Extracorporeal Membrane Oxygenation as a Bridge to Durable Mechanical Circulatory Support: An Analysis of the STS-INTERMACS Database

Multicenter evaluation of left ventricular assist device implantation with or without ECMO bridge in cardiogenic shock

BACKGROUND

The efficacy of extracorporeal membrane oxygenation (ECMO) as a bridge to left ventricular assist device (LVAD) remains unclear, and recipients of the more contemporary HeartMate 3 (HM3) LVAD are not well represented in previous studies. We therefore undertook a multicenter, retrospective study of this population.

METHODS AND RESULTS

INTERMACS 1 LVAD recipients from five U.S. centers were included. In-hospital and one-year outcomes were recorded. The primary outcome was the overall mortality hazard comparing ECMO versus non-ECMO patients by propensity-weighted survival analysis. Secondary outcomes included survival by LVAD type, as well as postoperative and one-year outcomes. One hundred and twenty-seven patients were included; 24 received ECMO as a bridge to LVAD. Mortality was higher in patients bridged with ECMO in the primary analysis (HR 3.22 [95%CI 1.06-9.77], p = 0.039). Right ventricular assist device was more common in the ECMO group (ECMO: 54.2% vs non-ECMO: 11.7%, p < 0.001). Ischemic stroke was higher at one year in the ECMO group (ECMO: 25.0% vs non-ECMO: 4.9%, p = 0.006). Among the study cohort, one-year mortality was lower in HM3 than in HeartMate II (HMII) or HeartWare HVAD (10.5% vs 46.9% vs 31.6%, respectively; p < 0.001) recipients. Pump thrombosis at one year was lower in HM3 than in HMII or HVAD (1.8% vs 16.1% vs 16.2%, respectively; p = 0.026) recipients.

CONCLUSIONS

Higher mortality was observed with ECMO as a bridge to LVAD, likely due to higher acuity illness, yet acceptable one-year survival was seen compared with historical rates. The receipt of the HM3 was associated with improved survival compared with older generation devices.

Predicting outcomes following short-term ventricular assist device implant with the MELD-XI score

BACKGROUND

Short-term continuous flow (STCF) ventricular assist devices (VADs) are utilized in adults with cardiogenic shock; however, mortality remains high. Previous studies have found that high pre-operative MELD-XI scores in durable VAD patients are associated with mortality. The use of the MELD-XI score to predict outcomes in STCF-VAD patients has not been explored. We sought to determine the relationship between MELD-XI and outcomes in adults with STCF-VADs.

METHODS

This was a retrospective review of adults implanted with STCF-VADs between 2009 and 2019. Receiver operating characteristic (ROC) analysis was performed to predict outcomes and Kaplan-Meier analysis was done to assess survival.

RESULTS

Seventy-nine patients were included with a median MELD-XI score of 21.2 (IQR 13.5, 27.0). Patients with an unsuccessful wean from support (p < 0.001) or major post-operative bleeding (p = 0.03) had significantly higher pre-implant MELD-XI scores. The optimal MELD-XI cut-point for mortality was 24.9 with 27.8 for major bleeding. Survival was worse among patients in the high-risk MELD-XI group, however, not statistically significant (p = 0.09). Prior ECMO support, but not MELD-XI, was an independent predictor of unsuccessful wean (p = 0.03).

CONCLUSIONS

Pre-operative MELD-XI score was a moderate predictor of unsuccessful wean with limited utility in predicting bleeding in patients on STCF-VAD support. This scoring system may be useful in the clinical setting for pre-implant risk stratification and counseling among patients and outcomes.

Bridging strategies and cardiac replacement outcomes in patients with acute decompensated heart failure-related cardiogenic shock

AIMS

To describe outcomes associated with bridging strategies in patients with acute decompensated heart failure-related cardiogenic shock (ADHF-CS) bridged to durable left ventricular assist device (LVAD) or heart transplantation (HTx).

METHODS AND RESULTS

Durable LVAD or HTx recipients from 2014 to 2019 with pre-operative ADHF-CS were identified in the Society of Thoracic Surgeons Adult Cardiac Surgery Database and stratified by bridging strategy. The primary outcome was operative or 30-day post-operative mortality. Secondary outcomes included post-operative major bleeding. Exploratory comparisons between bridging strategies and outcomes were performed using overlap weighting with and without covariate adjustment. Among 9783 patients with pre-operative CS, 8777 (89.7%) had ADHF-CS. Medical therapy (n = 5013) was the most common bridging strategy, followed by intra-aortic balloon pump (IABP; n = 2816), catheter-based temporary mechanical circulatory support (TMCS; n = 417), and veno-arterial extracorporeal membrane oxygenation (VA-ECMO; n = 465). Mortality was highest in patients bridged with VA-ECMO (22%), followed by catheter-based TMCS (10%), IABP (9%), and medical therapy (7%). Adverse post-operative outcomes were more frequent in LVAD recipients compared with HTx recipients.

