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

Current and future options for adult biventricular assistance: a review of literature

In cardiogenic shock various short-term mechanical assistances may be employed, including an Extra Corporeal Membrane Oxygenator and other non-dischargeable devices. Once hemodynamic stabilization is achieved and the patient evolves towards a persisting biventricular dysfunction or an underlying long-standing end-stage disease is present, aside from Orthotopic Heart Transplantation, a limited number of long-term therapeutic options may be offered. So far, only the Syncardia Total Artificial Heart and the Berlin Heart EXCOR (which is not approved for adult use in the United States unlike in Europe) are available for extensive implantation. In addition to this, the strategy providing two continuous-flow Left Ventricular Assist Devices is still off-label despite its widespread use. Nevertheless, every solution ensures at best a 70% survival rate (reflecting both the severity of the condition and the limits of mechanical support) with patients suffering from heavy complications and a poor quality of life. The aim of the present paper is to summarize the features, implantation techniques, and results of current devices used for adult Biventricular Mechanical Circulatory Support, as well as a glance to future options.

Minimally invasive versus conventional continuous-flow left ventricular assist device implantation for heart failure: a meta-analysis

Many studies have reported various minimally invasive techniques for continuous-flow left ventricular assist device implantation. There is no consensus on whether minimally invasive techniques can bring more benefits for patients compared with the conventional technique, due to the limited number of patients and diverse results in current studies. Our meta-analysis mainly discussed the comparison of minimally invasive and conventional techniques. We searched controlled trials from PubMed, Cochrane Library, and Embase databases until Dec 11, 2020. Perioperative and postoperative outcomes were analyzed among 10 included studies. The protocol has been registered with PROSPERO (CRD42020221532). There were no statistical differences in the 30-day mortality (OR 0.57; 95% CI 0.29 to 1.14), 6-month mortality (OR 0.66; 95% CI 0.41 to 1.05), neurological dysfunction (OR 1.10; 95% CI 0.69 to 1.76), major infection (OR 0.68; 95% CI 0.36 to 1.28), and pump thrombus (OR 1.49; 95% CI 0.63 to 3.52) among the cohorts. Minimally invasive techniques were associated with lower incidences of major bleeding (OR 0.39; 95% CI 0.22 to 0.68), severe right heart failure (OR 0.43; 95% CI 0.23 to 0.81), and less blood-product utilization (SMD -0.44). Sensitivity analysis suggested that minimally invasive techniques were associated with a lower incidence of respiratory failure (OR 0.50; 95% CI 0.26 to 0.96) and shorter mechanical ventilation time (SMD -0.53). Subgroup analysis demonstrated that patients, implanted with a centrifugal pump by minimally invasive techniques, were associated with a shorter length of intensive care unit (ICU) stay (SMD -0.27) and hospital stay (SMD -0.42), and less blood-product utilization (SMD -0.26). In conclusion, minimally invasive techniques can reduce the risks of major bleeding, severe right heart failure, and blood-product utilization, as well as have positive impacts on reducing mechanical ventilation time and the risk of respiratory failure. Minimally invasive centrifugal pump implantation can reduce the length of ICU and hospital stay.

Ventricular assist devices implantation: surgical assessment and technical strategies

Along with the worldwide increase in continuous left ventricular assist device (LVAD) strategy adoption, more and more patients with demanding anatomical and clinical features are currently referred to heart failure (HF) departments for treatment. Thus surgeons have to deal, technically, with re-entry due to previous cardiac surgery procedures, porcelain aorta, peripheral vascular arterial disease, concomitant valvular or septal disease, biventricular failure. New surgical techniques and surgical tools have been developed to offer acceptable postoperative outcomes to all mechanical circulatory support recipients. Several less invasive and/or thoracotomic approaches for surgery combined with various LVAD inflow and outflow graft alternative anastomotic sites for system placement have been reported and described to solve complex clinical scenarios. Surgical techniques have been upgraded with further technical tips to preserve the native anatomy in case of re-entry for heart transplantation, myocardial recovery or device explant. The current continuous-flow miniaturized and intrapericardial devices provide versatility and technical advantages. However, the surgical planning requires a careful multidisciplinary evaluation which must be driven by a dedicated and well-trained Heart Failure team. Biventricular assist device (BVAD) implantation by adoption of the newer radial pumps might be a challenge. However, the results are encouraging thus remaining a valid option. This paper reviews and summarizes LVAD preoperative assessment and current surgical techniques for implantation.

