Design, development and preliminary assessment in a porcine model of a novel peripheral intravenous catheter aimed at reducing early failure rates

BACKGROUND

Peripheral intravenous catheters (PIVCs) are the most commonly used invasive medical device, yet despite best efforts by end-users, PIVCs experience unacceptably high early failure rates. We aimed to design a new PIVC that reduces the early failure rate of in-dwelling PIVCs and we conducted preliminary tests to assess its efficacy and safety in a porcine model of intravenous access.

METHODS

We used computer-aided design and simulation to create a PIVC with a ramped tip geometry, which directs the infused fluid away from the vein wall; we called the design the FloRamp™. We created FloRamp prototypes (test device) and tested them against a market-leading device (BD Insyte™; control device) in a highly-controlled setting with five insertion sites per device in four pigs. We measured resistance to infusion and visual infusion phlebitis (VIP) every 6 h and terminated the experiment at 48 h. Veins were harvested for histology and seven pathological markers were assessed.

RESULTS

Computer simulations showed that the optimum FloRamp tip reduced maximum endothelial shear stress by 60%, from 12.7 Pa to 5.1 Pa, compared to a typical PIVC tip and improved the infusion dynamics of saline in the blood stream. In the animal study, we found that 2/5 of the control devices were occluded after 24 h, whereas all test devices remained patent and functional. The FloRamp created less resistance to infusion (0.73 ± 0.81 vs 0.47 ± 0.50, p = 0.06) and lower VIP scores (0.60 ± 0.93 vs 0.31 ± 0.70, p = 0.09) than the control device, although neither findings were significantly different. Histopathology revealed that 5/7 of the assessed markers were lower in veins with the FloRamp.

CONCLUSIONS

Herein we report preliminary assessment of a novel PIVC design, which could be advantageous in clinical settings through decreased device occlusion and reduced early failure rates.

Machine Learning for Myocardial Infarction Compared With Guideline-Recommended Diagnostic Pathways

BACKGROUND

Collaboration for the Diagnosis and Evaluation of Acute Coronary Syndrome (CoDE-ACS) is a validated clinical decision support tool that uses machine learning with or without serial cardiac troponin measurements at a flexible time point to calculate the probability of myocardial infarction (MI). How CoDE-ACS performs at different time points for serial measurement and compares with guideline-recommended diagnostic pathways that rely on fixed thresholds and time points is uncertain.

METHODS

Patients with possible MI without ST-segment-elevation were enrolled at 12 sites in 5 countries and underwent serial high-sensitivity cardiac troponin I concentration measurement at 0, 1, and 2 hours. Diagnostic performance of the CoDE-ACS model at each time point was determined for index type 1 MI and the effectiveness of previously validated low- and high-probability scores compared with guideline-recommended European Society of Cardiology (ESC) 0/1-hour, ESC 0/2-hour, and High-STEACS (High-Sensitivity Troponin in the Evaluation of Patients With Suspected Acute Coronary Syndrome) pathways.

RESULTS

In total, 4105 patients (mean age, 61 years [interquartile range, 50-74]; 32% women) were included, among whom 575 (14%) had type 1 MI. At presentation, CoDE-ACS identified 56% of patients as low probability, with a negative predictive value and sensitivity of 99.7% (95% CI, 99.5%-99.9%) and 99.0% (98.6%-99.2%), ruling out more patients than the ESC 0-hour and High-STEACS (25% and 35%) pathways. Incorporating a second cardiac troponin measurement, CoDE-ACS identified 65% or 68% of patients as low probability at 1 or 2 hours, for an identical negative predictive value of 99.7% (99.5%-99.9%); 19% or 18% as high probability, with a positive predictive value of 64.9% (63.5%-66.4%) and 68.8% (67.3%-70.1%); and 16% or 14% as intermediate probability. In comparison, after serial measurements, the ESC 0/1-hour, ESC 0/2-hour, and High-STEACS pathways identified 49%, 53%, and 71% of patients as low risk, with a negative predictive value of 100% (99.9%-100%), 100% (99.9%-100%), and 99.7% (99.5%-99.8%); and 20%, 19%, or 29% as high risk, with a positive predictive value of 61.5% (60.0%-63.0%), 65.8% (64.3%-67.2%), and 48.3% (46.8%-49.8%), resulting in 31%, 28%, or 0%, who require further observation in the emergency department, respectively.

CONCLUSIONS

CoDE-ACS performs consistently irrespective of the timing of serial cardiac troponin measurement, identifying more patients as low probability with comparable performance to guideline-recommended pathways for MI. Whether care guided by probabilities can improve the early diagnosis of MI requires prospective evaluation.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT00470587.

A novel speckle-tracking echocardiography parameter assessing left ventricular afterload

BACKGROUND

Left ventricular stroke work index (LVSWI) and afterload-related cardiac performance (ACP) consider left ventricular (LV) afterload and could be better prognosticators in septic cardiomyopathy. However, their invasive nature prevents their routine clinical applications. This study aimed to investigate (1) whether a proposed speckle-tracking echocardiography parameter, Pressure-Strain Product (PSP), can non-invasively predict catheter-based LVSWI, ACP and serum lactate in an ovine model of septic cardiomyopathy; and (2) whether PSP can distinguish the sub-phenotypes of acute respiratory distress syndrome (ARDS) with or without sepsis-like conditions.

METHODS

Sixteen sheep with ARDS were randomly assigned to either (1) sepsis-like (n = 8) or (2) non-sepsis-like (n = 8) group. Each ARDS and sepsis-like condition was induced by intravenous infusion of oleic acid and lipopolysaccharide, respectively. Pulmonary artery catheter-based LVSWI (the product of stroke work index, mean arterial pressure and .0136), ACP (the percentage of cardiac output measured to cardiac output predicted as normal) and serum lactate were measured simultaneously with transthoracic echocardiography. Two PSP indices were calculated by multiplying the mean arterial blood pressure and either global circumferential strain (PSPcirc) or radial strain (PSPrad).

RESULTS

PSPcirc showed a significant correlation with LVSWI (r2  = .66, p < .001) and ACP (r2  = .82, p < .001) in the sepsis-like group. Although PSP could not distinguish subphenotypes, PSPcirc predicted LVSWI (AUC .86) and ACP (AUC .88), and PSPrad predicted serum lactate (AUC .75) better than LV ejection fraction, global circumferential and radial strain.

CONCLUSIONS

A novel PSP has the potential to non-invasively predict catheter-based LVSWI and ACP, and was associated with serum lactate in septic cardiomyopathy.

External validation of the 0/1h-algorithm and derivation of a 0/2h-algorithm using a new point-of-care Hs-cTnI assay

BACKGROUND

The high-sensitivity cardiac troponin (hs-cTn) I point-of-care (POC) hs-cTnI-PATHFAST assay has recently become clinically available.

METHODS

We aimed to externally validate the hs-cTnI-PATHFAST 0/1h-algorithm recently developed for the early diagnosis of non-ST-segment-elevation myocardial infarction (NSTEMI) and derive and validate a 0/2-algorithm in patients presenting to the emergency department with acute chest discomfort included in a multicenter diagnostic study. Two independent cardiologists centrally adjudicated the final diagnoses using all the clinical and study-specific information available including serial measurements of hs-cTnI-Architect.

RESULTS

Among 1,532 patients (median age 60 years, 33% [n = 501] women), NSTEMI was the final diagnosis in 13%. External validation of the hs-cTnI-PATHFAST 0/1h-algorithm showed very high negative predictive value (NPV; 100% [95%CI, 99.5%-100%]) and sensitivity 100% (95%CI, 98.2%-100%) for rule-out of NSTEMI. Positive predictive value (PPV) and specificity for rule-in of NSTEMI were high (74.9% [95%CI, 68.3%-80.5%] and 96.4% [95%CI, 95.2%-97.3%], respectively). Among 1,207 patients (median age 61 years, 32% [n = 391] women) available for the derivation (n = 848) and validation (n = 359) of the hs-cTnI-PATHFAST 0/2h-algorithm, a 0h-concentration <3 ng/L or a 0h-concentration <4 ng/L with a 2h-delta <4ng/L ruled-out NSTEMI in 52% of patients with a NPV of 100% (95%CI, 98-100) and sensitivity of 100% (95%CI, 92.9%-100%) in the validation cohort. A 0h-concentration ≥90ng/L or a 2h-delta ≥ 55ng/L ruled-in 38 patients (11%): PPV 81.6% (95%CI, 66.6-90.8), specificity 97.7% (95%CI, 95.4-98.9%).

CONCLUSIONS

The POC hs-cTnI-PATHFAST assay allows rapid and effective rule-out and rule-in of NSTEMI using both a 0/1h- and a 0/2h-algorithm with high NPV/sensitivity for rule-out and high PPV/specificity for rule-in.

CLINICAL TRIAL REGISTRATION

NCT00470587.

An appraisal of lung computer tomography in very early anti-inflammatory treatment of two different ovine ARDS phenotypes

Mortality and morbidity of Acute Respiratory Distress Syndrome (ARDS) are largely unaltered. A possible new approach to treatment of ARDS is offered by the discovery of inflammatory subphenotypes. In an ovine model of ARDS phenotypes, matching key features of the human subphenotypes, we provide an imaging characterization using computer tomography (CT). Nine animals were randomized into (a) OA (oleic acid, hypoinflammatory; n = 5) and (b) OA-LPS (oleic acid and lipopolysaccharides, hyperinflammatory; n = 4). 48 h after ARDS induction and anti-inflammatory treatment, CT scans were performed at high (H) and then low (L) airway pressure. After CT, the animals were euthanized and lung tissue was collected. OA-LPS showed a higher air fraction and OA a higher tissue fraction, resulting in more normally aerated lungs in OA-LPS in contrast to more non-aerated lung in OA. The change in lung and air volume between H and L was more accentuated in OA-LPS, indicating a higher recruitment potential. Strain was higher in OA, indicating a higher level of lung damage, while the amount of lung edema and histological lung injury were largely comparable. Anti-inflammatory treatment might be beneficial in terms of overall ventilated lung portion and recruitment potential, especially in the OA-LPS group.

Comparing the utility of clinical risk scores and integrated clinical judgement in patients with suspected acute coronary syndrome

AIMS

The utility of clinical risk scores regarding the prediction of major adverse cardiac events (MACE) is uncertain. We aimed to directly compare the prognostic performance of five established clinical risk scores as well as an unstructured integrated clinical judgement (ICJ) of the treating emergency department (ED) physician.

