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BACKGROUND: The role of left atrial (LA) strain as an imaging biomarker in aortic stenosis is not well established. The aim of this study was to investigate the prognostic performance of phasic LA strain in relation to clinical and echocardiographic variables and N-terminal pro-B-type natriuretic peptide in asymptomatic and minimally symptomatic patients with moderate to severe aortic stenosis and left ventricular ejection fraction > 50%. METHODS: LA reservoir strain (LASr), LA conduit strain (LAScd), and LA contractile strain (LASct) were measured using speckle-tracking echocardiography. The primary outcome was a composite of all-cause mortality, heart failure hospitalization, progression to New York Heart Association functional class III or IV, acute coronary syndrome, or syncope. Secondary outcomes 1 and 2 comprised the same end points but excluded acute coronary syndrome and additionally syncope, respectively. The prognostic performance of phasic LA strain cutoffs was evaluated in competing risk analyses, aortic valve replacement being the competing risk. RESULTS: Among 173 patients (mean age, 69 ± 11 years; mean peak transaortic velocity, 4.0 ± 0.8 m/sec), median LASr, LAScd, and LASct were 27% (interquartile range [IQR], 22%-32%), 12% (IQR, 8%-15%), and 16% (IQR, 13%-18%), respectively. Over a median of 2.7 years (IQR, 1.4-4.6 years), the primary outcome and secondary outcomes 1 and 2 occurred in 66 (38%), 62 (36%), and 59 (34%) patients, respectively. LASr < 20%, LAScd < 6%, and LASct < 12% were identified as optimal cutoffs of the primary outcome. In competing risk analyses, progressing from echocardiographic to echocardiographic-clinical and combined models incorporating N-terminal pro-B-type natriuretic peptide, LA strain parameters outperformed other key echocardiographic variables and significantly predicted clinical outcomes. LASr < 20% was associated with the primary outcome and secondary outcome 1, LAScd < 6% with all clinical outcomes, and LASct < 12% with secondary outcome 2. LAScd < 6% had the highest specificity (95%) and positive predictive value (82%) for the primary outcome, and competing risk models incorporating LAScd < 6% had the best discriminative value. CONCLUSIONS: In well-compensated patients with moderate to severe aortic stenosis and preserved left ventricular ejection fractions, LA strain was superior to other echocardiographic indices and incremental to N-terminal pro-B-type natriuretic peptide for risk stratification. LAScd < 6%, LASr < 20%, and LASct < 12% identified patients at higher risk for adverse outcomes.
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Estenose da Valva Aórtica , Fibrilação Atrial , Humanos , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Prognóstico , Volume Sistólico , Função Ventricular Esquerda , Peptídeo Natriurético Encefálico , Átrios do Coração , Medição de Risco , Estenose da Valva Aórtica/diagnóstico por imagem , Estenose da Valva Aórtica/complicaçõesRESUMO
This chapter describes an epitope-directed approach to generate antipeptide monoclonal antibodies to multiple nonoverlapping protein sites using a cocktail of fusion peptides as immunogen. It provides a step-by-step protocol on how antigenic peptides on a target protein can be identified by in silico prediction and discusses considerations for final peptide selection. Each antigenic peptide (10-20 amino acids long) is displayed as three-copy inserts on the surface exposed loop of a thioredoxin scaffold protein. The corresponding DNA coding sequence specifying the tripeptide insert flanked by Gly-Ser-Gly-Ser-Gly linkers is cloned in-frame into the Rsr II site of the thioredoxin gene in the pET-32a vector. The presence of a C-terminal polyhistidine tag (His6-tag) allows the soluble fusion proteins to be purified by one-step native immobilized metal affinity chromatography (IMAC) to greater than 95% purity. Multiple thioredoxin fusion proteins are mixed in equimolar concentrations and used as an immunogen cocktail for animal immunization. The use of short antigenic peptides of known sequence facilitates direct epitope mapping requiring only small mutagenesis scan peptide libraries in the multipin peptide format.
