Role of percutaneous veno-arterial extracorporeal membrane oxygenation as bridge to left ventricular assist device

Impella Versus VA-ECMO for Patients with Cardiogenic Shock: Comprehensive Systematic Literature Review and Meta-Analyses

Impella and VA-ECMO are two possible therapeutic courses for the treatment of patients with cardiogenic shock (CS). The study aims to perform a systematic literature review and meta-analyses of a comprehensive set of clinical and socio-economic outcomes observed when using Impella or VA-ECMO with patients under CS. A systematic literature review was performed in Medline, and Web of Science databases on 21 February 2022. Nonoverlapping studies with adult patients supported for CS with Impella or VA-ECMO were searched. Study designs including RCTs, observational studies, and economic evaluations were considered. Data on patient characteristics, type of support, and outcomes were extracted. Additionally, meta-analyses were performed on the most relevant and recurring outcomes, and results shown using forest plots. A total of 102 studies were included, 57% on Impella, 43% on VA-ECMO. The most common outcomes investigated were mortality/survival, duration of support, and bleeding. Ischemic stroke was lower in patients treated with Impella compared to the VA-ECMO population, with statistically significant difference. Socio-economic outcomes including quality of life or resource use were not reported in any study. The study highlighted areas where further data collection is needed to clarify the value of complex, new technologies in the treatment of CS that will enable comparative assessments focusing both on the health impact on patient outcomes and on the financial burden for government budgets. Future studies need to fill the gap to comply with recent regulatory updates at the European and national levels.

Incremental cost-effectiveness of extracorporeal membranous oxygenation as a bridge to cardiac transplant or left ventricular assist device placement in patients with refractory cardiogenic shock

Objective

Emerging literature has described using venoarterial extracorporeal membranous oxygenation (ECMO) as a bridge to transplant or left ventricular assist device (LVAD) placement. We sought to identify the incremental cost-effectiveness ratio (ICER) of ECMO used as a bridge to cardiac transplant or LVAD.

Methods

Patients with refractory cardiogenic shock who received venoarterial ECMO and were bridged to either cardiac transplant (n = 7) or a HeartMate 3 LVAD (n = 6) placement were included. Markov modeling was used, comparing ECMO bridging with non–ECMO-bridged patients. Cohorts entered the model alive and at every 1-year cycle, were exposed to risk of death, and ran forward for 20 years after transplant or LVAD.

Results

Patients bridged with ECMO to cardiac transplant were stratified as group 1 whereas those bridged with ECMO to LVAD were stratified as group 2. The average ECMO run was 3 days in group 1 versus 11 days in group 2. Among group 1 patients, the ICER was $246,629 but was paired with a longer life expectancy. The ICER of group 2 patients was –$107,088 and was not paired with a longer life expectancy. The average inpatient cost for group 1 was found to be $636,023 versus $769,471 for group 2 patients. The average inpatient costs for patients not bridged to ECMO who received cardiac transplant or LVAD was $538,928 and $325,242, respectively.

Conclusions

Using ECMO to bridge to transplant or LVAD placement is not cost effective. However, patients bridged to transplant are paired with longer life expectancy in contrast to patients bridged to LVAD.

Predictors of mortality following extracorporeal membrane oxygenation support in an unselected, critically ill patient population

Introduction

Mechanical circulatory support (MCS) has been established as a means of augmenting circulation in patients with critically decreased systolic function due to a variety of underlying clinical reasons. Different methods of MCS may be used, with the venous-arterial extracorporeal membrane oxygenation system (VA-ECMO) being one of the most utilized devices in everyday care.

Aim

To determine independent predictors influencing mortality outcomes following VA-ECMO therapy in a large, unselected, adult, critically ill patient population in cardiogenic shock (CS).

Material and methods

Data on 235 consecutive, real-world VA-ECMO treatments were assessed. Analysis was conducted for all subjects requiring MCS with the VA-ECMO as the first instalment, regardless of underlying cause or eventual upgrade. All potential clinical factors influencing mortality were examined and evaluated.

Results

Overall mortality was ~66% at median 28 days follow-up and significantly depended upon pH < 7.3 (HR = 3.56; p < 0.001), and age ≥ 65 years (HR = 1.96; p = 0.001). Acute coronary syndrome (ACS) as an indication for VA-ECMO displayed a nearly significant value (HR = 1.44; p = 0.07). Heart transplant (hTX) primary graft failure as an indication for the VA-ECMO displayed a clearly favorable outcome (HR = 0.51, p = 0.025); all data based on multivariate Cox regression analysis.

Conclusions

Mortality in patients requiring VA-ECMO remains high. We conclude that only decreased pH values and advanced age clearly influence mortality in this MCS scenario. ACS also bodes unfavorably, whereas hTX as an indication clearly shows better survival.

