How well does physician risk assessment predict stroke and bleeding in atrial fibrillation? Results from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF)

GRADE concept paper 8: judging the certainty of discrimination performance estimates of prognostic models in a body of validation studies

BACKGROUND

Prognostic models incorporate multiple prognostic factors to estimate the likelihood of future events for individual patients based on their prognostic factor values. Evaluating these models crucially involves conducting studies to assess their predictive performance, like discrimination. Systematic reviews and meta-analyses of these validation studies play an essential role in selecting models for clinical practice.

METHODS

In this paper, we outline 3 thresholds to determine the target for certainty rating in the discrimination of prognostic models, as observed across a body of validation studies.

RESULTS AND CONCLUSION

We propose 3 thresholds when rating the certainty of evidence about a prognostic model's discrimination. The first threshold amounts to rating certainty in the model's ability to classify better than random chance. The other 2 approaches involve setting thresholds informed by other mechanisms for classification: clinician intuition or an alternative prognostic model developed for the same disease area and outcome. The choice of threshold will vary based on the context. Instead of relying on arbitrary discrimination cut-offs, our approach positions the observed discrimination within an informed spectrum, potentially aiding decisions about a prognostic model's practical utility.

A real-world study of different doses of rivaroxaban in patients with nonvalvular atrial fibrillation

To explore the anticoagulant effect and safety of utilizing different doses of rivaroxaban for the treatment of patients with atrial fibrillation (AF) in the real world. A retrospective case-control analysis was performed by applying the hospital database, and 3595 patients with non-valvular atrial fibrillation (NVAF) who were hospitalized and taking rivaroxaban at Wuhan Asia Heart Hospital and Wuhan Asia General Hospital from March 2018 to December 2021 were included in the study, and were divided into the rivaroxaban 10 mg and 15 mg groups according to the daily prescribed dose, of which 443 cases were in the 10 mg group and 3152 cases were in the 15 mg group. The patients were followed up regularly, and the incidence of thrombotic events, bleeding events and all-cause deaths were recorded and compared between the 2 groups, and logistic regression was applied to analyze the influencing factors for the occurrence of adverse events. Comparison of the incidence of thrombosis, bleeding and all-cause death between the 2 groups of patients showed that the 10 mg group was higher than the 15 mg group, but the difference was not statistically significant (χ2 = 0.36, 3.26, 1.99, all P > .05); the incidence of total adverse events between the 2 groups of patients was higher in the 10 mg group than in the 15 mg group, with a statistically significant difference (χ2 = 4.53, P = .033); multifactorial logistic regression results showed that age [OR (95% CI) = 1.02 (1.00-1.04)], diabetes mellitus [OR (95% CI) = 1.69 (1.09-2.62)], D-dimer level [OR (95% CI) = 1.06 (1.00-1.11)] and persistent AF [OR (95% CI) = 1.54 (1.03-2.31)] were risk factors for adverse events (P < .05). In the real world, Asian clinicians recommend rivaroxaban 10 mg once daily for NVAF patients for a variety of reasons; however, this dose is not superior or even inferior to the 15 mg group in terms of effectiveness and safety. Advanced age, elevated D-dimer levels, history of diabetes mellitus, and persistent AF are risk factors for adverse events, and the optimal dosage of rivaroxaban or optimal anticoagulation strategy for Asian patients with nonvalvular AF requires further study.

Clinical judgment shows similar and sometimes superior discrimination compared to prognostic clinical prediction models. A systematic review

OBJECTIVES

To systematically review the comparative statistical performance (discrimination and /or calibration) of prognostic clinical prediction models (CPMs) and clinician judgment (CJ).

STUDY DESIGN AND SETTING

We conducted a systematic review of observational studies in PubMed, Medline, Embase, and CINAHL. Eligible studies reported direct statistical comparison between prognostic CPMs and CJ. Risk of bias was assessed using the PROBAST tool.

RESULTS

We identified 41 studies, most with high risk of bias (39 studies). Of these, 41 studies, 39 examined discrimination and 12 studies assessed calibration. Prognostic CPMs had a median AUC of 0.73 (IQR, 0.62 - 0.81), while CJ had a median AUC of 0.71 (IQR, 0.62 - 0.81). 29 studies provided 124 discrimination metrics useful for comparative analysis. Among these, 58 (46.7%) found no significant difference between prognostic CPMs and CJ (p > 0.05); 31 (25%) favored prognostic CPMs, and 35 (28.2%) favored CJ. Four studies compared calibration, showing better performance on prognostic CPMs.

