To vent or not on veno-arterial extracorporeal membrane oxygenation, does it improve myocardial recovery and outcome?

Left-ventricular unloading in extracorporeal cardiopulmonary resuscitation due to acute myocardial infarction - A multicenter study

BACKGROUND

Guidelines advocate the use of extracorporeal cardio-pulmonary resuscitation with veno-arterial extracorporeal membrane oxygenation (VA-ECMO) in selected patients with cardiac arrest. Effects of concomitant left-ventricular (LV) unloading with Impella® (ECMELLA) remain unclear. This is the first study to investigate whether treatment with ECMELLA was associated with improved outcomes in patients with refractory cardiac arrest caused by acute myocardial infarction (AMI).

METHODS

This study was approved by the local ethical committee. Patients treated with ECMELLA at three centers between 2016 and 2021 were propensity score (PS)-matched to patients receiving VA-ECMO based on age, electrocardiogram rhythm, cardiac arrest location and Survival After Veno-Arterial ECMO (SAVE) score. Cox proportional-hazard and Poisson regression models were used to analyse 30-day mortality rate (primary outcome), hospital and intensive care unit (ICU) length of stay (LOS) (secondary outcomes). Sensitivity analyses on patient demographics and cardiac arrest parameters were performed.

RESULTS

95 adult patients were included in this study, out of whom 34 pairs of patients were PS-matched. ECMELLA treatment was associated with decreased 30-day mortality risk (Hazard Ratio [HR] 0.53 [95% Confidence Interval (CI) 0.31-0.91], P = 0.021), prolonged hospital (Incidence Rate Ratio (IRR) 1.71 [95% CI 1.50-1.95], P < 0.001) and ICU LOS (IRR 1.81 [95% CI 1.57-2.08], P < 0.001). LV ejection fraction significantly improved until ICU discharge in the ECMELLA group. Especially patients with prolonged low-flow time and high initial lactate benefited from additional LV unloading.

CONCLUSIONS

LV unloading with Impella® concomitant to VA-ECMO therapy in patients with therapy-refractory cardiac arrest due to AMI was associated with improved patient outcomes.

Enhancing cardiac arrest survival with extracorporeal cardiopulmonary resuscitation: insights into the process of death

Extracorporeal cardiopulmonary resuscitation (ECPR) is an emerging method of cardiopulmonary resuscitation to improve outcomes from cardiac arrest. This approach targets patients with out-of-hospital cardiac arrest previously unresponsive and refractory to standard treatment, combining approximately 1 h of standard CPR followed by venoarterial extracorporeal membrane oxygenation (VA-ECMO) and coronary artery revascularization. Despite its relatively new emergence for the treatment of cardiac arrest, the approach is grounded in a vast body of preclinical and clinical data that demonstrate significantly improved survival and neurological outcomes despite unprecedented, prolonged periods of CPR. In this review, we detail the principles behind VA-ECMO-facilitated resuscitation, contemporary clinical approaches with outcomes, and address the emerging new understanding of the process of death and capability for neurological recovery.

Atrial Septostomy for Left Ventricular Unloading During Extracorporeal Membrane Oxygenation for Cardiogenic Shock: Animal Model

OBJECTIVES

The aim of this study was to quantify and understand the unloading effect of percutaneous balloon atrial septostomy (BAS) in acute cardiogenic shock (CS) treated with venoarterial (VA) extracorporeal membranous oxygenation (ECMO).

BACKGROUND

In CS treated with VA ECMO, increased left ventricular (LV) afterload is observed that commonly interferes with myocardial recovery or even promotes further LV deterioration. Several techniques for LV unloading exist, but the optimal strategy and the actual extent of such procedures have not been fully disclosed.

METHODS

In a porcine model (n = 11; weight 56 kg [53-58 kg]), CS was induced by coronary artery balloon occlusion (57 minutes [53-64 minutes]). Then, a step-up VA ECMO protocol (40-80 mL/kg/min) was run before and after percutaneous BAS was performed. LV pressure-volume loops and multiple hemoglobin saturation data were evaluated. The Wilcoxon rank sum test was used to assess individual variable differences.

