Comparing novel oral anticoagulants to vitamin k antagonists in patients with hypertrophic cardiomyopathy and atrial fibrillation: an updated systematic review and meta-analysis

Funding Acknowledgements

Type of funding sources: None.

Background

Atrial fibrillation (AF) is a common occurrence in Hypertrophic cardiomyopathy (HCM), reported in approximately one third of cases. The 2011 ACC guidelines for management of HCM with concomitant AF recommend use of Vitamin K Antagonists (VKA); however, new research and randomized clinical trials present data which favor the use of Novel Oral Anticoagulants (NOAC) over VKA to prevent serious outcomes.

Purpose

We aim to identify the difference between NOAC and VKA in preventing ischemic stroke and thromboembolism, and calculate the rate of intracranial hemorrhage, major bleeding and all cause mortality in both treatment groups.

Methods

We conducted a systematic review and meta-analysis with the aim to answer the following clinical question: What is the efficacy of NOACs vs VKA in preventing thromboembolism and what are the associated risks with each group? We followed PRISMA guidelines. Scientific databases (PubMed, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Epistemonikos) were searched using relevant medical subject headings and keywords to retrieve studies published through September 24, 2020. Inclusion criteria were patients over 18 years old, use of NOACs and VKA in atrial fibrillation and HCM. Studies with patients who had catheter ablative therapy were excluded. After an exhaustive review, a total of 6 studies including 2 Randomized Control Trials (RCTs) and 4 retrospective cohort studies were analyzed using RevMan 5.4 to analyze event rate, hazard ratio and 95% confidence interval for ischemic stroke/thromboembolism, all-cause mortality, major bleeding and intracranial hemorrhage. One study was later excluded due to insufficient data. Heterogeneity was assessed by using the I2 statistic.

Results

A total of 9,168 patients [NOAC 5158 and VKA 4010] were pooled. Meta-analysis showed the NOAC treatment group had a significant improvement in preventing the primary outcome ischemic stroke/thromboembolism [HR 0.41; 95% CI 0.26 -0.63, p = <0.001], as well as secondary outcomes; all cause mortality [HR 0.37, 95% CI 0.19 - 0.73, p = 0.004, p = 0.004], Intracranial hemorrhage [HR 0.43; 95% CI, 0.11 - 1.65, p = 0.22], and Major Bleeding [HR 0.56; CI 95% 0.34 - 0.93, p = 0.02].

Conclusion

Anticoagulation of patients with HCM and AF using NOACs was associated with lower risk of ischemic stroke and thromboembolic events in the NOACs group. There was also a statistically significant reduction of all-cause mortality and major bleeding among patients with AF and HCM who had received NOACs as compared to VKA. There was a notable reduction of ICH in the NOACs group as well. Further clinical trials are needed to further assess the long term benefits of using NOACs in these patients.

Alterations of cytochrome P450 and the occurrence of persistent organic pollutants in tilapia caged in the reservoirs of the Iguaçu River

Environmental chemicals originating from human activities, such as persistent organic pollutants (POPs), may interfere with the endocrine system of aquatic organisms. The effect of these chemicals on biota and human populations is of high public concern but remains poorly understood, especially in aquatic environments of South America. The aim of this study was to investigate the bioavailability of POPs and the related effects in caged male tilapia (Oreochromis niloticus) in four cascading reservoirs of the Iguaçu River, Southern Brazil. POPs including organochlorine pesticides (OCPs), polychlorinated biphenyl (PCBs), and polybrominated diphenyl ethers (PBDEs) were determined in the reservoir water and tissue samples of tilapia after two months of exposure. The PCB levels in water (14.7 ng L^-1) were 14 times higher than the limits permitted by the Brazilian legislation in the Salto Santiago (SS) reservoir. Similarly, concentrations of aldrin and its metabolites (6.05 ng L^-1) detected in the water sample of the Salto Osório (SO) reservoir were also above the permitted limits. RT-qPCR analysis revealed different transcript levels of cytochrome P450 enzymes (CYP1A and CYP3A) in the liver among the four groups, with induced activity in tilapia from the SS reservoir. Quantification of the CYP3A mRNA expression and catalytic activity showed higher values for fish caged at the SS reservoir. The fish from this site also had a higher number of eosinophils observed in the testes. Although overt measurements of endocrine disruption were not observed in caged fish, alteration of CYP enzymes with co-occurrence of organochlorine contaminants in water may suggest bioavailability of contaminants from agricultural sources to biota. Additional studies with feral or caged animals for a longer duration may be necessary to evaluate the risks of the waterways to humans and wildlife.