CONCLUSIONS

In many instances CJ frequently demonstrates comparable or superior discrimination compared to prognostic CPMs, although models outperform CJ on calibration. Studies comparing performance of prognostic CPMs and CJ require large improvements in reporting.

Management of Gastrointestinal Bleeding and Resumption of Oral Anticoagulant Therapy in Patients with Atrial Fibrillation: A Multidisciplinary Discussion

Direct oral anticoagulants (DOACs) are recommended for the prevention of thromboembolism in patients with atrial fibrillation (AF), and are now preferred over vitamin K antagonists due to their beneficial efficacy and safety profile. However, all oral anticoagulants carry a risk of gastrointestinal (GI) bleeding. Although the risk is well documented and acute bleeding well codified, there is limited high-quality evidence and no guidelines to guide physicians on the optimal management of anticoagulation after a GI bleeding event. The aim of this review is to provide a multidisciplinary critical discussion of the optimal management of GI bleeding in patients with AF receiving oral anticoagulants to help physicians provide individualized treatment for each patient and optimize outcomes. It is important to perform endoscopy when a patient presents with bleeding manifestations or hemodynamic instability to determine the bleed location and severity of bleeding and then perform initial resuscitation. Administration of all anticoagulants and antiplatelets should be stopped and bleeding allowed to resolve with time; however, anticoagulant reversal should be considered for patients who have life-threatening bleeding or when the bleeding is not controlled by the initial resuscitation. Anticoagulation needs to be timely resumed considering that bleeding risk outweighs thrombotic risk when anticoagulation is resumed early after the bleeding event. To prevent further bleeding, physicians should prescribe anticoagulant therapy with the lowest risk of GI bleeding, avoid medications with GI toxicity, and consider the effect of concomitant medications on potentiating the bleeding risk.

Altered left atrial 4D flow characteristics in patients with paroxysmal atrial fibrillation in the absence of apparent remodeling

The pathophysiology behind thrombus formation in paroxysmal atrial fibrillation (AF) patients is very complex. This can be due to left atrial (LA) flow changes, remodeling, or both. We investigated differences for cardiovascular magnetic resonance (CMR)-derived LA 4D flow and remodeling characteristics between paroxysmal AF patients and patients without cardiac disease. In this proof-of-concept study, the 4D flow data were acquired in 10 patients with paroxysmal AF (age = 61 ± 8 years) and 5 age/gender matched controls (age = 56 ± 1 years) during sinus rhythm. The following LA and LA appendage flow parameters were obtained: flow velocity (mean, peak), stasis defined as the relative volume with velocities < 10 cm/s, and kinetic energy (KE). Furthermore, LA global strain values were derived from b-SSFP cine images using dedicated CMR feature-tracking software. Even in sinus rhythm, LA mean and peak flow velocities over the entire cardiac cycle were significantly lower in paroxysmal AF patients compared to controls [(13.1 ± 2.4 cm/s vs. 16.7 ± 2.1 cm/s, p = 0.01) and (19.3 ± 4.7 cm/s vs. 26.8 ± 5.5 cm/s, p = 0.02), respectively]. Moreover, paroxysmal AF patients expressed more stasis of blood than controls both in the LA (43.2 ± 10.8% vs. 27.8 ± 7.9%, p = 0.01) and in the LA appendage (73.3 ± 5.7% vs. 52.8 ± 16.2%, p = 0.04). With respect to energetics, paroxysmal AF patients demonstrated lower mean and peak KE values (indexed to maximum LA volume) than controls. No significant differences were observed for LA volume, function, and strain parameters between the groups. Global LA flow dynamics in paroxysmal AF patients appear to be impaired including mean/peak flow velocity, stasis fraction, and KE, partly independent of LA remodeling. This pathophysiological flow pattern may be of clinical value to explain the increased incidence of thromboembolic events in paroxysmal AF patients, in the absence of actual AF or LA remodeling.

Mitral annular calcification and its severity predict high risk for cardio-embolic stroke in elderly patients with first diagnosed atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) is the most common arrhythmia worldwide and a large proportion of patients with AF are older than 75 years of age. Mitral annular calcification (MAC), which is usually observed in advanced age, is associated with increased risk of AF and cardio-embolic stroke in the general population.

