Survival After Veno-arterial ECMO Research Articles

Low volume ECMO results study

Objectives: To report extracorporeal membrane oxygenation (ECMO) experience at Princess Alexandra and Gold Coast University hospitals and compare mortality with benchmarks. Design: Case series of patients treated with ECMO. Setting: Two adult tertiary Australian intensive care units with low ECMO case volumes. Participants: Patients treated with ECMO, aged > 18 years. Main outcome measures: Patients were categorised into respiratory, cardiac, and extracorporeal cardiopulmonary resuscitation (eCPR) groups. Observed mortality was compared with mortality predicted using individual risk of death predictions from the Survival after Veno-arterial ECMO (SAVE) and Respiratory ECMO Survival Prediction (RESP) scores; mortality predicted when mortality predictions of the SAVE score were modified to be consistent with the validation cohort in the SAVE study (Alfred Hospital); and with mortality predicted when eCPR patients were all assigned a risk of death equal to Extracorporeal Life Support Organization (ELSO) Registry eCPR mortality. Results: Over 10 years, 86 patients were treated with ECMO. Eight deaths were observed in 49 patients with respiratory failure, below the 95% CI (13-24) for the deaths predicted by the RESP score (P < 0.001). Nine deaths were observed in 27 patients with cardiac failure, below the 95% CI (14-23) for the deaths predicted by the SAVE score (P < 0.001), but within the 95% CI (9-17) for the deaths predicted by the SAVE score modified to be consistent with the Alfred Hospital cohort (P > 0.05). Seven deaths were observed in the ten eCPR patients, within the 95% CI (4-10) predicted using the risk of death derived from the ELSO Registry. Conclusions: Mortality in two low volume ECMO centres was not inferior to benchmarks.

Abstract 13800: Using Different Scoring Systems to Differentiate In-hospital Mortality in Patients With Extracorporeal Membrane Oxygenation

Introduction: The objective of this study was to evaluate the performance of different scoring systems in discriminating in-hospital mortality among patients receiving extracorporeal membrane oxygenation (ECMO). Methods: This observation registry involved adult patients who received ECMO from 2006 to 2016 in a medical center in Taiwan. Clinical variables collected when ECMO was instituted were used to generate the following scores: Charlson Comorbidity Index (CCI), Acute Physiology and Chronic Health Evaluation (APACHE), sequential organ failure assessment (SOFA) score, the logistic organ dysfunction score (LODS), the multiple organ dysfunction score (MODS), The Simplified Acute Physiology Score III (SAPS3), and the survival after venoarterial ECMO (SAVE) score. A logistic regression model incorporating statistically significant variables was applied to find the predicted probability of in-hospital death, which was then used as a new model-based estimator. Receiver-operating characteristic (ROC) curves were drawn and area under curves (AUC) was used as the marker for discriminatory power. Results: A total of 1342 patients (71.5% men) were included with mean age of 53.5 (15.7) years and in-hospital mortality rate 62.3%. Based on the valid observations, the AUCs were 0.590 (95% CI: 0.553~0.627, n = 929) for CCI, 0.672 (95% CI: 0.638~0.706, n = 998) for APACHE, 0.691 (95% CI: 0.655~0.727, n = 841) for SOFA, 0.696 (95% CI: 0.660~0.732, n = 820) for LODS, 0.657 (95% CI: 0.619~0.695, n = 974) for MODS, 0.660 (95% CI: 0.623~0.696, n = 840) for SAPS3, 0.649 (95% CI: 0.596~0.701, n = 429) for SAVE (all p &lt; 0.001), and 0.766 for the model-based estimator (95% CI: 0.740~0.791, n = 1342). When the cases were restricted to the 247 patients in whom all scores could be successfully calculated, the model-based estimator still resulted in the highest discriminatory power (AUC 0.747, 95% CI: 0.686~0.807), with other systems ranging from 0.590 (CCI) to 0.684 (SAPS3). Conclusions: The model-based algorithm incorporated mathematically optimized coefficients to produce a new estimator that outperformed different types of clinical risk scores, and could be used for future clinical prediction.