RESULTS

Immediately after BAS while on VA ECMO support, LV work decreased significantly: pressure-volume area, end-diastolic pressure, and stroke volume to ∼78% and end-systolic pressure to ∼86%, while superior vena cava and tissue oximetry did not change. During elevating VA ECMO support (40-80 mL/kg/min) with BAS vs without BAS, we observed 1) significantly less mechanical work increase (122% vs 172%); 2) no end-diastolic volume increase (100% vs 111%); and 3) a considerable increase in end-systolic pressure (134% vs 144%).

CONCLUSIONS

In acute CS supported by VA ECMO, atrial septostomy is an effective LV unloading tool. LV pressure is a key component of LV work load, so whenever LV work reduction is a priority, arterial pressure should carefully be titrated low while maintaining organ perfusion.

Left Heart Decompression on Veno-Arterial Extracorporeal Membrane Oxygenation in Children With Dilated Cardiomyopathy and Myocarditis: An Extracorporeal Life Support Organization Registry Review

OBJECTIVES

To describe the association between left heart decompression on veno-arterial extracorporeal membrane oxygenation and survival in patients with myocarditis and dilated cardiomyopathy. The secondary outcome is to study association of left heart decompression with survival in children with myocarditis compared with those with dilated cardiomyopathy.

DESIGN

Retrospective study of a multicenter registry database.

SETTING

Data reported to Extracorporeal Life Support Organization from international extracorporeal membrane oxygenation centers.

PATIENTS

Patients less than or equal to 18 years old with a diagnosis of myocarditis or dilated cardiomyopathy receiving extracorporeal membrane oxygenation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 1,438 pediatric extracorporeal membrane oxygenation runs were identified. Thirty-seven percent of the patients had myocarditis (n = 532), whereas the rest had dilated cardiomyopathy. Survival to hospital discharge was 63%. Median extracorporeal membrane oxygenation duration was 148 hours with interquartile range (84-248 hr). Nineteen percent of patients (n = 274) had left heart decompression. Multivariable analysis revealed using left heart decompression (adjusted odds ratio, 1.42; 95% CI, 1.06-1.89; p = 0.02), e-cardiopulmonary resuscitation (adjusted odds ratio, 0.63; 95% CI, 0.51-0.79; p < 0.001), higher pH (adjusted odds ratio, 3.69; 95% CI, 1.80-7.53; p < 0.001), and diagnosis of myocarditis (adjusted odds ratio, 1.69; 95% CI, 1.35-2.08; p < 0.001) were associated with greater odds of survival. In the multivariable analysis for patients with dilated cardiomyopathy, left heart decompression failed to reveal a significant association with survival (20% among survivors vs 17% among nonsurvivors, 95% CI, -2.2% to 8.0%). Meanwhile in patients with myocarditis, the multivariable analysis failed to exclude the possibility that left heart decompression was associated with up to a three-fold greater odds of survival (adjusted odds ratio, 1.77; 95% CI, 0.99-.15).

CONCLUSIONS

Retrospective review of the Extracorporeal Life Support Organization registry revealed an association between left heart decompression and greater odds of survival in children with myocarditis and dilated cardiomyopathy on extracorporeal membrane oxygenation. When comparing patients with dilated cardiomyopathy against those with myocarditis, we could not exclude a three-fold greater odds of survival associated with the use of left heart decompression. This finding warrants further prospective evaluation.

Extracorporeal Life Support for Cardiac Arrest and Cardiogenic Shock

The rising incidence and recognition of cardiogenic shock has led to an increase in the use of veno-arterial extracorporeal membrane oxygenation (VA-ECMO). As clinical experience with this therapy has increased, there has also been a rapid growth in the body of observational and randomized data describing the clinical and logistical considerations required to institute a VA-ECMO program with successful clinical outcomes. The aim of this review is to summarize this contemporary data in the context of four key themes that pertain to VA-ECMO programs: the principles of patient selection; basic hemodynamic and technical principles underlying VA-ECMO; contraindications to VA-ECMO therapy; and common complications and intensive care considerations that are encountered in the setting of VA-ECMO therapy.

