Anti-Xa Monitoring of Apixaban (ZyQuis) in Venous Thrombo-Embolism and Atrial Fibrillation.

Apixaban is a direct oral Xa inhibitor and is indicated for the treatment of venous thrombo-embolism (VTE) and prevention of stroke in atrial fibrillation (AF). Recently, a generic (ZyQuis, Zydus Lifesciences Limited, India) has received Food and Drug Administration approval. While bioequivalence has been demonstrated with Eliquis (Bristol-Myers Squibb/Pfizer, UK), it is necessary to monitor its effectiveness prior to acceptance in medical practice. This prospective study independently evaluated Apixaban (ZyQuis) at two accredited laboratories. Participants were converted from Warfarin or Rivaroxaban to Apixaban 5 mg bd for a duration of one month. Peak anti-Xa levels were measured 3-4 h post the morning dose. The samples were processed on the Atellica COAG 360 (Siemens Healthineers, Marburg, Germany) analyzers with a chromogenic anti-Xa assay (Innovance, reference interval 69-321 ng/mL). There were 26 participants; 5 men, 21 women; mean ± standard deviation age of 46 ± 12 years. Indications for anticoagulation included: VTE (88.5%) and AF (11.5%). 69.2% of the participants had at least one comorbidity. 96.2% of the anti-Xa levels were within the laboratory's 95% reference interval. Mean anti-Xa activity was 191 ± 69 ng/mL and 186 ± 68 ng/mL measured at respective laboratories. Mean differences in anti-Xa measurements represented by Bland-Altman statistics were small (bias of -2.6%, 95% confidence interval -1.11 to -4.09) and a strong correlation was observed on Deming regression analysis (0.995). Apixaban (ZyQuis) was effective for the management of VTE and AF as evidenced by anti-Xa activity.

Association of C-reactive protein level with adverse outcomes in patients with atrial fibrillation: A meta-analysis.

BACKGROUND: Studies on the association between C-reactive protein (CRP) level and poor outcomes have been yielded controversial results in patients with atrial fibrillation (AF). This meta-analysis sought to investigate the utility of elevated CRP level in predicting adverse outcomes in AF patients. METHODS: Two authors systematically searched PubMed and Embase databases (until December 10, 2022) for studies evaluating the value of elevated CRP level in predicting all-cause mortality, cardiovascular death, stroke, or major adverse cardiovascular events (MACEs) in AF patients. The predictive value of CRP was expressed by pooling adjusted hazard ratio (HR) with 95% confidence intervals (CI) for the highest versus the lowest level or per unit of log-transformed increase. RESULTS: Ten studies including 30,345 AF patients satisfied our inclusion criteria. For the highest versus the lowest CRP level, the pooled adjusted HR was 1.57 (95% CI 1.34-1.85) for all-cause mortality, 1.18 (95% CI 0.92-1.50) for cardiovascular death, and 1.57 (95% CI 1.10-2.24) for stroke, respectively. When analyzed the CRP level as continuous data, per unit of log-transformed increase was associated with a 27% higher risk of all-cause mortality (HR 1.27; 95% CI 1.23-1.32) and 16% higher risk of MACEs (HR 1.16; 95% CI 1.05-1.28). CONCLUSIONS: Elevated CRP level may be an independent predictor of all-cause mortality, stroke, and MACEs in patients with AF. CRP level at baseline can provide important prognostic information in risk classification of AF patients.

Association of proprotein convertase subtilisin/kexin type 9 (PCSK9) levels with abnormally high ankle-brachial index in atrial fibrillation.

