Clinical predictors of in-hospital mortality in venoarterial extracorporeal membrane oxygenation

The absolute lactate levels versus clearance for prognostication of post-cardiotomy patients on veno-arterial ECMO

AIMS

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is a life-saving procedure for supporting patients with cardiogenic shock after cardiac surgery. This work aimed to analyse the impact of changes in blood lactate levels on the survival of patients on post-cardiotomy ECMO (PC-ECMO) and whether lactate clearance (LC) performs better than absolute lactate levels.

METHODS AND RESULTS

We retrospectively analysed the data of adult patients who received PC-ECMO at our centre between 2016 and 2022. The primary outcome was the in-hospital mortality rate. Arterial lactate levels were measured at ECMO initiation, peak and 12 and 24 h after VA-ECMO support. LC was calculated at 12 and 24 h. Out of 2368 patients who received cardiac surgeries, 152 (median age, 48 years; 57.9% of them were men) received PC-ECMO. Of them, 48 (31.6%) survived and were discharged, while 104 (68.4%) died during the index hospitalization. Non-survivors had higher frequencies of atrial fibrillation (41.35% vs. 12.5%, P < 0.001), chronic kidney disease (26.9% vs. 6.3%, P = 0.004), prolonged cardiopulmonary bypass (237 vs. 192 min, P = 0.016) and aortic cross-clamping times (160 vs. 124 min, P = 0.04) than survivors. Non-survivors had a significantly higher median Sequential Organ Failure Assessment (SOFA) score at ECMO initiation (13.5 vs. 9, P < 0.001) and a lower median Survival After Veno-arterial ECMO (SAVE) score (-3 vs. 3, P < 0.001) with higher SAVE classes (P < 0.001) than survivors. After 12 h of VA-ECMO support, the blood lactate level was negatively correlated with LC in survivors (r = -0.755, P < 0.001) and non-survivors (r = -0.601, P < 0.001). After 24 h, the same negative correlation was identified between survivors (r = -0.764, P < 0.001) and non-survivors (r = -0.847, P < 0.001). Blood lactate levels measured at 12 h to determine hospital mortality [>8.2 mmol/L, area under the receiver operating characteristic curve (AUROC): 0.868] and 24 h (>2.6 mmol/L, AUROC: 0.896) had the best performance, followed by LC-T12 (<21.94%, AUROC: 0.807), LC-T24 (<40.3%, AUROC: 0.839) and peak blood lactate (>14.35 mmol/L, AUROC: 0.828). The initial pre-ECMO blood lactate (>6.25 mmol/L, AUROC: 0.731) had an acceptable ability to discriminate mortality but was less than the following measurements and clearance. Kaplan-Meier curves demonstrated that LC of <21.94% at T12 h and <40.3% at T24 h was associated with decreased survival (log-rank P < 0.001). Cox proportional hazards regression analysis for mortality revealed that LC of <21.94% at T12 h had an adjusted hazard ratio (HR) of 2.73 [95% confidence interval (CI): 1.64-5.762, P < 0.001] and LC of <40.3% at T24 h had an adjusted HR of 1.98 (95% CI: 1.46-4.173, P < 0.001). The predictors of hospital mortality after PC-ECMO were the lactate level at 12 h [odds ratio (OR): 1.67, 95% CI: 1.121-2.181, P = 0.001], initial SOFA score (OR: 1.593, 95% CI: 1.15-2.73, P < 0.001), initial blood lactate (OR: 1.21, 95% CI: 1.016-1.721, P = 0.032) and atrial fibrillation (OR: 6.17, 95% CI: 2.37-57.214, P = 0.003). Bivariate models using lactate levels and clearance at the same points revealed that blood lactate levels performed better than the clearance percentage.

CONCLUSIONS

Serial measurements of arterial blood lactate and LC help in obtaining early prognostic guidance in adult patients supported by VA-ECMO after cardiac surgery. Absolute lactate levels, compared with LC at the same time points, demonstrated better performance in differentiating mortality.

