SARS-CoV-2 Omicron-B.1.1.529 leads to widespread escape from neutralizing antibody responses.

On 24th November 2021, the sequence of a new SARS-CoV-2 viral isolate Omicron-B.1.1.529 was announced, containing far more mutations in Spike (S) than previously reported variants. Neutralization titers of Omicron by sera from vaccinees and convalescent subjects infected with early pandemic Alpha, Beta, Gamma, or Delta are substantially reduced, or the sera failed to neutralize. Titers against Omicron are boosted by third vaccine doses and are high in both vaccinated individuals and those infected by Delta. Mutations in Omicron knock out or substantially reduce neutralization by most of the large panel of potent monoclonal antibodies and antibodies under commercial development. Omicron S has structural changes from earlier viruses and uses mutations that confer tight binding to ACE2 to unleash evolution driven by immune escape. This leads to a large number of mutations in the ACE2 binding site and rebalances receptor affinity to that of earlier pandemic viruses.

Patient-specific risk factors for reintervention following primary endovascular treatment of iliac artery disease.

OBJECTIVE: Predictive models for reintervention may guide clinicians to optimize selection, education, and follow-up of patients undergoing endovascular iliac revascularization. Although the impact of lesion- and device-related characteristics on iliac restenosis and reintervention risk is well-defined, data on patient-specific risk factors are scarce and conflicting. This study aimed to explore the value of patient-related factors in predicting the need for clinically driven target-vessel revascularization (CD-TVR) in patients undergoing primary endovascular treatment of iliac artery disease. METHODS: Consecutively enrolled patients undergoing endovascular revascularization for symptomatic iliac artery disease at a tertiary vascular referral center between January 2008 and June 2020 were retrospectively analyzed. Primary and secondary outcomes were CD-TVR occurrence within 24 months and time to CD-TVR, respectively. Patients who died or did not require CD-TVR within 24 months were censored at the date of death or at 730 days, respectively. Multiple imputation was used to account for missing data in primary analyses. RESULTS: A total of 1538 iliac interventions were performed in 1113 patients (26% females; 68 years). CD-TVR occurred in 108 limbs (74 patients; 7.0%) with a median time to CD-TVR of 246 days. On multivariable analysis, increasing age was associated with lower likelihood of CD-TVR (odds ratio [OR], 0.64; 95% confidence interval [CI], 0.50-0.83; P = .001) and decreased risk of CD-TVR at any given time (hazard ratio [HR], 0.66; 95% CI, 0.52-0.84; P = .001). Similarly, a lower likelihood of CD-TVR (OR, 0.75; 95% CI, 0.59-0.95; P = .017) and decreased risk of CD-TVR at any given time (HR, 0.73; 95% CI, 0.58-0.93; P = .009) were observed with higher glomerular filtration rates. Lastly, revascularization of common vs external iliac artery disease was associated with lower likelihood of CD-TVR (OR, 0.48; 95% CI, 0.24-0.93; P = .030) and decreased risk of CD-TVR at any given time (HR, 0.48; 95% CI, 0.25-0.92; P = .027). No associations were observed between traditional cardiovascular risk factors (sex, hypertension, higher low-density lipoprotein cholesterol, higher hemoglobin A1c, smoking) and CD-TVR. CONCLUSIONS: In this retrospective cohort study, younger age, impaired kidney function, and external iliac artery disease were associated with CD-TVR. Traditional markers of cardiovascular risk were not seen to predict reintervention.

Endovascular revascularization strategies for aortoiliac and femoropopliteal artery disease: a meta-analysis.

