Ventricular Assist Devices for Durable Support

Role of cardiopulmonary exercise testing in clinical stratification in heart failure. A position paper from the Committee on Exercise Physiology and Training of the Heart Failure Association of the European Society of Cardiology

Traditionally, the main indication for cardiopulmonary exercise testing (CPET) in heart failure (HF) was for the selection of candidates to heart transplantation: CPET was mainly performed in middle-aged male patients with HF and reduced left ventricular ejection fraction. Today, CPET is used in broader patients' populations, including women, elderly, patients with co-morbidities, those with preserved ejection fraction, or left ventricular assistance device recipients, i.e. individuals with different responses to incremental exercise and markedly different prognosis. Moreover, the diagnostic and prognostic utility of symptom-limited CPET parameters derived from submaximal tests is more and more considered, since many patients are unable to achieve maximal aerobic power. Repeated tests are also being used for risk stratification and evaluation of intervention, so that these data are now available. Finally, patients, physicians and healthcare decision makers are increasingly considering how treatments might impact morbidity and quality of life rather than focusing more exclusively on hard endpoints (such as mortality) as was often the case in the past. Innovative prognostic flowcharts, with CPET at their core, that help optimize risk stratification and the selection of management options in HF patients, have been developed.

The future is here: ventricular assist devices for the failing heart

Mechanical circulatory support is an important adjunct to the management of patients with advanced heart failure. Technological advances in this area have improved overall survival and decreased the incidence of complications. In addition, they have expanded the population suitable for this therapy. The challenge for clinicians is to translate the clinical evidence into the selection of the most appropriate device that will benefit an individual patient. This paper will review ventricular assist devices currently available and their clinical indications.

Long-term outcomes and costs of ventricular assist devices among Medicare beneficiaries

CONTEXT

In 2003, Medicare expanded coverage of ventricular assist devices as destination, or permanent, therapy for end-stage heart failure. Little is known about the long-term outcomes and costs associated with these devices.

OBJECTIVE

To examine the acute and long-term outcomes of Medicare beneficiaries receiving ventricular assist devices alone or after open-heart surgery.

DESIGN, SETTING, AND PATIENTS

Analysis of inpatient claims from the Centers for Medicare & Medicaid Services for the period 2000 through 2006. Patients were Medicare fee-for-service beneficiaries who received a ventricular assist device between February 2000 and June 2006 alone as primary therapy (primary device group; n = 1476) or after cardiotomy in the previous 30 days (postcardiotomy group; n = 1467).

MAIN OUTCOME MEASURES

Cumulative incidence of device replacement, device removal, heart transplantation, readmission, and death, accounting for censoring and competing risks. Patients were followed up for at least 6 months and factors independently associated with long-term survival were identified. Medicare payments were used to calculate total inpatient costs and costs per day outside the hospital.

RESULTS

Overall 1-year survival was 51.6% (n = 669) in the primary device group and 30.8% (n = 424) in the postcardiotomy group. Among primary device patients, 815 (55.2%) were discharged alive with a device. Of those, 450 (55.6%) were readmitted within 6 months and 504 (73.2%) were alive at 1 year. Of the 493 (33.6%) postcardiotomy patients discharged alive with a device, 237 (48.3%) were readmitted within 6 months and 355 (76.6%) were alive at 1 year. Mean 1-year Medicare payments for inpatient care for patients in the 2000-2005 cohorts were $178,714 (SD, $142,549) in the primary device group and $111,769 (SD, $95,413) in the postcardiotomy group.

CONCLUSIONS

Among Medicare beneficiaries receiving a ventricular assist device, early mortality, morbidity, and costs remain high. Improving patient selection and reducing perioperative mortality are critical for improving overall outcomes.

Left ventricular assist device: a functional comparison with heart transplantation

BACKGROUND

A growing number of patients with end-stage heart failure undergo implantation of ventricular assist devices as a bridge to heart transplantation.

OBJECTIVES

In this study we investigated whether functional and haemodynamic recovery after implantation is sufficient to warrant the use of them as long-term alternative to heart transplantation.

METHODS

We compared peak VO(2) of a group of patients three months after implantation of a ventricular assist device and three months after heart transplantation. Furthermore, we analysed the degree of haemodynamic recovery, by comparing plasma levels of BNP and creatinine before and after implantation of the device.

RESULTS

After implantation of a ventricular assist device, exercise capacity improved considerably; three months after implantation peak VO(2) was 20.0+/-4.9 ml/kg/min (52% of predicted for age and gender). After heart transplantation exercise capacity improved even further; 24.0+/-3.9 ml/ kg/min (62% of predicted for age and gender) (p<0.001). In the three months after implantation, BNP plasma levels decreased from 570+/-307 pmol/l to 31+/-25 pmol/l and creatinine levels decreased from 191+/-82 mumol/l to 82+/-25 mumol/l, indicating significant unloading of the ventricles and haemodynamic recovery.

CONCLUSION

With regard to functional and haemodynamic recovery, the effect of implantation of a ventricular assist device is sufficient to justify its use as an alternative to heart transplantation. (Neth Heart J 2008;16:41-6.).