Mechanical circulatory support in children: past, present and future

Rapid advances in the field of mechanical circulatory support (MCS) have dramatically changed the management of pediatric patients with heart failure. There is now emphasis on timely implantation of ventricular assist devices (VADs) to preserve or recover end-organ function, and increased focus on post-implant management to improve the stroke rate. Transplant waitlist mortality has significantly decreased in the era of VAD use. Devices approved for adults are being used off-label in children with excellent outcomes, allowing chronic therapy and discharge home to become part of pediatric VAD therapy.

Contrast Microsphere Destruction by a Continuous Flow Ventricular Assist Device: An In Vitro Evaluation Using a Mock Circulation Loop

OBJECTIVES

Transthoracic echocardiography (TTE) is fundamental in managing patients supported with ventricular assist devices (VAD). However imaging can be difficult in these patients. Contrast improves image quality but they are hydrodynamically fragile agents. The aim was to assess contrast concentration following passage through a VAD utilising a mock circulation loop (MCL).

METHODS

Heartware continuous flow (CF) VAD was incorporated into a MCL. Definity® contrast was infused into the MCL with imaging before and after CF-VAD. 5 mm2 regions of interest were used to obtain signal intensity (decibels), as a surrogate of contrast concentration.

RESULTS

Four pump speeds revealed significant reduction in contrast signal intensity after CF-VAD compared to before CF-VAD (all p < 0.0001). Combined pre- and postpump data at all speeds showed a 22.2% absolute reduction in contrast signal intensity across the CF-VAD (14.8 ± 0.8 dB prepump versus 11.6 ± 1.4 dB postpump; p < 0.0001). Mean signal intensity reduction at each speed showed an inverse relationship between speed and relative reduction in signal intensity.

CONCLUSION

Contrast microsphere transit through a CF-VAD within a MCL resulted in significant reduction in signal intensity, consistent with destruction within the pump. This was evident at all CF-VAD pump speeds but relative signal drop was inversely proportional to pump speed.

Pulsatile-flow mechanical circulatory support (MCS) as a bridge to transplantation or recovery. Single-centre experience with the POLCAS system in 2014

Introduction

Mechanical circulatory support (MCS) is a recognised method of treatment for patients with end-stage chronic or acute heart failure. The POLCAS pulsatile-flow system has been used in our institution for 15 years. Currently, it is being widely replaced by continuous-flow mechanical circulatory support equipment of the second and third generations (HeartMateII, HeartWare). The MCS presented in this study is associated with a significant risk of complications and its use is increasingly considered controversial. The aim of the study was an evaluation of the results of treatment utilising the POLCAS MCS system at our institution in 2014.

Material and methods

The POLCAS system was implanted in 12 patients aged 16-63 years (42 ± 17 years) during a period of 12 months (from January to December, 2014). Full-blown cardiogenic shock was observed in all patients before MCS implantation. Four of the analysed patients (33%) required prior circulatory support with other devices: IABP (n = 2) or ECMO (n = 2). Episodes of cardiac arrest were reported in three patients; three other patients experienced serious arrhythmias, which accelerated the decision to implant MCS. The presented data was retrospectively obtained from the CliniNET system of the Institute of Cardiology. OpenOffice Calc spreadsheet was used for data analysis.

Results

Average MCS time was 41 days ± 25 (from 15 to 91 days). Survival until transplantation or explantation was 91.67%. The most frequent complications following the therapy were: cardiac tamponade or bleeding requiring an intervention – 25% (n = 3), renal failure requiring dialysis – 25% (n = 3), ischaemic stroke associated with the MCS – 16.6% (n = 2), bacteraemia – 16.6% (n = 2), and wound infection – 8% (n = 1). No malfunctions of the MCS system were reported. Early survival in patients who completed the MCS therapy, defined as discharge, amounted to 63.6% (n = 7).

Conclusions

The POLCAS heart assist system is an effective method of treatment as a bridge to transplantation or recovery in patients with end-stage heart failure. Early survival after the treatment remains at a satisfactory level. The main problem is the large number of complications related to the therapy.

Minimally invasive is the future of left ventricular assist device implantation

There have been many factors that have allowed for progressive improvement in outcomes and lower complication rates. These include the improvement in left ventricular assist device (LVAD) technologies, combined with better understanding of patient management, all these. Nowadays the numbers of LVAD implantations exceed the number of annual heart transplants worldwide. Minimally invasive procedures are shown to improve the surgical outcome in both LVAD insertion and replacement. These minimally invasive techniques can be grouped grossly into shifting from on-pump to off-pump implantation, alternative access for implantation other than sternotomy, and a combination of both, which should be the ultimate aim of minimally invasive LVAD implantation. Here we describe the alternative techniques and configurations of minimally invasive and sites of implantation.