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Anticorpos Monoclonais , Biblioteca de Peptídeos , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/genética , Antígenos , Mapeamento de Epitopos/métodos , Epitopos , Peptídeos/genética , Tiorredoxinas/genéticaRESUMO
Objectives: In dyspneic patients with atrial fibrillation (AF) or obesity, the diagnostic performance of NT-proBNP for acute heart failure is reduced. We evaluated the erythroblast derived protein erythroferrone (ERFE) as an ancillary biomarker for the diagnosis of acute decompensated heart failure (ADHF) in these comorbid subgroups in both Western and Asian populations. Methods: The diagnostic performance of ERFE (Intrinsic Lifesciences) and NT-proBNP (Roche Cobas e411) for ADHF was assessed in 479 New Zealand (NZ) and 475 Singapore (SG) patients presenting with breathlessness. Results: Plasma ERFE was higher in ADHF, compared with breathlessness from other causes, in both countries (NZ; 4.9 vs. 1.4â ng/ml, p < 0.001) and (SG; 4.2 vs. 0.4â ng/ml, p = 0.021). The receiver operating characteristic (ROC) areas under the curve (AUCs) for discrimination of ADHF were reduced in the NZ cohort compared to SG for ERFE (0.75 and 0.84, p = 0.007) and NT-proBNP (0.86 and 0.92, p = 0.004). Optimal cut-off points for ERFE yielded comparable sensitivity and positive predictive values in both cohorts, but slightly better specificity, negative predictive values and accuracy in SG compared with NZ. In patients with AF, the AUC decreased for ERFE in each cohort (NZ: 0.71, n = 105, SG: 0.61, n = 44) but increased in patients with obesity (NZ: 0.79, n = 150, SG: 0.87, n = 164). Conclusions: Circulating ERFE is higher in patients with ADHF than in other causes of new onset breathlessness with fair diagnostic utility, performing better in Asian than in Western patients. The diagnostic performance of ERFE is impaired in patients with AF but not patients with obesity.
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Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) inactivation is an important step toward enhanced biosafety in testing facilities and affords a reduction in the biocontainment level necessary for handling virus-positive biological specimens. Virus inactivation methods commonly employ heat, detergents, or combinations thereof. In this work, we address the dearth of information on the efficacy of SARS-CoV-2 inactivation procedures in plasma and their downstream impact on immunoassays. We evaluated the effects of heat (56 °C for 30 min), detergent (1-5% Triton X-100), and solvent-detergent (SD) combinations [0.3-1% tri-n-butyl phosphate (TNBP) and 1-2% Triton X-100] on 19 immunoassays across different assay formats. Treatments are deemed immunoassay-compatible when the average and range of percentage recovery (treated concentration relative to untreated concentration) lie between 90-110 and 80-120%, respectively. We show that SD treatment (0.3% TNBP/1% Triton-X100) is compatible with more than half of the downstream immunoassays tested and is effective in reducing SARS-CoV-2 infectivity in plasma to below detectable levels in plaque assays. This facile method offers enhanced safety for laboratory workers handling biological specimens in clinical and research settings.
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The effects of vitamin D supplementation on cardiovascular diseases are controversial. Data on effects of vitamin D upon cardiac biomarkers, as surrogate endpoints of cardiovascular diseases, are limited and inconclusive. Therefore, we carried out a post-hoc analysis of sub-samples of a randomized, double-blinded, placebo-controlled trial with community-based older adults who were randomized to receive monthly 100,000-IU vitamin D or placebo, to determine effect of monthly vitamin D supplementation on high-sensitivity cardiac troponin I (hs-cTnI), troponin T (hs-cTnT) and N-terminal-pro-B-type natriuretic peptide (NT-proBNP). Adjusted relative difference (aRD) of follow-up geometric mean of biomarkers and adjusted relative risk (aRR) of elevated biomarkers between two groups were calculated. A total of 779 participants aged 50-84 y, randomized to vitamin D (n = 395) or placebo (n = 384) groups underwent sampling for measurement of plasma biomarkers at baseline and after one or two years treatment. Over a mean follow-up of 1.6 years, we did not find significant relative difference of geometric mean levels of three biomarkers at follow-up between vitamin D and placebo groups: hs-cTnI (aRD=1.03, 95%CI=0.97-1.09), hs-cTnT (aRD=0.99, 95%CI=0.95-1.04), and NT-proBNP (aRD=1.01, 95%CI=0.92-1.10). No significant differences were found in likelihood of clinically elevated biomarkers between two groups: hs-cTnI (aRR=0.92, 95%CI=0.51-1.69), hs-cTnT (aRR=1.11, 95%CI=0.86-1.42), and NT-proBNP (aRR=1.03,95%CI=0.89-1.20). However, among participants with initial low vitamin D status (<50 nmol/L, n = 200), follow-up NT-proBNP were significantly lower in the vitamin D group compared to placebo (geometric mean 75.9 vs 94.5 pg/mL, respectively; aRD=0.84, 95%CI=0.71-<1.00). The same results were observed for the NT-proBNP levels change from baseline between two groups. Overall, in older adults, monthly vitamin D supplementation did not reduce concentrations of hs-cTnI, hs-cTnT, and NT-proBNP. In those with low vitamin D status, vitamin D treatment was associated, on follow up and change from baseline, with lower plasma NT-proBNP compared with placebo. This potentially signals reduced risk of subsequent heart failure within this sub-group. However, we acknowledge that these findings need to be considered exploratory. Further research is required to replicate them.
