Screening pulmonary angiogram and the effect on anticoagulation strategies in severe respiratory failure patients on venovenous extracorporeal membrane oxygenation

Temporal changes in markers of coagulation and fibrinolysis in adults during extracorporeal membrane oxygenation

INTRODUCTION

Bleeding and thrombotic events (BTE) are frequent during extracorporeal membrane oxygenation (ECMO). They occur at varying timepoints and may be affected by temporal changes in coagulation and fibrinolysis. We aimed to assess various coagulation and fibrinolytic markers over time and their relationship with BTE.

METHODS

A single-centre prospective study was performed in 17 patients with severe respiratory failure receiving veno-venous ECMO. Blood samples were collected before and during ECMO, and around circuit decannulation.

RESULTS

Prior to ECMO, D-Dimer, Plasmin-Antiplasmin complexes (PAP), Plasminogen-Activator Inhibitor-1 (PAI-1) and fibrinogen were elevated. There was an increase in D-Dimer and Prothrombin Fragments 1+2 (PF1+2) (729 to 1305pmol/L, p = .034) by day 1 and PAP increased by day 2 from baseline levels (median 1022 to 1797 µg/L, p = .023). There was a strong positive correlation in PAP, PF1+2 and thrombin-antithrombin complexes (TAT) to D-Dimer. BTE were frequent - 18% had major extracranial haemorrhage and 24% had intracranial haemorrhage. Over time, there was a progressive elevation PAP in patients developing subsequent extracranial haemorrhage, whereas D-Dimer, PAP and PF1+2 increased after intracranial haemorrhage.

CONCLUSIONS

There were early changes in coagulation activity during ECMO by PF1+2 followed by subsequent fibrinolysis by PAP. Changes in PAP, PF1+2 and TAT were associated with major haemorrhage.

Pulmonary perfusion in long-term survivors of COVID-19-related severe acute respiratory distress syndrome treated by extracorporeal membrane oxygenation

COVID-19 associates with a hypercoagulant state and an increased risk for venous thromboembolic events (VTEs). Whether severe COVID-19 infection requiring extracorporeal membrane oxygenation (ECMO) support might lead to chronic pulmonary perfusion abnormalities and chronic thromboembolic pulmonary disease/hypertension remains unclear. The purpose of this study was to evaluate chronic pulmonary perfusion abnormalities in long-term survivors of COVID-19-related severe acute respiratory distress syndrome (ARDS) treated by ECMO at our institution. Pulmonary perfusion was examined by ventilation/perfusion (V/Q) single-photon emission computed tomography or V/Q planar scintigraphy at least 3 months after ECMO explantation, comorbidities and incidence of thromboembolic events were recorded as well. Of 172 COVID-19 patients treated by ECMO for severe COVID-19 pneumonia between March 2020 and November 2021, only 80 were successfully weaned from ECMO. Of those, 37 patients were enrolled into the present analysis (27% female, mean age 52 years). Median duration of ECMO support was 12 days. In 24 (65%) patients VTE was recorded in the acute phase (23 patients developed ECMO cannula-related deep vein thrombosis, 5 of them had also a pulmonary embolism, and one thrombus was associated with a central catheter). The median duration between ECMO explantation and assessment of pulmonary perfusion was 420 days. No segmental or larger mismatched perfusion defects were then detected in any patient. In conclusion, in long-term survivors of COVID-19-related ARDS treated by ECMO, no persistent pulmonary perfusion abnormalities were detected although VTE was common.

The History of Extracorporeal Membrane Oxygenation and the Development of Extracorporeal Membrane Oxygenation Anticoagulation