CONCLUSION

Among patients with ADHF-CS bridged to HTx or durable LVAD, the highest rates of death and adverse events during index hospitalization were observed in those bridged with VA-ECMO, followed by catheter-based TMCS, IABP, and medical therapy. Patients who received durable LVAD had higher rates of post-operative complications compared with HTx recipients. Prospective trials are needed to define optimal bridging strategies in patients with ADHF-CS.

State of the art - Extracorporeal membrane oxygenation as a bridge to thoracic transplantation

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) has revolutionized the treatment of refractory cardiac and respiratory failure, and its use continues to increase, particularly in adults. However, ECMO-related morbidity and mortality remain high.

MAIN TEXT

In this review, we investigate and expand upon the current state of the art in thoracic transplant and extracorporeal life support (ELS). In particular, we examine recent increase in incidence of heart transplant in patients supported by ECMO; the potential changes in patient care and selection for transplant in the years prior to updated United Network for Organ Sharing (UNOS) organ allocation guidelines versus those in the years following, particularly where these guidelines pertain to ECMO; and the newly revived practice of heart-lung block transplants (HLT) and the prevalence and utility of ECMO support in patients listed for HLT.

CONCLUSIONS

Our findings highlight encouraging outcomes in patients bridged to transplant with ECMO, considerable changes in treatment surrounding the updated UNOS guidelines, and complex, diverse outcomes among different centers in their care for increasingly ill patients listed for thoracic transplant.

Use of Extracorporeal Membrane Oxygenation as Bridge to Replacement Therapies in Cardiogenic Shock: Insights From the Extracorporeal Life Support Organization

BACKGROUND

There has been increasing use of extracorporeal membrane oxygenation (ECMO) as bridge to heart transplant (orthotopic heart transplant [OHT]) or left ventricular assist device (LVAD) over the last decade. We aimed to provide insights on the population, outcomes, and predictors for the selection of each therapy.

METHODS

Using the Extracorporeal Life Support Organization Registry between 2010 and 2019, we compared in-hospital mortality and length of stay, predictors of OHT versus LVAD, and predictors of in-hospital mortality for patients with cardiogenic shock that were bridged with ECMO to OHT or LVAD. One hundred sixty-seven patients underwent LVAD versus 234 patients who underwent OHT.

RESULTS

The overall use of ECMO has increased from 1.7% in 2010 to 22.2% in 2019. Mortality was similar between groups (LVAD: 28.7% versus OHT: 29.1%) while length of stay was longer for OHT (LVAD: 49.6 versus OHT: 59.5 days, P=0.05). Factors associated with OHT included prior transplant (odds ratio [OR]=31.26 [CI, 3.84-780.5]), use of a temporary pacemaker (OR=6.5 [CI, 1.39-50.15]), and increased use of inotropes on ECMO (OR=3.77 [CI, 1.39-11.07]), whereas LVAD use was associated with weight (OR=0.98 [CI, 0.97-0.99]), cardiogenic shock presentation (OR=0.40 [CI, 0.21-0.78]), previous LVAD (OR=0.01 [CI, 0.0001-0.22]), respiratory failure (OR=0.28 [CI, 0.11-0.70]), and milrinone infusion (OR=0.32 [CI, 0.15-0.67]). Older age (OR=1.07 [CI, 1.02-1.12]), cannulation bleeding (OR=26.1 [CI, 4.32-221.3]), and surgical bleeding (OR=6.7 [CI, 1.26-39.9]) in patients receiving LVAD and respiratory failure (OR=5 [CI, 1.17-23.1]) and continuous renal replacement therapy (OR=3.82 [CI, 1.28-11.9]) in patients receiving OHT were associated with increased mortality.

CONCLUSIONS

ECMO use as a bridge to advanced therapies has increased over time, with more patients undergoing LVAD than OHT. Mortality was equal between the 2 groups while length of stay was longer for OHT.

Extracorporeal membrane oxygenation as a bridge to durable left ventricular assist device implantation in INTERMACS-1 patients

Left ventricular assist devices (LVADs) are increasingly used as destination therapy or as a bridge to future cardiac transplant in patients with end-stage heart failure. Extracorporeal membrane oxygenation (ECMO) can be used to bridge patients in cardiogenic shock or with decompensated heart failure to durable mechanical circulatory support. We assessed outcomes in patients in critical cardiogenic shock (Interagency Registry for Mechanically Assisted Circulatory Support [INTERMACS] profile 1) who underwent implantation of a continuous-flow (CF)-LVAD, with or without preoperative ECMO bridging. For this retrospective study, we selected INTERMACS profile 1 patients who underwent CF-LVAD implantation at our institution between Sep 1, 2004 and Nov 30, 2018. Of 768 patients identified, 133 (17.3%) were INTERMACS profile 1; 26 (19.5%) received preoperative ECMO support, and 107 (80.5%) did not. Postimplantation outcomes were compared between the ECMO and no-ECMO groups. No significant differences were found in 30-day mortality (15.4 vs. 15.9%, P = 0.95) or survival at 1 year (53.8 vs. 60.9%, P = 0.51). Three patients who received ECMO before CF-LVAD implantation subsequently underwent cardiac transplant. In the ECMO group, the lactate level 1 day after ECMO initiation was lower in survivors than nonsurvivors (2.7 ± 2.2 vs. 7.4 ± 4.2 mmol/L, P = 0.02; area under the curve = 0.85, P = 0.01) after CF-LVAD implantation. Bridging with ECMO to CF-LVAD implantation in carefully selected INTERMACS profile 1 patients (those who are at the highest risk for critical cardiogenic shock and for whom palliation may be the only other option) produced acceptable postoperative outcomes.Field of research: Artificial lung/ECMO.