METHODS AND RESULTS

Thirty-day MACE including all-cause death, life-threatening arrhythmia, cardiogenic shock, acute myocardial infarction (including the index event), and unstable angina requiring urgent coronary revascularization were centrally adjudicated by two independent cardiologists in patients presenting to the ED with acute chest discomfort in an international multicentre study. We compared the prognostic performance of the HEART score, GRACE score, T-MACS, TIMI score, and EDACS, as well as the unstructured ICJ of the treating ED physician (visual analogue scale to estimate the probability of acute coronary syndrome, ranging from 0 to 100). Among 4551 eligible patients, 1110/4551 patients (24.4%) had at least one MACE within 30 days. Prognostic accuracy was high and comparable for the HEART score, GRACE score, T-MACS, and ICJ [area under the receiver operating characteristic curve (AUC) 0.85-0.87] but significantly lower and only moderate for the TIMI score (AUC 0.79, P < 0.001) and EDACS (AUC 0.74, P < 0.001), resulting in sensitivities for the rule-out of 30-day MACE of 93-96, 87 (P < 0.001), and 72% (P < 0.001), respectively.

CONCLUSION

The HEART score, GRACE score, T-MACS, and unstructured ICJ of the treating physician, not the TIMI score or EDACS, performed well for the prediction of 30-day MACE and may be considered for routine clinical use.

TRIAL REGISTRATION

ClinicalTrials.gov number NCT00470587.

Application of anti-inflammatory treatment in two different ovine Acute Respiratory Distress Syndrome injury models: a preclinical randomized intervention study

Whilst the presence of 2 subphenotypes among the heterogenous Acute Respiratory Distress Syndrome (ARDS) population is becoming clinically accepted, subphenotype-specific treatment efficacy has yet to be prospectively tested. We investigated anti-inflammatory treatment in different ARDS models in sheep, previously shown similarities to human ARDS subphenotypes, in a preclinical, randomized, blinded study. Thirty anesthetized sheep were studied up to 48 h and randomized into: (a) OA: oleic acid (n = 15) and (b) OA-LPS: oleic acid and subsequent lipopolysaccharide (n = 15) to achieve a PaO2/FiO2 ratio of < 150 mmHg. Then, animals were randomly allocated to receive treatment with methylprednisolone or erythromycin or none. Assessed outcomes were oxygenation, pulmonary mechanics, hemodynamics and survival. All animals reached ARDS. Treatment with methylprednisolone, but not erythromycin, provided the highest therapeutic benefit in Ph2 animals, leading to a significant increase in PaO2/FiO2 ratio by reducing pulmonary edema, dead space ventilation and shunt fraction. Animals treated with methylprednisolone displayed a higher survival up to 48 h than all others. In animals treated with erythromycin, there was no treatment benefit regarding assessed physiological parameters and survival in both phenotypes. Treatment with methylprednisolone improves oxygenation and survival, more so in ovine phenotype 2 which resembles the human hyperinflammatory subphenotype.

Chest Pain in Cancer Patients: Prevalence of Myocardial Infarction and Performance of High-Sensitivity Cardiac Troponins

Background

Little is known about patients with cancer presenting with acute chest discomfort to the emergency department (ED).

Objectives

The aim of this study was to assess the prevalence of acute myocardial infarction (AMI), outcomes, and the diagnostic utility of recommended diagnostic tools in this population.

Methods

Patients presenting with chest pain to the ED were prospectively enrolled in an international multicenter diagnostic study with central adjudication. Cancer status was assessed prospectively and additional cancer details retrospectively. Findings were externally validated in an independent multicenter cohort.

Results

Among 8,267 patients, 711 (8.6%) had cancer. Patients with cancer had a higher burden of cardiovascular risk factors and pre-existing cardiac disease. Total length of stay in the ED (5.2 hours vs 4.3 hours) and hospitalization rate (49.8% vs 34.3%) were both increased in patients with cancer (P < 0.001 for both). Among 8,093 patients eligible for the AMI analyses, those with cancer more often had final diagnoses of AMI (184 of 686 with cancer [26.8%] vs 1,561 of 7,407 without cancer [21.1%]; P < 0.001). In patients with cancer, high-sensitivity cardiac troponin T (hs-cTnT) but not high sensitivity cardiac troponin I (hs-cTnI) concentration had lower diagnostic accuracy for non-ST-segment elevation myocardial infarction (for hs-cTnT, area under the curve: 0.89 [95% CI: 0.86-0.92] vs 0.94 [95% CI: 0.93-0.94] [P < 0.001]; for hs-cTnI, area under the curve: 0.93 [95% CI: 0.91-0.95] vs 0.95 [95% CI: 0.94-0.95] [P = 0.10]). In patients with cancer, the European Society of Cardiology 0/1-hour hs-cTnT and hs-cTnI algorithms maintained very high safety but had lower efficacy, with twice the number of patients remaining in the observe zone. Similar findings were obtained in the external validation cohort.

Conclusions

Patients with cancer have a substantially higher prevalence of AMI as the cause of chest pain. Length of ED stay and hospitalization rates are increased. The diagnostic performance of hs-cTnT and the efficacy of both the European Society of Cardiology 0/1-hour hs-cTnT and hs-cTnI algorithms is reduced. (Advantageous Predictors of Acute Coronary Syndromes Evaluation [APACE] Study; NCT00470587).

Combining glucose and high-sensitivity cardiac troponin in the early diagnosis of acute myocardial infarction

Glucose is a universally available inexpensive biomarker, which is increased as part of the physiological stress response to acute myocardial infarction (AMI) and may therefore help in its early diagnosis. To test this hypothesis, glucose, high-sensitivity cardiac troponin (hs-cTn) T, and hs-cTnI were measured in consecutive patients presenting with acute chest discomfort to the emergency department (ED) and enrolled in a large international diagnostic study (NCT00470587). Two independent cardiologists centrally adjudicated the final diagnosis using all clinical data, including serial hs-cTnT measurements, cardiac imaging and clinical follow-up. The primary diagnostic endpoint was index non-ST-segment elevation MI (NSTEMI). Prognostic endpoints were all-cause death, and cardiovascular (CV) death or future AMI, all within 730-days. Among 5639 eligible patients, NSTEMI was the adjudicated final diagnosis in 1051 (18.6%) patients. Diagnostic accuracy quantified using the area under the receiver-operating characteristics curve (AUC) for the combination of glucose with hs-cTnT and glucose with hs-cTnI was very high, but not higher versus that of hs-cTn alone (glucose/hs-cTnT 0.930 [95% CI 0.922-0.937] versus hs-cTnT 0.929 [95% CI 0.922-0.937]; glucose/hs-cTnI 0.944 [95% CI 0.937-0.951] versus hs-cTnI 0.944 [95% CI 0.937-0.951]). In early-presenters, a dual-marker strategy (glucose < 7 mmol/L and hs-cTnT < 5/hs-cTnI < 4 ng/L) provided very high and comparable sensitivity to slightly lower hs-cTn concentrations (cTnT/I < 4/3 ng/L) alone, and possibly even higher efficacy. Glucose was an independent predictor of 730-days endpoints. Our results showed that a dual marker strategy of glucose and hs-cTn did not increase the diagnostic accuracy when used continuously. However, a cutoff approach combining glucose and hs-cTn may provide diagnostic utility for patients presenting ≤ 3 h after onset of symptoms, also providing important prognostic information.

Donor heart ischemic time can be extended beyond 9 hours using hypothermic machine perfusion in sheep

BACKGROUND

The global shortage of donor hearts available for transplantation is a major problem for the treatment of end-stage heart failure. The ischemic time for donor hearts using traditional preservation by standard static cold storage (SCS) is limited to approximately 4 hours, beyond which the risk for primary graft dysfunction (PGD) significantly increases. Hypothermic machine perfusion (HMP) of donor hearts has been proposed to safely extend ischemic time without increasing the risk of PGD.

METHODS

Using our sheep model of 24 hours brain death (BD) followed by orthotopic heart transplantation (HTx), we examined post-transplant outcomes in recipients following donor heart preservation by HMP for 8 hours, compared to donor heart preservation for 2 hours by either SCS or HMP.

RESULTS

Following HTx, all HMP recipients (both 2 hours and 8 hours groups) survived to the end of the study (6 hours after transplantation and successful weaning from cardiopulmonary bypass), required less vasoactive support for hemodynamic stability, and exhibited superior metabolic, fluid status and inflammatory profiles compared to SCS recipients. Contractile function and cardiac damage (troponin I release and histological assessment) was comparable between groups.

CONCLUSIONS

Overall, compared to current clinical SCS, recipient outcomes following transplantation are not adversely impacted by extending HMP to 8 hours. These results have important implications for clinical transplantation where longer ischemic times may be required (e.g., complex surgical cases, transport across long distances). Additionally, HMP may allow safe preservation of "marginal" donor hearts that are more susceptible to myocardial injury and facilitate increased utilization of these hearts for transplantation.

Hyperacute T Wave in the Early Diagnosis of Acute Myocardial Infarction

STUDY OBJECTIVE

The diagnostic performance of T-wave amplitudes for the detection of myocardial infarction is largely unknown. We aimed to address this knowledge gap.

METHODS

T-wave amplitudes were automatically measured in 12-lead ECGs of patients presenting with acute chest discomfort to the emergency department within a prospective diagnostic multicenter study. The final diagnosis was centrally adjudicated by 2 independent cardiologists. Patients with left ventricular hypertrophy, complete left bundle branch block, or paced ventricular depolarization were excluded. The performance for lead-specific 95th-percentile thresholds were reported as likelihood ratios (lr), specificity, and sensitivity.

RESULTS

Myocardial infarction was the final diagnosis in 445 (18%) of 2457 patients. In most leads, T-wave amplitudes tended to be greater in patients without myocardial infarction than those with myocardial infarction, and T-wave amplitude exceeding the 95th percentile had positive and negative lr close to 1 or with confidence intervals (CIs) crossing 1. The exceptions were leads III, aVR, and V1, which had positive lrs of 3.8 (95% CI, 2.7 to 5.3), 4.3 (95% CI, 3.1 to 6.0) and 2.0 (95% CI, 1.4 to 2.9), respectively. These leads normally have inverted T waves, so T-wave amplitude exceeding the 95th percentile reflects upright rather than increased-amplitude hyperacute T waves.

CONCLUSION

Hyperacute T waves, when defined as increased T-wave amplitude exceeding the 95th percentile, did not provide useful information in diagnosing myocardial infarction in this sample.

Association of accompanying dyspnea with diagnosis and outcome of patients presenting with acute chest discomfort

AIM

The presence of accompanying dyspnea is routinely assessed and common in patients presenting with acute chest pain/discomfort to the emergency department (ED). We aimed to assess the association of accompanying dyspnea with differential diagnoses, diagnostic work-up and outcome.

