Stroke and bleeding risk in atrial fibrillation

Evaluation of Clinical, Echocardiographic, and Therapeutic Characteristics, and Prognostic Outcomes of Coexisting Heart Failure among Patients with Atrial Fibrillation: The Jordan Atrial Fibrillation (JoFib) Study

BACKGROUND

Atrial fibrillation (AF) is the most commonly encountered cardiac arrhythmia in clinical practice. Heart failure (HF) can occur concurrently with AF.

AIM

We compared different demographic, clinical, and echocardiographic characteristics between patients with AF+HF and patients with AF only. Furthermore, we explored whether concurrent HF independently predicts several outcomes (all-cause mortality, cardiovascular mortality, ischemic stroke/systemic embolism (IS/SE), major bleeding, and clinically relevant non-major bleeding (CRNMB)).

MATERIALS AND METHODS

Comparisons between the AF+HF and the AF-only group were carried out. Multivariable Cox proportional hazard models were constructed for each outcome to assess whether HF was predictive of any of them while controlling for possible confounding factors.

RESULTS

A total of 2020 patients were included in this study: 481 had AF+HF; 1539 had AF only. AF+HF patients were older, more commonly males, and had a higher prevalence of diabetes mellitus, dyslipidemia, coronary artery disease, and chronic kidney disease (p≤0.05). Furthermore, AF+HF patients more commonly had pulmonary hypertension and low ejection fraction (p≤0.001). Finally, HF was independently predictive of all-cause mortality (adjusted HR 2.17, 95% CI (1.66-2.85) and cardiovascular mortality (adjusted HR 2.37, 95% CI (1.68-3.36).

CONCLUSION

Coexisting AF+HF was associated with a more labile and higher-risk population among Jordanian patients. Furthermore, coexisting HF independently predicted higher all-cause mortality and cardiovascular mortality. Efforts should be made to efficiently identify such cases early and treat them aggressively.

Treatment of Cryptogenic Stroke Patients with Atrial Fibrillation Detected by Insertable Cardiac Monitors Reduces Recurrent Stroke Risk to Background Levels

Atrial fibrillation (AF) is a known risk factor of ischemic stroke with a reported fivefold increase in incidence. However, it is not well established whether treatment with oral anticoagulation (OAC) in cryptogenic stroke patients with AF, detected by insertable cardiac monitors (ICMs), reduces the risk of recurrent stroke. We aimed to compare recurrent stroke rates between cryptogenic stroke patients who have AF detected by ICMs and thus started on OAC treatment and those without detected AF. We performed a combined retrospective and prospective analysis of consecutive patients who received an ICM indicated for cryptogenic stroke and were followed up with between July 2015 and November 2019. Patients with a prior documented history of AF were excluded. All patients were required to have a home remote monitoring system. We calculated the rates of AF detection and OAC initiation, then compared recurrent annualized stroke rates (ASRs) between patients with and without AF detected. A total of 298 patients with ICMs were included in the study [mean ± standard deviation age: 77 ± 11.7 years; female/male: 147/151; virtual CHA₂DS₂-VASc score: 4.96 ± 1.28 points]. AF was discovered in 91 patients (~30%) over a mean 19.3 months follow-up. Of those, 65 (71.4%) were started on OAC, 12 (13.2%) were already on OAC, and 10 (11%) remained non-anticoagulated. In four (4.4%) patients, OAC was started after recurrent stroke when AF was diagnosed. A total of 24 of 298 patients developed recurrent strokes (ASR: 5.0%). Among the 24 patients with recurrent strokes, four had new AF and were on OAC (ASR: 3.23%), six had new AF and were not anticoagulated (ASR: 26.62%), and 14 had no AF detected and no OAC (ASR: 4.20%). Our study found new AF detected by ICMs in almost one-third (30%) of cryptogenic stroke patients (consistent with previous studies), and the majority of them (89%) received OACs. There was no significant difference in the recurrent stroke rate among patients without AF detected and those with AF detected and on OAC. Rigorous arrhythmia monitoring using ICMs can increase new AF detection rates in cryptogenic stroke patients, thereby allowing early initiation of OACs, ultimately reducing the risk of recurrent stroke to background levels.