EMS management of acute stroke--out-of-hospital treatment and stroke system development (resource document to NAEMSP position statement)

The American Heart Association estimates an annual incidence of stroke in the United States at 700,000, leading to over 150,000 deaths. Of all strokes, approximately 88% are ischemic and 12% are hemorrhagic. Almost half of all stroke deaths occur in the out-of-hospital environment. Within a given region, the emergency medical services (EMS) system has an important role in the management of the acute stroke patient. Decisions made by EMS personnel can affect treatment and contribute to the immediate, short-term, and long-term outcomes of the patient. Because the patient may require emergent treatment regardless if the stroke is ischemic or hemorrhagic, EMS personnel should manage all potential stroke patients in a time-dependent nature. Proper treatment and disposition of the stroke patient begins in the out-of-hospital environment, continues in the emergency department, and then extends to the inpatient admission. This article reviews the literature on the out-of-hospital treatment of stroke patients and the role of EMS in the development of stroke systems of care.

[Infection control measures and surveillance of patients with ventricular assist devices]

Ventricular assist devices (VAD) are a new routine therapy option for end-stage heart failure. However, the incidence of VAD-related infections varies between 20 and 188% and makes a major contribution to VAD-related morbidity. Therefore, optimised infection control policies should be applied to prevent VAD-related infections. As to date only a few studies exist investigating particular prevention measures for VAD recipients, we have tried to adapt evidence-based guidelines. In detail the following preventive measures are discussed: antibiotic prophylaxis, endocarditis prophylaxis, dressing technique for the driveline-exit site and education of patients and medical staff. A new patient-based surveillance system is proposed which reflects the different times since implantation of VADs and therefore allows a fair method for interhospital comparison.

Modeling payback from research into the efficacy of left-ventricular assist devices as destination therapy

OBJECTIVES

Ongoing developments in design have improved the outlook for left-ventricular assist device (LVAD) implantation as a therapy in end-stage heart failure. Nevertheless, early cost-effectiveness assessments, based on first-generation devices, have not been encouraging. Against this background, we set out (i) to examine the survival benefit that LVADs would need to generate before they could be deemed cost-effective; (ii) to provide insight into the likelihood that this benefit will be achieved; and (iii) from the perspective of a healthcare provider, to assess the value of discovering the actual size of this benefit by means of a Bayesian value of information analysis.

METHODS

Cost-effectiveness assessments are made from the perspective of the healthcare provider, using current UK norms for the value of a quality-adjusted life-year (QALY). The treatment model is grounded in published analyses of the Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure (REMATCH) trial of first-generation LVADs, translated into a UK cost setting. The prospects for patient survival with second-generation devices is assessed using Bayesian prior distributions, elicited from a group of leading clinicians in the field.

RESULTS

Using established thresholds, cost-effectiveness probabilities under these priors are found to be low (approximately .2 percent) for devices costing as much as 60,000 pounds. Sensitivity of the conclusions to both device cost and QALY valuation is examined.

CONCLUSIONS

In the event that the price of the device in use would reduce to 40,000 pounds, the value of the survival information can readily justify investment in further trials.

Development of a new method for endovascular aortic repair: combination therapy of cell transplantation and stent grafts with a drug delivery system

BACKGROUND

Endovascular aortic repair by stent grafts (S/Gs) has been developed as a less invasive treatment for aortic aneurysms. However, some aneurysmal cavities can remain without organization, causing re-expansion. We demonstrated previously that transplantation of a cell combination (myoblasts and fibroblasts) promoted thrombus organization in a rat model. We also developed basic fibroblast growth factor (bFGF) slow-delivery S/Gs coated with elastin and impregnated with bFGF. Here, we evaluated the effects of cell transplantation combined with bFGF slow release on canine thoracic aortic aneurysmal sacs after S/Gs repair.

METHODS AND RESULTS

Thoracic aortic aneurysms were surgically created with jugular vein patches in 15 beagles. Myoblasts and fibroblasts of autologous skeletal muscle were isolated and cultured for cell transplantation. The S/Gs had 6 holes and produced endoleaks in the excluded cavities. Collagen gel (gel group, n=5) or a mixture of skeletal myoblasts and fibroblasts with collagen gel (cell group, n=5) were injected into the aneurysmal sacs excluded by the S/Gs. We also studied the effects of combined therapy of bFGF slow-release S/Gs and cell transplantation (hybrid group, n=5). After 14 days, histological analyses revealed that the excluded aneurysmal cavities of the gel group were filled with fresh thrombus, whereas the excluded cavities in the cell-transplanted groups were occupied by organized tissue. The percentages of the organized areas relative to the excluded cavities, evaluated by Masson's trichrome staining, were 18.1+/-4.0%, 52.6+/-4.0%, and 77.1+/-6.9% in the gel, cell, and hybrid groups, respectively. Collagen fibers had already appeared, and increased numbers of alpha-smooth muscle actin-positive cells were observed in the hybrid group.

CONCLUSIONS

Cell transplantation accelerated thrombus organization. Moreover, slow release of bFGF enhanced the effects of cell transplantation. Cell transplantation into unorganized spaces may improve the outcomes of endovascular treatments of aortic aneurysms.