METHODS

We enrolled patients presenting to the ED with chest pain/discomfort. Final diagnoses were adjudicated by independent cardiologists using all information including cardiac imaging. The primary diagnostic endpoint was the final diagnosis. The secondary diagnostic endpoint was the performance of high-sensitivity cardiac troponin (hs-cTn) and the European Society of Cardiology (ESC) 0/1h-algorithms for the diagnosis of myocardial infarction (MI). The prognostic endpoints were cardiovascular and all-cause mortality at two years.

RESULTS

Among 6045 patients, 2892/6045 (48%) had accompanying dyspnea. The prevalence of ACS in patients with versus without dyspnea was comparable (MI 22.4% vs. 21.9%, p = 0.60, unstable angina 8.7% vs. 7.9%, p = 0.29). In contrast, patients with dyspnea more often had cardiac, non-coronary disease (15.3% vs. 10.2%, p < 0.001). Diagnostic accuracy of hs-cTnT/I concentrations was not affected by the presence of dyspnea (area under the curve 0.89-0.91 in both groups) and the safety of the ESC 0/1h-algorithms was maintained with negative predictive values >99.4%. Accompanying dyspnea was an independent predictor for cardiovascular and all-cause death at two years (Hazard Ratio [HR] 1.813 [95%CI, 1.453-2.261, p < 0.01]).

CONCLUSION

Accompanying dyspnea was not associated with a higher prevalence of ACS but with cardiac, non-coronary disease. While the safety of the diagnostic work-up was not affected, accompanying dyspnea was an independent predictor for cardiovascular and all-cause death.

Effect of flow change on brain injury during an experimental model of differential hypoxaemia in cardiogenic shock supported by extracorporeal membrane oxygenation

Differential hypoxaemia (DH) is common in patients supported by femoral veno-arterial extracorporeal membrane oxygenation (V-A ECMO) and can cause cerebral hypoxaemia. To date, no models have studied the direct impact of flow on cerebral damage. We investigated the impact of V-A ECMO flow on brain injury in an ovine model of DH. After inducing severe cardiorespiratory failure and providing ECMO support, we randomised six sheep into two groups: low flow (LF) in which ECMO was set at 2.5 L min-1 ensuring that the brain was entirely perfused by the native heart and lungs, and high flow (HF) in which ECMO was set at 4.5 L min-1 ensuring that the brain was at least partially perfused by ECMO. We used invasive (oxygenation tension-PbTO2, and cerebral microdialysis) and non-invasive (near infrared spectroscopy-NIRS) neuromonitoring, and euthanised animals after five hours for histological analysis. Cerebral oxygenation was significantly improved in the HF group as shown by higher PbTO2 levels (+ 215% vs - 58%, p = 0.043) and NIRS (67 ± 5% vs 49 ± 4%, p = 0.003). The HF group showed significantly less severe brain injury than the LF group in terms of neuronal shrinkage, congestion and perivascular oedema (p < 0.0001). Cerebral microdialysis values in the LF group all reached the pathological thresholds, even though no statistical difference was found between the two groups. Differential hypoxaemia can lead to cerebral damage after only a few hours and mandates a thorough neuromonitoring of patients. An increase in ECMO flow was an effective strategy to reduce such damages.

Pathogenesis Underlying Neurological Manifestations of Long COVID Syndrome and Potential Therapeutics

The development of long-term symptoms of coronavirus disease 2019 (COVID-19) more than four weeks after primary infection, termed "long COVID" or post-acute sequela of COVID-19 (PASC), can implicate persistent neurological complications in up to one third of patients and present as fatigue, "brain fog", headaches, cognitive impairment, dysautonomia, neuropsychiatric symptoms, anosmia, hypogeusia, and peripheral neuropathy. Pathogenic mechanisms of these symptoms of long COVID remain largely unclear; however, several hypotheses implicate both nervous system and systemic pathogenic mechanisms such as SARS-CoV2 viral persistence and neuroinvasion, abnormal immunological response, autoimmunity, coagulopathies, and endotheliopathy. Outside of the CNS, SARS-CoV-2 can invade the support and stem cells of the olfactory epithelium leading to persistent alterations to olfactory function. SARS-CoV-2 infection may induce abnormalities in innate and adaptive immunity including monocyte expansion, T-cell exhaustion, and prolonged cytokine release, which may cause neuroinflammatory responses and microglia activation, white matter abnormalities, and microvascular changes. Additionally, microvascular clot formation can occlude capillaries and endotheliopathy, due to SARS-CoV-2 protease activity and complement activation, can contribute to hypoxic neuronal injury and blood-brain barrier dysfunction, respectively. Current therapeutics target pathological mechanisms by employing antivirals, decreasing inflammation, and promoting olfactory epithelium regeneration. Thus, from laboratory evidence and clinical trials in the literature, we sought to synthesize the pathophysiological pathways underlying neurological symptoms of long COVID and potential therapeutics.

Temporal trends in mortality and provision of intensive care in younger women and men with acute myocardial infarction or stroke

BACKGROUND

Timely management of acute myocardial infarction (AMI) and acute stroke has undergone impressive progress during the last decade. However, it is currently unknown whether both sexes have profited equally from improved strategies. We sought to analyze sex-specific temporal trends in intensive care unit (ICU) admission and mortality in younger patients presenting with AMI or stroke in Switzerland.

METHODS

Retrospective analysis of temporal trends in 16,954 younger patients aged 18 to ≤ 52 years with AMI or acute stroke admitted to Swiss ICUs between 01/2008 and 12/2019.

RESULTS

Over a period of 12 years, ICU admissions for AMI decreased more in women than in men (- 6.4% in women versus - 4.5% in men, p < 0.001), while ICU mortality for AMI significantly increased in women (OR 1.2 [1.10-1.30], p = 0.032), but remained unchanged in men (OR 0.99 [0.94-1.03], p = 0.71). In stroke patients, ICU admission rates increased between 3.6 and 4.1% per year in both sexes, while ICU mortality tended to decrease only in women (OR 0.91 [0.85-0.95, p = 0.057], but remained essentially unaltered in men (OR 0.99 [0.94-1.03], p = 0.75). Interventions aimed at restoring tissue perfusion were more often performed in men with AMI, while no sex difference was noted in neurovascular interventions.

CONCLUSION

Sex and gender disparities in disease management and outcomes persist in the era of modern interventional neurology and cardiology with opposite trends observed in younger stroke and AMI patients admitted to intensive care. Although our study has several limitations, our data suggest that management and selection criteria for ICU admission, particularly in younger women with AMI, should be carefully reassessed.

Diagnostic discrimination of a novel high-sensitivity cardiac troponin I assay and derivation/validation of an assay-specific 0/1h-algorithm

BACKGROUND

We aimed to assess the diagnostic utility of the Dimension EXL LOCI High-Sensitivity Troponin I (hs-cTnI-EXL) assay.

METHODS

This multicenter study included patients with chest discomfort presenting to the emergency department. Diagnoses were centrally and independently adjudicated by two cardiologists using all available clinical information. Adjudication was performed twice including serial measurements of high-sensitivity cardiac troponin (hs-cTn) I-Architect (primary analysis) and serial measurements of hs-cTnT-Elecsys (secondary analysis) in addition to the clinically used (hs)-cTn. The primary objective was to assess and compare the discriminatory performance of hs-cTnI-EXL, hs-cTnI-Architect and hs-cTnT-Elecsys for acute myocardial infarction (MI). Furthermore, we derived and validated a hs-cTnI-EXL-specific 0/1h-algorithm.

RESULTS

Adjudicated MI was the diagnosis in 204/1454 (14%) patients. The area under the receiver operating characteristics curve for hs-cTnI-EXL was 0.94 (95%CI, 0.93-0.96), and comparable to hs-cTnI-Architect (0.95; 95%CI, 0.93-0.96) and hs-cTnT-Elecsys (0.93; 95%CI, 0.91-0.95). In the derivation cohort (n = 813), optimal criteria for rule-out of MI were <9ng/L at presentation (if chest pain onset >3h) or <9ng/L and 0h-1h-change <5ng/L, and for rule-in ≥160ng/L at presentation or 0h-1h-change ≥100ng/L. In the validation cohort (n = 345), these cut-offs ruled-out 56% of patients (negative predictive value 99.5% (95%CI, 97.1-99.9), sensitivity 97.8% (95%CI, 88.7-99.6)), and ruled-in 9% (positive predictive value 83.3% (95%CI, 66.4-92.7), specificity 98.3% (95%CI, 96.1-99.3)). Secondary analyses using adjudication based on hs-cTnT measurements confirmed the findings.

CONCLUSIONS

The overall performance of the hs-cTnI-EXL was comparable to best-validated hs-cTnT/I assays and an assay-specific 0/1h-algorithm safely rules out and accurately rules in acute MI.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov number, NCT00470587.

Extending the no objective testing rules to patients triaged by the European Society of Cardiology 0/1-hour algorithms

AIMS

After rule-out of non-ST elevation myocardial infarction (NSTEMI) with the European Society of Cardiology (ESC) 0/1 h-algorithms, it is unclear which patients require further anatomical or functional cardiac testing. To test the safety and efficacy of the no-objective-testing (NOT)-rules after NSTEMI rule-out by the ESC 0/1 h-algorithms.

METHODS AND RESULTS

International, prospective, diagnostic multicentre study enrolling adult patients presenting with chest pain to the emergency department. Central adjudication of final diagnosis by two independent cardiologists using information including cardiac imaging. Primary endpoints were the safety and efficacy of the NOT-rules for the rule-out of major adverse cardiovascular events (MACE). Secondary endpoints included 365-day and 2-year MACE. Among 4804 and 4569 patients with available 0/1 h high-sensitivity cardiac troponin (hs-cTn)T-Elecsys or hs-cTnI-Architect concentrations, 2783 (58%) and 2252 (49%) were eligible for application of the NOT-rules after rule-out of NSTEMI by the ESC hs-cTnT/I-0/1h-algorithm. The first rule identified 26% of patients with a sensitivity of 100% (95%CI 98.3-100%) and a negative predictive value (NPV) of 100% (95% CI, n.c.). The second and third rules both identified 31% of patients with a sensitivity of 99.5% (95% CI 97.4-99.9%) and a NPV of 99.9% (95% CI 99.2-99.9%). Similar findings emerged for hs-cTnI. High safety was confirmed for rule-out of 365-day and 2-year MACE and proven to be superior to the HEART Score.

CONCLUSION

All three NOT-rules performed very well for rule-out of MACE. The third NOT-rule best balanced feasibility, safety, and efficacy by identifying nearly one out of three patients as low-risk and may not require further cardiac testing. https://clinicaltrials.gov/ct2/show/NCT00470587.