Impact of left ventricular unloading using a peripheral Impella®-pump in eCPR patients

BACKGROUND

Extracorporeal cardiopulmonary resuscitation (eCPR) is a rapidly growing treatment strategy due to increasing survival rates in selected patients. Additional left ventricular mechanical unloading, using a transfemoral micro-axial blood pump (Impella® Denver, Massachusetts, USA), might improve patients' outcomes. In this regard, we sought to investigate patients who suffered OHCA (out-of hospital cardiac arrest) or IHCA (in-hospital cardiac arrest) with subsequent eCPR via VA-ECMO (veno-arterial extracorporeal membrane oxygenation) and concomitant Impella® implantation based on survival and feasibility of ECMO weaning.

METHODS

From January 2016 until December 2020, 108 patients underwent eCPR at our institution. Data prior to eCPR and early outcome parameters were analyzed comparing patients who were supported with an additional Impella® (2.5 or CP) (ECMO+Impella®, n = 18) and patients without additional (ECMO, n = 90) support during V-A ECMO therapy. The primary endpoint was in-hospital mortality; secondary endpoints were, among others: ECMO explantation, need for hemodialysis, stroke, and need for blood transfusions.

RESULTS

Low-flow time was significantly lower in the ECMO+Impella group (60 min vs. 55 min, p = .01). All-cause mortality was significantly lower in the ECMO+Impella® group (82% vs. 56%, p = .01). The time of circulatory support was shorter in the ECMO cohort (2.0 ± 1.73 vs. 4.76 ± 2.88 p = .05). ECMO decannulation was significantly more feasible in patients with ECMO+Impella® (72% vs. 32%, p = .01). Patients treated with additional Impella® showed significantly more acute kidney injury with the need for dialysis (72% vs. 18%, p ≤ .01).

CONCLUSION

Concomitant Impella® support might positively influence survival and ECMO weaning in eCPR patients. Treatment-associated complications such as the need for dialysis were more common in this highly selected patient group. Further studies with larger numbers are necessary to evaluate the clinical relevance of concomitant LV-unloading in eCPR patients using an Impella® device.

Transapical mitral valve-in-valve procedure with elective venoarterial ECMO in a patient with severe kyphoscoliosis

Transcatheter mitral valve-in-valve replacement (TMVR) is a feasible alternative in high-risk patients requiring reoperation for failing mitral bioprosthesis. Such patients may present with hemodynamic instability or sudden complications, which may jeopardize the outcomes. We report a successful transapical TMVR in a patient, with severe kyphoscoliosis and on prolonged mechanical ventilation, with prophylactic extracorporeal membrane oxygenator support. This combined procedure may be helpful to reduce the complications of TMVR in critically ill subjects.

Echocardiographic evaluation of cardiac recovery after refractory out-of-hospital cardiac arrest

BACKGROUND

The mechanisms and degree of myocardial recovery during treatment with venoarterial extracorporeal membrane oxygenation (VA-ECMO) are unclear. We performed a descriptive study to evaluate myocardial recovery and changes in parameters of myocardial loading using echocardiography.

METHODS

We retrospectively evaluated patients with refractory ventricular tachycardia/ventricular fibrillation out-of-hospital cardiac arrest who were treated with the Minnesota Resuscitation Consortium protocol. Left ventricular ejection fraction (LVEF), end-diastolic diameter (LVEDD), end-systolic diameter (LVESD), and fractional shortening were assessed using serial echocardiography. One-way analysis of variance (ANOVA) was used to compare parameters over six hospitalization stages. Two-way ANOVA was used to compare these parameters between patients that survived the index hospitalization and those that died.

