Nutrition and outcomes in venovenous extracorporeal membrane oxygenation: An observational cohort study.

BACKGROUND: Overfeeding and underfeeding are associated with negative outcomes during critical illness. The purpose of this retrospective study was to assess the association between nutrition intake and outcomes for patients receiving venovenous (VV) extracorporeal membrane oxygenation (ECMO). METHODS: Adults who received VV ECMO August 2017 to June 2020 were screened. Patients with <3 ECMO nutrition support days were excluded. Age, sex, height, weight, ideal body weight (IBW), body mass index, sequential organ failure assessment score, respiratory ECMO survival prediction score, energy, and protein goals were collected. All nutrition intake was collected for the first 14 days of ECMO or until death, decannulation, or oral diet initiation. Outcomes analyzed included mortality and VV ECMO duration. The relationship between nutrition delivery and outcomes was tested with multivariate analysis. Univariate analyses were conducted on obese and nonobese subgroups. RESULTS: A total of 2044 nutrition days in 178 patients were analyzed. The median estimated needs were 24 (interquartile range: 22.3-28.3) kcal/kg/day and 2.25 (interquartile range: 2.25-2.77) g/kg/day of protein using IBW in patients with obesity and actual weight in patients without obesity. Patients received 83% of energy and 63.3% of protein targets. Patients with obesity who received ≥2 g/kg IBW of protein had a significantly shorter ECMO duration (P = 0.037). Increased protein intake was independently associated with a reduced risk of death (odds ratio: 0.06; 95% confidence interval: 0.01-0.43). CONCLUSION: Higher protein intake was associated with reduced mortality. Optimal energy targets for patients receiving ECMO are currently unknown and warrant further study.

Functional recovery in a cohort of ECMO and non-ECMO acute respiratory distress syndrome survivors.

BACKGROUND: The mortality benefit of VV-ECMO in ARDS has been extensively studied, but the impact on long-term functional outcomes of survivors is poorly defined. We aimed to assess the association between ECMO and functional outcomes in a contemporaneous cohort of survivors of ARDS. METHODS: Multicenter retrospective cohort study of ARDS survivors who presented to follow-up clinic. The primary outcome was FVC% predicted. Univariate and multivariate regression models were used to evaluate the impact of ECMO on the primary outcome. RESULTS: This study enrolled 110 survivors of ARDS, 34 of whom were managed using ECMO. The ECMO cohort was younger (35 [28, 50] vs. 51 [44, 61] years old, p < 0.01), less likely to have COVID-19 (58% vs. 96%, p < 0.01), more severely ill based on the Sequential Organ Failure Assessment (SOFA) score (7 [5, 9] vs. 4 [3, 6], p < 0.01), dynamic lung compliance (15 mL/cmH20 [11, 20] vs. 27 mL/cmH20 [23, 35], p < 0.01), oxygenation index (26 [22, 33] vs. 9 [6, 11], p < 0.01), and their need for rescue modes of ventilation. ECMO patients had significantly longer lengths of hospitalization (46 [27, 62] vs. 16 [12, 31] days, p < 0.01) ICU stay (29 [19, 43] vs. 10 [5, 17] days, p < 0.01), and duration of mechanical ventilation (24 [14, 42] vs. 10 [7, 17] days, p < 0.01). Functional outcomes were similar in ECMO and non-ECMO patients. ECMO did not predict changes in lung function when adjusting for age, SOFA, COVID-19 status, or length of hospitalization. CONCLUSIONS: There were no significant differences in the FVC% predicted, or other markers of pulmonary, neurocognitive, or psychiatric functional recovery outcomes, when comparing a contemporaneous clinic-based cohort of survivors of ARDS managed with ECMO to those without ECMO.

Regadenoson for the treatment of COVID-19: A five case clinical series and mouse studies.

