Genetic variation in the β1-adrenergic receptor is associated with the risk of atrial fibrillation after cardiac surgery

Effect of Clinical and Genetic Factors on the Development of Postoperative Atrial Fibrillation After Coronary Artery Bypass Grafting (CABG) in Egyptian Patients Receiving Beta-Blockers

PURPOSE

Prophylactic beta-blockers are recommended to prevent postoperative atrial fibrillation (POAF) after coronary artery bypass grafting (CABG). Polymorphisms in the beta-1 adrenergic receptor (ADRB1) and G protein-coupled receptor kinase 5 (GRK5) genes are associated with variable responses to beta-blockers. The aim of this study was to determine the clinical and genetic factors that influence the response to beta-blockers for POAF prophylaxis after CABG.

METHODS

Patients undergoing isolated CABG and receiving prophylactic beta-blockers (n = 249) were prospectively recruited and followed up for 6 postoperative days. Genotyping of ADRB1 rs1801253, and 3 GRK5 SNPs (rs3740563, rs10787959, and rs17098707) was performed.

RESULTS

Of the 249 patients, 52 patients (20.8%) experienced POAF. Age, hypertension, vasopressor use, calculated POAF risk score, GRK5 rs2230345 T-allele, and GRK5 rs3740563 A-allele were associated with POAF despite beta-blocker prophylaxis. The multivariate analysis revealed that age [odds ratio (OR) 1.06, 95% CI 1.02-1.11, p = 0.003] and GRK5 rs2230345 T-allele [OR 2.81, 95% CI 1.39-5.67, p = 0.004] were independent predictors of POAF after CABG despite beta-blocker prophylaxis.

CONCLUSION

GRK5 rs2230345 T-allele carriers were less responsive than AA genotype carriers to prophylactic beta-blockers for the prevention of POAF after CABG. The study was registered on http://clinicaltrials.gov in March 2019, with trial registration number (TRN): NCT03871647.

β1-receptor polymorphisms and junctional ectopic tachycardia in children after cardiac surgery

Junctional ectopic tachycardia (JET) is a potentially life-threatening postoperative arrhythmia in children with specific congenital heart defects and can contribute significantly to postoperative morbidity for at-risk populations. In adults, β1-adrenergic receptor (ADRB1) and β2-adrenergic receptor (ADRB2) genotypes have been associated with increased risk for arrhythmias. However, their association with arrhythmia risk in children is unknown. We aimed to test associations between ADRB1 and ADRB2 genotypes and postoperative JET in patients with congenital heart defects. Children who underwent cardiac surgery were genotyped for the ADRB1 p.Ser49Gly (rs1801252; c.145A>G), p.Arg389Gly (rs1801253; c.1165C>G), ADRB2 p.Arg16Gly (rs1042713; c.46A>G), and p.Glu27Gln (rs1042714; c.79G>C) polymorphisms. The occurrence of postoperative JET was assessed via cardiologist-interpreted electrocardiograms. Genotype associations with JET were analyzed via logistic regression, adjusted for clinical variables associated with JET, with separate analysis in patients not on a β-blocker. Of the 343 children included (median age 8 months, 53% boys, 69% European ancestry), 45 (13%) developed JET. The Arg389Arg genotype was not significantly associated with JET in the overall population (odds ratio [OR] = 1.96, 95% confidence interval [CI] = 0.96-4.03, p = 0.064), but was nominally associated in patients not taking a β-blocker (n = 324, OR = 2.25, 95% CI = 1.05-4.80. p = 0.034). None of the other variants were associated with JET. These data suggest that the ADRB1 Arg389Arg genotype may predict risk for JET following cardiac surgery in pediatric patients in the absence of β-blockade. Whether treatment with a β-blocker ameliorates this association requires further research.

Optimising risk factors for atrial fibrillation post-cardiac surgery

Postoperative atrial fibrillation (POAF) is an ongoing complication following cardiac surgery, with an incidence of 15%-60%. It is associated with substantial mortality and morbidity, as well increased hospital stays and healthcare costs. The pathogenesis is not fully understood, but the literature suggests that POAF occurs when transient, postoperative triggers act on vulnerable atrial tissue produced by preoperative, procedure-induced and postoperative processes such as inflammation, oxidative stress, autonomic dysfunction and electrophysiological remodelling of the atrial tissues. This sets the stage for arrhythmogenic mechanisms, such as ectopic firing secondary to triggered activity and re-entry mechanisms generating POAF. Preoperative factors include advanced age, sex, ethnicity, cardiovascular risk factors, preoperative drugs, electrocardiogram and echocardiogram abnormalities. Procedural factors include: the use of cardiopulmonary bypass and aortic cross clamp, type of cardiac surgery, use of hypothermia, left ventricular venting, bicaval cannulation and exclusion of the left atrial appendage. Postoperative factors include postoperative drugs, electrolyte and fluid balance and infection. This review explores the pathogenesis of POAF and the contribution of these perioperative factors in the development of POAF. Patients can be risk stratified for targeted treatment and prophylaxis, and how these factors can be attenuated to improve POAF outcomes following cardiac surgery.

