Mechanical Circulatory Support—Results, Developments and Trends

Trends in utilization, mortality, and resource use after implantation of left ventricular assist devices in the United States

OBJECTIVES

Adoption of implantable left ventricular assist devices has dramatically improved survival and quality of life in suitable patients with end-stage heart failure. In the era of value-based healthcare delivery, assessment of clinical outcomes and resource use associated with left ventricular assist devices is warranted.

METHODS

Adult patients undergoing left ventricular assist device implantation from 2008 to 2016 were identified using the National Inpatient Sample. Hospitals were designated as low-volume, medium-volume, or high-volume institutions based on annual institutional left ventricular assist device case volume. Multivariable logistic regression was used to evaluate adjusted odds of mortality across left ventricular assist device volume tertiles.

RESULTS

Over the study period, an estimated 23,972 patients underwent left ventricular assist device implantation with an approximately 3-fold increase in the number of annual left ventricular assist device implantations performed (P for trend <.001). In-hospital mortality in patients with left ventricular assist devices decreased from 19.6% in 2008 to 8.1% in 2016 (P for trend <.001) and was higher at low-volume institutions compared with high-volume institutions (12.0% vs 9.2%, P < .001). Although the overall adjusted mortality was higher at low-volume compared with high-volume institutions (adjusted odds ratio, 1.66; 95% confidence interval, 1.28-2.15), this discrepancy was only significant for 2008 and 2009 (low-volume 2008 adjusted odds ratio, 5.5; 95% confidence interval, 1.9-15.8; low-volume 2009 adjusted odds ratio, 2.3; 95% confidence interval, 1.4-3.8).

CONCLUSIONS

Left ventricular assist device use has rapidly increased in the United States with a concomitant reduction in mortality and morbidity. With maturation of left ventricular assist device technology and increasing experience, volume-related variation in mortality and resource use has diminished. Whether the apparent uniformity in outcomes is related to patient selection or hospital quality deserves further investigation.

Simplified, less-invasive left ventricular assist device implantation in patients with post-coronary artery bypass grafting

Less-invasive left ventricular assist device implantation is becoming the technique of choice for implementation of new-generation heart pumps. The less-invasive technique is particularly useful for patients with a history of cardiac surgical procedures, such as coronary artery bypass grafting. Yet, in redo cases, severe pericardial adhesions may force experienced operators to opt for alternative outflow graft placement, such as in the descending aorta. We propose a surgical technique in which the left ventricular device is implanted through a limited thoracic incision, with the outflow graft anastomosed to the ascending aorta, avoiding collision with coronary bypass grafts. The key element of the proposed technique is a tunnel connecting 2 pleural cavities, in which the outflow graft is placed, entirely bypassing the pericardium.

Mechanical circulatory support: 60 years of evolving knowledge

Since the 1950s when the first devices for mechanical circulatory support were developed, there has been an impressive evolution of their technology. The first pioneering pumps were used to rescue acute complications after cardiac surgery. Advances in technology, increased knowledge of flow dynamics, and a more appropriate selection of the patients who actually need this support have contributed to significantly improve the benefits of this therapy. Today, mechanical circulatory support is an essential tool for the treatment of advanced heart failure. This strategy is used either as a bridge to heart transplantation or as a destination therapy for patients who do not meet the transplant criteria. A third indication is the bridge to recovery option for those patients in whom the improvement in cardiac function may be so important that the pump can be removed and the transplantation circumvented. In addition, mechanical circulatory support has fostered marked improvements in several clinical aspects affecting both patient health and quality of life. Despite the improvements in the technology of the devices of the last generation, severe adverse effects are still the Achilles heel of mechanical circulatory support therapy. This review summarizes the history, the technology, the clinical outcomes, and the possible future directions of this therapy.

Different surgical strategies for implantation of continuous-flow VADs-Experience from Deutsches Herzzentrum Berlin

OBJECTIVE

This manuscript summarizes our surgical experience with the implantation of recent continuous-flow left ventricular assist devices (LVADs), with special emphasis on the HeartWare HVAD pump.

METHODS

THE HEARTWARE HVAD IS, IN OUR EXPERIENCE CURRENTLY IMPLANTED IN FOUR DIFFERENT TECHNIQUES: (I) "Classical" LVAD implantation with heart-lung machine and median sternotomy; (II) "Minimally-invasive" implantation without sternotomy and without heart-lung machine; (III) "Lateral implantation" to the descending aorta; (IV) Using two continuous-flow LVADs for implantable biventricular support.

RESULTS

Five-hundred and four HeartWare HVADs have been implanted using the described techniques in our institution up to now.

CONCLUSIONS

The HeartWare HVAD is a versatile device. It has been found to be eminently suited to these four different modes of implantation.