BACKGROUND: Adenosine inhibits the activation of most immune cells and platelets. Selective adenosine A2A receptor (A2AR) agonists such as regadenoson (RA) reduce inflammation in most tissues, including lungs injured by hypoxia, ischemia, transplantation, or sickle cell anemia, principally by suppressing the activation of invariant natural killer T (iNKT) cells. The anti-inflammatory effects of RA are magnified in injured tissues due to induction in immune cells of A2ARs and ecto-enzymes CD39 and CD73 that convert ATP to adenosine in the extracellular space. Here we describe the results of a five patient study designed to evaluate RA safety and to seek evidence of reduced cytokine storm in hospitalized COVID-19 patients. METHODS AND FINDINGS: Five COVID-19 patients requiring supplemental oxygen but not intubation (WHO stages 4-5) were infused IV with a loading RA dose of 5 µg/kg/h for 0.5 h followed by a maintenance dose of 1.44 µg/kg/h for 6 hours, Vital signs and arterial oxygen saturation were recorded, and blood samples were collected before, during and after RA infusion for analysis of CRP, D-dimer, circulating iNKT cell activation state and plasma levels of 13 proinflammatory cytokines. RA was devoid of serious side effects, and within 24 hours from the start of infusion was associated with increased oxygen saturation (93.8 ± 0.58 vs 96.6 ± 1.08%, P<0.05), decreased D-dimer (754 ± 17 vs 518 ± 98 ng/ml, P<0.05), and a trend toward decreased CRP (3.80 ± 1.40 vs 1.98 ± 0.74 mg/dL, P = 0.075). Circulating iNKT cells, but not conventional T cells, were highly activated in COVID-19 patients (65% vs 5% CD69+). RA infusion for 30 minutes reduced iNKT cell activation by 50% (P<0.01). RA infusion for 30 minutes did not influence plasma cytokines, but infusion for 4.5 or 24 hours reduced levels of 11 of 13 proinflammatory cytokines. In separate mouse studies, subcutaneous RA infusion from Alzet minipumps at 1.44 µg/kg/h increased 10-day survival of SARS-CoV-2-infected K18-hACE2 mice from 10 to 40% (P<0.001). CONCLUSIONS: Infused RA is safe and produces rapid anti-inflammatory effects mediated by A2A adenosine receptors on iNKT cells and possibly in part by A2ARs on other immune cells and platelets. We speculate that iNKT cells are activated by release of injury-induced glycolipid antigens and/or alarmins such as IL-33 derived from virally infected type II epithelial cells which in turn activate iNKT cells and secondarily other immune cells. Adenosine released from hypoxic tissues, or RA infused as an anti-inflammatory agent decrease proinflammatory cytokines and may be useful for treating cytokine storm in patients with Covid-19 or other inflammatory lung diseases or trauma.

Pulmonary Co-Infections Detected Premortem Underestimate Postmortem Findings in a COVID-19 Autopsy Case Series.

Bacterial and fungal co-infections are reported complications of coronavirus disease 2019 (COVID-19) in critically ill patients but may go unrecognized premortem due to diagnostic limitations. We compared the premortem with the postmortem detection of pulmonary co-infections in 55 fatal COVID-19 cases from March 2020 to March 2021. The concordance in the premortem versus the postmortem diagnoses and the pathogen identification were evaluated. Premortem pulmonary co-infections were extracted from medical charts while applying standard diagnostic definitions. Postmortem co-infection was defined by compatible lung histopathology with or without the detection of an organism in tissue by bacterial or fungal staining, or polymerase chain reaction (PCR) with broad-range bacterial and fungal primers. Pulmonary co-infection was detected premortem in significantly fewer cases (15/55, 27%) than were detected postmortem (36/55, 65%; p < 0.0001). Among cases in which co-infection was detected postmortem by histopathology, an organism was identified in 27/36 (75%) of cases. Pseudomonas, Enterobacterales, and Staphylococcus aureus were the most frequently identified bacteria both premortem and postmortem. Invasive pulmonary fungal infection was detected in five cases postmortem, but in no cases premortem. According to the univariate analyses, the patients with undiagnosed pulmonary co-infection had significantly shorter hospital (p = 0.0012) and intensive care unit (p = 0.0006) stays and significantly fewer extra-pulmonary infections (p = 0.0021). Bacterial and fungal pulmonary co-infection are under-recognized complications in critically ill patients with COVID-19.

Regadenoson Reduces Soluble Receptor for Advanced Glycation End-Products in Lung Recipients.