Allantoin as an independent marker associated with carotid intima-media thickness in subclinical atherosclerosis

Allantoin is the main product of uric acid oxidation and was found to be augmented in atherosclerotic plaque in human autopsy and in animal models of atherosclerosis. Uric acid is abundant in human plasma and is prone to oxidation in inflammatory conditions such as atherosclerosis. In this study, we found a significant increase in plasma uric acid (P=0.002) and allantoin (P=0.025) in participants of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) that presented common carotid intima-media thickness (c-IMT) within the 75th percentile (c-IMT≥P75). Multiple linear regression showed an association of c-IMT with uric acid (β=0.0004, P=0.014) and allantoin (β=0.018, P=0.008). This association was independent of age, the traditional risk factor LDL/HDL ratio, and non-traditional risk factors: pulse pressure, neck circumference, and the inflammatory marker myeloperoxidase. The independent and strong association of allantoin with c-IMT shows that it might be a useful marker, along with other traditional risk factors, to evaluate an early stage of atherosclerosis.

Effects of dispersed oil exposure on biomarker responses and growth in juvenile wolfish Anarhichas denticulatus

This study evaluated the sensitivity of the wolfish Anarhichas denticulatus exposed to crude oil, comparing the effects of mechanically dispersed versus chemically dispersed oil using sub-lethal endpoints. To test the toxicity of this controversial technique, two experiments involving exposure of the organisms for 48 h were conducted. The first experiment assessed the effects of oil exposure on biomarker responses. The second experiment monitored the growth of juveniles over 5 weeks after exposure. Overall, this study demonstrated that polycyclic aromatic hydrocarbon (PAH) biliary metabolites, ethoxyresorufin-O-deethylase (EROD), and acetylcholinesterase (AChE) are appropriate biomarkers to assess exposure of A. denticulatus. Growth rate, both in length and weight, was significantly higher in control compared to oil exposure treatments. The lack of differences between chemically and mechanically dispersed oils in biomarker response and growth suggests that dispersant application is no more toxic than the natural oil dispersion. The results indicate the potential for population-level effects resulting from exposure to oil.

[Association of methemoglobinemia and glucose-6-phosphate dehydrogenase deficiency in malaria patients treated with primaquine]

This study had the aim of investigating occurrences of methemoglobinemia among individuals with glucose-6-phosphate dehydrogenase deficiency during treatment for malaria infection using primaquine. Patients with a diagnosis of malaria caused by Plasmodium vivax or the V+F mixture (Plasmodium vivax + Plasmodium falciparum) were selected. Group 1 consisted of 74 individuals with a clinical diagnosis of methemoglobinemia and Group 2 consisted of 161 individuals without a clinical diagnosis of methemoglobinemia. The glucose-6-phosphate dehydrogenase deficiency rates (numbers of enzymopenic individuals) in Groups 1 and 2 were 51.3% (38) and 8.7% (14) respectively. These data demonstrated a statistically significant association with methemoglobinemia only among the individuals in Group 1 (p<0.05). Investigation of the relationship between methemoglobinemia and glucose-6-phosphate dehydrogenase deficiency showed that there was a possible association such that enzymopenic individuals may develop methemoglobinemia more frequently.