The Relation Between Obesity and Mortality in Postcardiotomy Venoarterial Membrane Oxygenation

Impact of obesity on outcomes in patients receiving extracorporeal membrane oxygenation: A systematic review and meta-analysis

Given the growing obesity pandemic, the impact of obesity on outcomes of Extracorporeal Membrane Oxygenation (ECMO) would be increasingly relevant to our daily practise. This meta-analysis aims to evaluate the impact of obesity on ECMO outcomes, integrating the latest evidence. Systematic literature search was conducted from inception until December 2024 on MEDLINE, Embase and the Cochrane Library using the terms 'ECMO', 'obesity', and their related terms. Twenty-eight studies were included from 2013 to 2024, including a total of 74,330 ECMO patients (Mean age 52.84 ± 13.55 years). Obese patients had a similar risk of in-hospital or 30-day mortality when compared to non-obese patients (Risk difference -2%, 95%CI -5% to -1%, I2 = 85%, p = 0.25). Subgroup analysis of patients on V-V-ECMO showed a trend towards lower mortality in obese patients which did not reach statistical significance (risk difference -6%, 95%CI -13% to 0%, I2 = 53%, p = 0.06). Subgroup analysis of patients on V-A-ECMO showed significantly higher mortality in obese patients (risk difference 5%, 95%CI 1% to 9%, I2 = 54%, p = 0.007). Regarding secondary outcomes, obesity had no significant association with major bleeding or thrombotic complications (Risk difference 0%, 95%CI -1% to 2%, I2 = 15%, p = 0.63). Obesity was associated with significantly shorter hospital length-of-stay (Mean difference -2.92 days, 95% CI -5.03 to -0.80, I2 = 74%, p = 0.007), but had no impact on ECMO duration (Mean difference 0.35 days, 95%CI -0.03 to 0.74, I2 = 41%, p = 0.07). In summary, our meta-analysis showed that obesity was a favourable prognostic factor in V-V-ECMO. However, obesity increased mortality in V-A-ECMO patients. The modality of ECMO support should be taken into consideration when evaluating ECMO candidacy in individual obese patients.

Obesity Is Associated With Increased Mortality in Patients Undergoing Venoarterial Extracorporeal Membrane Oxygenation

OBJECTIVES

To determine the relationship between all-cause hospital mortality and morbidity in patients treated with venoarterial extracorporeal membrane oxygenation (ECMO) and to assess whether this relationship is mediated via body mass index (BMI).

DESIGN

Using the Extracorporeal Life Support Organization (ELSO) registry, venoarterial ECMO runs from 2015 to 2021 were retrospectively analyzed. Patient demographics, ECMO indications, and complications for survivors and decedents were univariately compared. Logistic regression with fractional polynomials was used to estimate the relationship between BMI and both mortality and complications in venoarterial ECMO patients.

SETTING

Contributing centers to the ELSO ECMO registry.

PATIENTS

Patients that underwent venoarterial ECMO at an ELSO contributing ECMO center.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Twenty-two thousand eight hundred twenty-five venoarterial ECMO runs met inclusion criteria for analysis. The mean BMI for survivors was 28.4 ± 6.5 vs. 29.5 ± 6.9 kg/m 2 for decedents. BMI was significantly associated with mortality ( p < 0.001), with the proportion of patients dying increasing with increasing BMI: 47% of underweight patients died, increasing to 50% for the normal range, to 53%, 56%, 58%, and 65% for preobese, class 1, class 2, and class 3 obese patients, respectively. Relative to a BMI of 25, a BMI of 35 had an odds ratio (OR) of death of 1.15 (1.09-1.18), and a BMI of 45 an OR of 1.46 (1.25-1.57). BMI was significantly associated with increased mechanical and renal complications, but decreased pulmonary complications.

CONCLUSIONS

In patients undergoing venoarterial ECMO, increasing BMI was associated with increasing all-cause mortality and mechanical and renal complications.

Post-cardiotomy extracorporeal life support: A cohort of cannulation in the general ward

OBJECTIVES

Post-cardiotomy extracorporeal life support (ECLS) cannulation might occur in a general post-operative ward due to emergent conditions. Its characteristics have been poorly reported and investigated This study investigates the characteristics and outcomes of adult patients receiving ECLS cannulation in a general post-operative cardiac ward.

METHODS

The Post-cardiotomy Extracorporeal Life Support (PELS) is a retrospective (2000-2020), multicenter (34 centers), observational study including adult patients who required ECLS for post-cardiotomy shock. This PELS sub-analysis analyzed patients´ characteristics, in-hospital outcomes, and long-term survival in patients cannulated for veno-arterial ECLS in the general ward, and further compared in-hospital survivors and non-survivors.