TGF-β1 polymorphism increases the risk of bleeding complications in patients on oral anticoagulant after cardiac valve replacement

Although an elevated INR is highly associated with an increased risk of warfarin-associated bleeding, it has been reported that some patients also experience bleeding complications at therapeutic INRs. TGF-β1 polymorphisms has been reported to cause vascular malformations, resulting in bleeding complications, but there are few published genetic studies regarding bleeding complications in patients on warfarin therapy. This study aimed to determine if there is an association between transforming growth factor beta-1 (TGF-β1) polymorphisms and bleeding complications in patients who maintain international normalized ratios (INRs) of 2.0-3.0 with warfarin therapy after cardiac valve replacement. Eleven single nucleotide polymorphis (SNPs) of TGF-β1 (rs1800469, rs2241718, rs4803455, rs2241717, rs2241716, rs2241715, rs2241714, rs11083616, rs2317130, rs747857, and rs1982073) were analyzed. Univariate and multivariable analyses were conducted to evaluate the associations between genetic polymorphisms and bleeding risk. Attributable risk and the number needed to genotype (NNG) were calculated to identify the potential clinical value of genotyping. A discrimination of model was assessed via an analysis of the area under the receiver operating curve (AUROC). To test the model's goodness of fit, a Hosmer-Lemeshow test was performed. Of 142 patients, 21 experienced bleeding complications. Among analyzed single nucleotide polymorphis (SNPs) of TGF-β1 (rs1800469, rs2241718, rs4803455, rs2241717, rs2241716, rs2241715, rs2241714, rs11083616, rs2317130, rs747857, and rs1982073), AA genotype carriers in rs2241718 had about 5.5 times more bleeding complications than those with the G allele after adjusting for other confounders. The attributable risk and NNG for rs2241718 were 81.9% and 57.8, respectively. The presence of atrial fibrillation and myocardial infarction increased bleeding complications 3.9- and 9.8-fold, compared with those without atrial fibrillation and myocardial infarction, respectively. Bleeding complications during warfarin therapy in patients with mechanical heart valves were associated with TGF-β1 polymorphisms as well as atrial fibrillation and myocardial infarction.

National Physician Survey for Nonvalvular Atrial Fibrillation (NVAF) Anticoagulation Comparing Knowledge, Attitudes and Practice of Cardiologist to PCPs

Introduction:

NVAF is estimated to affect between 6.4 and 7.4 million Americans in 2018, and increases the risk of stroke 5-fold. To mitigate this risk, guidelines recommend anticoagulating AF patients unless their stroke risk is very low. Despite these recommendations, 30.0-60.0% of NVAF patients do not receive indicated anticoagulation. To better understand why this may be, we surveyed PCPs and cardiologists nationwide on their attitudes, knowledge and practices toward managing NVAF with warfarin and direct-acting oral anticoagulants (DOACs).

Methods:

We surveyed 1,000 PCPs and 500 cardiologists selected randomly from a master list of the American Medical Association, using a paper based, anonymous, self-administered, mailed scannable survey. The survey contained questions on key demographics and data concerning attitudes, knowledge and practices related to prescribing DOACs. The surveys went out in the fall/winter of 2017-8 with a $10 incentive gift card. Survey responses were scanned into an Excel database and analyzed using SAS 9.3 (Cary, NC) for descriptive and inferential statistics.

Results:

Two hundred and forty-nine providers (167 PCPs, 82 cardiologists) participated in the study with a response rate of 18.8% (249/1320). Respondent mean years ±SD of experience since completing residency was 23.2 ± 13.8. Relative to cardiologists, less PCPs use CHADsVASC (36.8% vs. 74.4%) (p < 0.0001); more have never used HAS-BLED, HEMORR2HAGES, or ATRIA (38.5% vs. 9.8%) (p < .0001); more felt that their lack of knowledge/experience with DOACs was a barrier to prescribing the agents (p = 0.005); and more reported that they could use additional education on DOACs (87.0% vs. 47.0%) (p < 0.0001). Overall, cardiologists were more concerned about ischemic stroke outcomes, while PCPs were more concerned with GI bleeding. Cardiologists also felt that clinical trial data were most helpful in choosing the most appropriate DOAC for their patients, while PCPs felt that Real World Data was most useful.

Conclusions:

Cardiologists were more concerned with ischemic stroke while anticoagulating patients and utilized screening instruments like CHADsVASC in a majority of their patients. PCPs were concerned with GI bleeds when anticoagulating but nearly 40.0% utilized no screening tools to assess bleeding risk. Our findings show that future education about DOACs would be warranted especially with PCPs.