Clinical Outcomes Associated With Acute Mechanical Circulatory Support Utilization in Heart Failure Related Cardiogenic Shock

BACKGROUND

Cardiogenic shock occurring in the setting of advanced heart failure (HF-CS) is increasingly common. However, recent studies have focused almost exclusively on acute myocardial infarction-related CS. We sought to define clinical, hemodynamic, metabolic, and treatment parameters associated with clinical outcomes among patients with HF-CS, using data from the Cardiogenic Shock Working Group registry.

METHODS

Patients with HF-CS were identified from the multicenter Cardiogenic Shock Working Group registry and divided into 3 outcome categories assessed at hospital discharge: mortality, heart replacement therapy (HRT: durable ventricular assist device or orthotopic heart transplant), or native heart survival. Clinical characteristics, hemodynamic, laboratory parameters, drug therapies, acute mechanical circulatory support device (AMCS) utilization, and Society of Cardiovascular Angiography and Intervention stages were compared across the 3 outcome cohorts.

RESULTS

Of the 712 patients with HF-CS identified, 180 (25.3%) died during their index admission, 277 (38.9%) underwent HRT (durable ventricular assist device or orthotopic heart transplant), and 255 (35.8%) experienced native heart survival without HRT. Patients who died had the highest right atrial pressure and heart rate and the lowest mean arterial pressure of the 3 outcome groups (P<0.01 for all). Biventricular and isolated left ventricular congestion were common among patients who died or underwent HRT, respectively. Lactate, blood urea nitrogen, serum creatinine, and aspartate aminotransferase were highest in patients with HF-CS experiencing in-hospital death. Intraaortic balloon pump was the most commonly used AMCS device in the overall cohort and among patients receiving HRT. Patients receiving >1 AMCS device had the highest in-hospital mortality rate irrespective of the number of vasoactive drugs used. Mortality increased with deteriorating Society of Cardiovascular Angiography and Intervention stages (stage B: 0%, stage C: 10.7%, stage D: 29.4%, stage E: 54.5%, 1-way ANOVA=<0.001).

CONCLUSIONS

Patients with HF-CS experiencing in-hospital mortality had a high prevalence of biventricular congestion and markers of end-organ hypoperfusion. Substantial heterogeneity exists with use of AMCS in HF-CS with intraaortic balloon pump being the most common device used and high rates of in-hospital mortality after exposure to >1 AMCS device.

Contemporary Use of Venoarterial Extracorporeal Membrane Oxygenation: Insights from the Multicenter RESCUE Registry

BACKGROUND

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is increasingly used as a life-saving therapy for patients with cardiovascular collapse, but identifying patients unlikely to benefit remains a challenge.

METHODS AND RESULTS

We created the RESCUE registry, a retrospective, observational registry of adult patients treated with VA-ECMO between January 2007 and June 2017 at 3 high-volume centers (Columbia University, Duke University, and Washington University) to describe short-term patient outcomes. In 723 patients treated with VA-ECMO, the most common indications for deployment were postcardiotomy shock (31%), cardiomyopathy (including acute heart failure) (26%), and myocardial infarction (17%). Patients frequently suffered in-hospital complications, including acute renal dysfunction (45%), major bleeding (41%), and infection (33%). Only 40% of patients (n = 290) survived to discharge, with a minority receiving durable cardiac support (left ventricular assist device [n = 48] or heart transplantation [n = 7]). Multivariable regression analysis identified risk factors for mortality on ECMO as older age (odds ratio [OR], 1.26; 95% confidence interval [CI], 1.12-1.42) and female sex (OR, 1.44; 95% CI, 1.02-2.02) and risk factors for mortality after decannulation as higher body mass index (OR 1.17; 95% CI, 1.01-1.35) and major bleeding while on ECMO support (OR, 1.92; 95% CI, 1.23-2.99).

CONCLUSIONS

Despite contemporary care at high-volume centers, patients treated with VA-ECMO continue to have significant in-hospital morbidity and mortality. The optimization of outcomes will require refinements in patient selection and improvement of care delivery.