Left Ventricular Assist Devices A Rapidly Evolving Alternative to Transplant

AbstractLeft ventricular assist devices are becoming an increasingly prevalent therapy for patients with Stage D heart failure with reduced ejection fraction. Technological advances have improved the durability of these devices and have significantly lengthened survival in these patients. Quality of life is also improved, although adverse events related to device therapy remain common. Nevertheless, with the continuing organ donor shortage for cardiac transplantation, left ventricular assist devices are frequently serving as a substitute for transplant, particularly in the elderly patient

Respiratory muscle deoxygenation during exercise in patients with heart failure demonstrated with near-infrared spectroscopy

AbstractExertional dyspnea in patients with heart failure may be due, in part, to respiratory muscle underperfusion. Near-infrared spectroscopy is a new technique that permits noninvasive assessment of skeletal muscle oxygenation by monitoring changes in nearinfrared light absorption. With use of near-infrared spectroscopy, serratus anterior muscle oxygenation during maximal bicycle exercise was compared in 10 patients with heart failure (ejection fraction 16 ± 5%) and 7 age-matched normal subjects. Oxygen consumption (VO2), minute ventilation (VE) and arterial saturation were also measured. Changes in difference in absorption between 760 and 800 nm, expressed in arbitrary units, were used to detect muscle deoxygenation.Minimal change in this difference in absorption occurred in normal subjects during exercise, whereas patients with heart failure exhibited progressive changes throughout exercise consistent with respiratory muscle deoxygenation (peak exercise: normal 3 ± 6, heart failure 12 ± 4 near-infrared arbitrary units, p < 0.001). At comparable work loads patiente with heart failure had significantly greater minute ventilation and respiratory rate but similar tidal volume when contrasted with normal subjects. However, at peak exercise normal subjects achieved significantly greater minute ventilation and tidal volume with a comparable respiratory rate. No significant arterial desaturation occurred during exercise in either group.These findings indicate that respiratory muscle deoxygenation occurs in patients with heart failure during exercise. This deoxygenation may contribute to the exertional dyspnea experienced by such patients

Normalization of Pulmonary Hypertension by the Use of Left Ventricular Assist Device in Patients with End-stage Heart Failure: A Possible Contribution to Donor Pool Expansion in Lung Transplantation

SummaryHeart transplantation alone has been recognized to be contraindicated when pulmonary hypertension (PH) and elevated pulmonary vascular resistance (PVR) are irreversible, irrespective of any medical intervention by the use of inotropic agents or pulmonary vasodilators, because such patients are at an increased risk of post-transplantation right ventricular failure and mortality. Therefore, end-stage heart failure patients with concomitant fixed PH and irreversibly high PVR are considered to be heart–lung transplant candidates. Recently, left ventricular assist device (LVAD) therapy has been reported to normalize PVR through persistent unloading of the left ventricle, even in patients with medically refractory PH. Therefore, LVAD therapy could make such patients suitable for “heart-only” transplants, which contributes to appropriate donor lung allocation for lung-only candidates. We review the literature regarding LVAD use for secondary PH and present a case with end-stage heart failure that could avoid a heart–lung transplant owing to LVAD therapy

P for Politics D for Dialogue: Reflections on Participatory Design with Children and Animals

Participatory Design strives to open up the decision-making process and empower all those who may be affected by design. This is opposed to Design as a non-participatory process, in which the power to make decisions is vested in the hands of one group to the possible detriment of others. In this paper we interrogate the nature, possibilities and limitations of Participatory Design through the perspective of Child Computer Interaction (CCI) and Animal Computer Interaction (ACI). Due to the cognitive and communication characteristics, and to the social and legal status of their participants, researchers in these communities have to contend with and challenge existing notions of participation and design. Thus, their theories and practices provide a lens through which the nature and goals of Participatory Design can be examined with a view to facilitating the development of more inclusive participatory models and practices

Development of a Novel Echocardiography Ramp Test for Speed Optimization and Diagnosis of Device Thrombosis in Continuous-Flow Left Ventricular Assist Devices The Columbia Ramp Study

ObjectivesThis study sought to develop a novel approach to optimizing continuous-flow left ventricular assist device (CF-LVAD) function and diagnosing device malfunctions.BackgroundIn CF-LVAD patients, the dynamic interaction of device speed, left and right ventricular decompression, and valve function can be assessed during an echocardiography-monitored speed ramp test.MethodsWe devised a unique ramp test protocol to be routinely used at the time of discharge for speed optimization and/or if device malfunction was suspected. The patient's left ventricular end-diastolic dimension, frequency of aortic valve opening, valvular insufficiency, blood pressure, and CF-LVAD parameters were recorded in increments of 400 rpm from 8,000 rpm to 12,000 rpm. The results of the speed designations were plotted, and linear function slopes for left ventricular end-diastolic dimension, pulsatility index, and power were calculated.ResultsFifty-two ramp tests for 39 patients were prospectively collected and analyzed. Twenty-eight ramp tests were performed for speed optimization, and speed was changed in 17 (61%) with a mean absolute value adjustment of 424 ± 211 rpm. Seventeen patients had ramp tests performed for suspected device thrombosis, and 10 tests were suspicious for device thrombosis; these patients were then treated with intensified anticoagulation and/or device exchange/emergent transplantation. Device thrombosis was confirmed in 8 of 10 cases at the time of emergent device exchange or transplantation. All patients with device thrombosis, but none of the remaining patients had a left ventricular end-diastolic dimension slope >−0.16.ConclusionsRamp tests facilitate optimal speed changes and device malfunction detection and may be used to monitor the effects of therapeutic interventions and need for surgical intervention in CF-LVAD patients

2009 Focused Update Incorporated Into the ACC/AHA 2005 Guidelines for the Diagnosis and Management of Heart Failure in Adults A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines Developed in Collaboration With the International Society for Heart and Lung Transplantation

Heart failure (HF) is a major and growing public health problem in the United States. Approximately 5 million patients in this country have HF, and over 550,000 patients are diagnosed with HF for the first time each year. The disorder is the primary reason for 12 to 15 million office visits and 6.5 million hospital days each year. From 1990 to 1999, the annual number of hospitalizations has increased from approximately 810,000 to over 1 million for HF as a primary diagnosis and from 2.4 to 3.6 million for HF as a primary or secondary diagnosis. In 2001, nearly 53 000 patients died of HF as a primary cause. The number of HF deaths has increased steadily despite advances in treatment, in part because of increasing numbers of patients with HF due to better treatment and “salvage” of patients with acute myocardial infarctions (MIs) earlier in life. Heart failure is primarily a condition of the elderly, and thus the widely recognized “aging of the population” also contributes to the increasing incidence of HF. The incidence of HF approaches 10 per 1000 population after age 65, and approximately 80% of patients hospitalized with HF are more than 65 years old. Heart failure is the most common Medicare diagnosis-related group (i.e., hospital discharge diagnosis), and more Medicare dollars are spent for the diagnosis and treatment of HF than for any other diagnosis. The total estimated direct and indirect costs for HF in 2005 were approximately $27.9 billion. In the United States, approximately$2.9 billion annually is spent on drugs for the treatment of HF