Performance of high-sensitivity cardiac troponin T versus I for the early diagnosis of myocardial infarction

Background

Clinical practice guidelines assume that both cardiac troponin (cTn) T and cTnI concentrations reflect identical pathophysiological processes and are equally effective in the detection of myocardial injury. However, there are differences between cTnT and cTnI that have been reported.

Purpose

The aim of this study was to directly compare the diagnostic performance of high-sensitivity cardiac troponin (hs-cTn) T versus hs-cTnI for the early diagnosis of acute myocardial infarction (MI).

Methods

In a prospective multicentre study, diagnostic and prognostic accuracies of hs-cTnT and I were analyzed in consecutive patients presenting to the emergency department with acute chest pain. The final diagnosis was adjudicated by two independent cardiologists using all information pertaining to the individual patient according to the fourth universal definition of MI. Adjudication of the final diagnoses was performed twice: once using serial measurements of hs-cTnT and once using hs-cTnI. Furthermore, the clinical performance of hs-cTnT/I when embedded in the European Society of Cardiology (ESC) 0/1h-algorithm was assessed.

Results

Among 5087 consecutive patients (median [Interquartile range, IQR] age 61 [49.0, 74.0] years, 33.2% female), 951 (18.7%) and 901 patients (17.7%) had an adjudicated final diagnosis of non-ST-segment elevation myocardial infarction (NSTEMI) when using serial measurements of hs-cTnT and hs-cTnI for adjudication, respectively. Diagnostic accuracy was very high for both hs-cTnT and hs-cTnI and comparable when using hs-cTnT for adjudication (hs-cTnT: area under the curve [AUC] 0.93 [95% CI 0.92–0.94] versus hs-cTnI AUC 0.93 [95% CI 0.92–0.94]; p=0.891). However, when using serial measurements of hs-cTnI for adjudication, diagnostic accuracy was significantly higher for hs-cTnI (AUC 0.93 [95% CI 0.92–0.94] versus AUC 0.94 [95% CI 0.94–0.95], p&lt;0.001; Figure 1). This was confirmed in subgroup analyses including early presenter (≤3h), patients with renal failure, known coronary artery disease and elderly (≥70 years). However, both assays performed excellent with very high safety for rule-out and high accuracy for rule-in MI when embedded in the ESC 0/1h-algorithm. Prognostic accuracies for 730-day all-cause mortality and cardiovascular death were significantly higher for hs-cTnT compared to hs-cTnI (Figure 2).

Conclusions

While there seem to be differences between hs-cTnT and hs-cTnI in their diagnostic and prognostic performance, clinical relevance needs to be further evaluated since both assays performed excellent when embedded in their respective early triage algorithms.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Swiss National Foundation, Swiss Heart Foundation

Association of accompanying dyspnea with diagnoses and outcome of patients presenting with suspected acute coronary syndromes

Background

The presence of accompanying dyspnea is routinely assessed and common in chest pain patients with suspected acute coronary syndromes (ACS), but its impact on differential diagnoses, diagnostic work-up and outcome is incompletely understood.

Purpose

To determine the association of accompanying dyspnea with diagnoses, diagnostic work-up, and outcome of patients presenting with suspected ACS to the emergency department (ED).

Methods

We prospectively enrolled unselected patients presenting to the ED with chest pain as the main symptom suggestive of ACS in an international multicenter study. Final diagnoses were adjudicated by two independent cardiologists using all information including cardiac imaging. Patients were stratified by the presence or absence of self-reported dyspnea. The primary diagnostic endpoint was the differential diagnosis. The secondary diagnostic endpoint was the performance of high-sensitivity cardiac troponin (hs-cTn) and the European Society of Cardiology (ESC) 0/1h-algorithms for the diagnosis of myocardial infarction (MI). The primary prognostic endpoint was all-cause mortality at two years.

Results

Among 6045 patients, 2892/6045 (48%) had accompanying dyspnea. Final diagnoses in patients with versus without dyspnea were different (overall p&lt;0.001), but prevalence of ACS was comparable (MI 22.4% vs. 21.9%, p=0.602, unstable angina 8.7% vs. 7.9%, p=0.291). In contrast, patients with dyspnea more often had cardiac, non-coronary disease (15.3% vs. 10.2%, p&lt;0.001). Diagnostic accuracy of high-sensitivity cardiac troponin (hs-cTn)T/I concentrations at presentation for the diagnosis of MI was high and not affected by the presence of dyspnea (area under the curve 0.89–0.91 in both groups). The ESC 0/1h-algorithms performed excellent in both groups with negative predictive values &gt;99.4%. The presence of dyspnea was associated with all-cause death at two years (hazard ratio [HR] 2.487 [95% CI, 2.001–3.091, p&lt;0.001) and remained an independent predictor after adjustment for covariates at baseline (HR 1.813 [95% CI, 1.453–2.261, p=0.001]). Overall mortality rates were higher in patients with dyspnea at two years (9.0% vs. 3.7%, p&lt;0.001).

Conclusion

Accompanying dyspnea was not associated with a higher prevalence of ACS but with cardiac, non-coronary disease such as heart failure. While the safety of the diagnostic work-up was not affected, accompanying dyspnea was associated with and an independent predictor for two-year all-cause mortality.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Swiss Heart Foundation, University of Basel.

Combining qualitative and quantitative ECG criteria with the ESC 0/1h-hs-cTn-algorithm in the early diagnosis of non-ST-elevation myocardial infarction

Background

The electrocardiogram (ECG) is one of the three main diagnostic tools for the assessment of patients with suspected non-ST-elevation myocardial infarction (NSTEMI). However, it is unknown how established qualitative or novel quantitative ECG criteria can best be combined with high-sensitivity cardiac troponin (hs-cTn)-based diagnostic algorithms, such as the ESC 0/1h-algorithm, for the early diagnosis of NSTEMI.

Methods

ST-segment depression, T-wave inversion, and a novel modified ST-segment deviation score (1), defined as the sum of ST-segment elevation in aVR plus absolute, unsigned ST-segment depressions in the remaining leads, were assessed blinded to all clinical data among unselected patients presenting with acute chest discomfort to the emergency department in an international multicentre prospective diagnostic study. Final diagnoses were centrally adjudicated by two independent cardiologists based on complete cardiac work-up, cardiac imaging and serial hs-cTn. Direct rule-in thresholds for the modified ST-segment deviation score, achieving a positive predictive value (PPV) of &gt;70% justifying early monitorization and management, were derived, validated and compared to ST-segment depression and T-wave inversion and applied 1) alone and 2) in combination with the ESC 0/1h-hs-cTnT/I-algorithms.

Results

Among 3299 eligible patients, NSTEMI was present in 581 (17.6%) patients. ST-segment depression identified 243/3299 patients (7.4%) with a specificity of 96.5% (95% CI 95.7–97.1) and a PPV of 60.5% (95% CI 54.2–66.4) for the rule-in of NSTEMI, while T-wave inversion had a low PPV (38.0%; 95% CI 33.1–43.1). A modified ST-segment deviation score ≥6mm triaged 108/3299 patients (3.3%) towards direct rule-in upon ED arrival, resulting in a PPV of 71.3% (95% CI 62.1–79.0) and a specificity of 98.9% (95% CI 98.4–99.2), Figure 1. Bootstrap internal validation confirmed the robustness of these findings. Most patients ruled-in by ST-segment depression or a modified ST-segment deviation score ≥6mm would have been also ruled-in by the ESC 0/1h-hs-cTnT/I-algorithm, albeit 1–2h later. Combining ST-segment depression or a modified ST-segment deviation score ≥6mm with the ESC 0/1h-hs-cTnT-algorithm (Figure 2) accelerated the rule-in in those identified already by the ECG-criteria, and resulted in a modest number of reclassifications from rule-out or observe to rule-in. These results were confirmed in a secondary analysis assessing the combination of these ECG signatures with two ESC 0/1h-hs-cTnI-algorithms (Architect and Centaur).

Conclusion

Combining either ST-segment depression or a modified ST-segment deviation Score ≥6mm with the ESC 0/1h-hs-cTnT/I-algorithms accelerated and improved the early diagnosis of NSTEMI.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Swiss Heart Foundation (SHF) and Swiss National Science Foundation (SNSF)

0/1h-algorithm using a new high-sensitivity cardiac troponin I assay for early diagnosis of myocardial infarction

Background

The clinical performance of the novel high-sensitivity cardiac troponin I EXL (hs-cTnI-EXL) assay is unknown so far.

Purpose

We aimed to validate the clinical performance of the hs-cTnI-EXL assay and to derive and validate an hs-cTnI-EXL-specific 0/1h-algorithm for the early diagnosis of myocardial infarction (MI).

Methods

This multicenter study included patients presenting to the emergency department with symptoms suggestive of myocardial infarction. Central adjudication of final diagnoses was performed by two independent cardiologists using all clinical information including cardiac imaging twice: first, using serial hs-cTnI-Architect (primary analysis) and second, using serial hs-cTnT-Elecsys (secondary analysis) concentrations in addition to those clinically used (hs)-cTn. Hs-cTnI-EXL was measured at presentation and at 1h. The primary objective was to directly compare diagnostic accuracy quantified by the area under the receiver-operating-characteristic curve (AUC) of hs-cTnI-EXL, hs-cTnI-Architect and hs-cTnT-Elecsys. Secondary objectives included the derivation and validation of an hs-cTnI- EXL-specific 0/1h-algorithm.

Results

MI was the adjudicated final diagnosis in 204/1454 (14%) patients. At presentation, the AUC for hs-cTnI-EXL was 0.94 (95% CI, 0.93–0.96), being comparable to hs-cTnI-Architect (0.95; 95% CI, 0.93–0.96) and hs-cTnT-Elecsys (0.93; 95% CI, 0.91–0.95; Figure 1). In the derivation cohort (n=813), an optimal hs-cTnI-EXL-0/1h-algorithm was rule-out of MI with &lt;9ng/L if onset of chest pain &gt;3h or &lt;9ng/L & 0h-1h-change &lt;5ng/L, and rule-in with ≥160ng/L or 0h-1h-change ≥100ng/L. In the validation cohort (n=345), this hs-cTnI-EXL-0/1h-algorithm also performed well: rule-out in 56% of patients, negative predictive value 99.5% (95% CI, 97.1–99.9), sensitivity 97.8% (95% CI, 88.7–99.6), rule-in in 9% of patients, positive predictive value 83.3% (95% CI, 66.4–92.7), specificity 98.3% (95% CI, 96.1–99.3; Figure 2). Secondary analyses confirmed the findings using adjudication including serial measurements of hs-cTnT-Elecsys.