Association between HNF4A mutations and bleeding complications in patients with stable international normalized ratio

OBJECTIVES

This study aimed to determine the association between hepatocyte nuclear factor 4 alpha (HNF4A) polymorphisms and bleeding complications in patients on warfarin with international normalized ratios between 2.0 and 3.0 after cardiac valve replacement.

METHODS

Nineteen single nucleotide polymorphisms of HNF4A in addition to VKORC1 rs9934438 and CYP2C9 rs1057910 were analyzed. Univariate and multivariate analyses were conducted to evaluate associations between genetic polymorphisms and bleeding risk. Attributable risk and number needed to genotype (NNG) were calculated to assess clinical value of genotyping.

RESULTS

Of 142 patients, 21 experienced bleeding complications. Multivariate logistic regression analysis was conducted using factors with P <0.1 in univariate analysis. Multivariate analysis showed that patients with the CC genotype of rs6130615 had an 8.4-fold increased risk of bleeding, compared with patients with the T allele. Attributable risk and NNG were 88.1% and 32.2, respectively. Patients with the TT genotype of rs3212191 had a 3.8-fold increased risk of bleeding, compared with C allele carriers, while patients with variant-type homozygotes for rs1884613 showed an 8.7-fold higher bleeding complication than C allele carriers. The attributable risk/NNG of rs3212191 and rs1884613 were 73.4%/17.6 and 88.5%/22.8, respectively. Among comorbidities, atrial fibrillation was the only significant risk factor for bleeding complications.

CONCLUSION

Bleeding complications during warfarin therapy in patients with mechanical heart valves were associated with HNF4A polymorphisms and atrial fibrillation.

Intratumoural renal cell carcinoma haemorrhage following stereotactic radiotherapy: a case report

BACKGROUND

Stereotactic radiotherapy is an emerging treatment option for patients with inoperable renal cell carcinoma (RCC). Haemorrhage has not previously been reported to occur as a result of Stereotactic Body Radiotherapy (SBRT) to the kidney for primary RCC. We report an acute haemorrhage in a patient who received only one of three planned fractions of SBRT as part of a clinical trial.

CASE PRESENTATION

A 74 year old female had a left renal mass under observation for 4 years, during which time she was imaged repeatedly using ultrasound and CT scans. There has been no evidence of metastases, and the lesion has demonstrated a steady pattern of growth over the 4-year period. Fine needle aspiration histologically confirmed RCC. Following a multidisciplinary review, the patient was recommended for SBRT as she was not considered a surgical candidate. Treatment was planned for an ablative 42Gray (Gy) to be delivered in 3 fractions at 14Gy/fraction as part of a clinical trial. Our patient presented to the emergency department (ED) suffering left flank pain, fever and vomiting within 3 h of the first fraction of SBRT. CT showed the mass to have markedly increased in size, measuring 8.7 × 8.1 × 7.0 cm, from 6.5 × 5.4 × 5.6 cm. It was reported as an internal haemorrhage into the malignancy. The patient was admitted for analgesia, anti-pyretics, and transfusion of 2 units of packed red blood cells. The patient recovered without any further intervention but radiotherapy was discontinued. The patient was alive and free from disease progression two years after the aborted treatment.

CONCLUSION

Such events, though rare, are potentially serious, and therefore clinicians should be aware of such treatment related complications.

The safety of NOACs in atrial fibrillation patient subgroups: A narrative review

AIM

Four non-vitamin K oral anticoagulants (NOACs) have been evaluated in clinical trials for the prevention of stroke in patients with atrial fibrillation (AF). Although each of the NOACs have been shown to be at least non-inferior to warfarin for efficacy and safety outcomes, controversy remains over the relative safety of each NOAC inpatient subgroups. This narrative review provides an overview of phase III data on NOAC trials for the prevention of stroke in AF, with a focus on reporting the safety of each agent in key patient subgroups based on age, gender, accumulated risk factors, and primary or secondary prevention of stroke.

METHODS

A comprehensive literature search was completed and, where data permit, analyses of phase III trials of the NOACs are presented for each patient subgroup.

RESULTS

Analyses of key safety outcomes from NOAC trials were completed using primary trial data, including major bleeding and all-cause mortality. The safety of NOACs was generally consistent and favourable compared with warfarin according to patient age, gender, previous history of stroke, and the presence of risk factors for stroke.