Annotation of susceptibility SNPs associated with atrial fibrillation

OBJECTIVE

Genome-wide association studies (GWAS) and the candidate gene based association studies have identified a panel of variants associated with atrial fibrillation (AF), however, most of the identified single nucleotide polymorphisms (SNPs) were found located within intergenic or intronic genomic regions, and whether the positive SNPs have a real biological function is unknown, and the real disease causing gene need to be studied.

RESULTS

The current results of the genetic studies including common variants identified by GWAS (338 index SNPs) and candidate gene based association studies (40 SNPs) were summarized.

CONCLUSION

Our study suggests the relationship between genetic variants and possible targeted genes, and provides insight into potential genetic pathways underlying AF incidence and development. The results may provide an encyclopedia of AF susceptibility SNPs and shed light on the functional mechanisms of AF variants identified through genetic studies.

METHODS

We summarized AF susceptibility SNPs identified by GWAS and candidate gene based association studies, and give a comprehensive functional annotation of all these AF susceptibility loci. by genomic annotation, microRNA binding prediction, promoter activity analysis, enhancer activity analysis, transcription factors binding activity prediction, expression quantitative trait loci (eQTL) analysis, long-range transcriptional regulatory function analysis, gene ontology and pathway enrichment analysis.

Perioperative Precision Medicine: Where Are We in 2020?

PURPOSE OF REVIEW

The present review examines how targeted approaches to care, based on individual variability in patient characteristics, could be applied in the perioperative setting. Such an approach would enhance individualized risk assessment and allow for targeted preventive and therapeutic decision-making in patients at increased risk for adverse perioperative events.

RECENT FINDINGS

Prior and current studies highlight valuable lessons on how future investigations attempting to link specific patient-related characteristics or treatment modalities with outcomes and adverse drug responses might be designed in the perioperative setting.

SUMMARY

Our review highlights the past, present, and future directions of perioperative precision medicine. Current evidence provides important lessons on how a specific patient and disease tailored approach can help perioperative physicians in delivering the most appropriate and safest perioperative care.

Polymorphism of the Beta-1 Gly389Arg receptor in patients with dual atrioventricular nodal physiology

Introduction

Gly389Arg β1 adrenergic receptor polymorphisms seem to exert an influence on the modulation of the adrenergic effect in several types of patients. This study aimed to determine the prevalence of Gly389Arg polymorphisms among patients with evidence of double nodal pathway and to correlate the electrophysiological properties with the different genotypes of the respective polymorphisms.

Methods

A cross-sectional, descriptive and analytical study was designed to assess 49 patients, with evidence of double nodal pathway, submitted to electrophysiological study. Genomic DNA was extracted from peripheral blood leukocytes and the genotypes of the Arg389Gly polymorphisms were identified in all individuals by PCR/RFLP (polymerase chain reaction/restriction fragment length polymorphism).

Results

The majority of patients were female and had supraventricular tachycardia (75.5%). The prevalence of Arg389Arg genotype was found in 32 patients (65.3%), Arg389Gly genotype in 16 patients (32.7%) and Gly389Gly genotype in 1 patient (2%). With respect to the induction of nodal reentrant tachycardia, it was possible to induce non-isoproterenol tachycardia in 32 patients (65.3%), of whom 24 had the Arg389Arg genotype and 8 the Arg389Gly and Gly389Gly genotype (p = 0.05). The resting heart rate of patients of the Arg389Arg genotype was 81 ± 18 bpm and the Arg389Gly and Gly389Gly genotype of 71 ± 9 bpm (p = 0.044). Body mass index (BMI) among patients with genotype Arg389Gly and Gly389Gly was 29.8 ± 7.1 and patients with the Arg389Arg genotype was 26.2 ± 4.6 (p = 0.034).

Conclusion

The Arg389Arg genotype was more easily related to triggering arrhythmia, higher resting heart rate and lower BMI.

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The Arg389Arg genotype was more easily related to triggering arrhythmia.

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Patients with Gly389 allele had difficulty in triggering nodal reentry tachycardia.

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There is relationship between the Arg389Gly polymorphism and the higher BMI.

Pharmacogenomics of Bucindolol in Atrial Fibrillation and Heart Failure

PURPOSE OF REVIEW

We explore the pharmacogenomics of the beta-blocker bucindolol by discussing relevant beta-1 adrenergic receptor (ADRB1) polymorphisms and recent beta-blocker studies. Through this, we will understand how bucindolol may help patients with atrial fibrillation and heart failure with reduced ejection fraction (AF-HFrEF), which carries poor prognosis.