BACKGROUND: The selective adenosine A2A receptor (A2AR) agonist regadenoson reduces inflammation due to lung ischemia-reperfusion injury (IRI). The objective of this study was to investigate molecular and cellular mechanisms by which regadenoson reduces IRI in lung transplant recipients. METHODS: Fourteen human lung transplant recipients were infused for 12 hours with regadenoson and 7 more served as untreated controls. Plasma levels of high mobility group box 1 and its soluble receptor for advanced glycation end-products (sRAGE) were measured by Luminex. Matrix metalloproteinase (MMP) 2 and 9 were measured by gelatin zymography. Tissue inhibitor of metalloproteinase 1 was measured by mass spectroscopy. A2AR expression on leukocytes was analyzed by flow cytometry. MMP-9-mediated cleavage of RAGE was evaluated using cultured macrophages in vitro. RESULTS: Regadenoson treatment during lung transplantation significantly reduced levels of MMP-9 (P < .05), but not MMP-2, and elevated levels of tissue inhibitor of metalloproteinase 1 (P < .05), an endogenous selective inhibitor of MMP-9. Regadenoson infusion significantly reduced plasma levels of sRAGE (P < .05) during lung reperfusion compared with control subjects. A2AR expression was highest on invariant natural killer T cells and higher on monocytes than other circulating immune cells (P < .05). The shedding of RAGE from cultured monocytes/macrophages was increased by MMP-9 stimulation and reduced by an MMP inhibitor or by A2AR agonists, regadenoson or ATL146e. CONCLUSIONS: In vivo and in vitro studies suggest that A2AR activation reduces sRAGE in part by inhibiting MMP-9 production by monocytes/macrophages. These results suggest a novel molecular mechanism by which A2AR agonists reduce primary graft dysfunction.

Histopathology and SARS-CoV-2 Cellular Localization in Eye Tissues of COVID-19 Autopsies.

Ophthalmic manifestations and tissue tropism of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been reported in association with coronavirus disease 2019 (COVID-19), but the pathology and cellular localization of SARS-CoV-2 are not well characterized. The objective of this study was to evaluate macroscopic and microscopic changes and investigate cellular localization of SARS-CoV-2 across ocular tissues at autopsy. Ocular tissues were obtained from 25 patients with COVID-19 at autopsy. SARS-CoV-2 nucleocapsid gene RNA was previously quantified by droplet digital PCR from one eye. Herein, contralateral eyes from 21 patients were fixed in formalin and subject to histopathologic examination. Sections of the droplet digital PCR-positive eyes from four other patients were evaluated by in situ hybridization to determine the cellular localization of SARS-CoV-2 spike gene RNA. Histopathologic abnormalities, including cytoid bodies, vascular changes, and retinal edema, with minimal or no inflammation in ocular tissues were observed in all 21 cases evaluated. In situ hybridization localized SARS-CoV-2 RNA to neuronal cells of the retinal inner and outer layers, ganglion cells, corneal epithelia, scleral fibroblasts, and oligodendrocytes of the optic nerve. In conclusion, a range of common histopathologic alterations were identified within ocular tissue, and SARS-CoV-2 RNA was localized to multiple cell types. Further studies will be required to determine whether the alterations observed were caused by SARS-CoV-2 infection, the host immune response, and/or preexisting comorbidities.

Successful lung transplantation using an allograft from a COVID-19-recovered donor: a potential role for subgenomic RNA to guide organ utilization.

Although the risk of SARS-CoV-2 transmission through lung transplantation from acutely infected donors is high, the risks of virus transmission and long-term lung allograft outcomes are not as well described when using pulmonary organs from COVID-19-recovered donors. We describe successful lung transplantation for a COVID-19-related lung injury using lungs from a COVID-19-recovered donor who was retrospectively found to have detectable genomic SARS-CoV-2 RNA in the lung tissue by multiple highly sensitive assays. However, SARS-CoV-2 subgenomic RNA (sgRNA), a marker of viral replication, was not detectable in the donor respiratory tissues. One year after lung transplantation, the recipient has a good functional status, walking 1 mile several times per week without the need for supplemental oxygen and without any evidence of donor-derived SARS-CoV-2 transmission. Our findings highlight the limitations of current clinical laboratory diagnostic assays in detecting the persistence of SARS-CoV-2 RNA in the lung tissue. The persistence of SARS-CoV-2 RNA in the donor tissue did not appear to represent active viral replication via sgRNA testing and, most importantly, did not negatively impact the allograft outcome in the first year after lung transplantation. sgRNA is easily performed and may be a useful assay for assessing viral infectivity in organs from donors with a recent infection.

Veno-arterial extracorporeal membrane oxygenation without allogeneic blood transfusion: An observational cohort study.