CONCLUSIONS

The safety of the NOACs compared with warfarin was generally favourable across different patient subgroups, including those perceived to be at "high risk" for adverse outcomes. However, certain NOACs may be preferable to warfarin in some subgroups, based on indirect analyses.

Genetics of Atrial Fibrilation: In Search of Novel Therapeutic Targets

Atrial fibrillation (AF) is the most frequent arrhythmogenic disease in humans, ranging from 2% in the general population and rising up to 10-12% in 80+ years. Genetic analyses of AF familiar cases have identified a series of point mutations in distinct ion channels, supporting a causative link. However, these genetic defects only explain a minority of AF patients. Genomewide association studies identified single nucleotide polymorphisms (SNPs), close to PITX2 on 4q25 chromosome, that are highly associated to AF. Subsequent GWAS studies have identified several new loci, involving additional transcription and growth factors. Furthermore, these risk 4q25 SNPs serve as surrogate biomarkers to identify AF recurrence in distinct surgical and pharmacological interventions. Experimental studies have demonstrated an intricate signalling pathway supporting a key role of the homeobox transcription factor PITX2 as a transcriptional regulator. Furthermore, cardiovascular risk factors such as hyperthyroidism, hypertension and redox homeostasis have been identified to modulate PITX2 driven gene regulatory networks. We provide herein a state-of-the-art review of the genetic bases of atrial fibrillation, our current understanding of the genetic regulatory networks involved in AF and its plausible usage for searching novel therapeutic targets.

Impact of Sociodemographic and Clinical Factors on Health-Related Quality of Life in Older Adults With Atrial Fibrillation

Atrial fibrillation (AF) is more prevalent in older adults than other populations and affects health-related quality of life (HRQoL). However, few studies have investigated HRQoL and clinical factors in older adults with AF. The aim of the current cross-sectional study was to describe HRQoL using an AF-specific QoL instrument and identify factors influencing HRQoL in Korean older adults with AF. Data from 205 patients diagnosed with AF in a tertiary hospital were analyzed. Patients' mean age was 74.24 years and 43.9% of patients were female. The total HRQoL score was 49.6 of 100. The lowest score was in the physical dimension of HRQoL. Concern about lethal complications from AF was an essential concept related to QoL. In multiple linear regression, age and gender were significant predictors for the physical dimension of HRQoL. Gender and comorbidity were significant factors for the sexual activity dimension. Health care providers should help improve the HRQoL of older adults with AF by reducing physical burdens and concerns about health-related complications. [Res Gerontol Nurs. 2018; 11(4):207-215.].

Left Atrial Strain Predicts Pro-Thrombotic State in Patients with Non-Valvular Atrial Fibrillation

Background and Purpose

Atrial fibrillation (AF) has a high prevalence in the population and it is responsible for up to the 25% of the strokes in elderly people. The aim of our study was to assess the correlations of left atrial (LA) functional parameter, global peak atrial longitudinal strain (PALS), derived from speckle tracking echocardiography (STE), with transesophageal echocardiography (TEE) findings in patients with persistent AF undergoing TEE before electrical cardioversion or ablation procedures.

Methods

79 patients (58 males, 21 females) with persistent AF waiting for cardioversion were included in the study. The patients underwent conventional two-dimensional (2D) and 2D speckle tracking echocardiogram. PALS were measured in all subjects. Patients were divided into two groups according to the presence of reduced LA appendage (LAA) emptying velocity (<25 cm/s) and/or thrombus in the LAA at TEE examination.

Results

Patients with reduced LAA emptying velocity and/or thrombus at TEE examination showed a significantly higher LA volume and increased E/E' ratio. 4-chamber, 2-chamber and global PALS were significantly lower in patients with reduced LAA emptying velocity and/or thrombus (6.8 ± 2.0% vs. 27.5 ± 5.4%, P < 0.0001; 8.6 ± 3.5% vs. 29.4 ± 7.1%, P < 0.0001; 7.9 ± 3.2% vs. 28.5 ± 6.1%, P <0.0001, respectively). Among all variables analyzed, global PALS demonstrated the highest diagnostic accuracy (AUC of 0.92) and, with a cut-off value less than 8.1%, good sensitivity and specificity of 87% and 94%, respectively, to predict LAA thrombus and/or reduced LAA emptying velocity.