Extracorporeal membrane oxygenation (ECMO) was first started for humans in early 1970s by Robert Bartlett. Since its inception, there have been numerous challenges with extracorporeal circulation, such as coagulation and platelet activation, followed by consumption of coagulation factors and platelets, and biocompatibility of tubing, pump, and oxygenator. Unfractionated heparin (heparin hereafter) has historically been the defacto anticoagulant until recently. Also, coagulation monitoring was mainly based on bedside activated clotting time and activated partial thromboplastin time. In the past 50 years, the technology of ECMO has advanced tremendously, and thus, the survival rate has improved significantly. The indication for ECMO has also expanded. Among these are clinical conditions such as postcardiopulmonary bypass, sepsis, ECMO cardiopulmonary resuscitation, and even severe coronavirus disease 2019 (COVID-19). Not surprisingly, the number of ECMO cases has increased according to the Extracorporeal Life Support Organization Registry and prolonged ECMO support has become more prevalent. It is not uncommon for patients with COVID-19 to be on ECMO support for more than 1 year until recovery or lung transplant. With that being said, complications of bleeding, thrombosis, clot formation in the circuit, and intravascular hemolysis still remain and continue to be major challenges. Here, several clinical ECMO experts, including the "Father of ECMO"-Dr. Robert Bartlett, describe the history and advances of ECMO.

Clinical impact of screening computed tomography in extracorporeal membrane oxygenation: a retrospective cohort study

BACKGROUND

Data on the prevalence and clinical impact of extrapulmonary findings at screening computed tomography (CT) on initiation of veno-venous extracorporeal membrane oxygenation (V-V ECMO) are limited. We aimed to identify the prevalence of extrapulmonary findings on screening CT following V-V ECMO initiation. We hypothesized that extrapulmonary findings would influence clinical management and outcome.

METHODS

Retrospective analysis (2011-2021) of admission screening CT including head, abdomen and pelvis with contrast of consecutive patients on initiation of V-V ECMO. CT findings identified by the attending consultant radiologist were extracted. Demographics, admission physiological and laboratory data, clinical decision-making following CT and ECMO ICU mortality were recorded from the electronic medical record. We used multivariable logistic regression and Kaplan-Meier curves to evaluate associations between extrapulmonary findings and ECMO ICU mortality.

RESULTS

Of the 833 patients receiving V-V ECMO, 761 underwent routine admission CT (91.4%). ECMO ICU length of stay was 19 days (IQR 12-23); ICU mortality at the ECMO centre was 18.9%. An incidental extrapulmonary finding was reported in 227 patients (29.8%), leading to an invasive procedure in 12/227 cases (5.3%) and a change in medical management (mainly in anticoagulation strategy) in 119/227 (52.4%). Extrapulmonary findings associated with mortality were intracranial haemorrhage (OR 2.34 (95% CI 1.31-4.12), cerebral infarction (OR 3.59 (95% CI 1.26-9.86) and colitis (OR 2.80 (95% CI 1.35-5.67).

CONCLUSIONS

Screening CT frequently identifies extrapulmonary findings of clinical significance. Newly detected intracranial haemorrhage, cerebral infarction and colitis were associated with increased ICU mortality.

Complications related to extracorporeal membrane oxygenation support as a bridge to lung transplantation and their clinical significance

BACKGROUND

Incidence of complications related extracorporeal membrane oxygenation (ECMO) support as a bridge to lung transplantation (BTT) and its association with the patient outcome in lung transplantation (LT) has not been well documented in previous studies.

OBJECTIVES

We evaluated the incidence of complications related to the use of ECMO support as a BTT, and the association between the occurrence of the complications and patient outcomes in LTs.

METHODS

This retrospective cohort study investigated 100 consecutive patients who started ECMO support as a BTT between April 2013 and March 2020. Data for the analyses were retrieved from electronic medical records.

RESULTS

Fifty-six percent of the patients experienced at least one complication during the BTT with ECMO. Major bleeding was the most common complication. In multivariate logistic regression analysis, occurrence of oxygenator thromboses (OR 16.438, P = 0.008) and the use of renal replacement therapy (RRT) (OR 32.288, P < 0.001) were associated with a failed BTT. In the subgroup analysis of the LT recipients, intracranial hemorrhages, (OR 13.825, P = 0.021), RRT use, (OR 11.395, P = 0.038), and bloodstream infection occurrence (OR 6.210; P = 0.034) were identified as risk factors for in-hospital mortality.

CONCLUSIONS

The occurrence of complications during the use of ECMO support as a BTT was associated with unfavorable outcomes in LTs. Close monitoring and the proper management of these complications may be important to achieve better outcomes in patients using ECMO support as a BTT.