INTRODUCTION: It remains unclear whether patients who will not accept allogeneic blood transfusion can be managed successfully with veno-arterial (V-A) extracorporeal membrane oxygenation (ECMO). The objective of our study was to determine what percentage of V-A ECMO patients were managed without allogeneic blood transfusion. METHODS: This was a retrospective, observational cohort study of patients with cardiogenic shock requiring V-A ECMO between January 2016 and January 2019. The primary outcome was avoidance of any allogeneic blood transfusion. RESULTS: Of the 206 patients included, 23 (11.2%) were managed without any allogeneic blood transfusion. Fourteen (60.9%) avoided allogeneic blood transfusion during their entire hospitalization. "No-transfusion" patients were younger, more commonly men, were less likely to have a prior diagnosis of hypertension or coronary artery disease, had higher baseline hemoglobin, had higher SAVE scores, and were less likely to have received aspirin before ECMO. No patients in the "no-transfusion" group had major bleeding compared to 35% of patients in the blood transfusion group (p < 0.001). In-hospital mortality was 17.4% for those who avoided blood transfusion and 41.5% for those who received blood transfusion (p = 0.04). ECMO duration was significantly shorter in patients who avoided blood transfusion compared to those who received blood transfusion (median 3.5 vs 7 days, p < 0.001). CONCLUSIONS: Select patients can be successfully managed on V-A ECMO without allogeneic blood transfusion. Jehovah's Witnesses and other patients with objections to allogeneic transfusion might be offered V-A ECMO if its anticipated duration is short (e.g. <7 days) and baseline hemoglobin concentration is high (e.g. ≥10 mg/dL).

Decreased PRESET-Score corresponds with improved survival in COVID-19 veno-venous extracorporeal membrane oxygenation.

INTRODUCTION: The PREdiction of Survival on ECMO Therapy Score (PRESET-Score) predicts mortality while on veno-venous extracorporeal membrane oxygenation (VV ECMO) for acute respiratory distress syndrome. The aim of our study was to assess the association between PRESET-Score and survival in a large COVID-19 VV ECMO cohort. METHODS: This was a single-center retrospective study of COVID-19 VV ECMO patients from 15 March 2020, to 30 November 2021. Univariable and Multivariable analyses were performed to assess patient survival and score differences. RESULTS: A total of 105 patients were included in our analysis with a mean PRESET-Score of 6.74. Overall survival was 65.71%. The mean PRESET-Score was significantly lower in the survivor group (6.03 vs 8.11, p < 0.001). Patients with a PRESET-Score less than or equal to six had improved survival compared to those with a PRESET-Score greater than or equal to 8 (97.7% vs. 32.5%, p < 0.001). In a multivariable logistic regression, a lower PRESET-Score was also predictive of survival (OR 2.84, 95% CI 1.75, 4.63, p < 0.001). CONCLUSION: We demonstrate that lower PRESET scores are associated with improved survival. The utilization of this validated, quantifiable, and objective scoring system to help identify COVID-19 patients with the greatest potential to benefit from VV-ECMO appears feasible. The incorporation of the PRESET-Score into institutional ECMO candidacy guidelines can help insure and improve access of this limited healthcare resource to all critically ill patients.

SARS-CoV-2 infection and persistence in the human body and brain at autopsy.

Coronavirus disease 2019 (COVID-19) is known to cause multi-organ dysfunction1-3 during acute infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with some patients experiencing prolonged symptoms, termed post-acute sequelae of SARS-CoV-2 (refs. 4,5). However, the burden of infection outside the respiratory tract and time to viral clearance are not well characterized, particularly in the brain3,6-14. Here we carried out complete autopsies on 44 patients who died with COVID-19, with extensive sampling of the central nervous system in 11 of these patients, to map and quantify the distribution, replication and cell-type specificity of SARS-CoV-2 across the human body, including the brain, from acute infection to more than seven months following symptom onset. We show that SARS-CoV-2 is widely distributed, predominantly among patients who died with severe COVID-19, and that virus replication is present in multiple respiratory and non-respiratory tissues, including the brain, early in infection. Further, we detected persistent SARS-CoV-2 RNA in multiple anatomic sites, including throughout the brain, as late as 230 days following symptom onset in one case. Despite extensive distribution of SARS-CoV-2 RNA throughout the body, we observed little evidence of inflammation or direct viral cytopathology outside the respiratory tract. Our data indicate that in some patients SARS-CoV-2 can cause systemic infection and persist in the body for months.