Conclusions

Hs-cTnI-EXL has comparable diagnostic performance to the currently best-validated hs-cTnT/I assays.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Swiss National Foundation, Swiss Heart Foundation

Differential Protein Expression among Two Different Ovine ARDS Phenotypes-A Preclinical Randomized Study

Despite decades of comprehensive research, Acute Respiratory Distress Syndrome (ARDS) remains a disease with high mortality and morbidity worldwide. The discovery of inflammatory subphenotypes in human ARDS provides a new approach to study the disease. In two different ovine ARDS lung injury models, one induced by additional endotoxin infusion (phenotype 2), mimicking some key features as described in the human hyperinflammatory group, we aim to describe protein expression among the two different ovine models. Nine animals on mechanical ventilation were included in this study and were randomized into (a) phenotype 1, n = 5 (Ph1) and (b) phenotype 2, n = 4 (Ph2). Plasma was collected at baseline, 2, 6, 12, and 24 h. After protein extraction, data-independent SWATH-MS was applied to inspect protein abundance at baseline, 2, 6, 12, and 24 h. Cluster analysis revealed protein patterns emerging over the study observation time, more pronounced by the factor of time than different injury models of ARDS. A protein signature consisting of 33 proteins differentiated among Ph1/2 with high diagnostic accuracy. Applying network analysis, proteins involved in the inflammatory and defense response, complement and coagulation cascade, oxygen binding, and regulation of lipid metabolism were activated over time. Five proteins, namely LUM, CA2, KNG1, AGT, and IGJ, were more expressed in Ph2.

Validation of Messenger Ribonucleic Acid Markers Differentiating Among Human Acute Respiratory Distress Syndrome Subgroups in an Ovine Model of Acute Respiratory Distress Syndrome Phenotypes

Background

The discovery of biological subphenotypes in acute respiratory distress syndrome (ARDS) might offer a new approach to ARDS in general and possibly targeted treatment, but little is known about the underlying biology yet. To validate our recently described ovine ARDS phenotypes model, we compared a subset of messenger ribonucleic acid (mRNA) markers in leukocytes as reported before to display differential expression between human ARDS subphenotypes to the expression in lung tissue in our ovine ARDS phenotypes model (phenotype 1 (Ph1): hypoinflammatory; phenotype 2 (Ph2): hyperinflammatory).

Methods

We studied 23 anesthetized sheep on mechanical ventilation with observation times between 6 and 24 h. They were randomly allocated to the two phenotypes (n = 14 to Ph1 and n = 9 to Ph2). At study end, lung tissue was harvested and preserved in RNAlater. After tissue homogenization in TRIzol, total RNA was extracted and custom capture and reporter probes designed by NanoString Technologies were used to measure the expression of 14 genes of interest and the 6 housekeeping genes on a nCounter SPRINT profiler.

Results

Among the 14 mRNA markers, in all animals over all time points, 13 markers showed the same trend in ovine Ph2/Ph1 as previously reported in the MARS cohort: matrix metalloproteinase 8, olfactomedin 4, resistin, G protein-coupled receptor 84, lipocalin 2, ankyrin repeat domain 22, CD177 molecule, and transcobalamin 1 expression was higher in Ph2 and membrane metalloendopeptidase, adhesion G protein-coupled receptor E3, transforming growth factor beta induced, histidine ammonia-lyase, and sulfatase 2 expression was higher in Ph1. These expression patterns could be found when different sources of mRNA – such as blood leukocytes and lung tissue – were compared.

Conclusion

In human and ovine ARDS subgroups, similar activated pathways might be involved (e.g., oxidative phosphorylation, NF-κB pathway) that result in specific phenotypes.

A 0/1h-algorithm using cardiac myosin-binding protein C for early diagnosis of myocardial infarction

AIMS

Cardiac myosin-binding protein C (cMyC) demonstrated high diagnostic accuracy for the early detection of non-ST-elevation myocardial infarction (NSTEMI). Its dynamic release kinetics may enable a 0/1h-decision algorithm that is even more effective than the ESC hs-cTnT/I 0/1 h rule-in/rule-out algorithm.

METHODS AND RESULTS

In a prospective international diagnostic study enrolling patients presenting with suspected NSTEMI to the emergency department, cMyC was measured at presentation and after 1 h in a blinded fashion. Modelled on the ESC hs-cTnT/I 0/1h-algorithms, we derived a 0/1h-cMyC-algorithm. Final diagnosis of NSTEMI was centrally adjudicated according to the 4th Universal Definition of Myocardial Infarction. Among 1495 patients, the prevalence of NSTEMI was 17%. The optimal derived 0/1h-algorithm ruled-out NSTEMI with cMyC 0 h concentration below 10 ng/L (irrespective of chest pain onset) or 0 h cMyC concentrations below 18 ng/L and 0/1 h increase <4 ng/L. Rule-in occurred with 0 h cMyC concentrations of at least 140 ng/L or 0/1 h increase ≥15 ng/L. In the validation cohort (n = 663), the 0/1h-cMyC-algorithm classified 347 patients (52.3%) as 'rule-out', 122 (18.4%) as 'rule-in', and 194 (29.3%) as 'observe'. Negative predictive value for NSTEMI was 99.6% [95% confidence interval (CI) 98.9-100%]; positive predictive value 71.1% (95% CI 63.1-79%). Direct comparison with the ESC hs-cTnT/I 0/1h-algorithms demonstrated comparable safety and even higher triage efficacy using the 0h-sample alone (48.1% vs. 21.2% for ESC hs-cTnT-0/1 h and 29.9% for ESC hs-cTnI-0/1 h; P < 0.001).

CONCLUSION

The cMyC 0/1h-algorithm provided excellent safety and identified a greater proportion of patients suitable for direct rule-out or rule-in based on a single measurement than the ESC 0/1h-algorithm using hs-cTnT/I.

TRIAL REGISTRATION

ClinicalTrials.gov number, NCT00470587.

Recovery of organ-specific tissue oxygen delivery at restrictive transfusion thresholds after fluid treatment in ovine haemorrhagic shock

Background

Fluid resuscitation is the standard treatment to restore circulating blood volume and pressure after massive haemorrhage and shock. Packed red blood cells (PRBC) are transfused to restore haemoglobin levels. Restoration of microcirculatory flow and tissue oxygen delivery is critical for organ and patient survival, but these parameters are infrequently measured. Patient Blood Management is a multidisciplinary approach to manage and conserve a patient’s own blood, directing treatment options based on broad clinical assessment beyond haemoglobin alone, for which tissue perfusion and oxygenation could be useful. Our aim was to assess utility of non-invasive tissue-specific measures to compare PRBC transfusion with novel crystalloid treatments for haemorrhagic shock.

Methods

A model of severe haemorrhagic shock was developed in an intensive care setting, with controlled haemorrhage in sheep according to pressure (mean arterial pressure 30–40 mmHg) and oxygen debt (lactate > 4 mM) targets. We compared PRBC transfusion to fluid resuscitation with either PlasmaLyte or a novel crystalloid. Efficacy was assessed according to recovery of haemodynamic parameters and non-invasive measures of sublingual microcirculatory flow, regional tissue oxygen saturation, repayment of oxygen debt (arterial lactate), and a panel of inflammatory and organ function markers. Invasive measurements of tissue perfusion, oxygen tension and lactate levels were performed in brain, kidney, liver, and skeletal muscle. Outcomes were assessed during 4 h treatment and post-mortem, and analysed by one- and two-way ANOVA.

Results

Each treatment restored haemodynamic and tissue oxygen delivery parameters equivalently (p > 0.05), despite haemodilution after crystalloid infusion to haemoglobin concentrations below 70 g/L (p < 0.001). Recovery of vital organ-specific perfusion and oxygen tension commenced shortly before non-invasive measures improved. Lactate declined in all tissues and correlated with arterial lactate levels (p < 0.0001). The novel crystalloid supported rapid peripheral vasodilation (p = 0.014) and tended to achieve tissue oxygen delivery targets earlier. PRBC supported earlier renal oxygen delivery (p = 0.012) but delayed peripheral perfusion (p = 0.034).

Conclusions

Crystalloids supported vital organ oxygen delivery after massive haemorrhage, despite haemodilution to < 70 g/L, confirming that restrictive transfusion thresholds are appropriate to support oxygen delivery. Non-invasive tissue perfusion and oximetry technologies merit further clinical appraisal to guide treatment for massive haemorrhage in the context of Patient Blood Management.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40635-022-00439-6.

Characteristics and Outcomes of Type 2 Myocardial Infarction

Question

What are the characteristics and outcomes of type 2 myocardial infarction (T2MI) compared with type 1 myocardial infarction (T1MI) in patients presenting to the emergency department (ED) with acute chest discomfort?

Findings

In this cohort study 6253 patients, 251 patients (4.0%) and 1027 patients (16.4%) were diagnosed with T2MI and T1MI, respectively, and had comparable all-cause and cardiovascular mortality at 2 years. Tachyarrhythmia and hypertension were responsible for more than two-thirds of patients with T2MI and had lower mortality compared with patients with hypotension, hypoxemia, or anemia.

Meaning

Improved understanding of the specifics of patients with T2MI should help improve management strategies.

Importance

In contrast to type 1 myocardial infarction (T1MI) caused by atherothrombosis, characteristics and outcomes of type 2 myocardial infarction (T2MI) caused by supply-demand mismatch are incompletely understood.

Objective

To explore the characteristics and outcomes of patients with T2MI compared with those with T1MI.

Design, Setting, and Participants

In a prospective, international, multicenter cohort study including 12 emergency departments (EDs) in 5 European countries, unselected patients presenting with acute chest discomfort were enrolled from April 2006 to April 2018. Follow-up was done by telephone or in written form 3, 12, and 24 months after hospital discharge. Data were analyzed from April 2006 to April 2020.

Interventions

The final diagnoses of T2MI and T1MI were centrally adjudicated according to the Fourth Universal Definition of Myocardial Infarction by 2 independent cardiologists, including the pathophysiological trigger of T2MI.

Main Outcomes and Measures

Patient characteristics and outcomes, including 2-year all-cause and cardiovascular mortality and future T2MI and T1MI events.

Results

Of 6253 included patients, 2078 (33.2%) were women, and the median (IQR) age was 61 (48-74) years. Among 6253 patients with acute chest discomfort, the final adjudicated diagnosis was T2MI in 251 patients (4.0%), with tachyarrhythmia and hypertension responsible for two-thirds of cases, and T1MI in 1027 patients (16.4%). All-cause and cardiovascular mortality were comparable at 2 years (T2MI: adjusted hazard ratio, 1.0; 95% CI, 0.7-1.5; T1MI: adjusted hazard ratio, 0.7; 95% CI, 0.4-1.1). Patients with tachyarrhythmia or hypertension as their underlying trigger of T2MI had a lower mortality compared with patients with hypotension, hypoxemia, or anemia. Future T2MI was more likely among patients with index T2MI compared with patients with index T1MI (hazard ratio, 3.2; 95% CI, 1.4-7.5). Similarly, future T1MI was more likely to occur among patients with index T1MI (hazard ratio, 3.0; 95% CI, 1.2-7.4).

