In-hospital and 6-month outcomes in patients with COVID-19 supported with extracorporeal membrane oxygenation (EuroECMO-COVID): a multicentre, prospective observational study

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) has been widely used in patients with COVID-19, but uncertainty remains about the determinants of in-hospital mortality and data on post-discharge outcomes are scarce. The aims of this study were to investigate the variables associated with in-hospital outcomes in patients who received ECMO during the first wave of COVID-19 and to describe the status of patients 6 months after ECMO initiation.

METHODS

EuroECMO-COVID is a prospective, multicentre, observational study developed by the European Extracorporeal Life Support Organization. This study was based on data from patients aged 16 years or older who received ECMO support for refractory COVID-19 during the first wave of the pandemic-from March 1 to Sept 13, 2020-at 133 centres in 21 countries. In-hospital mortality and mortality 6 months after ECMO initiation were the primary outcomes. Mixed-Cox proportional hazards models were used to investigate associations between patient and management-related variables (eg, patient demographics, comorbidities, pre-ECMO status, and ECMO characteristics and complications) and in-hospital deaths. Survival status at 6 months was established through patient contact or institutional charts review. This study is registered with ClinicalTrials.gov, NCT04366921, and is ongoing.

FINDINGS

Between March 1 and Sept 13, 2020, 1215 patients (942 [78%] men and 267 [22%] women; median age 53 years [IQR 46-60]) were included in the study. Median ECMO duration was 15 days (IQR 8-27). 602 (50%) of 1215 patients died in hospital, and 852 (74%) patients had at least one complication. Multiorgan failure was the leading cause of death (192 [36%] of 528 patients who died with available data). In mixed-Cox analyses, age of 60 years or older, use of inotropes and vasopressors before ECMO initiation, chronic renal failure, and time from intubation to ECMO initiation of 4 days or more were associated with higher in-hospital mortality. 613 patients did not die in hospital, and 547 (95%) of 577 patients for whom data were available were alive at 6 months. 102 (24%) of 431 patients had returned to full-time work at 6 months, and 57 (13%) of 428 patients had returned to part-time work. At 6 months, respiratory rehabilitation was required in 88 (17%) of 522 patients with available data, and the most common residual symptoms included dyspnoea (185 [35%] of 523 patients) and cardiac (52 [10%] of 514 patients) or neurocognitive (66 [13%] of 512 patients) symptoms.

INTERPRETATION

Patient's age, timing of cannulation (<4 days vs ≥4 days from intubation), and use of inotropes and vasopressors are essential factors to consider when analysing the outcomes of patients receiving ECMO for COVID-19. Despite post-discharge survival being favourable, persisting long-term symptoms suggest that dedicated post-ECMO follow-up programmes are required.

FUNDING

None.

Case Report: Left Ventricular Unloading Using a Mechanical CPR Device in a Prolonged Accidental Hypothermic Cardiac Arrest Treated by VA-ECMO - a Novel Approach

We recently treated a 36-year-old previously healthy male with a prolonged hypothermic (lowest temperature 22.3°C) cardiac arrest after an alcohol intoxication with a return of spontaneous circulation after 230min of mechanical cardiopulmonary resuscitation and rewarming by veno-arterial ECMO with femoral cannulation and retrograde perfusion of the aortic arch. Despite functional veno-arterial ECMO, we continued mechanical cardiopulmonary resuscitation (Auto Pulse™ device, ZOLL Medical Corporation, Chelmsford, USA) until return of spontaneous circulation to prevent left ventricular distention from persistent ventricular fibrillation. The case was further complicated by extensive trauma caused by mechanical cardiopulmonary resuscitation (multiple rib fractures, significant hemothorax, and a liver laceration requiring massive transfusion), lung failure necessitating a secondary switch to veno-venous ECMO, and acute kidney injury with the need for renal replacement therapy. Shortly after return of spontaneous circulation, the patient was already following commands and could be discharged 3 weeks later without neurologic, cardiac, or renal sequelae and being entirely well. Prolonged accidental hypothermic cardiac arrest might present with excellent outcomes when supported with veno-arterial ECMO. Until return of spontaneous circulation, one might consider continuing with mechanical cardiopulmonary resuscitation in addition to ECMO to allow some left ventricular unloading. However, the clinician should keep in mind that prolonged mechanical cardiopulmonary resuscitation may cause severe injuries.