Extracorporeal life support as a bridge to lung transplantation: Where are we now?

The number of lung transplant procedures performed internationally is increasing but the donor organ pool is insufficient to meet demand and waiting list mortality is unacceptably high. As survival rates for patients with acute respiratory distress syndrome managed on extracorporeal life support (ECLS) have steadily improved, a potential role for ECLS to support critically ill patients awaiting a donor organ match has emerged. We explore the rapidly evolving landscape of ECLS as a bridge to lung transplantation with review of the patient selection criteria, predictors of survival, modes of pre and peri-transplant support, and the importance of a holistic multidisciplinary approach to care. Finally, we consider innovations that are envisaged to increase the accessibility, safety, and effectiveness of ECLS delivery for future lung transplant candidates.

Safety and Efficacy of Tocilizumab 4 or 8 mg/kg in Hospitalized Patients With Moderate to Severe Coronavirus Disease 2019 Pneumonia: A Randomized Clinical Trial.

BACKGROUND: Tocilizumab, an interleukin 6 receptor (IL-6R) antagonist monoclonal antibody, has shown efficacy in patients with coronavirus disease 2019 (COVID-19) pneumonia, but the optimal dose is unknown. METHODS: Patients hospitalized for moderate to severe COVID-19 pneumonia were randomized 1:1 to receive standard of care treatment and 1-2 doses of intravenous tocilizumab 4 mg/kg or 8 mg/kg (open-label). Primary pharmacokinetic and pharmacodynamic end points were serum concentrations of tocilizumab and soluble interleukin 6 receptor (sIL-6R), IL-6, ferritin, and C-reactive protein (CRP), from baseline to day 60. The secondary end point was safety. Key exploratory efficacy end points included clinical status, time to discharge, mortality rate, and incidence of mechanical ventilation. RESULTS: Of 100 patients randomized, 49 received tocilizumab 4 mg/kg and 48 received 8 mg/kg. In pharmacokinetic and sIL-6R assessments, dose-dependent differences were seen in patients who received 1 or 2 doses of 4 or 8 mg/kg. Serum concentrations of IL-6, ferritin, and CRP and safety outcomes were comparable between groups. Through day 60, serious adverse events were reported in 30.6% and 25.0% of patients in the 4- and 8-mg/kg groups, respectively. Eight patients (16.3%) in the 4-mg/kg group and 6 (12.5%) in the 8-mg/kg group died. Exploratory time-to-event outcomes favored 8 mg/kg within the first 2 weeks. CONCLUSIONS: In patients with moderate to severe COVID-19 pneumonia who received tocilizumab 4 or 8 mg/kg, pharmacokinetic and sIL-6R assessments showed expected dose-dependent effects; pharmacodynamic assessments and safety were comparable, with no new safety signals. Further study is required before a lower dose of tocilizumab can be recommended in patients with COVID-19 pneumonia. CLINICAL TRIALS REGISTRATION: NCT04363736.

Platelet Transfusion and In-Hospital Mortality in Veno-Arterial Extracorporeal Membrane Oxygenation Patients.

Thrombocytopenia is common during extracorporeal membrane oxygenation (ECMO), and platelets are sometimes transfused to meet arbitrary goals. We performed a retrospective cohort study of veno-arterial (VA) ECMO patients from a single academic medical center and explored the relationship between platelet transfusion and in-hospital mortality using multivariable logistic regression. One hundred eighty-eight VA ECMO patients were included in the study. Ninety-one patients (48.4%) were transfused platelets during ECMO. Patients who received platelet transfusion had more coronary artery disease, lower platelet counts at cannulation, higher predicted mortality, lower nadir platelet counts, more ECMO days, and more red blood cell (RBC) and plasma transfusion. Mortality was 19.6% for patients who received no platelets, 40.8% for patients who received 1-3 platelets, and 78.6% for patients who received 4 or more platelets ( P < 0.001). After controlling for confounding variables including baseline severity of illness, central cannulation, postcardiotomy status, RBC and plasma transfusion, major bleeding, and total ECMO days, transfusion of 4 or more platelets remained associated with in-hospital mortality; OR = 4.68 (95% CI = 1.18-27.28), P = 0.03. Our findings highlight the need for randomized controlled trials that compare different platelet transfusion triggers, so that providers can better understand when platelet transfusion is indicated in VA ECMO patients.

