Extra-corporeal membrane oxygenation for refractory cardiogenic shock after adult cardiac surgery: a systematic review and meta-analysis

Abstract

BackgroundPostcardiotomy cardiogenic shock (PCCS) refractory to inotropic support and intra-aortic balloon pump (IABP) occurs rarely but is almost universally fatal without mechanical circulatory support. In this systematic review and meta-analysis we looked at the evidence behind the use of veno-arterial extra-corporeal membrane oxygenation (VA ECMO) in refractory PCCS from a patient survival rate and determinants of outcome viewpoint.MethodsA systematic review was performed in January 2017 using PubMed (with no defined time period) using the keywords “postcardiotomy”, “cardiogenic shock”, “extracorporeal membrane oxygenation” and “cardiac surgery”. We excluded papers pertaining to ECMO following paediatric cardiac surgery, medical causes of cardiogenic shock, as well as case reports, review articles, expert opinions, and letters to the editor. Once the studies were collated, a meta-analysis was performed on the proportion of survivors in those papers that met the inclusion criteria. Meta-regression was performed for the most commonly reported adverse prognostic indicators (API).ResultsWe identified 24 studies and a cumulative pool of 1926 patients from 1992 to 2016. We tabulated the demographic data, including the strengths and weaknesses for each of the studies, outcomes of VA ECMO for refractory PCCS, complications, and APIs. All the studies were retrospective cohort studies. Meta-analysis of the moderately heterogeneous data (95% CI 0.29 to 0.34, p < 0.01, I 2 = 60%) revealed overall survival rate to hospital discharge of 30.8%. Some of the commonly reported APIs were advanced age (>70 years, 95% CI −0.057 to 0.001, P = 0.058), and long ECMO support (95% CI −0.068 to 0.166, P = 0.412). Postoperative renal failure, high EuroSCORE (>20%), diabetes mellitus, obesity, rising lactate whilst on ECMO, gastrointestinal complications had also been reported.ConclusionHaemodynamic support with VA ECMO provides a survival benefit with reasonable intermediate and long-term outcomes. Many studies had reported advanced age, renal failure and prolonged VA ECMO support as the most likely APIs for VA ECMO in PCCS. EuroSCORE can be utilized to anticipate the need for prophylactic perioperative VA ECMO in the high-risk category. APIs can be used to aid decision-making regarding both the institution and weaning of ECMO for refractory PCCS.

The role of extracorporeal membrane oxygenator therapy in the setting of Type A aortic dissection

“…Factors requiring ECMO support after open or endovascular repair for type A dissection include biventricular dysfunction from a persistent flap or tear in the main coronary arteries, propagation of the tear or dissection into the coronary arteries, or inadequate myocardial protection during open surgical repair. One group reported a high utilization of ECMO post‐TAAD repair of nearly 12% . This was a single institution series where ECMO utilization was associated with an in hospital mortality rate of 65%.…”

Generation of microbubbles in extracorporeal life support and assessment of new elimination strategies

“…Venoarterial extracorporeal life support (ECLS) is a promising, yet a highly invasive therapeutic option in cardiovascular intensive care medicine . It is associated with a high incidence of complications and recently attention has been directed to the emergence of microbubbles (MB) within the circulatory system . MB can lead to neurological morbidity or mortality due to a cascade of pathophysiological reactions, including diffuse cerebral microischemia as well as inflammatory reactions and activation of the complement system .…”

Postcardiotomy VA-ECMO for refractory cardiogenic shock

“…In their systematic review and meta-analysis of venoarterial extracorporeal membrane oxygenation (VA-ECMO) for postcardiotomy cardiogenic shock (PCCS), Khorsandi and colleagues report a pooled survival to hospital discharge of 30.8% and suggest a number of adverse prognostic indicators [1]. Whilst we agree that postcardiotomy VA-ECMO for refractory cardiogenic shock does indeed provide a significant survival benefit, we wish to highlight several limitations so as to aid interpretation of this study and inform future analyses.…”

“…The reason why we did not separate the postcardiotomy extracorporeal membrane oxygenation (ECMO) patient into transplant and non-transplant cohorts was the limited number of studies and the limited number of subjects within each study (table 1) [ 7]. We felt that in order for a meta-analysis to have the best chance at yielding any statistical significance these cohorts should be combined, albeit at the expense of greater heterogeneity.…”

“…In their systematic review and meta-analysis, Khorsandi and colleagues report a synthesis of case-series pertinent to the use of venoarterial extracorporeal membrane oxygenation (VA-ECMO) for PCCS. Whilst we acknowledge the potential survival benefit for carefully selected patients for what is ordinarily a condition with high mortality, we wish to comment on several aspects of the study in the context of its application to clinical practice.Keywords: Postcardiotomy, VA-EMO, Systematic review, Cardiogenic shockIn their systematic review and meta-analysis of venoarterial extracorporeal membrane oxygenation (VA-ECMO) for postcardiotomy cardiogenic shock (PCCS), Khorsandi and colleagues report a pooled survival to hospital discharge of 30.8% and suggest a number of adverse prognostic indicators [1]. Whilst we agree that postcardiotomy VA-ECMO for refractory cardiogenic shock does indeed provide a significant survival benefit, we wish to highlight several limitations so as to aid interpretation of this study and inform future analyses.…”