BACKGROUND: High ankle-brachial index (ABI) has been associated with increased risk of worse outcomes in the general population. Few data on atrial fibrillation (AF) exist. Experimental data suggest that proprotein convertase subtilisin/kexin type 9 (PCSK9) contributes to vascular calcification but clinical data on this association are lacking. AIMS: We wanted to investigate the relationship between circulating PCSK9 levels and an abnormally high ABI in patients suffering from AF. METHODS: We analyzed data from 579 patients included in the prospective ATHERO-AF study. An ABI≥1.4 was considered high. PCSK9 levels were measured coincidentally with ABI measurement. We used optimized cut-offs of PCSK9 for both ABI and mortality obtained from Receiver Operator Characteristic (ROC) curve analysis. All-cause mortality according to the ABI value was also analyzed. RESULTS: One hundred and fifteen patients (19.9%) had an ABI ≥1.4. The mean (standard deviation [SD]) age was 72.1 (7.6) years, and 42.1% of patients were women. Patients with ABI ≥1.4 were older, more frequently male, and diabetic. Multivariable logistic regression analysis showed an association between ABI ≥1.4 and serum levels of PCSK9 > 1150 pg/ml (odds ratio [OR], 1.649; 95% confidence interval [CI], 1.047-2.598; P = 0.031). During a median follow-up of 41 months, 113 deaths occurred. In multivariable Cox regression analysis, an ABI ≥1.4 (hazard ratio [HR], 1.626; 95% CI, 1.024-2.582; P = 0.039), CHA2DS2-VASc score (HR, 1.249; 95% CI, 1.088-1.434; P = 0.002), antiplatelet drug use (HR, 1.775; 95% CI, 1.153-2.733; P = 0.009), and PCSK9 > 2060 pg/ml (HR, 2.200; 95% CI, 1.437-3.369; P < 0.001) were associated with all-cause death. CONCLUSIONS: In AF patients, PCSK9 levels relate to an abnormally high ABI ≥1.4. Our data suggest PCSK9 role in contributing to vascular calcification in AF patients.

Relaxin-2 plasma levels in atrial fibrillation are linked to inflammation and oxidative stress markers.

Relaxin-2 exerts many favourable cardiovascular effects in pathological circumstances such as atrial fibrillation (AF) and heart failure, but the mechanisms underlying its actions are not completely understood. Since inflammation and fibrosis are pivotal processes in the pathogenesis of AF, our aim was to study the relationship between relaxin-2 plasma levels in left atrium (LA) and peripheral vein with molecules implicated in fibrosis, inflammation and oxidative stress in AF patients, and to evaluate the anti-fibrotic ability of relaxin-2 in normal human atrial cardiac fibroblasts (NHCF-A). Peripheral vein relaxin-2 plasma levels were higher than LA relaxin-2 plasma levels in men while, in women, peripheral vein relaxin-2 levels were increased compared to men. AF patients with higher levels of relaxin-2 exhibited a reduction in H2O2 plasma levels and in mRNA levels of alpha-defensin 3 (DEFA3) and IL-6 in leucocytes from LA plasma. Relaxin-2-in-vitro treatment inhibited NHCF-A migration and decreased mRNA and protein levels of the pro-fibrotic molecule transforming growth factor-ß1 (TGF-ß1). Our results support an association between relaxin-2 and molecules involved in fibrosis, inflammation and oxidative stress in AF patients, and reinforce an anti-fibrotic protective role of this hormone in NHCF-A; strengthening the relevance of relaxin-2 in AF physiopathology, diagnosis and treatment.

Galectin-3 is an independent predictor of postoperative atrial fibrillation and survival after elective cardiac surgery.

BACKGROUND: Postoperative atrial fibrillation (POAF) is a frequent complication after heart surgery and is associated with thromboembolic events, prolonged hospital stay, and adverse outcomes. Inflammation and fibrosis are involved in the pathogenesis of atrial fibrillation. OBJECTIVE: The purpose of this study was to assess whether galectin-3, which reflects preexisting atrial fibrosis, has the potential to predict POAF and mortality after cardiac surgery. METHODS: Four hundred seventy-five consecutive patients (mean age 67.4 ± 11.8 years; 336 (70.7%) male) undergoing elective heart surgery at the Medical University of Vienna were included in this prospective single-center cohort study. Galectin-3 plasma levels were assessed on the day before surgery. RESULTS: The 200 patients (42.1%) who developed POAF had significantly higher galectin-3 levels (9.60 ± 6.83 ng/mL vs 7.10 ± 3.54 ng/mL; P < .001). Galectin-3 significantly predicted POAF in multivariable logistic regression analysis (adjusted odds ratio per 1-SD increase 1.44; 95% confidence interval 1.15-1.81; P = .002). During a median follow-up of 4.3 years (interquartile range 3.4-5.4 years), 72 patients (15.2%) died. Galectin-3 predicted all-cause mortality in multivariable Cox regression analysis (adjusted hazard ratio per 1-SD increase 1.56; 95% confidence interval 1.16-2.09; P = .003). Patients with the highest-risk galectin-3 levels according to classification and regression tree analysis (>11.70 ng/mL) had a 3.3-fold higher risk of developing POAF and a 4.4-fold higher risk of dying than did patients with the lowest-risk levels (≤5.82 ng/mL). CONCLUSION: The profibrotic biomarker galectin-3 is an independent predictor of POAF and mortality after cardiac surgery. This finding highlights the role of the underlying arrhythmogenic substrate in the genesis of POAF. Galectin-3 may help to identify patients at risk of POAF and adverse outcome after cardiac surgery.