In Vitro Comparison of Recombinant and Plasma-Derived von Willebrand Factor Concentrate for Treatment of Acquired von Willebrand Syndrome in Adult Extracorporeal Membrane Oxygenation Patients.

BACKGROUND: Coagulopathic bleeding is common during adult extracorporeal membrane oxygenation (ECMO), and acquired von Willebrand syndrome is a contributing factor. We compared ECMO patient blood samples that were treated in vitro with recombinant von Willebrand Factor concentrate and plasma-derived von Willebrand Factor concentrate. Our hypothesis was that recombinant von Willebrand Factor (vWF) would have greater efficacy in increasing vWF function. Secondarily, we hypothesized that recombinant vWF would have less impact on thrombin generation. METHODS: Thirty ECMO patients and 10 cardiac surgical controls were enrolled in the study. ECMO patient blood samples were treated in vitro with low- and high-dose recombinant vWFs and low- and high-dose plasma-derived vWFs. Whole blood ristocetin-induced platelet aggregation (RIPA), plasma ristocetin cofactor activity (RCo), and thrombin generation were compared between ECMO patient blood samples and control blood samples and between vWF-treated ECMO patient blood samples and nontreated samples. RESULTS: ECMO patient blood samples had severely reduced median RIPA compared to control samples 2 ohms (1-12 [25th-75th percentile]) vs 20 ohms (11-42) (P < .001). Treatment of ECMO patient blood samples with high-dose recombinant vWF significantly increased median RIPA to 10 ohms (2-15) (P < .001), while low-dose recombinant vWF and low- and high-dose plasma-derived vWFs did not significantly increase RIPA; 6 ohms (3-14), 4 ohms (1-13), and 6 ohms (2-10), respectively (P = .25, >.99, and >.99). Treatment with high-dose recombinant vWF and low- and high-dose plasma-derived vWFs significantly increased median plasma RCo to 4.7 international units (IU)/mL (3.7-5.9), 3.3 IU/mL (2.7-4.8), and 3.9 IU/mL (3.4-5.3), respectively, compared to controls 1.8 IU/mL (1.5-2.3) (all P < .001). Treatment with low- and high-dose plasma-derived vWFs significantly increased mean endogenous thrombin potential (6270.2 ± 2038.7 and 6313.1 ± 1913.3) compared to nontreated samples (5856.7 ± 1924.6) (P = .04 and .006), whereas treatment with low- and high-dose recombinant vWFs had no significant effect on mean endogenous thrombin potential (5776.1 ± 2087.3 and 5856.2 ± 1946.4) (P > .99 for both comparisons). CONCLUSIONS: In vitro treatment of ECMO patient blood samples with high-dose recombinant vWF was superior to low-dose recombinant vWF and plasma-derived vWF in terms of improving RIPA. In addition, recombinant vWF treatment did not increase endogenous thrombin potential, which may reduce overall thrombotic risk if it used to treat acquired von Willebrand syndrome in ECMO patients.

Deep dissection of the antiviral immune profile of patients with COVID-19.

In light of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) variants potentially undermining humoral immunity, it is important to understand the fine specificity of the antiviral antibodies. We screened 20 COVID-19 patients for antibodies against 9 different SARS-CoV-2 proteins observing responses against the spike (S) proteins, the receptor-binding domain (RBD), and the nucleocapsid (N) protein which were of the IgG1 and IgG3 subtypes. Importantly, mutations which typically occur in the B.1.351 "South African" variant, significantly reduced the binding of anti-RBD antibodies. Nine of 20 patients were critically ill and were considered high-risk (HR). These patients showed significantly higher levels of transforming growth factor beta (TGF-ß) and myeloid-derived suppressor cells (MDSC), and lower levels of CD4+ T cells expressing LAG-3 compared to standard-risk (SR) patients. HR patients evidenced significantly higher anti-S1/RBD IgG antibody levels and an increased neutralizing activity. Importantly, a large proportion of S protein-specific antibodies were glycosylation-dependent and we identified a number of immunodominant linear epitopes within the S1 and N proteins. Findings derived from this study will not only help us to identify the most relevant component of the anti-SARS-CoV-2 humoral immune response but will also enable us to design more meaningful immunomonitoring methods for anti-COVID-19 vaccines.

SARS-CoV-2 infection of the oral cavity and saliva.