5-year results of a newly implemented mechanical circulatory support program for terminal heart failure patients in a Swiss non-cardiac transplant university hospital

Background

In Switzerland, long-term circulatory support programs have been limited to heart transplant centers. In 2014, to improve the management of patients with end-stage heart failure not eligible for transplantation, we implemented a left ventricular assist device (LVAD) program for destination therapy at the University Hospital of Basel.

Methods

We described the program set-up with practical aspects. Patients aged 65 and above with therapy refractory end-stage heart failure without major contraindication for LVAD implantation were included. Younger patients with bridge-to-candidacy profile were also considered. Using the Kaplan-Meier estimate, we retrospectively analyzed the overall survival and freedom from major adverse events after LVAD implantation. We compared our results to internationally reported data.

Results

Between October 2014 and September 2019, 16 patients received an LVAD in our center. The mean age at implantation was 67.1 years. The mean EuroSCORE II was 24.4% and the median INTERMACS level was 4. Thirteen patients received an LVAD as destination therapy and three patients as bridge-to-candidacy. The overall survival was 87.5 and 70% at 1 and 2 years, respectively. Freedom from stroke was 81.3% at 1 and 2 years. Freedom from device infection was 67.7 and 58.7% at 1 and 2 years, respectively. Freedom from gastrointestinal bleeding was 75 and 56.3% at 1 and 2 years, respectively. Freedom from readmission was 50 and 31.3% and at 6 months and 1 year, respectively.

Conclusions

The Basel experience demonstrated the possible implementation of an LVAD program for destination therapy or bridge-to-candidacy in a non-transplant comprehensive heart-failure center with midterm survival results and freedom from major adverse events comparable to international registries. Patient selection remains crucial.

Trial registration

This study was registered on the ClinicalTrials.gov database (NCT04263012).

Lean Ad hoc Extracorporeal Membrane Oxygenation Systems for COVID-19

Coronavirus disease (COVID-19) is overwhelming hospitals with patients requiring respiratory support, including ventilators and Extracorporeal Membrane Oxygenation (ECMO). Bottlenecks in device availability may contribute to mortality, and limited device availability even in ECMO centers has led to rationing recommendations. Therefore, we explored options for ad hoc construction of venovenous ECMO using readily available components, essentially, large cannulas, membrane oxygenators, and blood pumps. As thousands of certified cardiac Impella pumps are distributed worldwide, we assembled lean ECMO by embedding Impella pumps coaxially in tubes, combined with standard gas exchangers. Ad hoc integration of Impella blood pumps with gas exchange modules, large-bore venous cannulas, regular ECMO tubing, Y-pieces, and connectors led to lean ECMO systems with stable performance over several days. Oxygenation of 2.5-5 L of blood per minute is realistic. Benefit/risk analysis appears favorable if a patient needs respiratory support but required support systems in a center are exhausted. Ad hoc assembly of venovenous ECMO is feasible using Impella blood pumps, results in stable blood flow across gas exchange modules, and thus may offer another opportunity to oxygenate, "recover the lungs" and hopefully save lives in selected patients with severe COVID-19 disease even when conventional life support equipment is exhausted. The lean design also yields inspirations for future ECMO systems.

Clinical implementation of a novel myocardial protection pathway in coronary artery bypass surgery with minimal extracorporeal circulation

INTRODUCTION

The aim of this study was to report the clinical implementation of the joint use of the Myocardial Protection System (MPS^®) and the minimal extracorporeal circulation system (MiECC), in conjunction with an institutionally refined dose/volume-dependent microplegia in coronary artery bypass grafting (CABG).