Plasma lipoprotein-associated phospholipase A2 is associated with acute ischemic stroke in patients with atrial fibrillation.

OBJECTIVE: To investigate the association between lipoprotein-associated phospholipase A2 (Lp-PLA2) concentration and the incidence of acute ischemic stroke (AIS) in patients with atrial fibrillation (AF). METHODS: A total of 257 patients admitted to the Kaifeng Central Hospital were enrolled in this study. Receiver operating characteristic (ROC) curve analysis and multivariate logistic regression analysis were used to determine the association between Lp-PLA2 and AIS in patients with AF. RESULTS: In AF group, plasma Lp-PLA2 concentrations were significantly higher in patients with AIS than in those without it (277.4 vs 155.1, p < 0.001). And in the group of AIS patients, patients with AF also had a significantly higher level of Lp-PLA2 concentration than those without (277.4 vs 204.2, p < 0.001). The analysis of the ROC curve showed a significant diagnostic value of Lp-PLA2 for the incidence of AIS in patients with AF (AUC = 0.840, 95% CI: 0.737-0.871, p < 0.001), and the optimal cut-off point was 220.5 ng/ml, with a sensitivity and specificity of 82.14% and 75.5%, respectively. All AF patients were divided into two subgroups: the high Lp-PLA2 group (≥220.5 ng/ml) and the low Lp-PLA2 group (<220.5 ng/ml). And multivariate logistic regression analysis showed that after adjustment of confounders, Lp-PLA2 (OR 12.48, 95%CI 5.73-27.16, p < 0.001) was independently associated with the incidence of AIS in patients with AF. CONCLUSIONS: Plasma Lp-PLA2 concentration was independently associated with the development of AIS in patients with AF. Lp-PLA2 is a potential biomarker for stratification of risk for AIS in patients with AF.

Plasma growth differentiation factor-15 in patients with "lone" atrial fibrillation.

BACKGROUND: Growth differentiation factor-15 (GDF-15) is a member of the transforming growth factor ß superfamily, correlated with various stimuli, including cardiovascular disease. The association between plasma GDF-15 level and "lone" AF, that is, AF of unknown etiology (UeAF), is uncertain. METHODS: All patients aged 60 years or younger. AF patients were hospitalized for primary catheter ablation. Patients with sinus rhythm admitted for other diseases during the same period were included in the control group. ELISA was used to measure plasma GDF-15 concentrations. RESULTS: 60 UeAF patients, 60 paroxysmal AF (PAF) patients, and 70 control patients were enrolled. The mean age was 44.6 years. In the UeAF group, no patients had traditional clinical risk factors. The plasma GDF-15 level in the UeAF group was (1028.5 ± 180.5) pg/ml, higher than in the control group, and moderately lower than in the PAF group. In all patients, positive correlations were found between plasma GDF-15 level and age (R = 0.210, p < 0.05), and between plasma GDF-15 level and left atrial diameter (LAD; R = 0.338, p < 0.05; in the UeAF group: R = 0.475, p < 0.05; in the PAF group: R = 0.504, p < 0.05). CONCLUSIONS: Our study first investigated the role of GDF-15 in UeAF. The plasma GDF-15 level in UeAF patients was higher than in sinus rhythm patients and lower than in PAF patients. Moreover, GDF-15 was positively correlated with age and LAD. The role of GDF-15 in UeAF needs further study.

Influence of hemoglobin concentration on the in-hospital outcomes in newly diagnosed heart failure patients with atrial fibrillation: Finding from CCC-AF (improving care for cardiovascular disease in China-atrial fibrillation) project.

