Heart failure and mechanical circulatory support.

Cardiovascular disease (CVD) is defined as one of the following: hypertension, congestive heart failure (HF), stroke, coronary heart disease and congenital heart defects. CVD is the main cause of the disease burden (illness and death) in Europe (23% of all the disease burdens) and the second main cause of the disease burden in those European Union (EU) countries with very low child and adult mortality (17%).(1) Heart disease is a common health problem worldwide. According to the most recent Heart Disease and Stroke Statistics-2011 update,(2) greater than 82 000 000 adults living in the United States of America (USA) have one or more types of CVD. Many resources have been invested in attempting to understand and curtail the progression of congestive HF. This article attempts to address the growing concern over HF by looking at the epidemiology, pathophysiology and available therapies as anaesthesiologists encounter these patients more often nowadays in the operating room and intensive care units. Mechanical circulatory assistance and heart transplantation are two established treatment methods for end-stage HF. In this review, we also address the indications and contraindications for mechanical circulatory assistance, types and spectrum of available ventricular assist devices, efficacy, safety and cost analysis of circulatory support therapy.

Low-cost pulsatile cardiac assist device with compliant input chamber.

We propose a new, low-cost pulsatile ventricular assist device (VAD) for short-term applications. The new device could prove very useful in emergency ventricular failure in which patient survival is not assured. In these cases, the device allows ventricular function to be maintained as the patient's situation is evaluated and a decision is made on whether to perform a heart transplant or to replace the device with a long-term VAD. The device has a pneumatic tubular blood chamber, clip valves over the cannulae, and a compliant input chamber that improves filling of the pump. Clip valves and all other functions of the device are controlled by means of a computerized console. The use of clip valves reduces the cost of the disposable part of the device.

Study on mechanical circulatory support and currently available supporting parts in China.

The research and development on extracorporeal and assisted circulation in China have been painstaking. On one hand, China has the largest population of 1.3 [corrected] billion in the world, and the demands for supporting equipment are huge. On the other hand, as a developing country, China is not wealthy. It is urgent to design and fabricate affordable circulatory support parts, machines, and artificial hearts for Chinese market. In this regard, we have made our own heart-lung machine, mechanical and tissue valves, oxygenators, and artificial hearts and their improved versions. The cost of these parts is much lower as compared with those in the Western market. Although the results of clinical application are good so far, the quality of these lifesaving parts needs to be continuously improved.

Multicenter experience: prevention and management of left ventricular assist device infections.

Implantable left ventricular assist devices (LVADs) have demonstrated clinical success in both the bridge-to-transplantation and destination-therapy patient populations; however, infection remains one of the most common causes of mortality during mechanical circulatory support. Thus, serious LVAD infections may negate the benefits of LVAD implantation, resulting in decreased quality of life, increased morbidity and mortality, and increased costs associated with implantation. Prevention of device-related infection is crucial to the cost-effective use of mechanical circulatory support devices. Therefore, adherence to evidence-based infection control and prevention guidelines, meticulous surgical technique and optimal postoperative surgical site care form the foundation for LVAD associated infection prevention.

Developments in mechanical support as a bridge to cardiac transplant.

With the increasing incidence of congestive heart failure and limited numbers of donor hearts for transplantation, mechanical circulatory support devices are being used with greater frequency in Canada. The indications for device use, types of available pumps and centres performing these procedures are presented. A review of the results of use of these devices in Canada indicates that they may be a reasonable alternative for patients who might otherwise die without intervention. The cost implications of more widespread use of these pumps are not insignificant and must be compared with other life-saving technologies.

Treatment of endstage heart disease with mechanical circulatory assistance.

A great number of patients suffer and die from the sequelae of acute and chronic heart failure each year. Although advances in medical and surgical therapy have benefited many of these patients, the majority suffer from disease refractory to any definitive therapy. For these patients, cardiac transplantation is the only remaining hope. Unfortunately, because of the increasing demand for donor organs in the face of a fixed and limited supply, this option is only available to a small percentage of these patients. Even in patients accepted for transplantation, a significant waiting list mortality has been observed. A variety of ventricular assist devices (VAD) have been developed since the first successful case of mechanical cardiac assistance over 30 years ago. These devices differ in basic mechanical function, method of insertion, and degree of implantability, and thus have different indications and potential applications. While the intra-aortic balloon pump and centrifugal pumps are effective short-term support modalities, extracorporeal and implantable pulsatile devices have been used successfully for long-term support of patients with reversible and non-reversible cardiac failure. These pumps have most commonly been utilized as bridges to transplantation, but increasing clinical experience has supported the notion of long-term mechanical assistance as a definitive therapy for endstage heart disease. While complications, particularly infection and thromboembolism, pose significant challenges and long-term device reliability remains to be fully determined, available implantable devices seem capable of providing effective long-term support. As data is obtained from currently ongoing trials comparing VAD support to medical therapy for endstage heart failure, ethical and economic issues will assume increasing importance.