Incidence of thromboembolic and bleeding events in patients with newly diagnosed nonvalvular atrial fibrillation: An Asian multicenter retrospective cohort study in Singapore

BACKGROUND

Real-world effectiveness and safety of antithrombotics in nonvalvular atrial fibrillation (NVAF) patients in Singapore has not been thoroughly studied.

HYPOTHESIS

Users of various antithrombotics experience a significantly different risk of stroke and major bleed compared with warfarin users.

METHODS

This multicenter retrospective cohort study included patients age ≥ 21 years newly diagnosed with NVAF between July 2012 and September 2015. Using electronic medical records, data on patients' demographics, antithrombotics prescribed, and CHA₂ DS₂ -VASc and HAS-BLED risk factors were collected. Patients were followed for 1 year from diagnosis for the primary effectiveness and safety endpoints of incident stroke or systemic embolism and major bleed, respectively. The secondary safety endpoint was overall bleed. Hazard ratios (HR) were determined from Cox regression.

RESULTS

Of 743 patients included, 224 were on warfarin, 156 on direct oral anticoagulants (DOACs), 277 on single antiplatelet therapy (SAPT), 28 on dual antiplatelet therapy (DAPT), and 58 on no therapy. Mean age (±SD) was 68.7 ± 13.0 years. Compared with warfarin users, SAPT (adjusted [adj.] HR: 3.70, 95% confidence interval [CI]: 1.21-11.3) and DAPT users (adj. HR: 10.1, 95% CI: 1.51-67.2) were more likely to develop thromboembolic outcomes. Also, DOAC users (adj. HR: 0.304, 95% CI: 0.158-0.585), SAPT users (adj. HR: 0.142, 95% CI: 0.0680-0.295), and DAPT users (adj. HR: 0.112, 95% CI: 0.0146-0.857) were less likely to experience any bleed compared with warfarin users.

CONCLUSIONS

SAPT and DAPT are less effective than warfarin in NVAF patients. DOACs may be considered in view of lower risk of overall bleed.

No Evidence for an Association Between Renal Function and Serious Bleeding Events in Patients Treated With Coumarins: A Population-Based Study

BACKGROUND

Although anticoagulation therapy is closely monitored in the Netherlands, coumarin-induced serious bleeding events are still observed. Current literature suggests that renal impairment may contribute to this.

OBJECTIVE

To explore the association between renal function and bleeding events during coumarin treatment.

METHODS

A nested case-control study was conducted using data from the PHARMO Database Network. Patients hospitalized for a bleeding event during coumarin treatment were selected as cases and matched on sex, birth year, and geographic region to up to 2 controls using coumarins without hospitalization for bleeding. All values of estimated glomerular filtration rates (eGFRs) were selected in the year before index date (case hospitalization date) and compared between cases and controls using logistic regression analyses.

RESULTS

In total, 2224 cases were matched to 4398 controls (61% male; mean ± SD age 75 ± 11 and 78 ± 11 years among cases and controls, respectively). Availability of eGFR values was higher among cases compared with controls (mean ± SD eGFR values 4.5 ± 7.1 vs 3.2 ± 5.5), reflected in the significantly shorter time since last eGFR value (at index date, mean ± SD = 2.7 ± 3.0 vs 3.8 ± 3.1 months; odds ratio [OR] = 0.91, 95%CI = 0.89-0.92). No statistically significant difference was found for the mean eGFR value in the year before index date (mean ± SD 65.7 ± 22.8 vs 64.6 ± 20.9 mL/min/1.73 m²; OR per 10 units [95%CI] = 0.99 [0.96-1.02]).

CONCLUSIONS

No association between renal function and serious bleeding events during coumarin treatment was observed.

Increased Risk of Atrial Fibrillation and Thromboembolism in Patients with Severe Psoriasis: a Nationwide Population-based Study

Psoriasis increases the risk of atrial fibrillation (AF) and thromboembolic events (TE). There is limited information on the effect of psoriasis severity on AF and TE. In this study, psoriasis patients were enrolled from the Korean National Insurance Service-National Sample Cohort (2004–2008). Diagnosis and disease severity were determined from claims data. Newly diagnosed non-valvular AF and TE were identified during a 9.6-year follow-up. The effect of psoriasis severity on AF and TE was evaluated. We identified 13,385 psoriasis patients (1,947 with severe psoriasis). Severe psoriasis significantly increased the risk of AF (adjusted hazard ratio [HR_adjust] 1.44 [95% confidence interval (CI) 1.14–1.82], p = 0.002) and TE (HR_adjust 1.26 [95% CI 1.07–1.47], p = 0.005); mild psoriasis did not show any significant effects. Results were similar after propensity-score matching. Risk increments of AF and TE were prominent in patients with greater cardiovascular risk. A possible limitation of our study is that it has a retrospective design, and the effect of unmeasured confounders and risk of misclassification could bias the results. To conclude, our results showed that severe, but not mild, psoriasis significantly increased AF and TE risk. AF surveillance and active stroke prevention would be beneficial in such cases.