Caring for Patients Requiring Venous Arterial Extracorporeal Membrane Oxygenation: Can Upstream Palliative Care Make a Difference?

OBJECTIVE

Palliative care consultation is relevant for patients requiring Venous-Arterial Extracorporeal Membrane Oxygenation (VA-ECMO); however, evidence is limited to support its value. For this population, we compared length of stay (LOS) (primary outcome), operational metrics and goals of care (GOC) frequency before and after a collaboration between cardiothoracic (CT) surgery and Geriatrics and Palliative Medicine (GaP).

METHODS

Retrospective chart review of patients (18+) admitted to a quaternary center that required VA-ECMO between 2019-2021 and received GaP consultation. Demographics, LOS, times to consult, illness severity, GOC, and outcomes were analyzed.

RESULTS

120 patients met inclusion criteria and 64 (53.3%) had GaP consultation. No differences were observed regarding demographics and insertion status (emergent vs elective). Median (IQR) days to GaP consult for 2019, 2020 and 2021 were 6.5 (4.0-14.5), 5.0 (2.0-11.0) and 3.0 (2.0-5.0), respectively (P = .006). Median days from insertion to consult for 2019, 2020 and 2021 were 6.0 (4.0-20.0), 3.0 (1.0-6.0) and 2.0 (1.0-4.0) (P = .003). Among survivors, over the 3-year course, median LOS was not statistically different. Between expired patients, median (IQR) LOS for 2019, 2020, and 2021 was 28.5 (23.0-40.0), 12.0 (8.0-14.0), 11.0 (5.0-17.0) days (P = .013). For patients not seen by GaP, 8 (14.3%) GOC notes were documented, compared with 42 (65.6%) for patients seen. Mortality was similar (53.6% vs 53.1% [GaP]).

CONCLUSION

For patient on VA-ECMO, early GaP consultation may improve hospital LOS and GOC rates. We suggest organizations consider early palliative integration when instituting mechanical circulatory support.

ECMO in Myocardial Infarction-Associated Cardiogenic Shock: Blood Biomarkers as Predictors of Mortality

BACKGROUND

Veno-arterial extracorporeal membrane oxygenation (va-ECMO) can provide circulatory and respiratory support in patients with cardiogenic shock. The main aim of this work was to investigate the association of blood biomarkers with mortality in patients with myocardial infarction needing va-ECMO support.

METHODS

We retrospectively analyzed electronic medical charts from patients receiving va-ECMO support in the period from 2008 to 2021 at the Medical University Innsbruck, Department of Anesthesiology and Intensive Care Medicine.

RESULTS

Of 188 patients, 57% (108/188) survived to discharge, with hemorrhage (46%) and thrombosis (27%) as the most frequent adverse events. Procalcitonin levels were markedly higher in non-survivors compared with survivors during the observation period. The multivariable model identified higher blood levels of procalcitonin (HR 1.01, p = 0.002) as a laboratory parameter associated with a higher risk of mortality.

CONCLUSIONS

In our study population of patients with myocardial infarction-associated cardiogenic shock, deceased patients had increased levels of inflammatory blood biomarkers throughout the whole study period. Increased procalcitonin levels have been associated with a higher risk of mortality. Future studies are needed to show the role of procalcitonin in patients receiving ECMO support.

Mortality on extracorporeal membrane oxygenation: Evaluation of independent risk factors and causes of death during venoarterial and venovenous support

INTRODUCTION

Most patients on extracorporeal membrane oxygenation (ECMO) decease during therapy on the system. However, the actual causes of death have not been studied sufficiently. This study analyses the etiology, prevalence, and risk factors for the outcome variable death during ongoing ECMO for all patients and divided according to venoarterial (VA) or venovenous (VV) support.

METHODS

We retrospectively analysed all patients receiving ECMO support at our institution between March 2006 to January 2021. Only the patients deceased during ongoing support were included.