Predicting Survival After VA-ECMO for Refractory Cardiogenic Shock: Validating the SAVE Score

BackgroundVeno-arterial extracorporeal membrane oxygenation (VA-ECMO) is used increasingly to support patients who are in cardiogenic shock. Due to the risk of complications, prediction models may aid in identifying patients who would benefit most from VA-ECMO. One such model is the Survival After Veno-Arterial Extracorporeal Membrane Oxygenation (SAVE) score. Therefore, we wanted to validate the utility of the SAVE score in a contemporary cohort of adult patients. MethodsRetrospective data were extracted from electronic health records of 120 patients with cardiogenic shock supported with VA-ECMO between 2011 and 2018. The SAVE score was calculated for each patient to predict survival to hospital discharge. We assessed the SAVE score calibration by comparing predicted vs observed survival at discharge. We assessed discrimination with the area under the receiver operating curve using logistic regression. ResultsA total of 45% of patients survived to hospital discharge. Survivors had a significantly higher mean SAVE score (–9.3 ± 4.1 in survivors vs –13.1 ± 4.4, respectively; P = 0.001). SAVE score discrimination was adequate (c = 0.77; 95% confidence interval 0.69-0.86; P < 0.001). SAVE score calibration was limited, as observed survival rates for risk classes II-V were higher in our cohort (II: 67% vs 58%; III: 78% vs 42%; IV: 61% vs 30%; and V: 29% vs 18%). ConclusionsThe SAVE score underestimates survival in a contemporary North American cohort of adult patients with cardiogenic shock. Its inaccurate performance could lead to denying ECMO support to patients deemed to be too high risk. Further studies are needed to validate additional predictive models for patients requiring VA-ECMO.

Application and Comparison of Different Prognostic Scoring Systems in Patients Who Underwent Cardiologist-Managed Percutaneous Cardiopulmonary Support.

Temporary mechanical support, including percutaneous cardiopulmonary support (PCPS), is crucial for reversing patients' compromised hemodynamic function. Knowledge about whether cardiologists can directly manage patients receiving PCPS and about the predictive values of different prognostic scores is insufficient. We examined the data and in-hospital mortality of 45 eligible patients receiving cardiologist-managed PCPS from July 2012 to January 2019 in our institute. We compared different prognostic scores [namely Survival After Veno-arterial ECMO (SAVE), modified SAVE, prEdictioN of Cardiogenic shock OUtcome foR acute myocardial infarction patients salvaGed by VA-ECMO (ENCOURAGE), and Sequential Organ Failure Assessment (SOFA) scores] through area under the receiver operating characteristic curve (AUC) analysis. The patients' mean age was 64.3 ± 11.3 years, and 71.1% were men. The overall in-hospital survival rate was 35.6%. Compared to survivors, nonsurvivors were more likely to have an ischemic etiology, cardiopulmonary resuscitation, and higher lactate levels. Survivors had higher SAVE (-5.9 vs. -11.4) and modified SAVE (4.2 vs. -7.1) scores than nonsurvivors (both p = 0.001), but SOFA (9.7 vs. 10.3) and ENCOURAGE (24.8 vs. 26.8) scores were similar (both p > 0.1). In multivariate models, only modified SAVE score remained statistically significant (hazard ratio: 0.96, 95% confidence interval: 0.93-1.00; p = 0.047). Modified SAVE score showed the best risk discrimination (AUC = 0.78). Establishing regular and continual training protocols can enable cardiologists to perform emergency PCPS (without on-site surgery) and daily care for patients with refractory cardiogenic shock. The modified SAVE score facilitates risk stratification and future decision-making processes.

Predicting Survival After Extracorporeal Membrane Oxygenation by Using Machine Learning

Venoarterial (VA) extracorporeal membrane oxygenation (ECMO) undoubtedly saves many lives, but it is associated with a high degree of patient morbidity, mortality, and resource use. This study aimed to develop a machine learning algorithm to augment clinical decision making related to VA-ECMO. Patients supported by VA-ECMO at a single institution from May 2011 to October 2018 were retrospectively reviewed. Laboratory values from only the initial 48 hours of VA-ECMO support were used. Data were split into 70% for training, 15% for validation, and 15% withheld for testing. Feature importance was estimated, and dimensionality reduction techniques were used. A deep neural network was trained to predict survival to discharge, and the final model was assessed using the independent testing cohort. Model performance was compared with that of the SAVE (Survival After Veno-arterial ECMO) score by using a receiver operator characteristic curve. Of the 282 eligible adult patients who were undergoing VA-ECMO, 117 (41%) survived to discharge. A total of 1.96 million laboratory values were extracted from the electronic medical record, from which 270 different summary variables were derived for each patient. The most important variables in predicting the primary outcome included lactate, age, total bilirubin, and creatinine. For the testing cohort, the final model achieved 82% overall accuracy and a greater area under the curve than the SAVE score (0.92 vs 0.65; P= .01) in predicting survival to discharge. This proof of concept study demonstrates the potential for machine learning models to augment clinical decision making for patients undergoing VA-ECMO. Further development with multi-institutional data is warranted.