Impact of GGCX polymorphisms on warfarin dose requirements in atrial fibrillation patients

Background/aim: Warfarin is a common anticoagulant with large interindividual differences and a narrow therapeutic range. The polymorphisms of gamma-glutamyl carboxylase (GGCX) are important genetic factors for warfarin dose requirements. Materials and methods: Polymerase chain reaction and direct sequencing methods were used to detect the GGCX rs699664 genotype in 215 atrial fibrillation (AF) patients with warfarin administration. The effects on warfarin dose by different genotypes were analyzed. A warfarin dosing algorithm was developed based on age, height, CYP2C9, VKORC1, and GGCX genotype. Results: In 215 AF patients, there were 104 cases of wild-type GG genotype (48.4%), 92 cases of GA genotype (42.8%), and 19 cases of AA genotype (8.8%). Patients with the GGCX rs699664 A allele (GA or AA genotypes) needed higher warfarin doses than those with the GG genotype (P < 0.05). A warfarin dosing algorithm showed that age, height, CYP2C9, VKORC1, and GGCX genotype were the best variables for estimating warfarin dose (R2 = 41.2%). Another independent cohort of 60 AF patients showed a significant linear correlation between predicted warfarin maintenance dose and actual dose (R = 0.660, P < 0.01). Conclusion: AF patients with the GA and AA genotypes in GGCX rs699664 required significantly higher warfarin doses. GGCX rs699664 is a potential predictor for the warfarin dose of AF patients.

Management of Atrial Fibrillation in Elderly Adults

Driven in large part by the aging of the population and the increasing prevalence of cardiovascular comorbidities associated with atrial fibrillation (AF), there is a burgeoning epidemic of AF in elderly adults. Although there is a large body of literature to guide management of people with AF, elderly adults with AF are frequently underrepresented in clinical trials. This review provides a contemporary update on management of elderly adults with AF with a particular focus on the two main clinical challenges that AF poses: stroke risk reduction and control of symptoms. The evidence to support novel AF treatment strategies in elderly adults is reviewed, including novel oral anticoagulants and left atrial appendage closure for stroke risk reduction and catheter ablation for control of symptoms.

New Oral Anticoagulants in Nonvalvular Atrial Fibrillation

The choice of an oral anticoagulant (OAC) for patients with nonvalvular atrial fibrillation (NVAF) is a major and complex clinical decision taking into account the individual risk-benefit ratio and bearing in mind the chronicity of therapy. This review focuses on the safety and efficacy of new oral anticoagulants (NOACs) compared with conventional vitamin K antagonists (VKA) in patients with NVAF. Current data suggest that NOACs are at least as effective and safe as VKAs for most NVAF subjects. The NOACs do not mandate dietary restrictions and regular pharmacodynamic monitoring, and they seem to have lesser incidence of intracranial or fatal bleeding when compared with VKAs. However, both dabigatran 150 twice daily and rivaroxaban have a slightly higher incidence of gastrointestinal bleeding when compared with VKAs. The article will delineate the current knowledge as well as scientific gaps related to the choice and dosage of anticoagulation regimens for various NVAF subsets and will address certain common clinical scenarios requiring special considerations. The article also addresses the shortcomings of NOACs: lack of therapeutic pharmacokinetic and pharmacodynamic targets, absence of tools to assess compliance and efficacy, rigid and limited dosage options, and absence of effective and inexpensive reversal agents.

The Impact of Novel Anticoagulants: Should All AF Patients Now Be Anticoagulated?