ABSTRACT: Atrial fibrillation (AF) and heart failure (HF) coexistence is common of clinical significance. Although anemia is a well-recognized risk factor for adverse outcomes, the prognostic value of hemoglobin is controversial in AF and HF. We aimed to determine whether hemoglobin is associated with in-hospital outcomes in such patients.On the basis of the data from the CCC-AF (Improving Care for Cardiovascular Diseases in China-Atrial Fibrillation) project, 2367 inpatients with a definitive diagnosis of AF and HF and record of admission hemoglobin concentration were included. Logistic regression analysis was performed to investigate the relationship between hemoglobin and in-hospital outcomes.All patients were divided into 4 groups according to quartiles of hemoglobin values. Compared with patients with higher hemoglobin, patients with lower hemoglobin had higher proportion of males, heart rate (HR), and diastolic blood pressure (DBP). On the contrary, they had lower age, medical history, left ventricular ejection fraction (LVEF), and brain natriuretic peptide (P < .05). Spearman correlation showed that hemoglobin was negatively correlated with age, LVEF, international normalized ratio, and serum creatinine but positively correlated with HR, DBP, and blood urea nitrogen (P < .05). Multivariable logistic regression analysis revealed that increasing hemoglobin was an independent protective factor for in-hospital outcomes (odds ratio = 0.989; 95% confidence interval: 0.979-1.000; P = .046).Admission hemoglobin concentration was an independent protective factor for in-hospital outcomes in HF patients with AF. Our study indicated that increasing hemoglobin level and improving anemia degree might improve the prognosis of patients with AF and HF.

Biomarkers associated with rhythm status after cardioversion in patients with atrial fibrillation.

Biomarkers may help to improve our knowledge about the complex pathophysiology of atrial fibrillation (AF). In this study we sought to identify significant changes in biomarkers and clinical measures in patients with and without AF recurrence after electrical cardioversion. We measured 21 conventional and new biomarkers before and 30 days after electrical cardioversion and assessed the associations of changes in biomarker levels with rhythm status at follow-up. Significant between-group changes were observed for bone morphogenetic protein 10 (BMP10), N-terminal pro-B-type natriuretic peptide (NT-proBNP) and total bilirubin. Their respective changes were - 10.4%, - 62.0% and - 25.6% in patients with sinus rhythm, and 3.1%, 1.1% and - 9.4% in patients with recurrent AF, for a between-group difference of - 13.5% (95% confidence interval [CI] - 19.3% to - 7.6%; P < 0.001), - 63.1% (95% CI - 76.6% to - 49.6%; P < 0.001) and - 16.3% (95% CI - 27.9% to - 4.7%; P = 0.007). In multivariable models, the reductions of BMP10 and NT-proBNP were significantly associated with follow-up rhythm status (ß coefficient per 1 - SD decrease, - 3.85; 95% CI - 6.34 to - 1.35; P = 0.003 for BMP10 and - 5.84; 95% CI - 10.22 to - 1.47; P = 0.009 for NT-proBNP. In conclusion, changes in BMP10 und NT-proBNP levels were independently associated with rhythm status after cardioversion, suggesting that these markers may be dependent on the actual heart rhythm.

Serum Uric Acid Levels in Relation to Atrial Fibrillation: A Case-Control Study.

BACKGROUND Although serum uric acid (SUA) levels have been reported to be associated with atrial fibrillation (AF), the specific associations remain unclear. The purpose of this study was to investigate the potential relationship of serum uric acid levels to atrial fibrillation. MATERIAL AND METHODS We retrospectively analyzed clinical data of 970 consecutive hospitalized patients (M/F, 519/451; age, 64.78±13.49 years). The study included 478 patients with AF, and 492 age-matched patients with sinus rhythm and no history of arrhythmia as a control group. The t test, ANOVA, chi-squared test, or Fisher exact test were performed to analyze clinical baseline data. RESULTS Compared with the control group, patients with AF exhibited higher SUA levels (5.66±1.90 vs 5.35±1.55 mg/dL, P=0.006), especially women (P<0.001). Pearson correlation analysis showed SUA was influenced by A/G, PAB, and APOA1 in patients with AF. Logistic regression analysis showed SUA was associated with AF (total: OR=1.002, 95% CI: 1.000-1.003; women: OR=1.005, 95% CI: 1.003-1.007). After adjustment for clinical related factors for AF, SUA was still associated with AF (total: OR=1.004, 95% CI: 1.002-1.006; women: OR=1.005, 95% CI: 1.002-1.009). Also, elevated SUA was positively correlated with A/G and PAB and negatively correlated with APOA1. There were no significant differences in SUA levels in AF subtypes and complications. CONCLUSIONS Elevated SUA levels were associated with AF, but the independent association was significant only in women. Elevated SUA may promote other AF-related factors and participate in the pathological process of AF.