Predicting Survival with Mobile ECMO: A Single-Center Evaluation

Extracorporeal membrane oxygenation (ECMO) treats acute reversible severe heart/lung failure in adults at high mortality risk. While often initiated in-hospital, ECMO's portability allows for experienced centers to implant it off site. We examined the impact mobile ECMO on survival in patients with severe cardiopulmonary failure. This is a retrospective review of patients with in-hospital or mobile ECMO from January 2013 to October 2019. Participants were included if they were ≥ 18 years old and received ECMO performed at Hartford Hospital or through the mobile, "ECMO on the Go" unit. The Survival After Veno-Arterial ECMO (SAVE) and Respiratory ECMO Survival Prediction (RESP) scores were calculated. The primary endpoints were 48-hour and hospital discharge survival. We included 201 patients with a median (25th, 75th percentile) age 54.0 (39.5, 64.0) years and median ECMO time of 5.0 (3.0, 8.0) days. VA (median SAVE score -6.5 [-9.0, -3.0]) and VV ECMO (median RESP score 2.0 [-1.0, 5.0]) were initiated in 51.7% and 48.3% of patients, respectively. Mobile ECMO was initiated in 61 (30.3%) patients. 48-hour survival was higher in the mobile (65.6%) vs hospital ECMO patients (55.7%, p=0.192). Survival to hospital discharge was also higher with mobile (59.0%) vs hospital ECMO patients (41.4%, p=0.097). Baseline SAVE and RESP scores were higher in patients surviving to 48-hr and hospital discharge (p<0.006 for all)(Figure). We showed that mobile ECMO is effective for treatment of severe cardiopulmonary failure refractory to standard modalities. Mobile ECMO trended towards improved survival compared with in-hospital initiation. SAVE and RESP scores may be predictive of survival using mobile ECMO applications.

Optimizing Save Score for Intraoperative Complications

Veno-arterial extracorporeal membrane oxygenation (VA ECMO) is an effective support therapy for refractory cardiogenic shock and can be used as a bridge to more definitive therapy. However, VA ECMO has high rates of complications and requires considerable financial and human resources. Selecting patients most likely to benefit from ECMO is controversial. The Survival After Veno-arterial ECMO (SAVE) Score is a tool developed by Schmidt et al. to predict survival for patients receiving ECMO therapy for cardiogenic shock. We conducted a single-center, retrospective study to validate the relationship between SAVE scores and survival rates, and to identify additional factors that can predict prognosis. We retrospectively reviewed all cardiogenic shock patients who received VA-ECMO therapy at our institution between 2016 - 2019. We collected patient variables/outcomes, ECMO data, and calculated SAVE scores. We identified 66 cardiogenic shock patients treated with VA-ECMO and stratified them by SAVE score risk categories and measured survival to discharge with the following results: 33.33% (4/12) in category V (SAVE score ≤-10; 18% predicted survival); 29.63% (8/27) in category IV (SAVE score -9 to -5; 30% predicted survival); 36.84% (7/19) in category III (SAVE score -4 to 0; 42% predicted survival); 57.14% (4/7) in category II (SAVE score 1 to 5; 58% predicted survival); 0% (0/1) in category I (SAVE score >5; 75% predicted survival). Overall survival was 34.85% (23/66). When patients with an intraoperative complication causing hemodynamic compromise as the etiology of their cardiogenic shock were isolated (18 total) and a -2 SAVE score modifier applied, the following changes to overall survival patterns were seen: 28.57% (4/14) in category V patients, and 41.18% (7/17) in category III patients. Overall, the survival rates predicted by SAVE score risk categories matched well when applied to the patient population at our institution. Of note, risk category I was not considered in analysis due to limited sample size (n = 1). Applying a negative score modifier to intraoperative complication patients brought measured survival rates closer to predicted, suggesting this etiology of cardiogenic shock portends worse survival than reflected in original SAVE score. Further study to identify patterns of complications and survival may aid in more accurate risk stratification.