Atrial Fibrillation (AF) is accompanied by an increased risk for thromboembolic events in most affected patients. Current guidelines therefore recommend antithrombotic therapy with vitamin K antagonist (VKA) or non VKA oral anticoagulant (NOAC) in the majority of AF patients. Current AF treatment guidelines recommend that only patients younger than 65 years of age with lone AF, meaning without further concomitant risk factors for thromboembolic events should not be anticoagulated. NOACs, like the direct thrombin inhibitor dabigatran and the factor X inhibitors rivaroxaban, apixaban, and edoxaban have undergone large phase III clinical trials concerning treatment efficacy and bleeding risk in comparison to the VKA warfarin. In most cases, treatment with NOACs has been shown to decrease thromboembolic risk and/or decrease bleeding risk when compared with warfarin. Especially, as major hemorrhages like life threatening or intracranial bleeds are reduced, the question arises, if due to favourable adverse event ratios the indication for oral anticoagulation therapy should be broadened and all patients with diagnosed AF should be anticoagulated. This article gives a review on currently used thromboembolic and bleeding risk scores. Furthermore, the impact of NOAC therapy on stroke and bleeding risk is summarized, especially taking pharmacological interactions of NOAC therapy altering thromboembolic or bleeding risk into consideration. Differences of currently available guidelines are discussed. Finally, ongoing recent studies on treatment of low risk patients are debated.

Suboptimal Use of Oral Anticoagulants in Atrial Fibrillation: Has the Introduction of Direct Oral Anticoagulants Improved Prescribing Practices?

BACKGROUND AND OBJECTIVES

Atrial fibrillation (AF) and the associated risk of stroke are emerging epidemics throughout the world. Suboptimal use of oral anticoagulants for stroke prevention has been widely reported from observational studies. In recent years, direct oral anticoagulants (DOACs) have been introduced for thromboprophylaxis. We conducted a systematic literature review to evaluate current practices of anticoagulation in AF, pharmacologic features and adoption patterns of DOACs, their impacts on proportion of eligible patients with AF who receive oral anticoagulants, persisting challenges and future prospects for optimal anticoagulation.

LITERATURE SOURCE AND SELECTION CRITERIA

In conducting this review, we considered the results of relevant prospective and retrospective observational studies from real-world practice settings. PubMed (MEDLINE), Scopus (RIS), Google Scholar, EMBASE and Web of Science were used to source relevant literature. There were no date limitations, while language was limited to English. Selection was limited to articles from peer reviewed journals and related to our topic.

RESULTS

Most studies identified in this review indicated suboptimal use of anticoagulants is a persisting challenge despite the availability of DOACs. Underuse of oral anticoagulants is apparent particularly in patients with a high risk of stroke. DOAC adoption trends are quite variable, with slow integration into clinical practice reported in most countries; there has been limited impact to date on prescribing practice.

CONCLUSION

Available data from clinical practice suggest that suboptimal oral anticoagulant use in patients with AF and poor compliance with guidelines still remain commonplace despite transition to a new era of anticoagulation featuring DOACs.

Underweight is a risk factor for atrial fibrillation: A nationwide population-based study

BACKGROUND

Obesity is a well-known risk factor for development of atrial fibrillation (AF). However, the impact of underweight on AF has not been previously recognized. We sought to determine the risk of AF in subjects with underweight in this study.

METHODS

We analyzed clinical data from a total of 132,063 individuals with the age of 40years or older who received health care checkups arranged by the national insurance program between 2003 and 2004. Newly diagnosed nonvalvular AF was identified using claim data during a median follow-up duration of 9.0years.

RESULTS

The mean body mass index (BMI) of patients was 23.9kg/m(2), and 3,323 individuals (2.5%) were classified as being underweight (BMI <18.5kg/m(2)). During the study period, 3,237 individuals (2.5%) developed AF. There was a U-shaped relationship between BMI and AF occurrence: Each 1.0kg/m(2) increase of BMI above 20kg/m(2) was associated with a 6% increased risk of AF (p<0.001), while each 1.0kg/m(2) lower BMI below 20kg/m(2) was associated with a 13% increased risk of AF (p<0.001) after multivariable adjustment. Underweight was significantly associated with 23% increased risk of AF, while obesity classes I and II were with 26% and 120% increased risk of AF, respectively. Excess risk of AF in the underweight was independent of thyroid disease, chronic lung disease, or history of malignancy, and was not attributable to cigarette smoking, low socioeconomic status, excessive physical activity, or heavy alcohol consumption.