Conclusions and Relevance

Among patients with T2MI, tachyarrhythmia and hypertension were responsible for more than two-thirds of T2MI cases. While T2MI and T1MI had comparable all-cause and cardiovascular mortality at 2 years, patients with tachyarrhythmia or hypertension as their underlying trigger of T2MI had a lower mortality compared with patients with hypotension, hypoxemia, or anemia. Future T2MI occurred 3-fold more frequently among patients with T2MI vs T1MI as the index event. Improved understanding of the specifics of patients with T2MI should help improve management strategies.

A clinically relevant sheep model of orthotopic heart transplantation 24 h after donor brainstem death

Background

Heart transplantation (HTx) from brainstem dead (BSD) donors is the gold-standard therapy for severe/end-stage cardiac disease, but is limited by a global donor heart shortage. Consequently, innovative solutions to increase donor heart availability and utilisation are rapidly expanding. Clinically relevant preclinical models are essential for evaluating interventions for human translation, yet few exist that accurately mimic all key HTx components, incorporating injuries beginning in the donor, through to the recipient. To enable future assessment of novel perfusion technologies in our research program, we thus aimed to develop a clinically relevant sheep model of HTx following 24 h of donor BSD.

Methods

BSD donors (vs. sham neurological injury, 4/group) were hemodynamically supported and monitored for 24 h, followed by heart preservation with cold static storage. Bicaval orthotopic HTx was performed in matched recipients, who were weaned from cardiopulmonary bypass (CPB), and monitored for 6 h. Donor and recipient blood were assayed for inflammatory and cardiac injury markers, and cardiac function was assessed using echocardiography. Repeated measurements between the two different groups during the study observation period were assessed by mixed ANOVA for repeated measures.

Results

Brainstem death caused an immediate catecholaminergic hemodynamic response (mean arterial pressure, p = 0.09), systemic inflammation (IL-6 - p = 0.025, IL-8 - p = 0.002) and cardiac injury (cardiac troponin I, p = 0.048), requiring vasopressor support (vasopressor dependency index, VDI, p = 0.023), with normalisation of biomarkers and physiology over 24 h. All hearts were weaned from CPB and monitored for 6 h post-HTx, except one (sham) recipient that died 2 h post-HTx. Hemodynamic (VDI - p = 0.592, heart rate - p = 0.747) and metabolic (blood lactate, p = 0.546) parameters post-HTx were comparable between groups, despite the observed physiological perturbations that occurred during donor BSD. All p values denote interaction among groups and time in the ANOVA for repeated measures.

Conclusions

We have successfully developed an ovine HTx model following 24 h of donor BSD. After 6 h of critical care management post-HTx, there were no differences between groups, despite evident hemodynamic perturbations, systemic inflammation, and cardiac injury observed during donor BSD. This preclinical model provides a platform for critical assessment of injury development pre- and post-HTx, and novel therapeutic evaluation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40635-021-00425-4.

An Ovine Model of Hemorrhagic Shock and Resuscitation, to Assess Recovery of Tissue Oxygen Delivery and Oxygen Debt, and Inform Patient Blood Management

BACKGROUND

Aggressive fluid or blood component transfusion for severe hemorrhagic shock may restore macrocirculatory parameters, but not always improve microcirculatory perfusion and tissue oxygen delivery. We established an ovine model of hemorrhagic shock to systematically assess tissue oxygen delivery and repayment of oxygen debt; appropriate outcomes to guide Patient Blood Management.

METHODS

Female Dorset-cross sheep were anesthetized, intubated, and subjected to comprehensive macrohemodynamic, regional tissue oxygen saturation (StO2), sublingual capillary imaging, and arterial lactate monitoring confirmed by invasive organ-specific microvascular perfusion, oxygen pressure, and lactate/pyruvate levels in brain, kidney, liver, and skeletal muscle. Shock was induced by stepwise withdrawal of venous blood until MAP was 30 mm Hg, mixed venous oxygen saturation (SvO2) < 60%, and arterial lactate >4 mM. Resuscitation with PlasmaLyte® was dosed to achieve MAP > 65 mm Hg.

RESULTS

Hemorrhage impacted primary outcomes between baseline and development of shock: MAP 89 ± 5 to 31 ± 5 mm Hg (P < 0.01), SvO2 70 ± 7 to 23 ± 8% (P < 0.05), cerebral regional tissue StO2 77 ± 11 to 65 ± 9% (P < 0.01), peripheral muscle StO2 66 ± 8 to 16 ± 9% (P < 0.01), arterial lactate 1.5 ± 1.0 to 5.1 ± 0.8 mM (P < 0.01), and base excess 1.1 ± 2.2 to -3.6 ± 1.7 mM (P < 0.05). Invasive organ-specific monitoring confirmed reduced tissue oxygen delivery; oxygen tension decreased and lactate increased in all tissues, but moderately in brain. Blood volume replacement with PlasmaLyte® improved primary outcome measures toward baseline, confirmed by organ-specific measures, despite hemoglobin reduced from baseline 10.8 ± 1.2 to 5.9 ± 1.1 g/dL post-resuscitation (P < 0.01).

CONCLUSION

Non-invasive measures of tissue oxygen delivery and oxygen debt repayment are suitable outcomes to inform Patient Blood Management of hemorrhagic shock, translatable for pre-clinical assessment of novel resuscitation strategies.

Performance of the ESC 0/2h-algorithm using high-sensitivity cardiac troponin I in the early diagnosis of myocardial infarction

The 2020 guidelines of the European Society of Cardiology (ESC) recommend a novel ESC 0/2h-algorithm as the preferred alternative to the ESC 0/1h-algorithm in the early triage for rule-out and/or rule-in of Non-ST-segment-elevation myocardial infarction (NSTEMI). The aim was to prospectively validate the performance of the ESC 0/2h-algorithm using the high-sensitivity cardiac troponin I (hs-cTnI) assay (ARCHITECT) in an international, multicenter diagnostic study enrolling patients presenting with acute chest discomfort to the emergency department.

0/2 h-Algorithm for Rapid Triage of Suspected Myocardial Infarction Using a Novel High-Sensitivity Cardiac Troponin I Assay

Background

We aimed to derive and validate a 0/2 h-algorithm using the new high-sensitivity cardiac troponin I (hs-cTnI)-VITROS assay (VITROS® Immunodiagnostic Products hs-Troponin I Reagent Pack, Ortho Clinical Diagnostics) for rapid rule-out/in of non-ST-segment elevation myocardial infarction (NSTEMI).

Methods

The final diagnosis was centrally adjudicated by 2 independent cardiologists according to the fourth universal definition of myocardial infarction (MI) among 1888 patients presenting to the emergency department with acute chest pain. hs-cTnI-VITROS concentrations were measured at presentation and at 2 h in a blinded fashion. The optimal assay-specific thresholds for the hs-cTnI-VITROS 0/2 h-algorithm were derived in a randomly selected 70% of the cohort and validated in the remaining 30%.

Results

NSTEMI was the final diagnosis in 216/1322 (16.3%) patients of the derivation cohort. Rule-out was defined as baseline hs-cTnI concentrations of &lt;1 ng/L in patients presenting with chest pain onset &gt;3 h or a baseline hs-cTnI concentration of &lt;2 ng/L and an absolute change of &lt;3 ng/L within 2 h. Thresholds for rule-in were either ≥40 ng/L at presentation or an absolute change within 2 h of ≥ 5ng/L. In the derivation cohort, these thresholds ruled-out 50.8% of patients with a negative predictive value (NPV) and sensitivity of 99.7% (95% Confidence Interval (CI), 98.8–99.9%) and 99.1% (95% CI, 96.7–99.9%), and ruled-in 17.9% with a positive predictive value (PPV) of 79.2% (95% CI, 74.3–83.5%). In the validation cohort, NSTEMI was the final diagnosis in 91/566 (16.1%) patients. The derived 0/2 h-algorithm ruled-out 46.3% of patients with a NPV and sensitivity of 100% (95% CI, 95.6–100%) and 100% (95% CI, 96.0–100%), and ruled-in 18.9% with a PPV of 73.8% (95% CI, 66.1–80.3%) in the validation cohort.

Conclusion

hs-cTnI-VITROS concentrations at presentation combined with absolute changes within the first 2 h allowed safe rule-out and accurate rule-in of NSTEMI in two-thirds of unselected patients presenting with acute chest pain to the emergency department.

Trial registration

www.clinicaltrials.gov: NCT0047058

An innovative ovine model of severe cardiopulmonary failure supported by veno-arterial extracorporeal membrane oxygenation

Refractory cardiogenic shock (CS) often requires veno-arterial extracorporeal membrane oxygenation (VA-ECMO) to sustain end-organ perfusion. Current animal models result in heterogenous cardiac injury and frequent episodes of refractory ventricular fibrillation. Thus, we aimed to develop an innovative, clinically relevant, and titratable model of severe cardiopulmonary failure. Six sheep (60 ± 6 kg) were anaesthetized and mechanically ventilated. VA-ECMO was commenced and CS was induced through intramyocardial injections of ethanol. Then, hypoxemic/hypercapnic pulmonary failure was achieved, through substantial decrease in ventilatory support. Echocardiography was used to compute left ventricular fractional area change (LVFAC) and cardiac Troponin I (cTnI) was quantified. After 5 h, the animals were euthanised and the heart was retrieved for histological evaluations. Ethanol (58 ± 23 mL) successfully induced CS in all animals. cTnI levels increased near 5000-fold. CS was confirmed by a drop in systolic blood pressure to 67 ± 14 mmHg, while lactate increased to 4.7 ± 0.9 mmol/L and LVFAC decreased to 16 ± 7%. Myocardial samples corroborated extensive cellular necrosis and inflammatory infiltrates. In conclusion, we present an innovative ovine model of severe cardiopulmonary failure in animals on VA-ECMO. This model could be essential to further characterize CS and develop future treatments.

Characterizing preclinical sub-phenotypic models of acute respiratory distress syndrome: An experimental ovine study

The acute respiratory distress syndrome (ARDS) describes a heterogenous population of patients with acute severe respiratory failure. However, contemporary advances have begun to identify distinct sub-phenotypes that exist within its broader envelope. These sub-phenotypes have varied outcomes and respond differently to several previously studied interventions. A more precise understanding of their pathobiology and an ability to prospectively identify them, may allow for the development of precision therapies in ARDS. Historically, animal models have played a key role in translational research, although few studies have so far assessed either the ability of animal models to replicate these sub-phenotypes or investigated the presence of sub-phenotypes within animal models. Here, in three ovine models of ARDS, using combinations of oleic acid and intravenous, or intratracheal lipopolysaccharide, we investigated the presence of sub-phenotypes which qualitatively resemble those found in clinical cohorts. Principal Component Analysis and partitional clustering identified two clusters, differentiated by markers of shock, inflammation, and lung injury. This study provides a first exploration of ARDS phenotypes in preclinical models and suggests a methodology for investigating this phenomenon in future studies.