METHODS

Patients with isolated CABG surgery were included. The final protocol to achieve cardioplegic arrest consisted of warm blood cardioplegia with 20 mmol potassium (K), 1.6 g magnesium (Mg) and 40 mg lidocaine per liter (L) blood. We prospectively collected intra- and postoperative data to monitor and validate this novel approach.

RESULTS

Eighty patients were operated accordingly. Mean (SD) aortic clamping time and extracorporeal perfusion time were 67.5 (22.6) and 101.1 (31.9) minutes, respectively. Failure to induce cardiac arrest was seen in six patients at the early stage of refinement of the formula. Median (IQR) high -sensitivity cardiac troponin T (hs-cTnT) on the first postoperative day (POD) and peak hs-cTnT were 262.5 ng/L (194.3-405.8) and 265.5 ng/L (194.3-405.8), respectively. Median (IQR) creatine kinase-myocardial type (CK-MB) on POD 1 and peak CK-MB were 14.2 µg/L (10.5-22.7) and 14.2 µg/L (10.7-23.2), respectively. Median (IQR) creatine kinase (CK) on POD 1 and peak CK were 517.5 U/L (389.3-849.8) and 597.5 U/L (455.0-943.0), respectively. No patient died during hospitalization.

CONCLUSIONS

The combination of this cardioplegic formula with MPS^® and MiECC in CABG was safe and feasible. With the final chemical makeup, cardiac arrest was reliably achieved. Remarkably low postoperative cardiac markers indicate shielded cardiac protection during surgery.

Point-of-care coagulation management algorithms during ECMO support: are we there yet?

Haemorrhagic and thromboembolic events are common and the main cause for morbidity and mortality in patients treated with extracorporeal membrane oxygenation (ECMO). Monitoring of an adequate anticoagulation is, therefore, essential in patients during ECMO therapy. This review aims to describe the current evidence and emerging data relating to anticoagulation therapy and point-of-care (POC) coagulation monitoring in ECMO patients. Central laboratory-based coagulation testing including activated partial thromboplastin time (aPTT), international normalized ratio (INR) of the prothrombin time (PT), and activated clotting time (ACT) is most commonly used for coagulation monitoring. Several lines of coagulation monitoring devices have been explored for POC assessment of anticoagulation and/or haemostasis during ECMO. POC-type ACT, aPTT and PT have a shorter turn-around time, but they might exhibit a relevant bias in agreement with laboratory-based coagulation tests, and sensitivity and specificity for intervention are variable compared with laboratory- based tests. Whole-blood viscoelastic coagulation tests including ROTEM® and TEG® and platelet function testing have been increasingly used for monitoring haemostasis in ECMO patients. However, no single laboratory-based or POC coagulation test can reliably predict the emergence of haemorrhagic or thrombotic events. Further, treatment algorithms based on POC testing are scarce for ECMO patients. Larger prospective studies are necessary to evaluate the usefulness of POC coagulation monitors or a combination of them in potentially improving anticoagulation and decreasing haemorrhagic and thromboembolic complications.

Reduced aspirin responsiveness as assessed by impedance aggregometry is not associated with adverse outcome after cardiac surgery in a small low-risk cohort