Discriminatory power of scoring systems for outcome prediction in patients with extracorporeal membrane oxygenation following cardiovascular surgery†.

Although extracorporeal membrane oxygenation (ECMO) represents a rapidly evolving treatment option in patients with refractory heart or lung failure, survival remains poor and appropriate risk stratification challenging because established risk prediction models have not been validated for this specific population. This observational single-centre registry included a total of 240 patients treated with venoarterial ECMO therapy following cardiovascular surgery and analysed the discriminatory power of the European System of Cardiac Operative Risk Evaluation (EuroSCORE) additive, the EuroSCORE II, the Sequential Organ Failure Assessment (SOFA) score, the Simplified Acute Physiology Score (SAPS) II, the SAPS III, the Acute Physiology and Chronic Health Evaluation (APACHE) II, the Risk of renal failure, Injury to the kidney, Failure of kidney function, Loss of kidney function and End-stage renal failure (RIFLE) classification, the survival after venoarterial ECMO (SAVE) score, the prEdictioN of Cardiogenic shock OUtcome foR AMI patients salvaGed by VA-ECMO (ENCOURAGE) score and the Society of Thoracic Surgeons (STS) risk model for outcome prediction. During a median follow-up time of 37 months (interquartile range 19-67), 65% of the patients died. Only the SAVE score and the SAPS II were significantly associated with the 30-day mortality rate with a hazard ratio (HR) of 1.06 [95% confidence interval (CI) 1.02-1.11; P = 0.002] for the SAVE score and an HR of 1.02 (95% CI 1.01-1.03; P = 0.004) for the SAPS II with a modest discriminatory power displayed by a C-index of 0.61 and 0.57, respectively. Seven out of 10 scoring systems revealed significant association with long-term mortality, with the SAVE score and the SAPS II remaining the strongest predictors of long-term mortality with an HR of 1.06 (95% CI 1.03-1.09; P < 0.001, C-index 0.61) for the SAVE score and an HR of 1.02 (95% CI 1.01-1.03; P < 0.001, C-index 0.58) for the SAPS II. Risk assessment based on established risk models in patients with ECMO remains difficult. Only the SAPS II and the SAVE score were exclusively found to be suitable for short- and long-term outcome prediction in this specific vulnerable patient population.

An audit of mortality by using ECMO specific scores and APACHE II scoring system in patients receiving extracorporeal membrane oxygenation in a tertiary intensive care unit in Hong Kong

Outcomes of patients receiving extracorporeal membrane oxygenation (ECMO) therapies risk-adjusted by ECMO specific scores have rarely been reported. Our primary aim was to determine the risk adjusted outcome of these patients by the use of Respiratory Extracorporeal Membrane Oxygenation Survival Prediction (RESP), Survival After Veno-Arterial-ECMO (SAVE) and APACHE II scores. The differences in predicted mortality between these scoring systems were analyzed. This is a single-center retrospective study reviewing 62 patients who received venous-venous ECMO (VV-ECMO) and venous-arterial ECMO (VA-ECMO) between 2009 and 2017 in a tertiary ICU. Demographic, clinical, laboratory, imaging data were analyzed. Primary outcome measures were the crude mortality and standardized mortality ratio (SMR), expressed as observed mortality divided by expected mortality predicted from RESP, SAVE and APACHE II scores, respectively. We also examined the difference in predicted mortality derived from RESP, SAVE, and APACHE II by using Bland Altman plots. Twenty and Forty-two patients received VV-ECMO (20 runs) and VA-ECMO (43 runs) respectively. For VV-ECMO, the mean RESP was 0.6 [standard deviation (SD) 4.86] with RESP-SMR of 1.16 [95% confidence interval (95% CI) =0.44-1.88]. For VA-ECMO, the mean SAVE score was -7.8 (SD 5.6), with SAVE-SMR of 0.69 (95% CI =0.39-0.98). In the Bland Altman plot for VA-ECMO, mean difference in predicted mortality between SAVE and APACHE II was 17.6% (95% CI: 7.6% to 27.6%, P<0.0001), with 95% limit of agreement of -30.2% to 65.5% and beta coefficient of -1.04. APACHE II predicted mortality for VA-ECMO was lower than that for SAVE until it crossed SAVE prediction at about 80% mortality. After this point, it becomes progressively higher than that for SAVE. The mortality outcome of our patients on VV-ECMO and VA-ECMO compares favorably with predicted mortality based on RESP and SAVE, respectively. In our cohort of patients receiving VA-ECMO, APACHE II tends to underestimate mortality in lower risk patients, and overestimate the mortality in patients at high risk of death.

