFT) which included axial-non-pulsatile left ventricular assist device (LVAD) and/or heart transplant (HTx). Methods: Serum samples were collected from AHF patients pre and post AHFT and compared with normal controls. S-COP levels were assessed using an enzyme linked immunosorbant assay and correlated to clinical variables, serum Sodium (S-Na) and glomerular filtration rate (eGFR). Results: Among 89 consecutive (mean age 56.2±15.35; M=69) patients awaiting AHFT, 54 (60%) were hyponatremic. Preop S-COP was elevated compared to controls (0.68±0.50 vs 0.53±0.13 ng/ml, P=.02) and inversely correlated to S-Na and eGFR (r=-0.23, P<.05, r=-0.23, P<.05; N=81); conversely, eGFR and S-Na were uncorrelated. AHFT (n=42) normalized S-Na (133.2±4.1 vs 136.1±3.5 mmol/l; P=.001) and improved eGFR (47.7±13.6 vs 52.7±9.7 mL/min/1.73sqm; P=.001); however, post LVAD (n=34) S-COP rose (0.67±0.21 vs 1.84±0.76 ng/ml; P<.0001) with incomplete normalization of S-NA (132.9±4.3 vs 135.9±3.8 mmol/l; P<.01). In contrast, post HTx (n=9) S-COP was unchanged to pre-AHFT (0.59±0.32 vs 0.65±0.16 ng/ml; P>.1) and was lower compared to post LVAD (0.65±0.16 vs 1.84±0.76 ng/ml; P<.0001). Elevated S-COP with LVAD as bridge to transplant (n=3) showed a marked decrease post HTx (2.7±0.50 vs 1.0±0.29 ng/ml; P<.01). Conclusions: In AHF, the prevalence of hyponatremia is double compared to acute hospitalized HF and associated with S-COP surge prior to AHFT. Unexpectedly, LVAD but not HTx was associated with rising S-COP and incomplete S-Na recovery despite clinical improvement, suggesting inappropriate antidiuretic hormone release. The association of S-COP rise with non-pulsatile LVAD and potential benefit of long-term AVP inhibition post LVAD merits further studies.

Acid–Base Disturbances

2014 ◽  
pp. 594-602
Author(s):  
Julian L. Seifter
Keyword(s):  
United States ◽  
Cardiovascular Disease ◽  
Peritoneal Dialysis ◽  
Renal Transplantation ◽  
End Stage Renal Disease ◽  
The United States ◽  
Cardiovascular Complications ◽  
Diabetic Patients ◽  
Stage Renal Disease ◽  
End Stage

According to projections from the United States Renal Data Service (USRDS), 〉600,000 individuals in the United States will have end-stage renal disease (ESRD) by 2010. The leading cause of ESRD in the United State is diabetes, followed by hypertension. As the care of diabetic patients has improved, particularly in the area of cardiovascular disease, they are living through their cardiovascular complications long enough to develop ESRD. As a consequence, since the inception of the Medicare ESRD program. the dialysis population has gradually become older with increasing numbers of comorbid conditions. Renal replacement therapy in the form of hemodialysis or peritoneal dialysis may serve as a bridge to the best form of renal replacement, renal transplantation. The demand for suitable kidneys for transplantation far exceeds the supply, leaving many patients on dialysis for extended periods of time.

Sign in / Sign up

Export Citation Format

Share Document