AIMS: Optimal endovascular management of intermittent claudication (IC) remains disputed. This systematic review and meta-analysis compares efficacy and safety outcomes for balloon angioplasty (BA), bare-metal stents (BMS), drug-coated balloons (DCB), drug-eluting stents (DES), covered stents, and atherectomy. METHODS AND RESULTS: Electronic databases were searched for randomized, controlled trials (RCT) from inception through November 2021. Efficacy outcomes were primary patency, target-lesion revascularization (TLR), and quality-of-life (QoL). Safety endpoints were all-cause mortality and major amputation. Outcomes were evaluated at short-term (<1 year), mid-term (1-2 years), and long-term (≥2 years) follow-up. The study was registered on PROSPERO (CRD42021292639). Fifty-one RCTs enrolling 8430 patients/lesions were included. In femoropopliteal disease of low-to-intermediate complexity, DCBs were associated with higher likelihood of primary patency [short-term: odds ratio (OR) 3.21, 95% confidence interval (CI) 2.44-4.24; long-term: OR 2.47, 95% CI 1.93-3.16], lower TLR (short-term: OR 0.33, 95% CI 0.22-0.49; long-term: OR 0.42, 95% CI 0.29-0.60) and similar all-cause mortality risk, compared with BA. Primary stenting using BMS was associated with improved short-to-mid-term patency and TLR, but similar long-term efficacy compared with provisional stenting. Mid-term patency (OR 1.64, 95% CI 0.89-3.03) and TLR (OR 0.50, 95% CI 0.22-1.11) estimates were comparable for DES vs. BMS. Atherectomy, used independently or adjunctively, was not associated with efficacy benefits compared with drug-coated and uncoated angioplasty, or stenting approaches. Paucity and heterogeneity of data precluded pooled analysis for aortoiliac disease and QoL endpoints. CONCLUSION: Certain devices may provide benefits in femoropopliteal disease, but comparative data in aortoiliac arteries is lacking. Gaps in evidence quantity and quality impede identification of the optimal endovascular approach to IC.

Risk Stratification in Nonischemic Dilated Cardiomyopathy Using CMR Imaging: A Systematic Review and Meta-Analysis.

Importance: Accurate risk stratification of nonischemic dilated cardiomyopathy (NIDCM) remains challenging. Objective: To evaluate the association of cardiac magnetic resonance (CMR) imaging-derived measurements with clinical outcomes in NIDCM. Data Sources: MEDLINE, Embase, Cochrane Library, and Web of Science Core Collection databases were systematically searched for articles from January 2005 to April 2023. Study Selection: Prospective and retrospective nonrandomized diagnostic studies reporting on the association between CMR imaging-derived measurements and adverse clinical outcomes in NIDCM were deemed eligible. Data Extraction and Synthesis: Prespecified items related to patient population, CMR imaging measurements, and clinical outcomes were extracted at the study level by 2 independent reviewers. Random-effects models were fitted using restricted maximum likelihood estimation and the method of Hartung, Knapp, Sidik, and Jonkman. Main Outcomes and Measures: All-cause mortality, cardiovascular mortality, arrhythmic events, heart failure events, and major adverse cardiac events (MACE). Results: A total of 103 studies including 29 687 patients with NIDCM were analyzed. Late gadolinium enhancement (LGE) presence and extent (per 1%) were associated with higher all-cause mortality (hazard ratio [HR], 1.81 [95% CI, 1.60-2.04]; P < .001 and HR, 1.07 [95% CI, 1.02-1.12]; P = .02, respectively), cardiovascular mortality (HR, 2.43 [95% CI, 2.13-2.78]; P < .001 and HR, 1.15 [95% CI, 1.07-1.24]; P = .01), arrhythmic events (HR, 2.69 [95% CI, 2.20-3.30]; P < .001 and HR, 1.07 [95% CI, 1.03-1.12]; P = .004) and heart failure events (HR, 1.98 [95% CI, 1.73-2.27]; P < .001 and HR, 1.06 [95% CI, 1.01-1.10]; P = .02). Left ventricular ejection fraction (LVEF) (per 1%) was not associated with all-cause mortality (HR, 0.99 [95% CI, 0.97-1.02]; P = .47), cardiovascular mortality (HR, 0.97 [95% CI, 0.94-1.00]; P = .05), or arrhythmic outcomes (HR, 0.99 [95% CI, 0.97-1.01]; P = .34). Lower risks for heart failure events (HR, 0.97 [95% CI, 0.95-0.98]; P = .002) and MACE (HR, 0.98 [95% CI, 0.96-0.99]; P < .001) were observed with higher LVEF. Higher native T1 relaxation times (per 10 ms) were associated with arrhythmic events (HR, 1.07 [95% CI, 1.01-1.14]; P = .04) and MACE (HR, 1.06 [95% CI, 1.01-1.11]; P = .03). Global longitudinal strain (GLS) (per 1%) was not associated with heart failure events (HR, 1.06 [95% CI, 0.95-1.18]; P = .15) or MACE (HR, 1.03 [95% CI, 0.94-1.14]; P = .43). Limited data precluded definitive analysis for native T1 relaxation times, GLS, and extracellular volume fraction (ECV) with respect to mortality outcomes. Conclusion: The presence and extent of LGE were associated with various adverse clinical outcomes, whereas LVEF was not significantly associated with mortality and arrhythmic end points in NIDCM. Risk stratification using native T1 relaxation times, extracellular volume fraction, and global longitudinal strain requires further evaluation.