RESULTS

The PELS study included 2058 patients of whom 39 (1.9%) were cannulated in the general ward. Most patients underwent isolated coronary bypass grafting (CABG, n = 15, 38.5%) or isolated non-CABG operations (n = 20, 51.3%). The main indications to initiate ECLS included cardiac arrest (n = 17, 44.7%) and cardiogenic shock (n = 14, 35.9%). ECLS cannulation occurred after a median time of 4 (2-7) days post-operatively. Most patients' courses were complicated by acute kidney injury (n = 23, 59%), arrhythmias (n = 19, 48.7%), and postoperative bleeding (n = 20, 51.3%). In-hospital mortality was 84.6% (n = 33) with persistent heart failure (n = 11, 28.2%) as the most common cause of death. No peculiar differences were observed between in-hospital survivors and nonsurvivors.

CONCLUSIONS

This study demonstrates that ECLS cannulation due to post-cardiotomy emergent adverse events in the general ward is rare, mainly occurring in preoperative low-risk patients and after a postoperative cardiac arrest. High complication rates and low in-hospital survival require further investigations to identify patients at risk for such a complication, optimize resources, enhance intervention, and improve outcomes.

Characteristics and Outcomes of Prolonged Venoarterial Extracorporeal Membrane Oxygenation After Cardiac Surgery: The Post-Cardiotomy Extracorporeal Life Support (PELS-1) Cohort Study

OBJECTIVES

Most post-cardiotomy (PC) extracorporeal membrane oxygenation (ECMO) runs last less than 7 days. Studies on the outcomes of longer runs have provided conflicting results. This study investigates patient characteristics and short- and long-term outcomes in relation to PC ECMO duration, with a focus on prolonged (> 7 d) ECMO.

DESIGN

Retrospective observational cohort study.

SETTING

Thirty-four centers from 16 countries between January 2000 and December 2020.

PATIENTS

Adults requiring post PC ECMO between 2000 and 2020.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Characteristics, in-hospital, and post-discharge outcomes were compared among patients categorized by ECMO duration. Survivors and nonsurvivors were compared in the subgroup of patients with ECMO duration greater than 7 days. The primary outcome was in-hospital mortality. Two thousand twenty-one patients were included who required PC ECMO for 0-3 days ( n = 649 [32.1%]), 4-7 days ( n = 776 [38.3%]), 8-10 days ( n = 263 [13.0%]), and greater than 10 days ( n = 333 [16.5%]). There were no major differences in the investigated preoperative and procedural characteristics among ECMO duration groups. However, the longer ECMO duration category was associated with multiple complications including bleeding, acute kidney injury, arrhythmias, and sepsis. Hospital mortality followed a U-shape curve, with lowest mortality in patients with ECMO duration of 4-7 days ( n = 394, 50.8%) and highest in patients with greater than 10 days ECMO support ( n = 242, 72.7%). There was no significant difference in post-discharge survival between ECMO duration groups. In patients with ECMO duration greater than 7 days, age, comorbidities, valvular diseases, and complex procedures were associated with nonsurvival.

CONCLUSIONS

Nearly 30% of PC ECMO patients were supported for greater than 7 days. In-hospital mortality increased after 7 days of support, especially in patients undergoing valvular and complex surgery, or who had complications, although the long-term post-discharge prognosis was comparable to PC ECMO patients with shorter support duration.

Impact of obesity on outcomes of extracorporeal membrane oxygenation support: a systematic review and meta-analysis

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is used when standard methods of standard treatment methods are not successful. Obese patients present unique challenges during ECMO due to large body size hindering sufficient flows, difficulties with patient positioning and anatomical landmark identification, and restricted radiology scans. This meta-analysis aims to investigate the impact of obesity on the outcomes of patients undergoing ECMO.

METHODS

Databases (PubMed, Embase, and Scopus databases) were searched to identify relevant studies published until July 2023. Data were reported as odds ratios (OR) with 95% confidence interval (CI), and the descriptive data were reported as standard difference of means (SDM) by a random effects model.

RESULTS

A literature search identified 345 studies. Of them, 18 studies met the inclusion criteria. The findings from the meta-analysis revealed no significant association between obesity and survival outcomes after ECMO (odds ratio (OR): 0.91, 95% confidence interval (CI): 0.70-1.17, p: 0.46). Moreover, no comparative significant differences were found between obese and non-obese individuals on the duration of ECMO procedure (standardized mean difference (SMD): 0.07, -0.03-0.17), length of hospital stay (-0.03, -0.19 to 0.12), and duration of ventilation support (-0.10, -0.44 to 0.24).

CONCLUSION

The meta-analysis findings suggest no significant impact of obesity on the survival outcomes after the ECMO procedure. There was no significant impact of obesity on the duration of ECMO procedures, length of hospital stay, and duration of ventilation support.