RESULTS

77 patients had >1 echocardiographic turndown evaluations. Thirty-eight patients survived to discharge and 39 patients died. Of 39 in-hospital deaths, 17 patients died before VA-ECMO decannulation and 22 patients died after VA-ECMO decannulation. Among all patients, LVEF improved from 9.7 ± 10.1% from the first echocardiogram after rewarming to 43.1 ± 13.1% after decannulation (p < 0.001) and fractional shortening ratio improved from 0.14 ± 0.12 to 0.31 ± 0.14 (p < 0.001). The LVEDD and LVESD remained stable (p = 0.36 and p = 0.12, respectively). Patients that died had a lower LVEF by an average of 6.93% (95% confidence interval: -10.0 to -3.83, p < 0.001), but other parameters were similar.

CONCLUSION

Refractory cardiac arrest patients treated with VA-ECMO experience significant recovery of ventricular function during treatment. We postulate that this primarily occurs via reduction of LV preload.

Left ventricle unloading strategies in ECMO: A single-center experience

INTRODUCTION

Extracorporeal membrane oxygenation (ECMO) is a life-saving technology capable of restoring perfusion but is not without significant complications that limit its realizable therapeutic benefit. ECMO-induced hemodynamics increase cardiac afterload risking left ventricular distention and impaired cardiac recovery. To mitigate potentially harmful effects, multiple strategies to unload the left ventricle (LV) are used in clinical practice but data supporting the optimal approach is presently lacking.

MATERIALS & METHODS

We reviewed outcomes of our ECMO population from September 2015 through January 2019 to determine if our LV unloading strategies were associated with patient outcomes. We compared reactive (Group 1, n = 30) versus immediate (Group 2, n = 33) LV unloading and then compared patients unloaded with an Impella CP (n = 19) versus an intra-aortic balloon pump (IABP, n = 16), analyzing survival and ECMO-related complications.

RESULTS

Survival was similar between Groups 1 and 2 (33 vs 42%, P = .426) with Group 2 experiencing more clinically-significant hemorrhage (40 vs. 67%, P = .034). Survival and ECMO-related complications were similar between patients unloaded with an Impella versus an IABP. However, the Impella group exhibited a higher rate of survival (37%) than predicted by their median SAVE score (18%).

DISCUSSION

Based on this analysis, reactive unloading appears to be a viable strategy while venting with the Impella CP provides better than anticipated survival. Our findings correlate with recent large cohort studies and motivate further work to design clinical guidelines and future trial design.

Management of Peripheral Venoarterial Extracorporeal Membrane Oxygenation in Cardiogenic Shock

OBJECTIVES

Cardiogenic shock is a highly morbid condition in which inadequate end-organ perfusion leads to death if untreated. Peripheral venoarterial extracorporeal membrane oxygenation is increasingly used to restore systemic perfusion despite limited understanding of how to optimally titrate support. This review provides insights into the physiologic basis of extracorporeal membrane oxygenation support and presents an approach to extracorporeal membrane oxygenation management in the cardiogenic shock patient.

DATA SOURCES, STUDY SELECTION, AND DATA EXTRACTION

Data were obtained from a PubMed search of the most recent medical literature identified from MeSH terms: extracorporeal membrane oxygenation, cardiogenic shock, percutaneous mechanical circulatory support, and heart failure. Articles included original articles, case reports, and review articles.

DATA SYNTHESIS

Current evidence detailing the use of extracorporeal membrane oxygenation to support patients in cardiogenic shock is limited to isolated case reports and single institution case series focused on patient outcomes but lacking in detailed approaches to extracorporeal membrane oxygenation management. Unlike medical therapy, in which dosages are either prescribed or carefully titrated to specific variables, extracorporeal membrane oxygenation is a mechanical support therapy requiring ongoing titration but without widely accepted variables to guide treatment. Similar to mechanical ventilation, extracorporeal membrane oxygenation can provide substantial benefit or induce significant harm. The widespread use and present lack of data to guide extracorporeal membrane oxygenation support demands that intensivists adopt a physiologically-based approach to management of the cardiogenic shock patient on extracorporeal membrane oxygenation.