Machine learning in sudden cardiac death risk prediction: a systematic review.

AIMS: Most patients who receive implantable cardioverter defibrillators (ICDs) for primary prevention do not receive therapy during the lifespan of the ICD, whilst up to 50% of sudden cardiac death (SCD) occur in individuals who are considered low risk by conventional criteria. Machine learning offers a novel approach to risk stratification for ICD assignment. METHODS AND RESULTS: Systematic search was performed in MEDLINE, Embase, Emcare, CINAHL, Cochrane Library, OpenGrey, MedrXiv, arXiv, Scopus, and Web of Science. Studies modelling SCD risk prediction within days to years using machine learning were eligible for inclusion. Transparency and quality of reporting (TRIPOD) and risk of bias (PROBAST) were assessed. A total of 4356 studies were screened with 11 meeting the inclusion criteria with heterogeneous populations, methods, and outcome measures preventing meta-analysis. The study size ranged from 122 to 124 097 participants. Input data sources included demographic, clinical, electrocardiogram, electrophysiological, imaging, and genetic data ranging from 4 to 72 variables per model. The most common outcome metric reported was the area under the receiver operator characteristic (n = 7) ranging between 0.71 and 0.96. In six studies comparing machine learning models and regression, machine learning improved performance in five. No studies adhered to a reporting standard. Five of the papers were at high risk of bias. CONCLUSION: Machine learning for SCD prediction has been under-applied and incorrectly implemented but is ripe for future investigation. It may have some incremental utility in predicting SCD over traditional models. The development of reporting standards for machine learning is required to improve the quality of evidence reporting in the field.

Effect of serial awake prone positioning on oxygenation in patients admitted to intensive care with COVID-19.

INTRODUCTION: Awake prone positioning (APP) might benefit patients with COVID-19 by improving oxygenation, but it is unknown whether this improvement can be sustained with serial proning episodes. METHODS: We conducted a retrospective review of adults with COVID-19 admitted to one intensive care unit, in those who underwent APP and controls. Patients in both groups had type 1 respiratory failure requiring oxygen (but not initially intubated), confirmed SARS-CoV-2 PCR by nasopharyngeal swab and findings of multifocal ground-glass opacities on imaging. For the APP group, serial SpO2/FiO2 measurements were recorded after each proning episode. RESULTS: Of 77 patients admitted, 50 (65%) were excluded because they had already been intubated. Another 7 (9%) had undergone APP prior to admission. Of the remaining 20, 10 underwent APP and 10 were controls. Patients in both groups had similar demographics, subsequent intubation and survival. Of those who underwent APP, SpO2/FiO2 was most likely to increase after the first episode (before median: 152, IQR 135-185; after: median 192, IQR 156-234, p=0.04). Half of participants (5) in the APP group were unable to tolerate more than two APP episodes. CONCLUSIONS: Most patients with COVID-19 admitted to the intensive care are not suitable for APP. Of those who are, many cannot tolerate more than two episodes. Improvements in SpO2/FiO2 secondary to APP are transient and most likely in the first episode. Our findings may explain why other studies have failed to show improvements in mortality from APP despite improvements in oxygenation.

Accelerating the Evolution of Severe Acute Respiratory Syndrome Coronavirus 2: A Risk of Combining Dexamethasone and Tocilizumab for Severe Coronavirus Disease 2019.

Emerging data from open-label randomized trials without placebo controls suggest potential mortality benefits for combining corticosteroids with the interleukin 6 receptor antagonist tocilizumab in severe coronavirus disease 2019. Conversely, dual immunomodulation may weaken antiviral responses and delay viral clearance, allowing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to expand its population and accrue genetic diversity within individual hosts. Generating a pool of hosts with genetically diverse viral populations while introducing new selective pressures in the form of vaccination-induced immunity could accelerate the process of antigenic drift in SARS-CoV-2. However, clinical trials to date have largely disregarded viral outcomes, and data on viral kinetics in response to immunomodulation are scarce. Coadministration of antiviral agents with immunomodulation could serve as a potential strategy to aid viral clearance and reduce the risk of genetic diversification.