RESULTS

2016 patients were placed on VA (n = 1168; 58%) or VV (n = 848; 42%) ECMO; 759 patients (37.7%) deceased on support. The causes of death differed between the support types: VA ECMO patients mostly died from cerebral ischemia (34%), low-cardiac output (LCO; 24.1%) and multi-organ failure (MOF; 21.6%), whereas in VV ECMO cases, refractory respiratory failure (28.2%), and sepsis (20.4%) dominated. Multivariate regression analysis revealed cardiopulmonary resuscitation (CPR) and acidosis prior to ECMO as risk factors for dying on VA ECMO, while high inotropic doses pre-ECMO, a high fraction of inspired oxygen on day 1, elevated lactate dehydrogenase, and international normalized ratio levels lead to an unfavourable outcome in VV ECMO patients.

CONCLUSION

Even in highly experienced centers, ECMO mortality remains high and occurs mainly on support or 24 h after its termination. The causes of death differ between VV and VA ECMO, depending on the underlying diseases responsible for the need of extracorporeal support.

Is Fasciotomy Associated With Increased Mortality in Extracorporeal Cardiopulmonary Resuscitation?

Our primary objective was to identify if fasciotomy was associated with increased mortality in patients who developed acute compartment syndrome (ACS) on extracorporeal cardiopulmonary resuscitation (ECPR). Additionally, we sought to identify any additional risk factors for mortality in these patients and report the amputation-free survival following fasciotomy. We retrospectively reviewed adult ECPR patients from the Extracorporeal Life Support Organization registry who were diagnosed with ACS between 2013 and 2021. Of 764 ECPR patients with limb complications, 127 patients (17%) with ACS were identified, of which 78 (63%) had fasciotomies, and 14 (11%) had amputations. Fasciotomy was associated with a 23% rate of amputation-free survival. There were no significant differences in demographics or baseline laboratory values between those with and without fasciotomy. Overall, 88 of 127 (69%) patients with ACS died. With or without fasciotomy, the mortality of ACS patients was similar, 68% vs. 71%. Multivariable logistic regression demonstrated that body mass index (BMI; adjusted odds ratio [aOR] = 1.22, 95% confidence interval [CI] = 1.01-1.48) and 24 hour mean blood pressure (BP; aOR = 0.93, 95% CI = 0.88-0.99) were independently associated with mortality. Fasciotomy was not an independent risk factor for mortality (aOR = 0.24, 95% CI = 0.03-1.88). The results of this study may help guide surgical decision-making for patients who develop ACS after ECPR. However, the retrospective nature of this study does not preclude selection bias in patients who have received fasciotomy. Thus, prospective studies are necessary to confirm these findings.

Body mass index is not associated with time on veno-venous extracorporeal membrane oxygenation or in-hospital mortality

Morbid obesity, as characterized by BMI, is often utilized as an exclusion criterion for VV-ECMO because of presumed poor prognosis and technically complex cannulation. However, the "obesity paradox" suggests obesity may be protective during critical illness, and BMI does not capture variations in body type, adiposity, or fluid balance. This study examines relationships between BMI and patient outcomes. Adult VV-ECMO patients with BMI ≥ 35 kg/m2 admitted January 2012 to June 2021 were identified from an institutional registry. BMI and outcomes were analyzed with Mann-Whitney U tests and Pearson correlations with Bayesian post-hoc analyses. 116 of 960 ECMO patients met inclusion criteria. Median (Q1, Q3) BMI was 42.3 (37.3, 50.8) and min, max of 35.0, 87.8 with 9.0 (5.0, 15.5) ECMO days. BMI was not significantly correlated with ECMO days (r = -0.102; p = .279). Bayesian analyses showed moderate evidence against BMI correlating with ECMO days. In-hospital mortality (27%) was significantly associated with ECMO days (p = .014) but not BMI (p = .485). In this cohort of high-BMI patients, BMI was not associated with survival or time on ECMO. BMI itself should not be used as an exclusion criterion for VV-ECMO.

Sex differences in utilisation of extracorporeal membrane oxygenation support and outcomes in Taiwan

BACKGROUND

The impact of sex-related differences in patients receiving extracorporeal membrane oxygenation support (ECMO) support is still inconclusive. This population-based study aimed to investigate sex differences in short- or long-term outcomes in order to improve clinical practice.