Bridge experience with long-term implantable left ventricular assist devices. Are they an alternative to transplantation?

BACKGROUND: If long-term use of left ventricular assist devices (LVADs) as bridges to transplantation is successful, the issue of permanent device implantation in lieu of transplantation could be addressed through the creation of appropriately designed trials. Our medium-term experience with both pneumatically and electrically powered ThermoCardiosystems LVADs is presented to outline the benefits and limitations of device support in lieu of transplantation. METHODS AND RESULTS: Detailed records were kept prospectively for all patients undergoing LVAD insertion. Fifty-eight LVADs were inserted over 5 years, with a survival rate of 74%. Mean patient age was 50 years, and duration of support averaged 98 days. Although common, both preexisting infection and infection during LVAD support were not associated with increased mortality or decreased rate of successful transplantation. Thromboembolic complications were rare, occurring in only three patients (5%) despite the absence of anticoagulation. Ventricular arrhythmias were well tolerated in all patients except in cases of early perioperative right ventricular failure, with no deaths. Right ventricular failure occurred in one third of patients and was managed in a small percentage by right ventricular assist device (RVAD) support and/or inhaled nitric oxide therapy. There were no serious device malfunctions, but five graft-related hemorrhages resulted in two deaths. Finally, a variety of noncardiac surgical procedures were performed in LVAD recipients, with no major morbidity and mortality. CONCLUSIONS: Over all, our medium-term experience with implantable LVAD support is encouraging. Although additional areas of investigation exist, improvements in patients selection and management together with device alterations that have reduced the thromboembolic incidence and facilitated patient rehabilitation lead us to believe that a prospective, randomized trial is indicated to study the role that LVADs may have as an alternative to medical management.

[Terminal cardiac failure. Circulatory assist devices]. / Insuffisance cardiaque terminale. Les moyens d'assistance circulatoire.

There is a great variety of circulatory assist devices because of the diversity of clinical applications, age of the patient, required performances, energy used for activation... The oldest assistance device is intra-aortic balloon counterpulsation. There are two groups of devices: light, partial and short-term assist devices versus total, sophisticated and long-term machines. Examples of the first group are the Hemo-pump and Centrifugal pumps. Many of the second group are pneumatically driven: either external heterotopic uni/biventricular assist devices (Thoractec, Medos) or implantable heterotopic left ventricle (TCI), or orthotopic and implantable total artificial heart (Jarvik-CardioWest). The aim to assist the left ventricle over a longer period of time has lead laboratories to develop electrically powered ventricles implanted in the abdominal wall like the Novacor or HeartMate Systems. Because these new devices make patients more independent, they open the way for chronic applications as an alternative to transplantation.

[Uni- or biventricular circulatory assist devices. Selection criteria and patients' follow-up, choice of device]. / Assistances uni- ou biventriculaires. Critères de sélection et de surveillance des patients, choix du dispositif.

Therapy of patients presenting with cardiogenic shock refractory to medical treatment can be undertaken with uni or biventricular circulatory assist devices. Pre implantation evaluation of patients is aimed at defining the etiology as well as the extent of uni versus biventricular heart failure, the possibility of recovery of myocardial function improvement of vital organ function and the possibility of cardiac transplantation. Circulatory assist devices must provide efficient support of the failing ventricles, allow recovery of myocardial function or cardiac transplantation under optimal circumstances. The choice of uni-biventricular support of total artificial heart is discussed as well as criteria useful in defining a therapeutic strategy.

[Baxter-Novacor type implanted ventricular device: a possible alternative to transplantation]. / Assistance ventriculaire implantée type Baxter-Novacor: vers l'alternative à la transplantation.

After nearly 25 years of continuous technological development, the therapeutic arsenal for treating severe cardiac failure has been reinforced by the addition of a new weapon: a mechanical bridge whilst waiting for emergency cardiac transplantation for patients in cardiogenic shock and an alternative to transplantation in certain categories of chronic disease. The author describes the system and the results in the indication of a bridge to transplantation and the problems posed by the indication of chronic cardiac failure are discussed.