Cardiovascular Events After Chimeric Antigen Receptor T-Cell Therapy for Advanced Hematologic Malignant Neoplasms: A Meta-Analysis.

Importance: The frequency and clinical phenotypes of cardiotoxic events in chimeric antigen receptor (CAR) T-cell recipients remain poorly understood given that landmark approval trials typically exclude patients with high-risk cardiovascular profiles and data from nontrial settings are scarce. Objective: To summarize the prevalence of adverse cardiovascular events among adults receiving CAR T-cell therapies for advanced hematologic malignant neoplasms. Data Sources: MEDLINE, Embase, Cochrane Library, and Google Scholar were systematically searched from database inception until February 26, 2024. Study Selection: Observational studies were included if they comprised adult CAR T-cell recipients with advanced hematologic malignant neoplasms and if they systematically evaluated cardiovascular complications. Data Extraction and Synthesis: Extraction of prespecified parameters related to the patient population, study design, and clinical events was performed at the study level by 2 independent reviewers in accordance with the Meta-Analysis of Observational Studies in Epidemiology (MOOSE) reporting guideline. Meta-analysis of single proportions was conducted using random-effect models with Freeman-Tukey double arcsine transformations to calculate pooled prevalence estimates. Sensitivity analysis was performed using generalized linear mixed models with logit transformations. Main Outcomes and Measures: Ventricular and supraventricular arrhythmias, heart failure events, reduction in left ventricular ejection fraction, myocardial infarction, and cardiovascular and all-cause mortality. Results: Thirteen studies comprising 1528 CAR T-cell recipients (median [IQR] age, 61 [58.7-63.0] years; 1016 males [66%]; 80% patients with lymphoma) were included. The median (IQR) duration of follow-up was 487 (294-530) days. On random-effects meta-analysis, we observed a pooled prevalence of 0.66% (95% CI, 0.00%-2.28%) for ventricular arrhythmia, 7.79% (95% CI, 4.87%-11.27%) for supraventricular arrhythmia, 8.68% (95% CI, 2.26%-17.97%) for left ventricular dysfunction, 3.87% (95% CI, 1.77%-6.62%) for heart failure events, 0.62% (95% CI, 0.02%-1.74%) for myocardial infarction, and 0.63% (95% CI, 0.13%-1.38%) for cardiovascular death. The pooled prevalence of all-cause mortality was 30.01% (95% CI, 19.49%-41.68%). Sensitivity analyses generated similar findings. Conclusions and Relevance: This meta-analysis found a low prevalence of ventricular arrhythmia, myocardial infarction, and cardiovascular death among CAR T-cell recipients over a short-term to midterm follow-up. Left ventricular dysfunction and supraventricular arrhythmia were the most commonly reported cardiovascular complications, suggesting that cardiovascular surveillance strategies should focus on decreases in ejection fraction and supraventricular arrhythmia.

Criteria to predict midterm outcome after stenting of chronic iliac vein obstructions (PROMISE trial).