OBJECTIVES

This study was performed to assess whether presence of MAC and its severity predict cardio-embolic stroke in elderly patients with first diagnosed AF.

METHODS

In this cross-sectional study, 72 elderly patients suffering from acute cardio-embolic stroke with first diagnosed AF and 79 elderly control group patients with first diagnosed AF and without stroke were investigated. A parasternal short-axis view at the level of the mitral annulus was used for MAC measurements. The severity of MAC was measured from the anterior to posterior edge at its greatest width.

RESULTS

MAC thicknesses were significantly higher in the stroke group. ROC curve analysis showed that a cut point of 2.5 mm for the value of MAC thickness exhibited 68.1% sensitivity and 77.2% specificity for detecting cardio-embolic stroke in elderly patients with AF. In multivariate logistic regression analysis, MAC thickness (OR = 1.173, 95% CI 1.083-1.270; p < 0.001) was found to be independent predictor of cardio-embolic stroke in elderly patients with AF.

CONCLUSION

MAC thickness may provide useful information for the relevant risk evaluation of elderly patients with AF. Pre-stroke MAC presence and its severity appear to have better clinical value for predicting cardio-embolic stroke in elderly patients with AF, independent from traditional risk factors for stroke.

The prevalence and predictors of Stroke among atrial fibrillation patients attending at Gondar University Referral Hospital, Northwest Ethiopia

INTRODUCTION

Recently, stroke is becoming the major public health problem in developing countries including Ethiopia. Atrial fibrillation patients are the most vulnerable group for the occurrence of stroke. Knowing the predictors and being aware for it is important for preventing severe complications and death. Therefore, the aim of this study is to assess the prevalence of stroke and identifying significant predictors.

METHODS

A hospital-based cross-sectional study was performed from 1 December 2018 to 30 September 2019 at University of Gondar Referral Hospital. A total of 242 patients with atrial fibrillation were included in the study. Atrial fibrillation patients were diagnosed by using 12 lead electrocardiographic tracing, in addition to thorough medical history and physical examination and analyzed by the Modular ECG Analysis System (MEANS). We used Epi info 7 and SPSS version 22 software for data entry and analysis purpose, respectively. Both bivariable and multivariable binary logistic regression model were computed to show the relationship of dependent and independent variables.

RESULT

The prevalence of stroke among atrial fibrillation patients was 19.4% (95% confidence interval (CI): 14.9-25.2). Patients with heart failure (adjusted odds ratio (AOR): 5.70, 95% CI: 2.50-13.24) and thyroid disorder (AOR: 4.98, 95% CI: 1.47-16.85) are at risk of developing stroke.

CONCLUSION

The prevalence of stroke was higher compared with others studies. Patients with heart failure and thyroid disorders were the risk factor for the development of stroke; therefore, physicians and cardiologists may better to consider all these two disorders when they diagnose stroke in patients with atrial fibrillation.

Accuracy of HAS-BLED and other bleeding risk assessment tools in predicting major bleeding events in atrial fibrillation: A network meta-analysis

BACKGROUND

Preventing thrombosis is an important part of atrial fibrillation (AF) treatment. However, it may increase the risk of bleeding, and bleeding risk assessment tools' predictive value remains unclear. This network meta-analysis investigated the sensitivity and specificity of HAS-BLED, and other bleeding risk assessment tools, to predict major bleeding events in AF patients.

METHODS

The PubMed, EMBASE, and Cochrane Central Register of Controlled Trials databases were searched using keywords, including "AF," "bleeding," and "HAS-BLED," for results published through 30 November 2018. The predictive sensitivity and specificity of each bleeding risk assessment tool was analyzed by network meta-analysis.

RESULTS

Our analysis included 18 studies, recruiting a total of 321 888 people. The bleeding risk assessment tools analyzed in this study included the ABC-bleeding score, ATRIA, European score, GARFIELD-AF, HAS-BLED, HEMORR2HAGES, ORBIT, Shireman, and mOBRI. A comprehensive analysis of sensitivity and specificity, based on an inconsistency model, showed that European score, ABC, and mOBRI have relatively high-sensitivity but low-specificity tools, whereas HAS-BLED and HEMORR2HAGES have balanced sensitivity and specificity. ORBIT, ATRIA, Shireman, and GARFIELD-AF had relatively high specificity but low sensitivity. A consistency model analysis showed similar results.