RECENT FINDINGS

Retrospective study of the Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training trial revealed the interaction between the optimal beta-blocker dose and the ADRB1 Arg389 genotype for HFrEF clinical outcomes. Further, a combinatorial genotype analysis in the Beta-Blocker Evaluation of Survival Trial showed that the Arg389Arg genotype, but not the Gly carrier, was associated with 40% lower mortality risk with bucindolol. Finally, the AF-HFrEF subgroup with the ADRB1 Arg389Arg genotype had greater heart rate reduction and suggestion for mortality benefit. Therapeutic response to beta-blockers varies by beta-blocker mechanism, ADRB1 Arg389 genotype, and clinical setting (AF, HFrEF, AF-HFrEF). The ongoing trial A Genotype-Directed Comparative Effectiveness Trial of Bucindolol and Toprol-XL for Prevention of Symptomatic Atrial Fibrillation/Atrial Flutter in Patients with Heart Failure prospectively identifies AF-HFrEF patients with favorable genotype for bucindolol to prevent AF recurrence.

Correlation of ADRB1 rs1801253 Polymorphism with Analgesic Effect of Fentanyl After Cancer Surgeries

BACKGROUND Our study aimed to explore the association between β1-adrenoceptor (ADRB1) rs1801253 polymorphism and analgesic effect of fentanyl after cancer surgeries in Chinese Han populations. MATERIAL AND METHODS Postoperative fentanyl consumption of 120 patients for analgesia was recorded. Genotype distributions were detected by allele specific amplification-polymerase chain reaction (ASA-PCR) method. Postoperative pain was measured by visual analogue scale (VAS) method. Differences in postoperative VAS score and postoperative fentanyl consumption for analgesia in different genotype groups were compared by analysis of variance (ANOVA). Preoperative cold pressor-induced pain test was also performed to test the analgesic effect of fentanyl. RESULTS Frequencies of Gly/Gly, Gly/Arg, Arg/Arg genotypes were 45.0%, 38.3%, and 16.7%, respectively, and passed the Hardy-Weinberg Equilibrium (HWE) test. The mean arterial pressure (MAP) and the heart rate (HR) had no significant differences at different times. After surgery, the VAS score and fentanyl consumption in Arg/Arg group were significantly higher than in other groups at the postoperative 2nd hour, but the differences were not obvious at the 4th hour, 24th hour, and the 48th hour. The results suggest that the Arg/Arg homozygote increased susceptibility to postoperative pain. The preoperative cold pressor-induced pain test suggested that individuals with Arg/Arg genotype showed worse analgesic effect of fentanyl compared to other genotypes. CONCLUSIONS In Chinese Han populations, ADRB1 rs1801253 polymorphism might be associated with the analgesic effect of fentanyl after cancer surgery.

G protein-coupled receptor kinase 5 gene polymorphisms are associated with postoperative atrial fibrillation after coronary artery bypass grafting in patients receiving β-blockers

BACKGROUND

We hypothesized that genetic variations in the adrenergic signaling pathway and cytochrome P450 2D6 enzyme are associated with new-onset atrial fibrillation (AF) in patients who underwent coronary artery bypass grafting and were treated with perioperative β-blockers (BBs).

METHODS AND RESULTS

Two cohorts of patients who underwent coronary artery bypass grafting and received perioperative BBs at Duke University Medical Center were studied. In a discovery cohort of 563 individuals from the Perioperative Genetics and Safety Outcomes Study (PEGASUS), using a covariate-adjusted logistic regression analysis, we tested 492 single-nucleotide polymorphisms (SNPs) in 10 candidate genes of the adrenergic signaling pathway and cytochrome P450 2D6 for association with postoperative AF despite perioperative BB therapy. SNPs meeting a false discovery rate ≤0.20 (P<0.002) were then tested in the replication cohort of 245 individuals from the Catheterization Genetics biorepository. Of the 492 SNPs examined, 4 intronic SNPs of the G protein-coupled kinase 5 (GRK5) gene were significantly associated with postoperative AF despite perioperative BB therapy in the discovery cohort with additive odds ratios between 1.72 and 2.75 (P=4.78×10(-5) to 0.0015). Three of these SNPs met nominal significance levels in the replication cohort with odds ratios between 2.07 and 2.60 (P=0.007 to 0.016). However, meta-analysis of the 2 data sets cohorts suggested strong association with postoperative AF despite perioperative BB therapy in all 4 SNPs (meta-P values from 1.66×10(-6) to 3.39×10(-5)).

CONCLUSIONS

In patients undergoing coronary artery bypass grafting, genetic variation in GRK5 is associated with postoperative AF despite perioperative BB therapy.