METHODS

Patients who received ECMO between 2001 to 2017 were identified from the Taiwan National Health Insurance Research Database. Propensity score matching with a 1:1 ratio was conducted in female-to-male groups, to reduce confounding of baseline covariates. Outcomes included in-hospital mortality, all-cause mortality, all-cause readmission, and ECMO-related complications. Logistic regression analysis, Cox proportional hazard model, and join point regression were used to compare sex differences in both short- or long-term outcomes.

RESULTS

In total, 7,010 matched patients from 11,734 ECMO receivers were included for analysis. The use of ECMO increased dramatically in past years, although the proportion of females was still lower than males. There was a decreasing trend of females undergoing ECMO over time. Female patients have lower risks of in-hospital mortality (64.08% in females vs 66.48% in males; P = 0.0352) and ECMO-related complications compared with males. Furthermore, females also had favorable long-term late outcomes such as all-cause mortality (73.35% in females vs 76.98% in males; P = 0.009) and readmission rate (6.99% in females vs 9.19% in males; P = 0.001).

CONCLUSIONS

Female patients had more favorable in-hospital and long-term survival outcomes. Despite improvement in modern ECMO technique and equipment, ECMO remains underutilized in eligible female patients. Thus, females should undergo ECMO treatment if available and indicated.

TRIAL REGISTRATION

The institutional review board of Chang Gung Memorial Hospital approved all data usage and the study protocol (registration number: 202100151B0C502; date of registration: 23/08/2021).

ECMO in Cardiogenic Shock: Time Course of Blood Biomarkers and Associated Mortality

BACKGROUND

Veno-arterial extracorporeal membrane oxygenation (va-ECMO) is a temporary life support for severe cardiogenic shock, gaining time for organ recovery, permanent assistance, or transplantation. In this work, we aimed to investigate the trends of blood biomarkers over the period of ECMO support and their role in patient outcome.

METHODS

This retrospective study comprised patients receiving va-ECMO support over the period of 14 years at a tertiary university center.

RESULTS

Of 435 patients, 62% (268/435) survived to discharge, and the most frequent adverse event was hemorrhage (46%), followed by thrombosis (25%). Deceased patients had increased blood levels of C-reactive protein, procalcitonin, and white blood cells during the whole observation period, with higher peaks compared with survivors. The multivariable model identified hemorrhage (HR 1.73, p = 0.005) and higher levels of procalcitonin (HR 1.01, p = 0.001) as independent risk factors for death.

CONCLUSIONS

In our population of critically ill patients receiving va-ECMO support, deceased patients had increased inflammatory biomarkers during the whole observation period. Patients having higher values of procalcitonin and experiencing bleeding events showed an increased risk for mortality. Further studies focusing on inflammation in ECMO patients, clarifying its role in patient outcome and potential therapeutic interventions, are warranted.

Extracorporeal membrane oxygenation for cardiogenic shock: a meta-analysis of mortality and complications

BACKGROUND

Venoarterial extracorporeal membrane oxygenation (va-ECMO) is an advanced life support for critically ill patients with refractory cardiogenic shock. This temporary support bridges time for recovery, permanent assist, or transplantation in patients with high risk of mortality. However, the benefit of this modality is still subject of discussion and despite the continuous development of critical care medicine, severe cardiogenic shock remains associated with high mortality. Therefore, this work aims to analyze the current literature regarding in-hospital mortality and complication rates of va-ECMO in patients with cardiogenic shock.

METHODS

We conducted a systematic review and meta-analysis of the most recent literature to analyze the outcomes of va-ECMO support. Using the PRISMA guidelines, Medline (PubMed) and Scopus (Elsevier) databases were systematically searched up to May 2022. Meta-analytic pooled estimation of publications variables was performed using a weighted random effects model for study size.