Reduced aspirin responsiveness (i.e. persistent high platelet reactivity in platelet function testing) might be associated with increased risk of myocardial ischemia and cardiac mortality in patients with coronary disease. However, the impact in patients undergoing coronary artery bypass grafting (CABG) is unclear. The aim of this prospective cohort study was to evaluate the predictive value of reduced aspirin responsiveness on cardiac and thromboembolic events in patients undergoing elective isolated CABG surgery with aspirin intake until at least two days before surgery. We included 304 patients in this prospective single-center cohort study. Impedance platelet aggregometry (Multiplate®) was performed directly before and on the first day after surgery. Reduced aspirin responsiveness was defined as area under the curve in ASPItest (AUCASPI) ≥300 U. The primary outcome was a composite of all-cause mortality and/or major adverse cardiac or thromboembolic events within 1 year. Reduced aspirin responsiveness was found in 13 and 24% of patients pre and postoperatively, respectively. There was no difference in the outcomes between patients with normal and reduced aspirin responsiveness in the preoperative measurement (log-rank test, p = 0.540). Multivariate analysis including logistic EuroSCORE I and postoperative troponin T levels did not show any association of reduced aspirin responsiveness with adverse outcome (hazard ratio, 0.576; (95% CI 0.128-2.585; p = 0.471). Similarly, postoperative reduced aspirin responsiveness was not associated with adverse events. To conclude, reduced aspirin responsiveness as evaluated by Multiplate® platelet function analyzer was not associated with increased incidence of major adverse cardiac and thromboembolic events and mortality after CABG surgery.

Impact of loss of high-molecular-weight von Willebrand factor multimers on blood loss after aortic valve replacement

BACKGROUND

Severe aortic stenosis is associated with loss of the largest von Willebrand factor (vWF) multimers, which could affect primary haemostasis. We hypothesized that the altered multimer structure with the loss of the largest multimers increases postoperative bleeding in patients undergoing aortic valve replacement.

METHODS

We prospectively included 60 subjects with severe aortic stenosis. Before and after aortic valve replacement, vWF antigen, activity, and multimer structure were determined and platelet function was measured by impedance aggregometry. Blood loss from mediastinal drainage and the use of blood and haemostatic products were evaluated perioperatively.

RESULTS

Before operation, the altered multimer structure was present in 48 subjects (80%). Baseline characteristics and laboratory data were similar in all subjects. The median blood loss after 6 h was 250 (105-400) and 145 (85-240) ml in the groups with the altered and normal multimer structures, respectively (P=0.182). After 24 h, the cumulative loss was 495 (270-650) and 375 (310-600) ml in the groups with the altered and normal multimer structures, respectively (P=0.713). Multivariable analysis revealed no significant influence of multimer structure and platelet function on bleeding volumes after 6 and 24 h. After 24 h, there was no obvious difference in vWF antigen, activity, and multimer structure in subjects with and without the altered multimer structure before operation or in subjects with and without perioperative plasma transfusion.

CONCLUSIONS

The altered vWF multimer structure before operation was not associated with increased bleeding after aortic valve replacement. Our findings might be explained by perioperative release of vWF and rapid recovery of the largest vWF multimers.

Cerebrovascular carbon dioxide reactivity during exposure to equipotent isoflurane and isoflurane in nitrous oxide anaesthesia

We have studied the effects of hypocapnia on cerebrovascular changes in two MAC-equivalent anaesthetic regimens, using the transcranial Doppler technique as an index of cerebral blood flow (CBF) in 24 healthy ASA I patients undergoing spinal surgery. Eight of the patients were subjected to carbon dioxide reactivity challenges in the awake state. Before surgery, the other 16 patients received, in random order, either 1.15% isoflurane in oxygen or 0.5% isoflurane with 70% nitrous oxide. Carbon dioxide reactivity was calculated for each group as the increase in flow velocity per kPa change in PE'CO2 (cm s-1 kPa-1). It was significantly greater for the isoflurane group (14.09 (SD 2.44) cm s-1 kPa-1) and significantly less for the isoflurane-nitrous oxide group (7.95 (1.32) cm s-1 kPa-1) compared with the awake group (11.24 (0.95) cm s-1 kPa-1). We conclude that cerebrovascular responsiveness to changes in arterial carbon dioxide concentration is influenced markedly by the anaesthetic procedure. Hyperventilation is more likely to affect CBF during isoflurane anaesthesia than during an MAC-equivalent isoflurane-nitrous oxide anaesthesia.