Ventricular assist devices: initial orientation

Ventricular assist device (VAD) technology has come from large pulsatile-flow devices with a high rate of technical malfunctions to small continuous flow (cf) devices. Mechanical circulatory support (MCS) systems may be used as short-, mid- or long-term support. Especially if mid- or long-term support is anticipated left VADs (LVADs) have been reported with excellent one and two year survival rates and improved quality of life (QoL). Timing of implantation, patient selection, assessing function of the right ventricular and surgical considerations regarding surgical access side, valve pathology and exit side of the percutaneous lead remain crucial issues for the outcome. In contrast VADs designed for children especially for all age groups, are still underrepresented but increased experience with existing pediatric VADs as well as introduction of second and third generation VADs into in the pediatric age group, offer new perspectives.

Mechanical circulatory support: devices, outcomes and complications

Systolic heart failure is a problem of substantial magnitude worldwide. Over the last 25 years great progress has been made in the medical management of heart failure with the recognition of the benefits of beta-adrenergic blockade, modulation of the renin-angiotensin and mineralocorticoid axes and judicious diuretic therapy. In addition, cardiac resynchronization therapy and prophylactic implantation of cardiac defibrillators have been responsible for measurable benefits in terms of functional status and dysrhythmia-related mortality, respectively. Unfortunately, progressive cardiac dysfunction often results in activity limitation, symptoms at rest, hospital admission, end-organ dysfunction and death despite maximal implementation of standard therapies. Heart transplantation has been a dramatic and effective therapy for end-stage heart failure, but it remains limited by a shortage of donor organs, strict criteria defining acceptable recipients and often unsatisfactory long-term success. Mechanical alternatives to support the failing circulation have been sought for the last 50 years. The history of device development has been marked in general by the slow progress achieved by a few dedicated and persevering pioneers. In the past decade, however, evolving technology has dramatically changed the field and broadened the options for the treatment of advanced heart failure. This review will detail the important milestones and the current state of the art, with an emphasis on implantable devices for intermediate to long term support.

Complication profile of the Berlin Heart EXCOR biventricular support in children

In chronic cardiomyopathy, mechanical circulatory support (MCS) plays an increasingly important role for children as the shortage of suitable donor hearts increases waiting time on the transplant list. We report our experience with the paracorporal Berlin Heart EXCOR System (Berlin Heart AG, Berlin, Germany) used as a biventricuclar assist device (BVAD). Nine patients with a BVAD EXCOR system were treated between 2006 and 2012; out of these patients, four were less than 18 years old (6, 14, 14, and 17 years old). Their diagnoses were postcardotomy failure (n = 1), dilatative cardiomyopathy (n = 2), and terminal heart failure (n = 1). Overall survival, waiting time for heart transplantation (HTx) and complication profile for the BVAD were analyzed retrospectively. Thirty days' mortality was 25% (n = 1). One child died after 84 days on support due to cerebral bleeding. Mean support time was 218.75 days (4, 84, 262, and 525 days). Pump chamber exchange was necessary three times due to pump chamber thrombosis (n = 2) and partial pump chamber membrane rupture (n = 1). Complications included: sepsis (n = 1), drive line infection requiring intravenous antibiotics (n = 2), and recurrent epistaxis (n = 3). Two children were successfully transplanted after 262/525 days on BVAD; they are currently at home (follow-up: 1.9 and 2.3 years). The EXCOR is a life-saving MCS system suitable for long-term paracorporeal biventricular assistance.

Mechanical bridging to orthotopic heart transplantation in children

This article discusses the main methods currently used in clinical practice to support patients with end-stage heart failure and the research into new devices under development, particularly for young children. With an increasing demand on the supply of organs available for heart transplant, alternative strategies are being sought to maintain patients with end-stage cardiac failure for longer periods of time. Devices that support a failing heart, allowing cardiac recovery in some cases, or more commonly accommodate the time to source a suitable donor heart for transplantation, provide crucial therapeutic options. Extra-corporeal membrane oxygenation and ventricular assist devices are the mainstay of such bridging therapy. Although providing essential support to critically ill patients, they are not without their own significant associated risks. Therapeutic advances aim to reduce the risks associated with these bridging systems, and new artificial devices are being developed to improve this supportive care.

Pulsed or continuous flow in long-term assist devices: a debated topic

The end-stage cardiomyopathy is an increasing worldwide problem. Cardiac transplantation lacks sufficient donors to treat all patients, and there is thus debate about alternative strategies. The use of left ventricular assist devices for long-term support is increasing with a positive impact on patient survival. Although there is an ongoing debate regarding the risks and benefits of maintaining pulsatile flow during long-term ventricular assist device support, there has been a significant move towards implantation of continuous flow devices due to the lower surgical morbidity and better long-term reliability of these pumps. The following is a review of the literature on continuous and pulsatile flow for long-term support. Starting from the definition of flow, we analyze the current evidence and consider gastrointestinal complications.