CONCLUSIONS

HAS-BLED is a balanced bleeding risk assessment tool in terms of sensitivity and specificity, whereas the European score, ABC, and mOBRI are high-sensitivity tools and ORBIT, ATRIA, Shireman, and GARFIELD-AF are high-specificity tools.

Anticoagulation risk assessment for patients with non-valvular atrial fibrillation and venous thromboembolism: A clinical review

Non-valvular atrial fibrillation and venous thromboembolism anticoagulation risk assessment tools have been increasingly utilized to guide implementation and duration of anticoagulant therapy. Anticoagulation significantly reduces stroke and recurrent venous thromboembolism risk, but comes at the cost of increased risk of major and clinically relevant non-major bleeding. The decision for anticoagulation in high-risk patients is complicated by the fact that many risk factors associated with increased thromboembolic risk are simultaneously associated with increased bleeding risk. Traditional risk assessment tools rely heavily on age, sex, and presence of cardiovascular comorbidities, with newer tools additionally taking into account changes in risk factors over time and novel biomarkers to facilitate more personalized risk assessment. These tools may help counsel and inform patients about the risks and benefits of starting or continuing anticoagulant therapy and can identify patients who may benefit from more careful management. Although the ability to predict anticoagulant-associated hemorrhagic risk is modest, ischemic and bleeding risk scores have been shown to add significant value to therapeutic management decisions. Ultimately, further work is needed to optimally implement accurate and actionable risk stratification into clinical practice.

Frequency and Outcomes of Reduced Dose Non-Vitamin K Antagonist Anticoagulants: Results From ORBIT-AF II (The Outcomes Registry for Better Informed Treatment of Atrial Fibrillation II)

Background

Non–vitamin K antagonist oral anticoagulants (NOACs) are indicated for stroke prevention in atrial fibrillation (AF) but require lower doses in certain patients. We sought to describe the frequency, appropriateness (according to Food and Drug Administration labeling), and outcomes of patients prescribed reduced doses of NOACs in community practice.

Methods and Results

We analyzed data from the ORBIT‐AF II (The Outcomes Registry for Better Informed Treatment of Atrial Fibrillation II) registry, a prospective, national, observational registry of AF patients. Among 7925 AF patients receiving NOACs, we assessed patterns of use of reduced NOAC doses and associated cardiovascular and bleeding outcomes at median follow‐up of 1 year. Overall, 6636 patients (84%) received a NOAC at standard dose, which was consistent with US Food and Drug Administration labeling in 6376 (96%). Reduced NOAC dose was prescribed to 1289 (16% overall), which was consistent with Food and Drug Administration labeling in only 555 patients (43%). Compared with those whose NOAC dose was appropriately reduced, patients receiving inappropriate dose reductions were younger (median age 79 versus 84, P<0.0001) and had lower ORBIT bleeding risk scores (26% ≥4 versus 45%, P<0.0001). Compared with those appropriately receiving standard dosing, patients receiving inappropriately reduced‐dose NOACs had higher unadjusted rates of thromboembolic events (2.11 versus 1.35 events per 100 patient years, hazard ratio 1.56, 95% confidence interval 0.92‐2.67) and death (6.77 versus 2.60, hazard ratio 2.61, 95% confidence interval 1.86‐3.67). After adjustment, outcomes were not significantly different but tended to favor patients dosed appropriately.

Conclusions

The majority of dose reductions of NOACs in AF are inconsistent with US Food and Drug Administration recommendations. There appear to be opportunities to improve current NOAC dosing in community practice.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01701817.

Appropriate dosing of nonvitamin K antagonist oral anticoagulants for stroke prevention in atrial fibrillation

The development of nonvitamin K antagonist oral anticoagulants (NOACs) has been a major advance in therapy for patients requiring oral anticoagulation, particularly for long-term indications such as stroke prevention in atrial fibrillation (AF). The NOACs are generally easier to dose and manage due to less heterogeneity of effect across individuals and fewer drug and food interactions, compared with warfarin. However, the treatment effect of NOACs may vary based on important patient characteristics, particularly renal function. Therefore, the package inserts for these drugs have dosing recommendations for patients with impaired kidney function, which are frequently but not always based on evidence from large-scale, randomized, clinical trials. Furthermore, there is evidence that NOAC dosing inconsistent with the regulatory labeling may be associated with adverse clinical outcomes. This review discusses the evidence supporting the current NOAC dosing, current dosing practices, associated outcomes, and gaps in knowledge regarding use of NOACs in patients with AF.