Current results of left ventricular assist device therapy in France: the ASSIST-ICD registry

OBJECTIVES

Our goal was to provide a picture of left ventricular assist device (LVAD) activity in France between 2007 and 2016 based on the multicentric ASSIST-ICD registry.

METHODS

We retrospectively collected 136 variables including in-hospital data, follow-up survival rates and adverse events from 671 LVAD recipients at 20 out of 24 LVAD implant centres in France. The average follow-up time was 1.2 years (standard deviation: 1.4); the total follow-up time was 807.5 patient-years.

RESULTS

The included devices were the HeartMate II®, HeartWare LVAS® or Jarvik 2000®. The overall likelihood of being alive while on LVAD support or having a transplant (primary end point) at 1, 2, 3 and 5 years postimplantation was 65.2%, 59.7%, 55.9% and 47.7%, respectively, given a cumulative incidence of 29.2% of receiving a transplant at year 5. At implantation, 21.5% of patients were on extracorporeal life support. The overall rate of cardiogenic shock at implantation was 53%. The major complications were driveline infection (26.1%), pump pocket or cannula infection (12.6%), LVAD thrombosis (12.2%), ischaemic (12.8%) or haemorrhagic stroke (5.4%; all strokes 18.2%), non-cerebral haemorrhage (9.1%) and LVAD exchange (5.2%). The primary end point (survival) was stratified by age at surgery and by the type of device used, with inference from baseline profiles. The primary end point combined with an absence of complications (secondary end point) was also stratified by device type.

CONCLUSIONS

The ASSIST-ICD registry provides a real-life picture of LVAD use in 20 of the 24 implant centres in France. Despite older average age and a higher proportion of patients chosen for destination therapy, survival rates improved compared to those in previous national registry results. This LVAD registry contrasts with other international registries because patients with implants have more severe disease, and the national policy for graft attribution is distinct. We recommend referring patients for LVAD earlier and suggest a discussion of the optimal timing of a transplant for bridged patients (more dismal results after the second year of support?).

Outcomes of transported and in-house patients on extracorporeal life support: a propensity score-matching study

OBJECTIVES

Patients on extracorporeal life support (ECLS), like other critically ill patients, are transported to other institutions for various reasons. However, little has been reported concerning the characteristics and clinical outcomes of transported patients compared with those of in-house patients.

METHODS

A total of 281 adult patients received ECLS between January 2014 and August 2016. Patients who underwent cannulation at another institution by our team were excluded. Patients were divided into 2 groups: transported group (N = 46) and in-house group (N = 235). All 46 patients were safely transported without serious adverse events. The mean travel distance was 206±140 km, with a mean travel time of 78 ± 57 min. Following propensity score matching, 44 transported patients were matched to 148 in-house patients.

RESULTS

In the matched population, the mean age was 48 ± 13 years in the transported group and 49 ± 17 years in the in-house group (P = 0.70). The ECLS type (venoarterial/venovenous) comprised 35/9 (79.5/20.5%) in the transported group and 119/29 (80.4/19.6%) in the in-house group (P = 0.93). Seventeen (38.6%) extracorporeal cardiopulmonary resuscitations were performed in the transported group and 59 (39.9%) were performed in the in-house group (P = 0.91). The incidence of limb ischaemia and acute kidney injury was higher in the transported group (P = 0.007 and P = 0.001, respectively). However, the rate of survival to discharge did not differ between the groups (63.6% in the transported group vs 64.2% in the in-house group, P = 0.94) and there was no difference in overall mortality (P = 0.99).

CONCLUSIONS

Although transported patients had more complications than in-house ECLS patients, clinical outcomes were comparable in the matched population. Transporting ECLS patients to an experienced centre may be justified based on our experience.

Less Invasive Approach to Left Ventricular Assist Device Implantation May Improve Survival in High-Risk Patients

OBJECTIVE

Despite improvement in outcomes after left ventricular assist device (LVAD) implantation over the past 2 decades, high-risk recipients continue to have a prohibitive rate of morbidity and mortality. We hypothesized that a less invasive approach to LVAD implantation would be associated with improved survival compared to a conventional approach in this high-risk cohort.

METHODS

All consecutive LVAD recipients (2013 to 2017) that underwent centrifugal LVAD implantation were retrospectively reviewed. Patients were classified as high-risk if INTERMACS 1 or required temporary VAD/venoarterial extracorporeal membrane oxygenation prior to durable VAD implantation. Patients were stratified into 3 groups: left thoracotomy with hemi-sternotomy (LTHS) high-risk, conventional sternotomy (CS) high-risk, and non-high-risk. The primary outcome was 1-year survival.