Correlation analysis between heart rate variability, epicardial fat thickness, visfatin and AF recurrence post radiofrequency ablation.

BACKGROUND: The aim of the present study is to investigate the possible correlation between heart rate variability (HRV), epicardial fat thickness (EFT), visfatin and AF recurrence post radiofrequency ablation. METHODS: Data of 337 AF patients to whom radiofrequency ablation therapy had been initiated at our hospital over the past three years were evaluated. The patients enrolled were divided into the non-recurrence group (102 patients) and the recurrence group (235 patients) according to AF recurrence in the preceding 12 months. General data in the two groups were collected and HRV, EFT, and visfatin levels were comprehensively compared for each patients of the two groups. RESULTS: The recurrence group showed significantly higher results in rMSSD, PNN50, HF, total EFT, and visfatin but with evidently lower results in LF/HF when comparing the non-recurrence group (P < 0.05). The significantly different general variables in the general data and laboratory parameters, rMSSD, PNN50, HF, total EFT, visfatin, LF/HF were used as independent variables, and AF recurrence post radiofrequency ablation was used as dependent variables. Logistic regression analysis revealed that the risk factors of AF recurrence post radiofrequency ablation were rMSSD, PNN50, HF, total EFT, visfatin, and LF/HF, and the difference was statistically significant (P < 0.05). CONCLUSION: HRV, EFT, visfatin appear to show high association with AF recurrence post radiofrequency ablation.

Therapeutic implications of galectin-3 in patients with atrial fibrillation.

Atrial fibrosis can present as an arrhythmogenic substrate that is correlated with higher recurrence after catheter ablation for atrial fibrillation. Galectin-3, a beta-galactoside-binding lectin, is highly expressed and secreted from macrophages and is important in inflammation and fibrosis. We assessed the clinical implications of serum galectin-3 in patients with atrial fibrillation. This was a prospective cohort study of consecutive patients who underwent radiofrequency catheter ablation in a tertiary referral center from February 2017 to September 2017. Intracardiac blood sampling, echocardiographic measurements, magnetic resonance imaging with late gadolinium enhancement, electrophysiologic testing, and endocardial voltage mapping were consistently implemented in 75 patients before the ablation. Serum galectin-3 level was higher in patients with diabetes mellitus and was correlated with values that indicated the left atrial size. During a median 14 months of follow-up, atrial tachyarrhythmia recurred in 27% of patients. In multivariable Cox regression analysis, non-paroxysmal atrial fibrillation (hazard ratio 6.8; 95% confidence interval 1.6-28.9) and higher galectin-3 levels (hazard ratio 1.3; 95% confidence interval 1.0-1.7) were associated with increased risk of recurrence. Serum galectin-3 may be a prognostic biomarker for risk stratification in patients with atrial fibrillation planned catheter ablation.

Assessment of Serum IgG Titers to Various Periodontal Pathogens Associated with Atrial Fibrillation in Acute Stroke Patients.

OBJECTIVES: There is accumulating evidence that periodontal disease is associated with atrial fibrillation (AF) or stroke, but it is unclear which causative species of periodontal disease are present in stroke patients with AF. We aimed to investigate the associations between AF and specific periodontal pathogens using serum titers of IgG antibodies of bacteria in acute stroke patients. MATERIALS AND METHODS: Acute stroke patients were registered at two hospitals. Serum samples were evaluated for titers of antibodies against 9 periodontal pathogens (16 genotypes) using ELISAs. We identified AF in patients according to the following criteria: (1) a history of sustained or paroxysmal AF or (2) AF detection upon arrival or during admission. We carried out propensity score matching to categorize the patients as those with AF and those without. RESULTS: Of the 664 acute stroke patients, 123 (18.5%) had AF. After propensity score matching, 234 patients were selected. Patients with AF had a higher prevalence of positive serum titers of antibodies against Porphyromonas gingivalis (FimA type III) and Porphyromonas gingivalis (FimA type V) than those without AF (59.0% vs. 39.3%, p=0.004 and 58.2% vs. 40.2%, p=0.009, respectively). CONCLUSIONS: Porphyromonas gingivalis, especially FimA type III and type V, might be associated with AF in stroke patients.

