Outcomes of biventricular mechanical support patients discharged to home to await heart transplantation

Right and left ventricular assist devices are an option for bridge to heart transplant

Background

Patients with a left ventricular assist device with right ventricular failure are prioritized on the heart transplant waitlist; however, their post-transplant survival is less well characterized. We aimed to determine whether pretransplant right ventricular failure affects postoperative survival in patients with a left ventricular assist device as a bridge to transplant.

Methods

We performed a retrospective review of the 2005-2018 Organ Procurement and Transplantation Network/United Network for Organ Sharing registry for candidates aged 18 years or more waitlisted for first-time isolated heart transplantation after left ventricular assist device implantation. Candidates were stratified on the basis of having right ventricular failure, defined as the need for right ventricular assist device or intravenous inotropes. Baseline demographic and clinical characteristics were compared among the 3 groups, and post-transplant survival was assessed.

Results

Our cohort included 5605 candidates who met inclusion criteria, including 450 patients with right ventricular failure, 344 patients with a left ventricular assist device and intravenous inotropes as a bridge to transplant, 106 patients with a left ventricular assist device and right ventricular assist device, and 5155 patients with a left ventricular assist device as a bridge to transplant without the need for right side support. Compared with patients without right ventricular failure, patients with a left ventricular assist device as a bridge to transplant with right ventricular failure were younger (median age 51 years, 55 vs 56 years, P < .001) and waited less time for organs (median 51 days, 93.5 vs 125 days, P < .001). These patients also had longer post-transplant length of stay (median 18 days, 20 vs 16 days, P < .001). Right ventricular failure was not associated with decreased post-transplant long-term survival on unadjusted Kaplan–Meier analysis (P = .18). Neither preoperative right ventricular assist device nor intravenous inotropes independently predicted worse survival on multivariate Cox proportional hazards analysis. However, pretransplant liver dysfunction (total bilirubin >2) was an independent predictor of worse survival (hazard ratio, 1.74; 95% confidence interval, 1.39-2.17; P < .001), specifically in the left ventricular assist device group and not in the left ventricular assist device + right ventricular assist device/intravenous inotropes group.

Conclusions

Patients with biventricular failure are prioritized on the waiting list, because their critical pretransplant condition has limited impact on their post-transplant survival (short-term effect only); thus, surgeons should be confident to perform transplantation in these severely ill patients. Because liver dysfunction (a surrogate marker of right ventricular failure) was found to affect long-term survival in patients with a left ventricular assist device, surgeons should be encouraged to perform transplantation in these severely ill patients after a recipient's optimization by inotropes or a right ventricular assist device because even when the bilirubin level is elevated in these patients (treated with right ventricular assist device/inotropes), their long-term survival is not affected. Future studies should assess recipients' optimization before organ acceptance to improve long-term survival.

Short-term mechanical circulatory support as bridge to heart transplantation: paracorporeal ventricular assist device as alternative to extracorporeal life support

Extracorporeal life support (ECLS) is generally considered to be the treatment of choice for bridging to heart transplantation (HTx) patients with cardiogenic shock; however, alternative mechanical circulatory support (MCS) devices have been proposed with satisfactory results and, among those, paracorporeal systems have demonstrated to be safe and effective. This technology has been used for decades as bridge to transplant, especially in patients with advanced right ventricular dysfunction or evidence of multiorgan failure (MOF), which could be difficult to manage with an isolated left ventricular support. Paracorporeal systems are defined by having the pump located outside of the body, with inflow and outflow cannulas that traverse the skin connecting the pump with the heart and great vessels. They can be utilised in a uni- or bi-ventricular configuration and can provide pulsatile or continuous flow, depending on the device technology (pneumatic vs. centrifugal). In particular, pneumatic devices allow for patient mobilization and hospital discharge, improving rehabilitation and organ recovery while bridging to transplant. In our institution at the University Hospital of Udine, 34 pneumatic paracorporeal ventricular assist devices (VADs) have been implanted since 1998: in most cases (32 pts), as biventricular support for patients in INTERMACS class I-II. After a median support time of 34 (range, 0-385) days, with 19 patients (56%) supported for more than 1 month, 23 patients (68%) underwent HTx and 3 (9%) were successfully weaned to hospital discharge, resulting in an overall combined 76% survival to HTx or weaning. After transplant, the survival rate was similar to the one of the patients not bridged with MCS. In conclusion, pneumatic VADs can effectively assist patients with severe biventricular failure, especially those with contraindications to ECLS or expected long waiting times for HTx. Moreover, they can potentially result in hospital discharge, optimal organ and patient recovery and donor-recipient matching, resulting in a satisfactory transplant outcome.

Mechanical circulatory assist devices: a primer for critical care and emergency physicians

Mechanical circulatory assist devices are now commonly used in the treatment of severe heart failure as bridges to cardiac transplant, as destination therapy for patients who are not transplant candidates, and as bridges to recovery and “decision-making”. These devices, which can be used to support the left or right ventricles or both, restore circulation to the tissues, thereby improving organ function. Left ventricular assist devices (LVADs) are the most common support devices. To care for patients with these devices, health care providers in emergency departments (EDs) and intensive care units (ICUs) need to understand the physiology of the devices, the vocabulary of mechanical support, the types of complications patients may have, diagnostic techniques, and decision-making regarding treatment. Patients with LVADs who come to the ED or are admitted to the ICU usually have nonspecific clinical symptoms, most commonly shortness of breath, hypotension, anemia, chest pain, syncope, hemoptysis, gastrointestinal bleeding, jaundice, fever, oliguria and hematuria, altered mental status, headache, seizure, and back pain. Other patients are seen for cardiac arrest, psychiatric issues, sequelae of noncardiac surgery, and trauma. Although most patients have LVADs, some may have biventricular support devices or total artificial hearts. Involving a team of cardiac surgeons, perfusion experts, and heart-failure physicians, as well as ED and ICU physicians and nurses, is critical for managing treatment for these patients and for successful outcomes. This review is designed for critical care providers who may be the first to see these patients in the ED or ICU.

Biventricular mechanical support devices--clinical perspectives

Cardiac transplantation remains the optimal treatment for end stage heart failure in selected patients. However, the shortage of donor hearts, rigorous eligibility criteria and long waiting lists have increased the demand for alternative treatment strategies such as mechanical circulatory support. While many patients are adequately supported with left ventricular assist devices, frequently there is right heart failure or involvement of the right ventricle, requiring biventricular support. Pulsatile flow biventricular devices and total artificial hearts approved for temporary biventricular support have limitations including size, high rates of adverse events and restricted mobility which makes them unsuitable for long term support. A number of centres have reported dual continuous flow left ventricular assist devices as a means of supporting the left and right heart. This review will summarise the literature on the outcomes and complications from current biventricular support devices and assess the role of dual continuous flow VAD therapy, and the new continuous flow total heart replacement devices.