Despite signs of infection-including taste loss, dry mouth and mucosal lesions such as ulcerations, enanthema and macules-the involvement of the oral cavity in coronavirus disease 2019 (COVID-19) is poorly understood. To address this, we generated and analyzed two single-cell RNA sequencing datasets of the human minor salivary glands and gingiva (9 samples, 13,824 cells), identifying 50 cell clusters. Using integrated cell normalization and annotation, we classified 34 unique cell subpopulations between glands and gingiva. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral entry factors such as ACE2 and TMPRSS members were broadly enriched in epithelial cells of the glands and oral mucosae. Using orthogonal RNA and protein expression assessments, we confirmed SARS-CoV-2 infection in the glands and mucosae. Saliva from SARS-CoV-2-infected individuals harbored epithelial cells exhibiting ACE2 and TMPRSS expression and sustained SARS-CoV-2 infection. Acellular and cellular salivary fractions from asymptomatic individuals were found to transmit SARS-CoV-2 ex vivo. Matched nasopharyngeal and saliva samples displayed distinct viral shedding dynamics, and salivary viral burden correlated with COVID-19 symptoms, including taste loss. Upon recovery, this asymptomatic cohort exhibited sustained salivary IgG antibodies against SARS-CoV-2. Collectively, these data show that the oral cavity is an important site for SARS-CoV-2 infection and implicate saliva as a potential route of SARS-CoV-2 transmission.

Tissue Factor Pathway Inhibitor Levels During Veno-Arterial Extracorporeal Membrane Oxygenation in Adults.

Tissue factor pathway inhibitor (TFPI) has multiple anticoagulant properties. To our knowledge, no studies have measured TFPI levels in adult veno-arterial (VA) extracorporeal membrane oxygenation patients. We hypothesized that adult VA ECMO patients would have increased TFPI levels and slowed tissue factor triggered thrombin generation. Twenty VA ECMO patients had TFPI levels and thrombin generation lag time measured on ECMO day 1 or 2, day 3, and day 5. TFPI levels and thrombin generation lag time were compared against healthy control plasma samples. Mean TFPI levels were significantly higher in ECMO patients on ECMO day 1 or 2 = 81,877 ± 19,481 pg/mL, day 3 = 73,907 ± 26,690 pg/mL, and day 5 = 77,812 ± 23,484 pg/mL compared with control plasma = 38,958 ± 9,225 pg/mL (P < 0.001 for all comparisons). Median thrombin generation lag time was significantly longer in ECMO patients on ECMO day 1 or 2 = 10.0 minutes [7.5, 13.8], day 3 = 9.0 minutes [6.8, 12.1], and day 5 = 10.7 minutes [8.3, 15.2] compared with control plasma = 3.6 minutes [2.9, 4.2] (P < 0.001 for all comparisons). TFPI is increased in VA ECMO patients and tissue factor triggered thrombin generation is slowed. Increased TFPI levels could contribute to the multifactorial coagulopathy that occurs during ECMO.

Minimally Invasive Left Ventricular Assist Device Insertion Facilitates Subsequent Heart Transplant.

OBJECTIVE: We have observed that minimally invasive left ventricular assist device (LVAD) insertion leads to more facile re-entry and easier cardiac transplantation. We hypothesize minimally invasive LVAD implantation results in improved outcomes at the time of subsequent heart transplant. METHODS: All adults undergoing cardiac transplantation between October 2015 and March 2019 at our institution were retrospectively reviewed. Those bridged to transplantation with a HeartWare HVAD were identified and divided into 2 cohorts based upon the surgical approach: those who underwent HVAD placement by conventional sternotomy versus minimally invasive insertion via lateral thoracotomy and hemisternotomy (LTHS). Patient demographics, as well as perioperative transplant outcomes, including survival, length of stay (LOS), blood utilization, ischemic time, bypass time, and postoperative extracorporeal membrane oxygenation (ECMO) were compared between cohorts. RESULTS: Forty-two patients were bridged to heart transplant with a HVAD implanted via either sternotomy (n = 22) or LTHS technique (n = 20). Demographics were similar between groups. There was 1 predischarge death in the sternotomy group and none in the LTHS group. Body surface area, cardiopulmonary bypass time, ischemic time, ECMO utilization, and reoperation for bleeding were similar. Red blood cell units transfused were significantly lower in the LTHS cohort (3.0 [1.0-5.0] vs 6.0 [2.5-10.0] P = 0.046). The LTHS cohort had a significantly shorter hospital LOS (12.0 [11.0-28.0] vs 22.5 [15.7-41.7] P = 0.022) with a trend toward shorter intensive care unit LOS (6.0 [5.0-10.5] vs 11.0 [6.0-21.5] days P = 0.057). CONCLUSIONS: Minimally invasive HVAD implantation improves outcomes at subsequent heart transplantation, resulting in shorter LOS and less red cell transfusion. Larger multi-institutional studies are necessary to validate these findings.