RESULTS

Thirty-two studies comprising 12756 patients were included in the final analysis. Between 1994 and 2019, 62% (pooled estimate, 8493/12756) of patients died in the hospital. More than one-third of patients died during ECMO support. The most frequent complications were renal failure (51%, 693/1351) with the need for renal replacement therapy (44%, 4879/11186) and bleeding (49%, 1971/4523), bearing the potential for permanent injury or death. Univariate meta-regression analyses identified age over 60 years, shorter ECMO duration and presence of infection as variables associated with in-hospital mortality, while the studies reporting a higher incidence of cannulation site bleeding were unexpectedly associated with a reduced in-hospital mortality.

CONCLUSIONS

Extracorporeal membrane oxygenation is an invasive life support with a high risk of complications. We identified a pooled in-hospital mortality of 62% with patient age, infection and ECMO support duration being associated with a higher mortality. Protocols and techniques must be developed to reduce the rate of adverse events. Finally, randomized trials are necessary to demonstrate the effectiveness of va-ECMO in cardiogenic shock.

Sixteen-year national trends in use & outcomes of VA-ECMO in cardiogenic shock

There is a lack of data on contemporary trends in the use and outcomes of Veno-Arterial Extracorporeal Membrane Oxygenation (VA-ECMO) for cardiogenic shock (CS) at a national level. Patients with CS admitted during January 1st, 2002-December 31, 2018, were identified from the United States National Inpatient Sample. Among all patients admitted with CS, those who received VA-ECMO were identified. We report the trends in use and outcomes in terms of mortality, exit strategies and complications among all patients who received VA ECMO for CS. Among a total of approximately 1.6 million patients admitted with CS during the period from January 1st, 2002 to December 31, 2018; 25, 621(1.5 %) received VA-ECMO. There has been a 23-fold increase in the use of VA-ECMO over the study period, from 0.1 % in 2002 to 3 % in 2018, with a simultaneous decreasing trend of in hospital mortality from 77 % in 2002 to 50 % in 2018. Only approximately 15 % of VA-ECMO patients are discharged home with most survivors discharged to a skilled nursing facility or short-term rehabilitation. Moreover, only a minor proportion of patients on VA ECMO are bridged to heart replacement therapy with durable LVAD (6 %) or cardiac transplantation (2.5 %). In conclusion, the use of VA-ECMO in CS has increased 23-fold from January 2002 to December 2018 with a concomitant decrease in mortality from 77 % in 2002 to 50 % in 2018, only a minority of patients on VA-ECMO for CS are bridged to durable LVAD or cardiac transplantation.

Use of extracorporeal membrane oxygenation in high-risk acute pulmonary embolism: A systematic review and meta-analysis

Extracorporeal membrane oxygenation (ECMO) represents a therapeutic option for cardiopulmonary support in patients with high-risk pulmonary embolism (PE); however, no definite consensus exists on ECMO use in high-risk PE. Hence, we aim to provide insights into its real-world use pooling together all available published experiences. We performed a systematic review and pooled analysis of all published studies (up to April 17, 2020) investigating ECMO support in high-risk PE. All studies including at least four patients were collectively analyzed. Study outcomes were early all-cause death (primary endpoint) and relevant in-hospital adverse events. A total of 21 studies were included in the pooled analysis (n = 635 patients). In this population (mean age 47.8 ± 17.3 years, 44.5% females), ECMO was indicated for cardiac arrest in 62.3% and immediate ECMO support was pursued in 61.9% of patients. Adjunctive reperfusion therapies were implemented in 57.0% of patients. Pooled estimate rate of early all-cause mortality was 41.1% (95% CI 27.7%-54.5%). The most common in-hospital adverse event was major bleeding, with an estimated rate of 28.6% (95%CI 21.0%-36.3%). At meta-regression analyses, no significant impact of multiple covariates on the primary endpoint was found. In this systematic review of patients who received ECMO for high-risk PE, pooled all-cause mortality was 41.1%. Principal indication for ECMO was cardiac arrest, cannulation was chiefly performed at presentation, and major bleeding was the most common complication.