The plasma galectin-3 level has high specificity and sensitivity for predicting postoperative atrial fibrillation after coronary artery bypass surgery.

OBJECTIVE: Postoperative new-onset atrial fibrillation (POAF) commonly occurs after coronary artery bypass graft (CABG) surgery. This study aimed to determine the utility of the preoperative netrin-1 and galectin-3 levels for predicting POAF following CABG surgery, as well as that of postoperative serial measurement for assessing these markers' patterns of expression. PATIENTS AND METHODS: This prospective cohort study included 50 patients that underwent CABG surgery. The plasma netrin-1 and galectin-3 levels were measured via enzyme-linked immunosorbent assay (ELISA) before surgery (baseline) and at 6, 12, and 24 h after surgery. The patients were divided into two groups according to the occurrence of POAF; the POAF (+) group and the POAF (-) group. RESULTS: In total, 26 patients developed POAF, whereas 24 remained in sinus rhythm. Baseline galectin-3 levels were higher in the POAF (+) group than in the POAF (-) group (30.7 ± 10.1 pg mL-1 and 15.7 ± 3.6 pg mL-1, respectively). The post-CABG surgery galectin-3 level increased in both the POAF (+) and POAF (-) groups at 6 h (46.2 ± 26.3 pg mL-1 and 24.9 ± 5.9 pg mL-1, respectively), 12 h (45.2 ± 24.1 pg mL-1 and 26.6 ± 9.3 pg mL-1, respectively), and 24 h (54.2 ± 33.5 pg mL-1and 28.6 ± 7.7 pg mL-1, respectively). The plasma netrin-1 level did not differ between groups at baseline or at 6, 12, and 24 h post CABG surgery. CONCLUSIONS: Whereas netrin-1 does not appear to have any utility as a marker for the development of POAF in CABG surgery patients, the plasma galectin-3 level has high specificity and sensitivity for predicting POAF following CABG surgery and could be considered a marker for predicting POAF.

Biomarkers for Predicting the Occurrence and Progression of Atrial Fibrillation: Soluble Suppression of Tumorigenicity 2 Protein and Tissue Inhibitor of Matrix Metalloproteinase-1.

Background: Soluble suppression of tumorigenicity 2 protein (sST2) and tissue inhibitor of matrix metalloproteinase (TIMP)-1 are involved in multiple pathogenic pathways, including cardiac remodeling, which is the main pathology of atrial fibrillation (AF). This study aims to investigate the previously unexplored relationship between the serum levels of sST2, TIMP-1, and AF. Methods: This was a prospective cross-sectional study conducted at the Capital Medical University Affiliated Beijing Anzhen Hospital between June 2019 and July 2020, with a total of 359 participants. The clinical characteristics and laboratory results of the patients were compared, and multivariable ordinal logistic regression was used to evaluate the relationship between serum sST2, TIMP-1, and AF. Results: The participants included 110 patients with sinus rhythm (SR), 113 with paroxysmal AF (the paroxysmal AF group), and 136 with persistent AF (the persistent AF group). It was found that the sST2 levels gradually increased in these three groups, from 9.1 (6.7-12.4 pg/ml) in the SR group to 14.0 (10.4-20.8 pg/ml) in the paroxysmal AF group and to 19.0 (13.1-27.8) pg/ml) in the persistent AF group (p < 0.001). The multivariable ordinal logistic regression model for sST2 and TIMP-1 demonstrated that sST2 had an area under the receiver operating characteristic (ROC) curve (AUC) of 0.797 (95% confidence interval (CI) 0.749-0.846, p < 0.001) and TIMP-1 had an AUC of 0.795 (95% CI 0.750-0.841, p=0.000). The multivariable ordinal logistic regression model for sST2 and TIMP-1 showed good discrimination between SR and AF, with an AUC of 0.846, and the addition of clinical factors, such as brain natriuretic peptide (BNP), left atrial diameter, age, and gender, to the biomarker model improved the detection of SR and AF (AUC 0.901). Conclusions: In this cohort study, sST2 and TIMP-1 were associated with AF progression, independent of clinical characteristics and biomarkers. Soluble ST2 and TIMP-1 combined with age, elevated N-terminal-pro hormone BNP(NT-BNP), and an enlarged left atrium were able to demonstrate the progression of AF reliably.