CONCLUSION

BMI has a U-shaped relationship with the risk of AF. Underweight was an independent risk factor for AF independent of confounding factors such as chronic lung disease and malignancy. These findings suggest that underweight is associated with biological effects that contribute to the development of AF.

Gene regulatory networks in atrial fibrillation

Atrial fibrillation (AF) is the most frequent arrhythmogenic syndrome in humans. With an estimate incidence of 1%-2% in the general population, AF raises up to almost 10%-12% in 80+ years. Thus, AF represents nowadays a highly prevalent medical problem generating a large economic burden. At the electrophysiological level, distinct mechanisms have been elucidated. Yet, despite its prevalence, the genetic and molecular culprits of this pandemic cardiac electrophysiological abnormality have remained largely obscure. Molecular genetics of AF familiar cases have demonstrated that single nucleotide mutations in distinct genes encoding for ion channels underlie the onset of AF, albeit such alterations only explain a minor subset of patients with AF. In recent years, analyses by means of genome-wide association studies have unraveled a more complex picture of the etiology of AF, pointing out to distinct cardiac-enriched transcription factors, as well as to other regulatory genes. Furthermore a new layer of regulatory mechanisms have emerged, i.e., post-transcriptional regulation mediated by non-coding RNA, which have been demonstrated to exert pivotal roles in cardiac electrophysiology. In this manuscript, we aim to provide a comprehensive review of the genetic regulatory networks that if impaired exert electrophysiological abnormalities that contribute to the onset, and subsequently, on self-perpetuation of AF.

Clinical application of a new warfarin-dosing regimen based on the CYP2C9 and VKORC1 genotypes in atrial fibrillation patients

The polymorphisms of cytochrome P450 2C9 (CYP2C9) and vitamin K epoxide reductase complex 1 (VKORC1) are important genetic factors for warfarin dose determinations. The present study aimed to investigate the contribution of the CYP2C9 and VKORC1 genotypes to warfarin dose requirement in atrial fibrillation (AF) patients, and to evaluate the clinical application of a warfarin-dosing algorithm. A total of 122 AF patients with a target international normalized ratio of 2.0 to 3.0 were included to determine the genotypes of CYP2C9 (rs1057910) and VKORC1 (rs9923231). A warfarin-dosing algorithm was developed based on age, height, and the CYP2C9 and VKORC1 genotypes of AF patients. The results indicated that the mean warfarin daily dose requirement was lower in the CYP2C9*1/*3 genotype compared with those in the homozygous wild-type CYP2C9*1/*1 patients (P<0.05), and was higher in patients with the VKORC1 AG and GG genotypes compared with those with the AA genotype (P<0.05). The multivariate regression model showed that age, height, and the CYP2C9 and VKORC1 genotypes were the best variables for estimating warfarin dose (R2=56.4%). A new warfarin-dosing algorithm was developed and its validity was confirmed in a second cohort of AF patients. During the 50-day follow-up, 63.3% (19/30) of control group patients and 86.7% (26/30) of patients in the experimental group acquired the warfarin maintenance dose. Among all the patients who acquired the warfarin maintenance dose, the mean time elapse from initiation until warfarin maintenance dose was significantly less in the experimental group (25.8±1.7 day) compared to the control group (33.1±1.9 day) (P<0.05). There was significant linear correlation between predicted warfarin maintenance dose and actual dose (r=0.822, P<0.01). In conclusion, a new warfarin-dosing algorithm was developed based on the CYP2C9 and VKORC1 genotypes, and it can shorten the time elapse from initiation until warfarin maintenance dose in AF patients with warfarin therapy.

Bridging the gender gap in atrial fibrillation

Women have a similar lifetime prevalence of non-valvular atrial fibrillation (NVAF) compared with that of men. Given the significant morbidity and potential mortality associated with NVAF, it is crucial to understand gender differences with NVAF. Women can be more symptomatic than men. Despite a higher baseline stroke risk, they are less likely to be on anticoagulation. Women have a greater risk of thromboembolism and a similar rate of bleeding risk compared with men on anticoagulation. Initial experience suggests that novel oral anticoagulants have similar safety and efficacy profile in men and women. Although women can have more adverse reactions from antiarrhythmic therapies, they are often referred later than men for ablation. As a group, a mitigating factor in ablation referral is that women also have a higher incidence of procedural complications from catheter ablation. This review summarizes the available literature highlighting significant gender-based differences and also highlights areas for research to improve NVAF outcomes in women.