CONCLUSIONS

Extracorporeal membrane oxygenation is a powerful mechanical circulatory support modality capable of rapidly restoring systemic perfusion yet lacking in defined approaches to management. Adopting a management approach based physiologic principles provides a basis for care.

Left Ventricle Unloading with Veno-Arterial Extracorporeal Membrane Oxygenation for Cardiogenic Shock. Systematic Review and Meta-Analysis

During veno-arterial extracorporeal membrane oxygenation (VA-ECMO), the increase of left ventricular (LV) afterload can potentially increase the LV stress, exacerbate myocardial ischemia and delay recovery from cardiogenic shock (CS). Several strategies of LV unloading have been proposed. Systematic review and meta-analysis in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement included adult patients from studies published between January 2000 and March 2019. The search was conducted through numerous databases. Overall, from 62 papers, 7581 patients were included, among whom 3337 (44.0%) received LV unloading concomitant to VA-ECMO. Overall, in-hospital mortality was 58.9% (4466/7581). A concomitant strategy of LV unloading as compared to ECMO alone was associated with 12% lower mortality risk (RR 0.88; 95% CI 0.82–0.93; p < 0.0001; I² = 40%) and 35% higher probability of weaning from ECMO (RR 1.35; 95% CI 1.21–1.51; p < 0.00001; I² = 38%). In an analysis stratified by setting, the highest mortality risk benefit was observed in case of acute myocardial infarction: RR 0.75; 95%CI 0.68–0.83; p < 0.0001; I² = 0%. There were no apparent differences between two techniques in terms of complications. In heterogeneous populations of critically ill adults in CS and supported with VA-ECMO, the adjunct of LV unloading is associated with lower early mortality and higher rate of weaning.

Efficacy of left heart decompression during extracorporeal membrane oxygenation: a case-control study

Background

Veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) is used in various cardiogenic shocks. In severe myocardial dysfunction, left heart (LH) distension may occur and aggravate pulmonary edema. Despite the recent case reports on various venting catheter insertion methods for LH decompression, the necessity and efficacy of LH venting procedure are still controversial. Therefore, we focused on evaluating efficacy of LH venting catheter insertion for LH decompression.

Methods

In total, 373 patients received VA ECMO at our institution from May 2012 to January 2016. Of these, 25 patients underwent LH venting catheter insertion. Indication for the procedure included pulmonary congestion observed on chest radiogram, with arterial pulse pressure ≤10 mmHg. The control group comprised of 45 patients with peripheral VA ECMO having arterial pulse pressure ≤ for ≥24 hours during the same study period who did not undergo LH venting procedure. Finally, 70 patients were compared and analyzed.

Results

Mean age of the patients was 52.6±17.1 years. The ECMO running time in each group was 7.2±7.1 days in the vent (-) group and 9.2±8.5 days in the vent (+) group. Successful weaning rate was higher in the LH vent (+) group (P=0.08). Moreover, LH venting catheter insertion was identified as a predictor of weaning success with marginal significance (OR =2.47; 95% CI: 0.90-6.72; P=0.07).

Conclusions

LH decompression by venting catheter insertion in patients on VA ECMO may be more effective and helpful for successful ECMO weaning than conventional medical management without survival benefit.

Clinical complications during veno-arterial extracorporeal membrane oxigenation in post-cardiotomy and non post-cardiotomy shock: still the achille's heel

Extracorporeal membrane oxygenation (ECMO) is life-saving for potentially reversible heart failure and respiratory injuries not responsive to conventional therapies. Technological innovations have produced over the years significant improvements in ECMO devices (pump, cannula design and oxygenator) and have allowed a better risk/benefit profile. Alongside with recognized advantages in the treatment of very sick patients, ECMO remains an invasive procedure for mechanical circulatory support (MCS) and it is associated with complications that strongly influence the prognosis. Current review was designed to provide a comprehensive outline on ECMO complications, analyzing risk factors and strategies of management, focusing on adult population undergoing veno-arterial ECMO (VA-ECMO) therapy.