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Doenças Cardiovasculares , Vitamina D , Idoso , Biomarcadores , Suplementos Nutricionais , Humanos , Fragmentos de Peptídeos , Troponina T , VitaminasRESUMO
BACKGROUND: Highly trained athletes running 42 km or more demonstrate elevated cardiac biomarkers, ventricular dysfunction, and decreased glomerular filtration rate (GFR). Whether similar changes occur in the much larger population of recreational runners following half-marathon distance running is unclear. HYPOTHESIS: Recreational runners exhibit changes in myocardial and renal biomarkers, including ventricular strain, after a half-marathon treadmill run. METHODS: 10 recreational subjects (mean age 36.5 ± 6.5 years) ran 21 km on a treadmill (mean completion time 121.6 ± 16.1 minutes). Serum high-sensitivity troponin T (hsTnT), amino-terminal pro-brain natriuretic peptide (NT-proBNP), creatinine, and neutrophil gelatinase-associated lipocalin (NGAL) were measured prior to, 1 hour post-, and 24 hours post-exercise. Pre- and post-exercise echocardiograms were performed. RESULTS: All biomarkers increased 1 hour post-exercise: hsTnT by 8.5 ± 8.5 pg/ml (P < .05), NT-ProBNP by 26.2 ± 22.8 pg/ml (P < .05) and NGAL by 29.5 ± 37.7 ng/ml (P=NS). By 24 hours post-run, these biomarkers declined toward baseline levels. Right ventricle (RV) free wall and left ventricle global longitudinal strain decreased by 5.5% and 1.8%, respectively (P < .001). Changes in NGAL correlated well with changes in serum creatinine (R = 0.79, P < .01) and GFR (R = -0.73, P < .05). Faster 21 km completion times, and a larger reduction in post-exercise RV strain, were associated with higher NGAL levels: (R = -0.75, P = .01) and (R = 0.66, P < .05), respectively. CONCLUSION: A 21 km run in recreational runners is associated with transient ventricular stunning and reversible changes in myocardial and renal biomarkers. Whether repeated bouts of similar activity contributes to chronic cardiac or kidney dysfunction deserves further evaluation.