Mechanical circulatory support in the 1990s.

The current experience in bridging patients to weaning (more than 965 implants) and to transplantation (more than 544 implants) has shown the feasibility of mechanical circulatory support in patients with major cardiac dysfunction, who are unresponsive to optimal medical management. The complications are mostly related to the patient's initial condition at the time of implantation. The rehabilitation of the patient is related to both the extent of recovery from organ dysfunction and the type of device. This analysis proposes some new orientations for research. Firstly, in clinical research, definition of precise indices of the patient condition, not exclusively related to the haemodynamic situation, should allow better patient and device selection. Secondly, in technological research, precise definition of the actual clinical objectives should help in the development of various systems: for resuscitation, for bridging purposes and for long-term or permanent implantation.

[Assisted circulation by external heterotopic prosthesis as a bridge to heart transplantation]. / Assistance circulatoire en attente de transplantation cardiaque par prothèse hétérotopique externe.

Eleven patients aged 7 to 58 years were placed on assisted circulation with Pierce (2 cases) or Abiomed (9 cases) external prosthetic ventricles as a bridge to cardiac transplantation. The indications were terminal cardiac failure following cardiomyopathy (7 cases), decompensated ischemic heart disease (3 cases) and subacute post-transplantation rejection (1 case). The duration of the assisted circulation ranged from 24 hours to 11 days. All patients were transplanted but 3 died after transplantation (27%). The circulatory assistance was satisfactory in all patients as shown by the regression of clinical signs of low cardiac output and the normalisation of diuresis. The complications observed during assisted circulation and after cardiac transplantation were: haemorrhage (36%), infection (27%) and thromboembolism (9%). These preliminary results with a 72% post-transplantation survival rate, show that both systems are effective "bridges to cardiac transplantation". The Abiomen device is excellent value for money and relatively simple to install and represents a good compromise between the sophisticated techniques of circulatory assistance and the problems of the cost of health care.

State of the art. Circulatory support.

Beginning in midlife, chronic congestive heart failure (CCHF) is a major health problem in the United States. For patients over 65, the costs incurred in treating CCHF are vast, accounting for the highest hospitalization charges among all DRG's for Medicare patients. Heart transplants are an important but insufficient solution to the problem. Consistent progress is being made in the development of left ventricular assist devices, and, along with preventive and other therapeutic approaches, left ventricular assist devices have the potential for being a significant part of the solution for CCHF.

Artificial heart and assist devices: directions, needs, costs, societal and ethical issues.

A Working Group appointed by the Director of the National Heart, Lung, and Blood Institute (NHBLI) has reviewed the current status of mechanical circulatory support systems (MCSS), and has examined the potential need for such devices, their cost, and certain societal and ethical issues related to their use. The media have reported the limited clinical investigative use of pneumatically energized total artificial hearts (which actually replace the patient's heart) and left ventricular assist devices (which support or replace the function of the left ventricle by pumping blood from the left heart to the aorta with the patient's heart in place). However, electrically energized systems, which will allow full implantation, permit relatively normal everyday activity, and involve battery exchange or recharge two or three times a day, are currently approaching long-term validation in animals prior to clinical testing. Such long-term left ventricular assist devices have been the primary goal of the NHLBI targeted artificial heart program. Although the ventricular assist device is regarded as an important step in the sequence of MCSS development, the Working Group believes that a fully implantable, long-term, total artificial heart will be a clinical necessity and recommends that the mission of the targeted program include the development of such systems. Past estimates of the potential usage of artificial hearts have been reviewed in the context of advances in medical care and in the prevention of cardiovascular disease. In addition, a retrospective analysis of needs was carried out within a defined population. The resulting projection of 17,000-35,000 cases annually, in patients below age 70, falls within the general range of earlier estimates, but is highly sensitive to many variables. In the absence of an actual base of data and experience with MCSS, projection of costs and prognoses was carried out using explicit sets of assumptions. The total cost of a left ventricular assist device, its implantation and maintenance for a projected average of 4 1/2 years of survival might be approximately $150,000 (in 1983 dollars). The gross annual cost to society could fall in the range of $2.5-$5 billion. Ethical issues associated with use of the artificial heart are not unique. For individual patients these relate primarily to risk-benefit, informed consent, patient selection, and privacy. However, for society as a whole, the larger concern relates to the distribution of national resources.(ABSTRACT TRUNCATED AT 400 WORDS)