Elsevier

Heart, Lung and Circulation

Volume 29, Issue 12, December 2020, Pages 1865-1872
Heart, Lung and Circulation

Original Article
Post Cardiotomy Extra Corporeal Membrane Oxygenation: Australian Cohort Review

https://doi.org/10.1016/j.hlc.2020.05.092Get rights and content

Background

Over the last two decades, technological advancements in the delivery of extra corporeal membrane oxygenation (ECMO) have seen its use broaden and results improve. However, in the post cardiotomy ECMO patient group, survival remains very poor without significant improvements over the last two decades. Our study aims to report on the Australian experience, with the intention of providing background data for the formation of guidelines in the future.

Methods

Retrospective analysis of prospectively collected data from the Australian and New Zealand Society of Cardiothoracic Surgeons (ANZSCTS) Database was performed. The ANZSCTS database captures at least 60% of cardiac surgical data in Australia, annually. Data was collected on adult patients who received ECMO post cardiotomy from September 2016 to November 2017 inclusive. Transplant and primary cardiomyopathy patients were excluded.

Results

Of the 16,605 adult patients undergoing cardiac surgery in the 15-month period of the study, 87 patients required post cardiotomy ECMO (0.52%). The average age of the entire cohort was 56 years. Overall survival to discharge was 43.7% (n=38). Multivariable logistic regression analysis demonstrated that multiorgan failure (MOF), increasing age and longer cardiopulmonary bypass time were significant predictors of in hospital mortality.

Conclusions

Post cardiotomy ECMO support is an uncommon condition. Survival in this study appears to be better than historical reports. Identification of poor prognostic indicators in this study may help inform the development of guidelines for the most appropriate use of this support modality.

Introduction

Over the last two decades, technological improvements in the delivery of extra corporeal membrane oxygenation (ECMO) have seen its use broaden. Latest generation membrane oxygenators, magnetically levitated pumps and heparin coated circuits have reduced equipment related complications, particularly thrombosis. Despite these improvements, survival after post cardiotomy ECMO remains poor, with survival to discharge figures ranging from 23 to 42% (Table 1) [[1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15]].

Post cardiotomy cardiogenic shock (PCCS) has been defined in the literature as cardiac failure that results in an inability to wean off cardiopulmonary bypass, or cardiac failure that occurs in the immediate postoperative period. More specific parameters include systolic blood pressure <100 mmHg, mean pulmonary artery pressure >25 mmHg, central venous pressure >15 mmHg, and cardiac index <2.01 L/min/m2 [16]. The aetiology is most commonly attributed to myocardial infarction, stunning, or poor myocardial preservation perioperatively.

The incidence of PCCS has been shown to reach 3–5%, however, use of inotropes and an intra-aortic balloon pump (IABP) is usually sufficient management to bridge to recovery [17,18]. A smaller subset, approximately 1% of patients, require mechanical circulatory support beyond this. This is often provided in the form of VA-ECMO, although support devices such as bi- and left-ventricular assist devices (BiVAD, LVAD) have been utilised [4]. These alternatives will not be considered in this study due to minimal use—often restricted to transplant centres only.

Use of ECMO for all indications is expanding, and has become a recent regulatory focus in Australia with the aim of identifying centres of excellence where ECMO can be centralised. Furthermore, it is anticipated that identifying and supporting high volume centres will aid in improving results. In terms of post cardiotomy ECMO, there is little agreement on specific prognostic indicators which could assist centres in identifying suitable patients for this level of support. Although most studies on this subject identify older age, there is no consensus on a cut-off [[1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15]]. Ideally, identifying other prognostic indicators could assist in optimising patients and assist in patient selection, thus improving outcomes.

Our study aims to report on the Australian experience, with intent to contribute to the formation of guidelines.

Section snippets

Materials and Methods

This study utilised the Australian and New Zealand Society of Cardiothoracic Surgeons (ANZSCTS) Database. Currently, 40 centres in Australia (23 public, 17 private) contribute to this database. Twenty (20) hospitals (19 private, 1 public) do not currently contribute to the registry. The database curates data prospectively collected in each contributing hospital, and patients have a choice to opt out. However, only their identifiable data is removed, whilst the de-identified procedural data is

Results

Of the 16,605 adult patients undergoing cardiac surgery in the 15-month period of the study, 87 patients required post cardiotomy ECMO (0.52%).

Demographics of the patient group are outlined in Table 1. The average age of the entire cohort was 56 years. Demographics were compared between patients who died and survived, and significant differences found in age, history of hypertension and peripheral vascular disease, and baseline renal function (Table 1).

Operative variables are outlined in Table 2

Discussion

Cardiogenic shock is an uncommon complication of cardiac surgery, with the incidence of post cardiotomy shock (PCS)-ECMO in our ANZSCTS database at 0.52%. This was somewhat lower than that reported in the literature, which ranges from 0.58% to 2.9% [5,7]. We specifically excluded patients whose primary procedure was cardiac/cardiopulmonary transplantation, or ventricular assist device (VAD) insertion as these cases tend to have a different postoperative course.

Although studies identify the

Conclusions

This study provides us with a contemporary snapshot of post cardiotomy ECMO practice in Australia. Although the incidence of post cardiotomy ECMO is low, the overall numbers accrued in only 15 months are larger than many previously published series which span many years and often reflect changing practice over time.

Funding Sources

The ANZSCTS National Cardiac Surgery Database Program is funded by the Department of Health (Victoria), the Clinical Excellence Commission (NSW), Queensland Health (Qld), and funding from individual Units. ANZSCTS Database Research activities are supported through a National Health and Medical Research Council Senior Research Fellowship and Program Grant awarded to CM Reid. The Database thanks all of the investigators, data managers, and institutions that participate in the Program.

This

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