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Creatinina/sangue , Ventrículos do Coração/diagnóstico por imagem , Rim/metabolismo , Lipocalina-2/sangue , Peptídeo Natriurético Encefálico/sangue , Fragmentos de Peptídeos/sangue , Corrida/fisiologia , Troponina T/sangue , Adulto , Biomarcadores/sangue , Ecocardiografia , Teste de Esforço , Feminino , Taxa de Filtração Glomerular/fisiologia , Humanos , Masculino , Adulto JovemRESUMO
BACKGROUND: We evaluated the effects of sleep-study guided multidisciplinary therapy (SGMT) of obstructive sleep apnoea (OSA) in patients presenting with acute coronary syndrome. METHODS: Eligible patients were randomized into (1) SGMT, comprised a sleep study during the index admission and continuous positive airway pressure and behavioral therapy for those with at least mild OSA or (2) standard therapy. The primary end point was the change in the plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) level from baseline to the 7-month follow-up. RESULTS: A total of 159 patients completed the trial. Of the 70 patients randomized to SGMT, 21 (30%), 15 (22%) and 27 (39%) were diagnosed with mild, moderate and severe OSA, respectively. Continuous positive airway pressure and a positional pillow were prescribed to 57 (91%) and 6 (9%) patients with OSA. Although plasma NT-proBNP levels were lower after 7â¯months compared to the baseline, the levels did not differ significantly between the SGMT and standard therapy groups at baseline (579⯱â¯1117 vs. 611⯱â¯899â¯pg/dL, pâ¯=â¯.851) or at 7â¯months (90⯱â¯167 vs. 93⯱â¯174â¯pg/dL, pâ¯=â¯.996). The changes in NT-proBNP levels from baseline to 7â¯months were similar with SGMT and standard therapy (-489 vs. -518â¯pg/dL, pâ¯=â¯.726). Similar findings were observed for the plasma ST2 and hs-CRP levels. CONCLUSIONS: OSA screening and multifaceted treatment during the sub-acute phase of acute coronary syndrome did not further reduce the levels of cardiovascular biomarkers when compared with standard therapy. CLINICAL TRIAL REGISTRATION: clinicaltrial.gov NCT02599298.
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Síndrome Coronariana Aguda/complicações , Proteína C-Reativa/análise , Terapia Cognitivo-Comportamental/métodos , Pressão Positiva Contínua nas Vias Aéreas/métodos , Peptídeo Natriurético Encefálico/sangue , Fragmentos de Peptídeos/sangue , Polissonografia/métodos , Apneia Obstrutiva do Sono , Síndrome Coronariana Aguda/terapia , Assistência ao Convalescente/métodos , Biomarcadores/sangue , Terapia Combinada/métodos , Feminino , Humanos , Masculino , Programas de Rastreamento/métodos , Pessoa de Meia-Idade , Apneia Obstrutiva do Sono/sangue , Apneia Obstrutiva do Sono/etiologia , Apneia Obstrutiva do Sono/psicologia , Apneia Obstrutiva do Sono/terapia , Resultado do TratamentoRESUMO
AIMS: The performance of N-terminal pro-B-type natriuretic peptide (NT-proBNP) in diagnosing acute decompensated heart failure (ADHF) among patients presenting with breathlessness is markedly impaired in the presence of atrial fibrillation (AF). We evaluated the diagnostic performance of mid-regional pro-adrenomedullin (MR-proADM) and cardiac troponin T as possible alternative markers for discrimination of ADHF in this setting. METHODS AND RESULTS: Breathless patients (n = 1107) were prospectively and contemporaneously recruited in emergency departments in Singapore and New Zealand. The diagnoses of ADHF and presence of AF were adjudicated by two clinician specialists, blinded to MR-proADM, NT-proBNP and high-sensitivity cardiac troponin T (hs-cTnT) results. MR-proADM exhibited strong discrimination of ADHF with little change in performance irrespective of the presence of AF (area under the curve 0.83 in non-AF vs. 0.76 in AF) compared to NT-proBNP (0.91 vs. 0.71) and hs-cTnT (0.83 vs. 0.62), respectively. The accuracy of MR-proADM (73.3%) for diagnosing ADHF among patients with AF was superior to both NT-proBNP (61.6%) and hs-cTnT (64.6%). The superior performance of MR-proADM remained apparent when data from Singapore and New Zealand were analysed separately. CONCLUSION: In the presence of AF, MR-proADM showed greater discrimination and accuracy, and less impairment in performance compared to that in non-AF cases, for the diagnosis of ADHF, compared to the guideline-endorsed NT-proBNP.