Design and Rationale of a Prospective International Follow-Up Study on Intensive Care Survivors of COVID-19: The Long-Term Impact in Intensive Care Survivors of Coronavirus Disease-19-AFTERCOR

Background: In a disease that has only existed for 18 months, it is difficult to be fully informed of the long-term sequelae of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. Evidence is growing that most organ systems can be affected by the virus, causing severe disabilities in survivors. The extent of the aftermath will declare itself over the next 5-10 years, but it is likely to be substantial with profound socio-economic impact on society. Methods: This is an international multi-center, prospective long-term follow-up study of patients who developed severe coronavirus disease-2019 (COVID-19) and were admitted to Intensive Care Units (ICUs). The study will be conducted at international tertiary hospitals. Patients will be monitored from time of ICU discharge up to 24 months. Information will be collected on demographics, co-existing illnesses before ICU admission, severity of illness during ICU admission and post-ICU quality of life as well as organ dysfunction and recovery. Statistical analysis will consist of patient trajectories over time for the key variables of quality of life and organ function. Using latent class analysis, we will determine if there are distinct patterns of patients in terms of recovery. Multivariable regression analyses will be used to examine associations between baseline characteristics and severity variables upon admission and discharge in the ICU, and how these impact outcomes at all follow-up time points up to 2 years. Ethics and Dissemination: The core study team and local principal investigators will ensure that the study adheres to all relevant national and local regulations, and that the necessary approvals are in place before a site may enroll patients. Clinical Trial Registration:anzctr.org.au: ACTRN12620000799954.

Direct comparison of high-sensitivity cardiac troponin T and I in the early differentiation of type 1 vs. type 2 myocardial infarction

AIMS

To directly compare the diagnostic accuracy of high-sensitivity cardiac troponin (hs-cTn) T vs. hs-cTnI in the early non-invasive differentiation of Type 1 myocardial infarction (T1MI) due to plaque rupture and atherothrombosis from Type 2 myocardial infarction (T2MI) due to supply-demand mismatch.

METHODS AND RESULTS

In a prospective multicentre diagnostic study, two independent cardiologists centrally adjudicated the final diagnosis of T1MI vs. T2MI according to the fourth universal definition of myocardial infarction (MI), using all available clinical information including cardiac imaging in patients presenting with acute chest pain. Diagnostic accuracy was quantified by the area under the receiver operating characteristics curve (AUC). The most extensively validated hs-cTnT-Elecsys and hs-cTnI-Architect assays were measured at presentation, 1 h, and 2 h. Among 5887 patients, 1106 (19%) had a final diagnosis of MI, including 860 (78%) T1MI and 246 (22%) T2MI. The AUC of hs-cTnT-Elecsys to differentiate T1MI from T2MI was moderate and comparable to that provided by hs-cTnI-Architect: hs-cTnT-Elecsys AUC-presentation 0.67 [95% confidence interval (CI) 0.64-0.71], AUC-1 h 0.70 (95% CI 0.66-0.74), and AUC-2 h 0.71 (95% CI 0.66-0.75) vs. hs-cTnI-Architect AUC-presentation 0.71 (95% CI 0.67-0.74), AUC-1 h 0.72 (95% CI 0.68-0.76), and AUC-2 h 0.74 (95% CI 0.69-0.78), all P = not significant (NS). Similarly, the AUC of absolute changes was moderate and comparable for hs-cTnT-Elecsys and hs-cTnI-Architect (all P = NS). Cut-off concentrations achieving at least 90% specificity for the differentiation of T1MI vs. T2MI were >114 ng/L for hs-cTnT-Elecsys [odds ratio (OR) 4.2, 95% CI 2.7-6.6] and >371 ng/L for hs-cTnI-Architect (OR 4.0, 95% CI 2.6-6.2).

CONCLUSION

hs-cTnT-Elecsys and hs-cTnI-Architect provided comparable, albeit only moderate, diagnostic accuracy for the early differentiation of T1MI vs. T2MI.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov number, NCT00470587, https://clinicaltrials.gov/ct2/show/NCT00470587.

External Validation and Extension of a Clinical Score for the Discrimination of Type 2 Myocardial Infarction

BACKGROUND

The early non-invasive discrimination of Type 2 versus Type 1 Myocardial Infarction (T2MI, T1MI) is a major unmet clinical need. We aimed to externally validate a recently derived clinical score (Neumann) combing female sex, no radiating chest pain, and high-sensitivity cardiac troponin I (hs-cTnI) concentration ≤40.8 ng/L.

METHODS

Patients presenting with acute chest discomfort to the emergency department were prospectively enrolled into an international multicenter diagnostic study. The final diagnoses of T2MI and T1MI were centrally adjudicated by two independent cardiologists using all information including cardiac imaging and serial measurements of hs-cTnT/I according to the fourth universal definition of MI. Model performance for T2MI diagnosis was assessed by formal tests and graphical means of discrimination and calibration.

RESULTS

Among 6684 enrolled patients, MI was the adjudicated final diagnosis in 1079 (19%) patients, of which 242 (22%) had T2MI. External validation of the Neumann Score showed a moderate discrimination (C-statistic 0.67 (95%CI 0.64-0.71)). Model calibration showed underestimation of the predicted probabilities of having T2MI for low point scores. Model extension by adding the binary variable heart rate >120/min significantly improved model performance (C-statistic 0.73 (95% CI 0.70-0.76, p < 0.001) and had good calibration. Patients with the highest score values of 3 (Neumann Score, 9.9%) and 5 (Extended Neumann Score, 3.3%) had a 53% and 91% predicted probability of T2MI, respectively.

CONCLUSION

The Neumann Score provided moderate discrimination and suboptimal calibration. Extending the Neumann Score by adding heart rate >120/min improved the model's performance.

Correction to: The discovery of biological subphenotypes in ARDS: a novel approach to targeted medicine?

An amendment to this paper has been published and can be accessed via the original article.

External validation of the clinical chemistry score

BACKGROUND

Combining high-sensitivity cardiac troponin (hs-cTn) with estimated glomerular filtration rate and glucose within the Clinical Chemistry Score (CCS) could help in the assessment of patients with suspected acute myocardial infarction (AMI).

METHODS

In patients presenting with suspected AMI to the emergency department, we aimed to externally validate the performance of the CCS in a prospective international multicenter study and to directly compare the diagnostic and prognostic performance of the CCS with hs-cTnT and hs-cTnI baseline levels alone using a single cut-off approach. The diagnostic endpoint was diagnostic accuracy for AMI as centrally adjudicated by two independent cardiologists including cardiac imaging and serial hs-cTnT/I measurements. The prognostic endpoint was 30-day AMI or death.

RESULTS

AMI was the final diagnosis in 620/3827 patients (16.2%) adjudicated with hs-cTnT and 599 patients (15.7%) adjudicated with hs-cTnI. The CCS resulted in high diagnostic accuracy for AMI and prognostic accuracy for 30-days AMI/death as quantified by the area under the receiver-operating characteristic curve (AUC), using hs-cTnT 0.90 (95%CI 0.89-0.91) and 0.89 (95%CI 0.88-0.90), using hs-cTnI 0.91 (95%Cl 0.90-0.92) and 0.90 (95%CI 0.89-0.91) respectively. E.g. a CCS of 0 points resulted in a sensitivity of 99.8% (95%CI 99.1-100%) for rule-out of index AMI and 99.5% (95%CI 98.5-100%) for AMI/death at 30 days for hs-cTnT and 99.8% (95%CI 98.9-100%) and 99.6% (95%CI 98.6-100%) using hs-cTnI. Overall, the single hs-cTnT/I measurement approach provided comparable diagnostic (sensitivity 99.5-99.7%) and prognostic (sensitivity 98.9-99.5%) performance versus the CCS.

INTERPRETATION

The CCS provided high diagnostic and prognostic performance also in this independent large validation cohort. A single hs-cTnT/I measurement approach for rule-out MI yielded similar estimates.

The discovery of biological subphenotypes in ARDS: a novel approach to targeted medicine?

The acute respiratory distress syndrome (ARDS) is a severe lung disorder with a high morbidity and mortality which affects all age groups. Despite active research with intense, ongoing attempts in developing pharmacological agents to treat ARDS, its mortality rate remains unaltered high and treatment is still only supportive. Over the years, there have been many attempts to identify meaningful subgroups likely to react differently to treatment among the heterogenous ARDS population, most of them unsuccessful. Only recently, analysis of large ARDS cohorts from randomized controlled trials have identified the presence of distinct biological subphenotypes among ARDS patients: a hypoinflammatory (or uninflamed; named P1) and a hyperinflammatory (or reactive; named P2) subphenotype have been proposed and corroborated with existing retrospective data. The hyperinflammatory subphenotyope was clearly associated with shock state, metabolic acidosis, and worse clinical outcomes. Core features of the respective subphenotypes were identified consistently in all assessed cohorts, independently of the studied population, the geographical location, the study design, or the analysis method. Additionally and clinically even more relevant treatment efficacies, as assessed retrospectively, appeared to be highly dependent on the respective subphenotype. This discovery launches a promising new approach to targeted medicine in ARDS. Even though it is now widely accepted that each ARDS subphenotype has distinct functional, biological, and mechanistic differences, there are crucial gaps in our knowledge, hindering the translation to bedside application. First of all, the underlying driving biological factors are still largely unknown, and secondly, there is currently no option for fast and easy identification of ARDS subphenotypes. This narrative review aims to summarize the evidence in biological subphenotyping in ARDS and tries to point out the current issues that will need addressing before translation of biological subohenotypes into clinical practice will be possible.

Design and rationale of the COVID-19 Critical Care Consortium international, multicentre, observational study

INTRODUCTION

There is a paucity of data that can be used to guide the management of critically ill patients with COVID-19. In response, a research and data-sharing collaborative-The COVID-19 Critical Care Consortium-has been assembled to harness the cumulative experience of intensive care units (ICUs) worldwide. The resulting observational study provides a platform to rapidly disseminate detailed data and insights crucial to improving outcomes.