Efficacy and Safety of Extracorporeal Membrane Oxygenation in Patients under Mechanical Ventilation with COVID-19 and Severe Acute Respiratory Distress Syndrome: A Health Technology Assessment

We aimed to assess the efficacy and safety of extracorporeal membrane oxygenation (ECMO) in patients under mechanical ventilation with COVID-19 and severe acute respiratory distress syndrome (ARDS). A systematic review of the literature published in PubMed, Cochrane Library and LILACS databases, was performed. A manual search was also conducted using the reference lists of the studies included in the full-text assessment, as well as a grey-literature search on Google. Additionally, websites of state institutions and organizations developing clinical practice guidelines and health technology assessments were reviewed. The ClinicalTrials.gov website was screened along with the websites of the International Clinical Trial Registry Platform and the National Registry of Health Research Projects of the Peruvian National Institute of Health. No restrictions were applied in terms of language, time, or country. A total of 13 documents were assessed, which included 7 clinical practice guidelines, 3 health technology assessments, 1 systematic review, 1 randomized clinical trial, and 1 observational study. A critical appraisal was conducted for each document. After this, we considered that the currently available evidence is insufficient for a conclusion supporting the use of ECMO in patients under mechanical ventilation with severe ARDS associated to COVID-19 in terms of mortality, safety, and quality of life.

Clinical Characteristics Between Survivors and Nonsurvivors of COVID-19 Patients Requiring Extracorporeal Membrane Oxygenation (ECMO) Support: A Systematic Review and Meta-Analysis

Background: The use of extracorporeal membrane oxygenation (ECMO) in coronavirus disease 2019 (COVID-19) for refractory respiratory failure, severe cardiac dysfunction, and bridge to lung transplantation has been steadily increasing during the ongoing global pandemic. Objective: Our meta-analysis aims to compare the clinical characteristics between COVID-19 survivors and nonsurvivors requiring ECMO support. Methods: A systematic search of Pubmed, Cochrane, Embase, Scopus, and Web of Science databases was performed between December first, 2019, to June first, 2021. Studies with comparative data of COVID-19 ECMO patients were selected, in which clinical characteristics and complications were assessed. Results: Sixteen cohort studies involving 706 COVID-19 patients requiring ECMO support with pooled mortality rate of 40% were included. Younger age (mean 51 years vs 55 years; P < .001), fewer comorbidities (23% vs 31%; odds ratio [OR] 0.55; P  =  .02), and less renal replacement therapy (RRT) (21% vs 39%; OR 0.41; P  =  .007) and vasopressor (76% vs 92%; OR 0.35; P  =  .008) requirement were demonstrated in COVID-19 survivors requiring ECMO support than nonsurvivors. Survivors also had higher pre-ECMO pH (mean 7.33 vs 7.26; P < .001) than nonsurvivors. No difference was observed in gender, body mass index, duration of mechanical ventilation (MV) before ECMO support initiation, total ECMO support duration, and pre-ECMO parameters of PaO2/FiO2 ratio, tidal volume (mL/kg), positive end-expiratory pressure, and plateau pressure. The rate of bleeding complications was lower in survivors (32% vs 59%; OR 0.36; P  =  .001) than nonsurvivors, but no difference was observed in thromboembolism and secondary infections. Conclusions: We found advanced age, multiple comorbidities, lower pre-ECMO pH, greater RRT, and vasopressor requirements, and bleeding are predictors of death in COVID-19 patients requiring ECMO support. The duration of MV before ECMO support initiation and total ECMO support duration was similar among survivors and nonsurvivors. Our study results have important clinical implications when considering ECMO support in critically ill COVID-19 patients.

A Comparison of Thrombosis and Hemorrhage Rates in Patients With Severe Respiratory Failure Due to Coronavirus Disease 2019 and Influenza Requiring Extracorporeal Membrane Oxygenation

OBJECTIVES

Extracorporeal membrane oxygenation is a lifesaving therapy for patients with severe acute respiratory distress syndrome refractory to conventional mechanical ventilation. It is frequently complicated by both thrombosis and hemorrhage. A markedly prothrombotic state associated with high rates of venous thromboembolism has been described in patients with severe acute respiratory syndrome coronavirus 2 (coronavirus disease 2019) infection. These rates have currently not been described during extracorporeal membrane oxygenation in comparison to other viral pneumonias.