Genetically Predicted Cardiac Troponin I Concentrations and Risk of Stroke and Atrial Fibrillation.

OBJECTIVES: Observational studies have shown that elevated circulating cardiac troponin I (cTnI) concentrations were linked to higher risk of stroke and atrial fibrillation, but the causality remains unclear. Therefore, we used mendelian randomization to assess the potential causal effects of cTnI concentrations on the risk of stroke, its subtypes and atrial fibrillation. MATERIALS AND METHODS: The instrumental variables for circulating cTnI concentrations were selected from a genome-wide association study meta-analysis of 48,115 European individuals. We examined the associations of circulating cTnI concentrations with stroke, ischemic stroke, ischemic stroke subtypes (cardioembolic, large artery, small vessel stroke), intracerebral hemorrhage and atrial fibrillation. RESULTS: Genetically predicted elevated circulating cTnI concentrations were associated with higher risk of cardioembolic stroke (odds ratio [OR], 1.80; 95% confidence interval [CI], 1.20-2.68; P = 0.004), but not associated with large artery stroke, small vessel stroke, total stroke, ischemic stroke and intracerebral hemorrhage. Additionally, we also found that elevated cTnI concentrations were causally linked to higher risk of atrial fibrillation (OR, 1.30; 95% CI, 1.10-1.53; P = 0.003). CONCLUSIONS: This study provides evidence that genetically predicted circulating cTnI concentrations are causally linked to higher risk of cardioembolic stroke and atrial fibrillation.

Circulating biomarkers, echocardiographic parameters, and incident subclinical atrial fibrillation in patients with diabetes and hypertension.

BACKGROUND: Long-term rhythm monitoring (LTRM) can detect undiagnosed atrial fibrillation (AF) in patients at high risk of AF and stroke. Biomarkers and echocardiographic parameters could, however, help identify patients benefitting most from LTRM. The aim of this study was to investigate, whether circulating biomarkers of cardiac and vascular function (brain natriuretic peptide (BNP), cardiac troponin I (cTnI), copeptin, and mid-regional proadrenomedullin (MR-proADM)) and echocardiographic parameters were associated with incident subclinical AF (SCAF) in a population at high risk of stroke in the presence of AF. For this purpose, we investigated individuals ≥65 years of age with hypertension and diabetes mellitus, but no history or symptoms of AF or other cardiovascular disease (CVD). METHODS: We included 82 consecutive patients (median age 71.3 years (IQR 67.4-75.1)). All patients received an insertable cardiac monitor (ICM) and were followed for a median of 588 days (IQR 453-712). On the day of ICM implantation, a comprehensive echocardiogram and blood samples were obtained. RESULTS: During a median follow-up of 588 days (IQR: 453-712 days), incident SCAF occurred in 17 patients (20.7%) with a median time to first-detected episode of 91 days (IQR 41-251 days). MR-proADM (median 0.87 nmol/L (IQR 0.76-1.02) vs 0.78 nmol/L (IQR 0.68-0.98)) and copeptin (median 13 pmol/L (IQR 9-17) vs 8 pmol/L (IQR 4-18)) levels were insignificantly higher in patients with incident SCAF. BNP and cTnI concentrations and echocardiographic parameters were similar in the two groups. CONCLUSIONS: MR-proADM, BNP, cTnI, copeptin, and several echocardiographic parameters were not associated with incident SCAF in this cohort of patients with hypertension and diabetes, but without any underlying CVD.

Using a Simple Prescription Gap to Determine Warfarin Discontinuation Can Lead to Substantial Misclassification.