METHODS AND ANALYSIS

This is an international, multicentre, observational study of patients with confirmed or suspected SARS-CoV-2 infection admitted to ICUs. This is an evolving, open-ended study that commenced on 1 January 2020 and currently includes >350 sites in over 48 countries. The study enrols patients at the time of ICU admission and follows them to the time of death, hospital discharge or 28 days post-ICU admission, whichever occurs last. Key data, collected via an electronic case report form devised in collaboration with the International Severe Acute Respiratory and Emerging Infection Consortium/Short Period Incidence Study of Severe Acute Respiratory Illness networks, include: patient demographic data and risk factors, clinical features, severity of illness and respiratory failure, need for non-invasive and/or mechanical ventilation and/or extracorporeal membrane oxygenation and associated complications, as well as data on adjunctive therapies.

ETHICS AND DISSEMINATION

Local principal investigators will ensure that the study adheres to all relevant national regulations, and that the necessary approvals are in place before a site may contribute data. In jurisdictions where a waiver of consent is deemed insufficient, prospective, representative or retrospective consent will be obtained, as appropriate. A web-based dashboard has been developed to provide relevant data and descriptive statistics to international collaborators in real-time. It is anticipated that, following study completion, all de-identified data will be made open access.

TRIAL REGISTRATION NUMBER

ACTRN12620000421932 (http://anzctr.org.au/ACTRN12620000421932.aspx).

Clinical presentation of patients with prior coronary artery bypass grafting and suspected acute myocardial infarction

AIMS

Diagnosis of acute myocardial infarction (AMI) can be challenging in patients with prior coronary artery bypass grafting (CABG).

METHODS AND RESULTS

Final diagnoses were adjudicated by two independent cardiologists using the universal definition of AMI among patients presenting to the emergency department (ED) with suspected AMI. Diagnostic accuracy of 34 chest pain characteristics (CPCs) and four electrocardiogram (ECG) signatures stratified according to the presence or absence of prior CABG were prospectively quantified. Among 4015 patients (no prior CABG: n = 3686; prior CABG: n = 329), prevalence of AMI and unstable angina were higher in patients with prior CABG (35% vs. 18%; 26% vs. 8%; both P < 0.001). Three CPCs (9%) and two electrocardiographic findings (50%) showed a different diagnostic performance (interaction P < 0.05) with loss of diagnostic value in patients with prior CABG. The diagnostic accuracy as quantified by the area under the curve (AUC) of the integrated clinical judgement was moderate to good in patients with prior CABG, and significantly lower compared to patients without prior CABG [AUC 0.80 (95% confidence interval (CI) 0.75-0.84) vs. AUC 0.87 (95% CI 0.86-0.89); P = 0.004]. Time to discharge from the ED was significantly longer in patients with prior CABG [359 (215-525) min vs. 300 (192-435) min; P < 0.001]. Key findings were confirmed in a large independent external validation cohort (n = 13 653).

CONCLUSIONS

Patients with prior CABG presenting with suspected AMI have a high prevalence of AMI and unstable angina and lower diagnostic accuracy of CPCs and the ECG, possibly justifying liberal use of early coronary angiography in these vulnerable patients.

CLINICALTRIALS.GOV REGISTRY

Number NCT00470587.

Clinical risk scores and integrated clinical judgment in patients with suspected acute coronary syndrome

Background

Clinical risk scores are recommended for formal risk stratification in patients presenting with suspected acute coronary syndrome (ACS). It is unknown, whether these scores still provide additional value in the era of high-sensitivity cardiac troponin (hs-cTn) compared to simple integrated clinical judgment.

Purpose

To evaluate the diagnostic and prognostic performance of integrated clinical judgment compared to clinical risk scores.

Methods

We prospectively enrolled patients presenting to the emergency department with symptoms suggestive of ACS such as acute chest discomfort. The primary prognostic endpoint was the composite of 30-day major adverse cardiac events (MACE) including all-cause death, life-threatening arrhythmia, cardiogenic shock, acute myocardial infarction (AMI, including the index event), and urgent coronary revascularization and was adjudicated by two independent cardiologists. The performance of five well-established formal risk scores (T-MACS, HEART, GRACE, TIMI, and EDACS) for the prediction of 30-day MACE was directly compared with simple integrated clinical judgment for the ACS likelihood by the treating ED physician. Integrated clinical judgment was quantified using a visual analogue scale at 90 minutes after patient's presentation to the ED. The primary diagnostic endpoint was index AMI.

Results

Among 2031 patients, 417/2031 patients (20.5%) had at least one MACE within 30 days. Prognostic accuracy for 30-day MACE quantified by the area under the receiver-operating characteristics curve (AUC) was 0.87 (95% CI 0.85–0.89) for T-MACS, 0.87 (95% CI 0.85–0.89) for HEART, 0.84 (95% CI 0.82–0.86) for GRACE, 0.81 (95% CI 0.79–0.83) for TIMI, 0.75 (95% CI 0.73–0.78) for EDACS, versus 0.89 (95% CI 0.87–0.91) for simple integrated clinical judgment (p&lt;0.01 versus GRACE, TIMI, and EDACS; Figure 1). Similarly, diagnostic accuracy was 0.92 (95% CI 0.90–0.94) for T-MACS, 0.89 (95% CI 0.87–0.90) for HEART, 0.88 (95% CI 0.86–0.89) for GRACE, 0.80 (95% CI 0.78–0.82) for TIMI, 0.74 (95% CI 0.72–0.77) for EDACS, versus 0.89 (95% CI 0.88–0.91) for simple integrated clinical judgment (p&lt;0.01 versus GRACE, TIMI, and EDACS).

Conclusion

None of the formal clinical risk scores outperformed simple integrated clinical judgment for ACS in the prediction of 30-day MACE or the diagnosis of AMI. Therefore, in the era of hs-cTn testing as part of integrated clinical judgment, clinical risk scores seem to no longer provide incremental value.

Figure 1. Diagnostic accuracy for MACE at 30-days

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Swiss National Science Foundation, Swiss Heart Foundation

Early diagnosis of myocardial infarction in patients presenting late after chest pain onset

Background

The European Society of Cardiology (ESC) recommends the clinical use of the 0/1h-algorithms in patients with suspected acute coronary syndrome (ACS) to rule-out or rule-in non-ST elevation myocardial infarction (NSTEMI). However, the diagnostic performance of the ESC 0/1h-algorithms was only validated in patients presenting within 12 hours after chest pain onset (=early presenters) to the emergency department (ED). To this date, evidence regarding their performance in patients with chest pain onset &gt;12h (=late presenters) is lacking.

Purpose

To evaluate the diagnostic performance of the ESC 0/1h-algorithms in late presenters.

Methods

We prospectively enrolled patients presenting to the ED with symptoms suggestive of ACS such as acute chest discomfort. Two independent cardiologists adjudicated the final diagnoses based on all available clinical information including serial hs-cTn concentrations, follow-up information and cardiac imaging. Hs-cTnT/I concentrations at 0h and 1h were measured in a blinded fashion. The primary diagnostic endpoint was the diagnostic performance of the hs-cTnT/I ESC 0/1h-algorithms in patients presenting late after chest pain onset compared to those presenting early. Diagnostic performance was quantified by safety of rule-out (sensitivity and negative predictive value), accuracy of rule-in (specificity and positive predictive value), and efficacy (proportion of patients) classified as rule-out or rule-in within 1 hour after presentation to the ED. The primary prognostic endpoint was all-cause mortality after 30-days and two-years in patients in whom NSTEMI was ruled-out by the ESC 0/1h-algorithms.

Results

Among 4733 patients, 308/4733 (7%) presented late to the ED. The ESC hs-cTnT 0/1h-algorithm ruled-out 185/308 (60%) of late presenters with a sensitivity of 100% (95% CI, 93.7–100) and a negative predictive value (NPV) of 100% (95% CI, 98.0–100). Sixty-one of 308 (20%) were ruled-in with a specificity of 95.2 (95% CI, 91.8–97.2) and a positive predictive value (PPV) of 80.3% (95% CI, 68.7–88.4). The remaining 62/308 (20%) were classified as observe with a NSTEMI prevalence of 13%. In comparison, 59% of early presenters were ruled-out (sensitivity 99.3% [95% CI, 98.4–99.7]; NPV 99.8 [99.5–99.9]), 17% were ruled-in (specificity 96.2 [95% CI, 95.5–96.8]; PPV 81.4 [95% CI, 78.4–84.0]), and 45% were classified as observe. Late presenters in whom NSTEMI was ruled-out had 30-day and two-year survival rates of 100% and 98.2%, respectively. Similar findings were made for the ESC hs-cTnI 0/1h-algorithm.

Conclusion

The ESC hs-cTnT/I algorithms also provide excellent diagnostic performance for early triage and specifically safe rule-out of NSTEMI in patients presenting late after chest pain onset to the ED.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Swiss Heart Foundation, Swiss National Science Foundation

Incidence of major adverse cardiac events following non-cardiac surgery

AIMS

Major adverse cardiac events (MACE) triggered by non-cardiac surgery are prognostically important perioperative complications. However, due to often asymptomatic presentation, the incidence and timing of postoperative MACE are incompletely understood.

METHODS AND RESULTS

We conducted a prospective observational study implementing a perioperative screening for postoperative MACE [cardiovascular death (CVD), acute heart failure (AHF), haemodynamically relevant arrhythmias, spontaneous myocardial infarction (MI), and perioperative myocardial infarction/injury (PMI)] in patients at increased cardiovascular risk (≥65 years OR ≥45 years with history of cardiovascular disease) undergoing non-cardiac surgery at a tertiary hospital. All patients received serial measurements of cardiac troponin to detect asymptomatic MACE. Among 2265 patients (mean age 73 years, 43.4% women), the incidence of MACE was 15.2% within 30 days, and 20.6% within 365 days. CVD occurred in 1.2% [95% confidence interval (CI) 0.9-1.8] and in 3.7% (95% CI 3.0-4.5), haemodynamically relevant arrhythmias in 1.2% (95% CI 0.9-1.8) and in 2.1% (95% CI 1.6-2.8), AHF in 1.6% (95% CI 1.2-2.2) and in 4.2% (95% CI 3.4-5.1), spontaneous MI in 0.5% (95% CI 0.3-0.9) and in 1.6% (95% CI 1.2-2.2), and PMI in 13.2% (95% CI 11.9-14.7) and in 14.8% (95% CI 13.4-16.4) within 30 days and within 365 days, respectively. The MACE-incidence was increased above presumed baseline rate until Day 135 (95% CI 104-163), indicating a vulnerable period of 3-5 months.

CONCLUSION

One out of five high-risk patients undergoing non-cardiac surgery will develop one or more MACE within 365 days. The risk for MACE remains increased for about 5 months after non-cardiac surgery.

TRIAL REGISTRATION

https://www.clinicaltrials.gov. Unique identifier: NCT02573532.