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Fibrilação Atrial , Adrenomedulina , Fibrilação Atrial/complicações , Fibrilação Atrial/diagnóstico , Fibrilação Atrial/epidemiologia , Biomarcadores , Insuficiência Cardíaca/complicações , Insuficiência Cardíaca/diagnóstico , Insuficiência Cardíaca/epidemiologia , Humanos , Peptídeo Natriurético Encefálico , Nova Zelândia , Fragmentos de Peptídeos , Precursores de Proteínas , Singapura/epidemiologiaRESUMO
Obstructive sleep apnea (OSA) is an emerging risk marker for acute coronary syndrome (ACS). This randomized trial aims to determine the effects of sleep study-guided multidisciplinary therapy (SGMT) comprising overnight sleep study, continuous positive airway pressure, and behavioral therapy for OSA during the subacute phase of ACS. We hypothesize that SGMT will reduce (1) the plasma levels of N-terminal pro brain natriuretic peptide and suppression of tumorigenicity 2; (2) the estimated 10-year risk of cardiovascular mortality as measured by the European Systematic Coronary Risk Evaluation (SCORE) algorithm; and (3) the cardiovascular event rate during a 3-year follow-up, compared with standard therapy. In the SGMT trial, 180 patients presenting with ACS will be randomly assigned to SGMT (n = 90) and standard therapy (n = 90) groups. Both groups will receive guideline-mandated treatment for ACS. Those assigned to SGMT will additionally undergo a sleep study and, if OSA is diagnosed, attend a multidisciplinary OSA clinic where they will receive personalized treatment including continuous positive airway pressure and behavioral/lifestyle counseling. The primary endpoint is the plasma N-terminal pro brain natriuretic peptide concentration at 7-month follow-up. This report presents the baseline characteristics of 117 patients (SGMT group: n =54; standard therapy group: n =63) who had been enrolled into the study as of August 31, 2017. The results of this trial will help us to understand whether active OSA diagnosis and treatment will improve the physiologic and clinical cardiovascular outcomes of this group of patients.
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Síndrome Coronariana Aguda/terapia , Terapia Comportamental , Pressão Positiva Contínua nas Vias Aéreas , Apneia Obstrutiva do Sono/terapia , Sono , Síndrome Coronariana Aguda/diagnóstico , Síndrome Coronariana Aguda/mortalidade , Síndrome Coronariana Aguda/fisiopatologia , Biomarcadores/sangue , Protocolos Clínicos , Terapia Combinada , Pressão Positiva Contínua nas Vias Aéreas/efeitos adversos , Pressão Positiva Contínua nas Vias Aéreas/mortalidade , Feminino , Humanos , Proteína 1 Semelhante a Receptor de Interleucina-1/sangue , Masculino , Pessoa de Meia-Idade , Peptídeo Natriurético Encefálico/sangue , Equipe de Assistência ao Paciente , Fragmentos de Peptídeos/sangue , Projetos de Pesquisa , Fatores de Risco , Singapura , Apneia Obstrutiva do Sono/diagnóstico , Apneia Obstrutiva do Sono/mortalidade , Apneia Obstrutiva do Sono/fisiopatologia , Fatores de Tempo , Resultado do TratamentoRESUMO
AIMS: This study was conducted to test the diagnostic performance of NT-proBNP for discrimination of acute decompensated heart failure (ADHF) among breathless patients presenting in an Asian compared with a Western centre. METHODS AND RESULTS: Patients with breathlessness were prospectively and contemporaneously recruited in Emergency Departments in Singapore and New Zealand (NZ). The diagnosis of ADHF was adjudicated by two clinician specialists. A total of 606 patients were recruited in Singapore and 500 in NZ. The discriminative power of NT-proBNP for ADHF was superior in Singapore compared with NZ [area under the curve (AUC) 0.926 vs. 0.866; P = 0.012] both overall and among selected subgroups stratified according to age, renal function, body mass index, and presence or absence of AF or diabetes. Previously established cut-off point values of plasma NT-proBNP yielded comparable sensitivity and negative predictive values, but superior specificity and accuracy in Singapore compared with NZ. The difference in test performance was driven by the younger age (median age 56 years vs. 73 years; P < 0.001), associated with better renal function (estimated glomerular filtration rate 89 vs. 62 mL/min/1.73 m2 ; P < 0.001), and lower prevalence of AF (9.7% vs. 25.7%; P < 0.001) in acutely breathless patients in Singapore. CONCLUSION: Considering emerging evidence of a lower average age of presentation with ADHF over most of Asia compared with Western countries, NT-proBNP is likely to be more accurate when applied in Asian centres than in the West.