RESULTS

A total of 57 patients (LTHS high-risk: 11, CS high-risk: 12, non-high-risk: 34) were identified. Preoperative right ventricular failure scores, HeartMate-II mortality scores, and end-organ dysfunction were similar between the 2 high-risk groups. While operative time was similar between the 3 groups, cardiopulmonary bypass time was significantly shorter in the LTHS high-risk group compared to other groups. There was a trend toward decreased intensive care unit length of stay and ventilator time in LTHS high-risk compared to CS high-risk patients. Moreover, between these 2 groups, there was a significant decrease in temporary right VAD support (50% vs 0%, P = 0.014), and 1-year survival was significantly higher in the LTHS group (42% vs 91%, P = 0.025).

CONCLUSIONS

Less invasive LVAD implantation appears to be associated with improved survival compared to conventional LVAD implantation in high-risk patients.

Veno-Arterial Extracorporeal Membrane Oxygenation for Cardiogenic Shock

Extracorporeal membrane oxygenation has evolved, from a therapy that was selectively applied in the pediatric population in tertiary centers, to more widespread use in diverse forms of cardiopulmonary failure in all ages. We provide a practical review for cardiovascular clinicians on the application of veno-arterial extracorporeal membrane oxygenation in adult patients with cardiogenic shock, including epidemiology of cardiogenic shock, indications, contraindications, and the extracorporeal membrane oxygenation circuit. We also summarize cannulation techniques, practical management and troubleshooting, prognosis, and weaning and exit strategies, with attention to end of life and ethical considerations.

Can we expect improvements in outcomes with centrifugal vs axial flow left ventricular assist devices in patients transitioned from extracorporeal life support?

BACKGROUND

Several patient-related characteristics have been associated with inferior outcomes following durable left ventricular assist device (LVAD) implantation in patients transitioned from venoarterial extracorporeal membrane oxygenation (VA ECMO). The impact of LVAD pump type used is less well-known.

METHODS

We compared outcomes between patents who received axial and centrifugal flow LVADs following stabilization with VA ECMO.

RESULTS

From January 2011 to December 2018, we implanted 28 LVADs in patients transitioned from VA ECMO. This included 17 axial flow devices (HeartMate II LVAD, Abbott Laboratories, Chicago, IL) and 11 centrifugal flow pumps (eight HeartWare HVADs; Medtronic, Minneapolis, MN and three HeartMate 3 LVAS pumps; Abbott Laboratories, Chicago, IL). There was no difference in hospital mortality (23.5% vs 18.2%, P = .74) or 1-year survival (P = .31) between the devices. There were no differences in adverse event rates between the two pump types, apart from a higher rate of gastrointestinal bleeding in patients who received centrifugal flow pumps (1.44 events per 100 patient-months vs 14.67 events per 100 patient-months, P = .010). Preimplantation levels of alanine aminotransferase (hazard ratio [HR], 1.001; 95% confidence interval [CI], 1.000 to 1.002; P = .004) and elevated serum creatinine level (HR, 3.480; 95% CI, 1.121-10.807; P = .031) emerged as significant predictors of decreased 1-year survival.

CONCLUSIONS

Preimplantation optimization of end-organ function is the single most important determinant of successful post-LVAD survival in patients transitioned from extracorporeal life support. There is no association of pump type with LVAD outcomes up to 1-year post implantation.

Extracorporeal resuscitation as a further modifier of clinical outcome in patients with left ventricular assist device implantation and Interagency Registry for Mechanically Assisted Circulatory Support level 1

In cardiogenic shock patients with Interagency Registry for Mechanical Circulatory Support (INTERMACS) level 1, the need for temporary circulatory support is a predictor and modifier of patient outcome. Because this group includes patients with and without cardiopulmonary resuscitation (CPR) and is thus very heterogeneous, we investigated whether a further subclassification is useful. We compared 30-day and 1-year mortality of patients who underwent left ventricular assist device implantation after extracorporeal CPR with the aid of an extracorporeal life support system (CPR+ group; n = 40) with cardiogenic shock patients in which the extracorporeal life support system was implanted under non-CPR conditions (CPR- group, n = 68). In the CPR+ and CPR- groups, 30-day mortality was 27.5% (n = 11) and 8.8% (n = 6), respectively (P = 0.014). The values for 1-year mortality were 57.5% (n = 23) and 36.8% (n = 25), respectively (P = 0.023). The age- and gender-adjusted hazard ratios of 30-day and 1-year mortality for the CPR+ group versus the CPR- group were 3.88 (95% confidence interval 1.29-11.7; P = 0.016) and 1.79 (95% confidence interval 1.01-3.17; P = 0.045), respectively. In conclusion, our data show that left ventricular assist device implantation with extracorporeal life support following CPR is associated with high 30-day and 1-year mortality. Further multicentre studies are needed to confirm these results and potentially add CPR as a new modifier to the INTERMACS profile.