BACKGROUND: Warfarin remains widely used and a key comparator in studies of other direct oral anticoagulants. As longer-than-needed warfarin prescriptions are often provided to allow for dosing adjustments according to international normalized ratios (INRs), the common practice of using a short allowable gap between dispensings to define warfarin discontinuation may lead to substantial misclassification of warfarin exposure. We aimed to quantify such misclassification and determine the optimal algorithm to define warfarin discontinuation. METHODS: We linked Medicare claims data from 2007 to 2014 with a multicenter electronic health records system. The study cohort comprised patients ≥65 years with atrial fibrillation and venous thromboembolism initiating warfarin. We compared results when defining warfarin discontinuation by (1) different gaps (3, 7, 14, 30, and 60 days) between dispensings and (2) having a gap ≤60 days or bridging larger gaps if there was INR ordering at least every 42 days (60_INR). Discontinuation was considered misclassified if there was an INR ≥2 within 7 days after the discontinuation date. RESULTS: Among 3,229 patients, a shorter gap resulted in a shorter mean follow-up time (82, 95, 117, 159, 196, and 259 days for gaps of 3, 7, 14, 30, 60, and 60_INR, respectively; p < 0.001). Incorporating INR (60_INR) can reduce misclassification of warfarin discontinuation from 68 to 4% (p < 0.001). The on-treatment risk estimation of clinical endpoints varied significantly by discontinuation definitions. CONCLUSION: Using a short gap between warfarin dispensings to define discontinuation may lead to substantial misclassification, which can be improved by incorporating intervening INR codes.

Using a low-molecular weight heparin-calibrated anti-factor Xa assay to assess the concentration of apixaban and rivaroxaban.

INTRODUCTION: Direct oral anticoagulant (DOAC)-inhibiting factor Xa (FXa-DOAC) are being increasingly used as prophylaxis of venous thromboembolism and for prevention of stroke in patients with atrial fibrillation. In contrast to vitamin K antagonists, DOACs do not require monitoring in general. However, it is sometimes of value in the acute setting, for instance when considering a reversal agent in uncontrolled bleeding in patients on DOAC. METHODS: We evaluated if a low-molecular weight heparin (LMWH)-calibrated anti-factor Xa assay could be used to estimate FXa-DOAC concentration in the concentration range <100 ng/mL by spiking known concentrations of FXa-DOAC and from those result calculate the FXa-DOAC concentration from the response of the LMWH assay. This procedure was then evaluated by comparing the result with a drug-calibrated chromogenic assay and liquid chromatography tandem mass spectrometry (LC-MS/MS) on clinical plasma samples from patients treated with apixaban or rivaroxaban. RESULTS: Although the measuring range was narrower for the LMWH-calibrated assay, concentrations recalculated from the LMWH assay was comparable with those measured by the drug-calibrated method when compared with LC-MS/MS. CONCLUSION: We suggest that an LMWH-calibrated anti-factor Xa assay can be used after characterization of the response of FXa-DOACs to give guidance on the concentration of apixaban and rivaroxaban. Shorter turnaround time than LC-MS/MS and the greater availability than drug-calibrated chromogenic assays could make this a valuable option in the acute setting.

Proteomics and Risk of Atrial Fibrillation in Older Adults (From the Atherosclerosis Risk in Communities [ARIC] Study).

Plasma proteomic profiling may aid in the discovery of novel biomarkers upstream of the development of atrial fibrillation (AF). We used data from the Atherosclerosis Risk in Communities study to examine the relation between large-scale proteomics and incident AF in a cohort of older-aged adults in the United States. We quantified 4,877 plasma proteins in Atherosclerosis Risk in Communities participants at visit 5 (2011-2013) using an aptamer-based proteomic profiling platform. We used Cox proportional hazards models to assess the association between protein levels and incident AF, and explored relation of selected protein biomarkers using annotated pathway analysis. Our study included 4,668 AF-free participants (mean age 75 ± 5 years; 59% female; 20% Black race) with proteomic measures. A total of 585 participants developed AF over a mean follow-up of 5.7 ± 1.7 years. After adjustment for clinical factors associated with AF, N-terminal pro-B-type natriuretic peptide (NT-proBNP) was associated with the risk of incident AF (hazard ratio, 1.82; 95% CI, 1.68 to 1.98; p, 2.91 × 10-45 per doubling of NT-proBNP). In addition, 36 other proteins were also significantly associated with incident AF after Bonferroni correction. We further adjusted for medication use and estimated glomerular filtration rate and found 17 proteins, including angiopoietin-2 and transgelin, that remained significantly associated with incident AF. Pathway analyses implicated the inhibition of matrix metalloproteases as the top canonical pathway in AF pathogenesis. In conclusion, using a large-scale proteomic platform, we identified both novel and established proteins associated with incident AF and explored mechanistic pathways of AF development.