Left Ventricular Assist Device Therapy for Destination Therapy: Is Less Invasive Surgery a Safe Alternative?

[Heart failure: ventricular assist devices and cardiac transplantation : A review of current surgical innovations]

BACKGROUND

End-stage heart failure is one of the leading causes of death in Germany. Cardiac transplantation is still considered the gold standard for the treatment of terminal heart failure; however, there is a discrepancy between patients on the waiting list and yearly performed transplantations. As an alternative, ventricular assist devices have achieved a high level of importance but treatment is still associated with challenges. Novel systems as well as innovative surgical techniques contribute to improving the safety and effectiveness of the treatment.

OBJECTIVE

To generate an overview of current surgical innovations in cardiac transplantation and mechanical circulatory support.

MATERIAL AND METHODS

A Medline search was conducted regarding innovations in cardiac transplantation and mechanical circulatory support.

RESULTS AND CONCLUSION

Not only the number of yearly performed cardiac transplantations has changed but also recipient profiles. While in the pioneering era of transplantation the typical candidate was young, not previously operated on and with lower levels of comorbidities, today's patients are significantly older, have been fitted with ventricular assist devices and have increased operative risk profiles. Modern methods of organ preservation enable longer transportation and operation times as well as an improved assessment of graft function and perspectives for graft optimization in the future. In the area of ventricular assist devices, advances in the reduction of the stroke rate seem to have been achieved by the latest generation devices. From a surgical perspective, less invasive surgical techniques with promising initial results have been established at numerous centers.

The influence of less invasive ventricular assist device implantation on renal function

BACKGROUND

End-stage heart failure is associated with severe after-effects such as heart valve insufficiency, cardiac arrhythmias or end-organ dysfunctions. Renal failure or 'cardiorenal syndrome' is a critical end-organ disorder associated with advanced heart failure, which occurs due to low-output failure. Drug therapy or surgical interventions involving left ventricular assist device (LVAD) implantation may impede the progress of heart insufficiency and its after-effects including renal failure. In this study, we investigated the impact of a minimally invasive ventricular assist device implantation through upper hemisternotomy combined with anterolateral thoracotomy on renal function, in patients with perioperative renal failure.

METHODS

We analyzed data obtained from 103 patients (80 males, 23 females; mean age 53.8±11.7) who underwent LVAD implantation at our clinic within a 15-year interval (2001-2016) and were dialyzed due to renal dysfunction. 90 patients were operated with the conventional LVAD implantation technique (standard approach surgery, SAS) and 13 underwent less invasive approach implantation (less invasive surgery, LIS).

RESULTS

For all patients, data analysis showed significant increase of glomerular filtration rate (GFR) (44.2±56.48 mL/min; 95% CI: 33.81-55.28; P<0.001) along with a significant decrease in the levels of creatinine (-1.08±1.83 mg/dL; 95% CI: 0.75-1.46; P<0.001) and urea (-4.62±13.66 mmol/L; 95% CI: 1.95-7.29; P<0.001). There was a considerable difference in change of renal parameters in patients treated with LIS in comparison to patients who underwent SAS, which was however not statistically significant (GFR: P=0.494; creatinine: P=0.543; urea P=0.918).

CONCLUSIONS

LVAD implantation improves kidney function in patients with renal dysfunction. A considerable difference in the change of renal parameters was detected in patients with LIS as compared to SAS, which was not significant possibly due to the limited size of the patient cohort (n=13).

Left ventricular assist device (LVAD) program in Chile: first successful experience in South America

Background

The need to have a variety of tools to deal with end-stage heart failure (ES-HF), along with the limited heart transplantation availability encouraged us to create a pilot Left ventricular assist device (LVAD) program in a public health care system hospital in Chile.

Methods

A retrospective analysis of the first nine patients of an ongoing LVAD program initiated on August 2013 was performed, completing an average of 30 months of follow-up. The most important events regarding to morbidity and mortality are described.

Results

Nine patients with ES-HF underwent LVAD implantation surgery; one of them died 23 days after surgery and another died after 11 months. One patient successfully underwent heart transplantation after 16 months of HeartWare ventricular assist device (HVAD) support; the other six patients remain in the program and have an average follow-up of 846 days at the time of this study (range, 23-1,481 days). The survival rate at 6, 12 and 18 months follow-up was 89%, 78% and 78% respectively.

Conclusions

This new pioneering LVAD program in Chile has been successful and now constitutes a vital adjunct to all who work in heart transplantation and ES-HF programs. It offers an effective therapeutic alternative when there is a severe donor shortage, in cases of atypical blood types, emergencies, exceptional cases with contraindication for heart transplantation or when there is important donor-receiver size mismatch.

Clinical overview of the HVAD: a centrifugal continuous-flow ventricular assist device with magnetic and hydrodynamic bearings including lateral implantation strategies

Growing worldwide incidences of end-stage heart failure and declining rates of cardiac transplants have given rise to the need for alternative treatment options, based on mechanical circulatory support (MCS) devices such as left ventricular assist devices (LVADs). Technologically advanced LVADs such as the HVAD^® (HeartWare^®, Medtronic) facilitate safe and efficient treatment of heart failure patients with reduced post-operative complications, which is attributed to their considerably miniaturized size. This also facilitates the development and implementation of novel, minimally-invasive surgical techniques. The HVAD is a centrifugal pump, manufactured by HeartWare Inc., (Framingham, MA, USA) and subsequently by Medtronic Inc., (Minnesota, MN, USA), and has been approved for clinical application after receiving the CE Mark approval in 2008 and the FDA approval in 2012. Current research efforts are focused on further miniaturization alongside optimization of electronic and software controllers as well as implementation of the transcutaneous energy transfer (TET) technology. Salient features of the HVAD pump technology, clinical applications and future optimization strategies have been discussed in this article.

Minimally invasive approaches for implantation of left ventricular assist devices

The era of intracorporal continuous flow pumps has initiated significant success of left ventricular assist device (LVAD) surgery. However, median sternotomy has been the only surgical approach for implantation over many years. During the last decade, less-invasive access ways gained popularity. Within this review, we describe our own clinical experience in minimally invasive ventricular assist device (VAD) surgery and summarize the current scientific literature on this topic.