BACKGROUND: Endovenous stent placement has become a first-line approach to prevent post-thrombotic syndrome in patients with chronic post-thrombotic obstruction (PTO) or nonthrombotic iliac vein lesions if conservative management fails. This study aims to identify factors associated with loss of patency to facilitate patient selection for endovenous stenting. METHODS: We retrospectively analyzed 108 consecutive patients after successful endovenous stenting for chronic vein obstruction performed at a single institution from January 2008 to July 2020. Using multivariable logistic regression, we explored potential predictive factors for loss of stent patency, including baseline demographics, post-thrombotic changes, and peak flow velocities measured in the common femoral vein (CFV), deep femoral vein, and femoral vein (FV) using duplex ultrasound examination. RESULTS: The mean follow-up duration was 41 ± 26 months, and participants had a mean age of 47.4 ± 15.4 years with 46.3% women. Ninety (83.3%) patients had PTO and 18 (16.7%) had nonthrombotic iliac vein lesions, predominantly due to May-Thurner syndrome. Loss of patency occurred in 20 (18.5%) patients, all treated for PTO. Comorbidities, side of intervention, and sex did not differ between patients with occluded and patent stents. Stent occlusion was more common with increasing number of stents implanted (P < .001) and with distal stent extension into and beyond the CFV (P < .001). Preinterventional predictive factors for stent occlusion were lower duplex ultrasound peak velocity in the CFV (odds ratio [OR]: 7.52, 95% confidence interval [CI]: 2.54-22.28; P < .001) and FV (OR: 10.75, 95% CI: 2.07-55.82; P < .005), and post-thrombotic changes in the deep femoral vein (OR: 4.51, 95% CI: 1.53-13.25; P = .006) and FV (OR: 3.62: 95% CI: 1.11-11.84; P = .033). Peak velocities of ≤7 cm/s (interquartile range: 0-20 cm/s) in the CVF and ≤8 cm/s (interquartile range: 5-10 cm/s) in the FV were significantly associated with loss of patency. CONCLUSIONS: Insufficient venous inflow as assessed by low peak velocities in the CFV and FV as well as post-thrombotic findings represent reliable risk predictors for stent occlusions, warranting their inclusion into the decision-making process for invasive treatment of PTO.

The new UK SARS-CoV-2 variant and lockdown - causes and consequences.

The new variant of concern (VOC), B.1.1.7, has a distinct set of mutations in nucleotides encoding the spike (S) protein on the surface of SARS-CoV-2. SARS-CoV-2 previously accumulated mutations at a much slower rate, of 1-2 per month; the sudden appearance of a large cluster of mutations was thought to be unusual. We now suspect that VOC may have arisen from immunosuppressed individuals who shed virus for longer periods. Epidemiological analyses estimate VOC to be more infectious; this is of most concern because these estimates were calculated during periods where many regions of the UK were in high social distancing restrictions. Therefore, the previous 'tiered' system implemented in the UK was ineffective at containing VOC. The most likely reason for this is that previous restrictions, no matter how strict, still allowed for gatherings in certain places. VOC also has implications for the national vaccination programme - a higher proportion of people will need to be vaccinated with a more infectious virus. Prolongation of the second dose of vaccines to increase vaccine uptake has understandably caused concern, but is based on sound immunological principles. There is now an urgent need to monitor the effect of new variants on vaccine efficacy - marking a new chapter in the global fight against COVID-19.

Omicron-B.1.1.529 leads to widespread escape from neutralizing antibody responses.

On the 24 th November 2021 the sequence of a new SARS CoV-2 viral isolate spreading rapidly in Southern Africa was announced, containing far more mutations in Spike (S) than previously reported variants. Neutralization titres of Omicron by sera from vaccinees and convalescent subjects infected with early pandemic as well as Alpha, Beta, Gamma, Delta are substantially reduced or fail to neutralize. Titres against Omicron are boosted by third vaccine doses and are high in cases both vaccinated and infected by Delta. Mutations in Omicron knock out or substantially reduce neutralization by most of a large panel of potent monoclonal antibodies and antibodies under commercial development. Omicron S has structural changes from earlier viruses, combining mutations conferring tight binding to ACE2 to unleash evolution driven by immune escape, leading to a large number of mutations in the ACE2 binding site which rebalance receptor affinity to that of early pandemic viruses.

Fighting liver fat.

Non-alcoholic fatty liver disease is a chronic liver disease which is closely associated with components of the metabolic syndrome. Its high clinical burden results from the growing prevalence, inherent cardiometabolic risk and potential of progressing to cirrhosis. Patients with non-alcoholic fatty liver disease show variable rates of disease progression through a histological spectrum ranging from steatosis to steatohepatitis with or without fibrosis. The presence and severity of fibrosis are the most important prognostic factors in non-alcoholic fatty liver disease. This necessitates risk stratification of patients by fibrosis stage using combinations of non-invasive methods, such as composite scoring systems and/or transient elastography. A multidisciplinary approach to treatment is advised, centred on amelioration of cardiometabolic risk through lifestyle and pharmacological interventions. Despite the current lack of licensed, liver-targeted pharmacotherapy, several promising agents are undergoing late-phase clinical trials to complement standard management in patients with advanced disease. This review summarises the current concepts in diagnosis and disease progression of non-alcoholic liver disease, focusing on pragmatic approaches to risk assessment and management in both primary and secondary care settings.