DESIGN

Retrospective observational study.

SETTING

Single high-volume tertiary critical care department at a university hospital.

PATIENTS

Patients 16 years old or greater receiving venovenous extracorporeal membrane oxygenation between March 1, 2020, and May 31, 2020, with coronavirus disease 2019 were compared with a cohort of patients with influenza pneumonia between June 1, 2012, and May 31, 2020.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The rates of venous thromboembolism and hemorrhage were compared in patients with coronavirus disease 2019 against a historic population of patients with influenza pneumonia who required extracorporeal membrane oxygenation. There were 51 patients who received extracorporeal membrane oxygenation due to coronavirus disease 2019 and 80 patients with influenza. At cannulation for extracorporeal membrane oxygenation, 37% of patients with coronavirus disease 2019 compared with 8% of patients with influenza had filling defects on CT pulmonary angiography (p = 0.0001). Catheter-associated deep vein thrombosis shown on ultrasound Doppler after decannulation was present in 53% with coronavirus disease 2019 versus 25% with influenza (p = 0.01). The rates of intracranial hemorrhage at the time of cannulation were 16% with coronavirus disease 2019 and 14% with influenza (p = 0.8). Elevated d-dimer levels were seen in both conditions and were significantly higher in those with pulmonary thromboembolism than those without in coronavirus disease 2019 (p = 0.02). Fibrinogen and C-reactive protein levels were significantly higher in those with coronavirus disease 2019 than influenza (p < 0.01).

CONCLUSIONS

Significant rates of pulmonary thromboembolism and of catheter-associated deep vein thrombosis were seen in both viral infections but were greater in those requiring the use of extracorporeal membrane oxygenation in coronavirus disease 2019 than for influenza.

Veno-venous extracorporeal membrane oxygenation in coronavirus disease 2019: a case series

Background

The use of veno-venous extracorporeal membrane oxygenation (VV-ECMO) in severe hypoxaemic respiratory failure from coronavirus disease 2019 (COVID-19) has been described, but reported utilisation and outcomes are variable, and detailed information on patient characteristics is lacking. We aim to report clinical characteristics, management and outcomes of COVID-19 patients requiring VV-ECMO, admitted over 2 months to a high-volume centre in the UK.

Methods

Patient information, including baseline characteristics and clinical parameters, was collected retrospectively from electronic health records for COVID-19 VV-ECMO admissions between 3 March and 2 May 2020. Clinical management is described. Data are reported for survivors and nonsurvivors.

Results

We describe 43 consecutive patients with COVID-19 who received VV-ECMO. Median age was 46 years (interquartile range 35.5–52.5) and 76.7% were male. Median time from symptom onset to VV-ECMO was 14 days (interquartile range 11–17.5). All patients underwent computed tomography imaging, revealing extensive pulmonary consolidation in 95.3%, and pulmonary embolus in 27.9%. Overall, 79.1% received immunomodulation with methylprednisolone for persistent maladaptive hyperinflammatory state. Vasopressors were used in 86%, and 44.2% received renal replacement therapy. Median duration on VV-ECMO was 13 days (interquartile range 8–20). 14 patients died (32.6%) and 29 survived (67.4%) to hospital discharge. Nonsurvivors had significantly higher d-dimer (38.2 versus 9.5 mg·L⁻¹, fibrinogen equivalent units; p=0.035) and creatinine (169 versus 73 μmol·L⁻¹; p=0.022) at commencement of VV-ECMO.

Conclusions

Our data support the use of VV-ECMO in selected COVID-19 patients. The cohort was characterised by high degree of alveolar consolidation, systemic inflammation and intravascular thrombosis.

VV-ECMO, when offered to #COVID19 patients in refractory respiratory failure, can be associated with favourable outcomes. This is a detailed case series of 43 COVID-19 patients requiring VV-ECMO from a UK centre. 67.4% survived to hospital discharge.https://bit.ly/3ko9Ucu