The modified SAVE score: predicting survival using urgent veno-arterial extracorporeal membrane oxygenation within 24hours of arrival at the emergency department.

BackgroundAlthough many risk models have been tested in patients who undergo extracorporeal membrane oxygenation, few have been assessed for patients who received veno-arterial extracorporeal membrane oxygenation (VA-ECMO) support in the emergency department (ED). This study aimed to successfully predict outcomes of patients with cardiac or noncardiac failure who received VA-ECMO in the ED within 24 hours of arrival at the ED.MethodThis retrospective, observational cohort study included 154 patients, who were classified as cardiac (n = 127) and noncardiac (n = 27) patients and received VA-ECMO within 24 hours after arrival at the China Medical University Hospital ED in Taiwan between January 2009 and September 2014. We recorded mechanical ventilation settings, arterial blood gases, laboratory parameters including plasma lactate level, requirement of catecholamines, and risk scores at time of ECMO initiation. ECMO and mechanical ventilation support duration, length of stay in the hospital, and 90-day mortality data were also examined.ResultsThe overall mortality rate was 64.9 %. We used “survival after veno-arterial ECMO (SAVE)” scores to assess survival prediction in survival and nonsurvival groups, which was statistically different (–3.2 vs. –8.3, p <0.001). According to multivariate Cox proportional regression of survival, lactate (hazard ratio [HR] = 1.01, 95 % confidence interval [CI], 1.01–1.01, p <0.001) and SAVE score (HR = 0.92, [95 % CI, 0.88–0.96], p = 0.001) were independent predictors of outcome. Excellent discrimination (area under curve (AUC) = 0.843) was observed when lactate and SAVE score were combined, which we referred to as “the modified SAVE score.”ConclusionsModified SAVE scores improved outcome prediction for patients who underwent urgent VA-ECMO in the ED.

Predicting survival after ECMO for refractory cardiogenic shock: the survival after veno-arterial-ECMO (SAVE)-score.

Extracorporeal membrane oxygenation (ECMO) may provide mechanical pulmonary and circulatory support for patients with cardiogenic shock refractory to conventional medical therapy. Prediction of survival in these patients may assist in management of these patients and comparison of results from different centers. To identify pre-ECMO factors which predict survival from refractory cardiogenic shock requiring ECMO and create the survival after veno-arterial-ECMO (SAVE)-score. Patients with refractory cardiogenic shock treated with veno-arterial ECMO between January 2003 and December 2013 were extracted from the international Extracorporeal Life Support Organization registry. Multivariable logistic regression was performed using bootstrapping methodology with internal and external validation to identify factors independently associated with in-hospital survival. Of 3846 patients with cardiogenic shock treated with ECMO, 1601 (42%) patients were alive at hospital discharge. Chronic renal failure, longer duration of ventilation prior to ECMO initiation, pre-ECMO organ failures, pre-ECMO cardiac arrest, congenital heart disease, lower pulse pressure, and lower serum bicarbonate (HCO3) were risk factors associated with mortality. Younger age, lower weight, acute myocarditis, heart transplant, refractory ventricular tachycardia or fibrillation, higher diastolic blood pressure, and lower peak inspiratory pressure were protective. The SAVE-score (area under the receiver operating characteristics [ROC] curve [AUROC] 0.68 [95%CI 0.64-0.71]) was created. External validation of the SAVE-score in an Australian population of 161 patients showed excellent discrimination with AUROC = 0.90 (95%CI 0.85-0.95). The SAVE-score may be a tool to predict survival for patients receiving ECMO for refractory cardiogenic shock (www.save-score.com).