Mortality Risk Assessment in COVID-19 Venovenous Extracorporeal Membrane Oxygenation.

BACKGROUND: A life-threatening complication of coronavirus disease 2019 (COVID-19) is acute respiratory distress syndrome (ARDS) refractory to conventional management. Venovenous (VV) extracorporeal membrane oxygenation (ECMO) (VV-ECMO) is used to support patients with ARDS in whom conventional management fails. Scoring systems to predict mortality in VV-ECMO remain unvalidated in COVID-19 ARDS. This report describes a large single-center experience with VV-ECMO in COVID-19 and assesses the utility of standard risk calculators. METHODS: A retrospective review of a prospective database of all patients with COVID-19 who underwent VV-ECMO cannulation between March 15 and June 27, 2020 at a single academic center was performed. Demographic, clinical, and ECMO characteristics were collected. The primary outcome was in-hospital mortality; survivor and nonsurvivor cohorts were compared by using univariate and bivariate analyses. RESULTS: Forty patients who had COVID-19 and underwent ECMO were identified. Of the 33 patients (82.5%) in whom ECMO had been discontinued at the time of analysis, 18 patients (54.5%) survived to hospital discharge, and 15 (45.5%) died during ECMO. Nonsurvivors presented with a statistically significant higher Prediction of Survival on ECMO Therapy (PRESET)-Score (mean ± SD, 8.33 ± 0.8 vs 6.17 ± 1.8; P = .001). The PRESET score demonstrated accurate mortality prediction. All patients with a PRESET-Score of 6 or lowers survived, and a score of 7 or higher was associated with a dramatic increase in mortality. CONCLUSIONS: These results suggest that favorable outcomes are possible in patients with COVID-19 who undergo ECMO at high-volume centers. This study demonstrated an association between the PRESET-Score and survival in patients with COVID-19 who underwent VV-ECMO. Standard risk calculators may aid in appropriate selection of patients with COVID-19 ARDS for ECMO.

A Retrospective Study of Infection in Patients Requiring Extracorporeal Membrane Oxygenation Support.

BACKGROUND: Healthcare-associated infections (HAIs) in critically ill patients are a serious public health problem. Extracorporeal membrane oxygenation (ECMO) has been used increasingly for patients with severe cardiac or respiratory failure, but it may increase HAI risk. The goal of our study was to characterize HAIs in ECMO patients at an ECMO referral center. METHODS: This institutional review board-approved study identified all consecutive adult ECMO patients admitted to the cardiac surgery intensive care unit (CSICU) between January 1, 2015, and December 31, 2017. Demographic data, diagnosis, ECMO cannulation technique, and survival were collected. Urinary tract infection, pneumonia, and bacteremia incidence during ECMO and within 3 months of decannulation were collected. Outcomes of patients with HAIs were compared with noninfected patients, the CSICU infection incidence, and overall Extracorporeal Life Support Organization survival data. RESULTS: There were 288 ECMO patients and 3396 CSICU admissions during this period. Survival was 72.3% for venoarterial ECMO, 85.3% for venovenous ECMO, and 57.1% for multimodality or veno-arteriovenous ECMO, with discharge survival of 60.2%, 72.0%, and 28.6%, respectively. Bacteremia incidence while cannulated was 6.8% for venoarterial ECMO and 9.3% for venovenous ECMO. Bacteremia occurred in 22 of 288 (7.6%) ECMO patients, compared with 48 of 3109 (1.5%) in non-ECMO CSICU patients, which was statistically significant (P < .002). Bacteremia and pneumonia were associated with decreased VA-ECMO survival, with prolonged overall requirements for ECMO support. CONCLUSIONS: Nosocomial ECMO infections are significantly higher than in other CSICU patients. Infection risk remains significant even after decannulation. Infection is associated with increased mortality and longer duration of ECMO support. Further efforts are needed to determine HAI reduction strategies in this high-risk patient population.