Effect of vitamin D deficiency on the development of postoperative atrial fibrillation in coronary artery bypass patients

Effect of preoperative vitamin D on postoperative atrial fibrillation incidence after coronary artery bypass grafting

BACKGROUND

Post-operative atrial fibrillation (POAF) is associated with adverse long-term cardiovascular events.

OBJECTIVES

This study investigated the effects of a high-dose vitamin D administered preoperatively on the postoperative atrial fibrillation (POAF) incidence in patients with vitamin D deficiency following coronary artery bypass grafting (CABG) surgery.

METHODS

This randomized controlled clinical trial was conducted on 246 CABG patients with vitamin D deficiency. All patients were randomly divided into intervention and control groups including 123 cases for each group. In the intervention group, from 3 days before surgery, they received a daily dose of 150,000 units of vitamin D orally (50,000 units of Vit D tablet three times a day) and the patients in the control group received placebo tablets before surgery. All patients in the intervention group were assessed continuously for the occurrence of POAF during the recovery period.

RESULTS

In terms of gender, age, and BMI there were no significant differences between intervention and control groups. Our findings showed that the use of vitamin D supplements did not cause a significant change in the duration of intubation and hospitalization. The ratio of POAF following CABG surgery in the control and treatment groups was 26% and 11.4%, respectively (odds ratio = 0.36; 95% CI = 0.18-0.72; P = 0.003).

CONCLUSIONS

Our findings revealed that high-dose vitamin D supplementation before CABG surgery significantly reduced the incidence of POAF. Further multicenter randomized trials with larger sample sizes are certainly warranted to confirm our results.

Prognostic value of circulating macrophage inhibitory cytokine 1-growth differentiation factor 15 (MIC-1/GDF15) in obesity: Relation with vascular endothelial growth factor (VEGF) and markers of oxidative stress

Background: Macrophage inhibitory cytokine 1-Growth differentiation Factor 15 (MIC-1/GDF15) and vascular endothelial growth factor (VEGF) are novel regulators of obesity and energy homeostasis and food intake. Aims: In the current cross-sectional study, we aimed to evaluate MIC-1 and VEGF concentrations and their association with serum lipids and biomarkers of oxidative stress in obese individuals. Methods: Fifty six obese subjects, aged between 20-50 years old, participated in the current study. Anthropometric and nutritional parameters were assessed and serum and blood concentrations of MIC-1/GDF15, VEGF, markers of oxidative stress and serum lipids were evaluated. Results: Serum VEGF was strongly associated with serum lipids and MIC-1/GDF15 concentrations while serum MIC-1/GDF15 was associated with total cholesterol (TC) and VEGF levels. In multivariate regression analysis, serum VEGF, appetite and GPX were potent determinants of MIC-1/GDF15 concentrations while VEGF was only associated with serum MIC-1/GDF15. Conclusion: The findings of the current study demonstrated the association between MIC-1/GDF15 and VEGF. Moreover, a positive association between these cytokines and serum lipids, was also observed. The results suggest that MIC-1/GDF15 and VEGF might be considered as prognostic markers in obesity-related metabolic disorders. Although further mechanistic studies are needed to better clarify the underlying mechanism.

Vitamin D and Cardiovascular Diseases: An Update

Vitamin D is a vital nutrient that plays a significant part in several physiological processes within the human body, including calcium metabolism, bone health, immune function, and cell growth and differentiation. It is obtained mainly through exposure to sunlight but can be acquired from certain foods and supplements as well. Vitamin D deficiency (VDD) could be the risk factor for cardiovascular diseases (CVDs), such as heart disease and stroke. In blood vitamin D low levels have been linked with an enhanced risk of developing CVDs. However, it is unclear whether vitamin D levels are the leading cause or consequence of these conditions. While some studies highlight that taking vitamin D supplements could decrease the risk of CVD; however, more research is required to better understand the association between vitamin D and cardiovascular health. In this review, we aimed to summarize the currently available evidence supporting the association between vitamin D and CVDs and anesthesia considerations.

The Possible Influence of Vitamin D Levels on the Development of Atrial Fibrillation-An Update

Atrial fibrillation (AF) is a severe and most common supraventricular arrhythmia in humans, which, if left untreated or treated ineffectively, can lead to ischemic stroke or heart failure. It has been suggested that serum vitamin D (VitD) deficiency may be one of the critical factors influencing the onset of AF, especially in the period after cardiac surgery, such as coronary artery bypass grafting. Several papers have indicated that VitD supplementation reduces the risk of AF, significantly reducing the proportion of patients between the control and study groups in both the pre- and postoperative periods. Factors that increase the risk of AF from VitD deficiency are also further indicated, and these are age, gender, weight, season or comorbidities. In addition, the cardiodepressive mechanism of VitD is not fully understood; however, it is suggested that it acts through at least two pathways. The first indicates a direct effect of VitD on atrial muscle degradation, while the second is related to the modulation of cardiovascular depression factors. Despite many reports showing correlations between no VitD concentrations on the development of AF, this topic is still widely debated and the results from these papers are still subject to doubt. Therefore, this review aims at describing in detail the problem of correlation between VitD deficiency and the development of AF associated mainly with the postoperative period, i.e., after cardiac surgery, especially pathogenesis, and results of this correlation, taking into account recent studies, limitations and future perspectives. Due to the fact that this is still a topical problem, we believe that the collection of the latest reports and a detailed description of the problem is most appropriate in this case.

1,25-Dihydroxycholecalciferol down-regulates 3-mercaptopyruvate sulfur transferase and caspase-3 in rat model of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the commonest cause of liver morbidity and mortality and has multiple unclear pathogenic mechanisms. Vitamin D deficiency was associated with increased incidence and severity of NAFLD. Increased hepatic expression of 3-mercaptopyruvate sulfur transferase (MPST) and dysregulated hepatocyte apoptosis were involved in NAFLD pathogenesis. We aimed to explore the protective effect of 1,25-Dihydroxycholecalciferol (1,25-(OH)₂ D3) against development of NAFLD and the possible underlying mechanisms, regarding hepatic MPST and caspase-3 expression. 60 male adult rats were divided into 4 and 12 week fed groups; each was subdivided into control, high-fat diet (HFD), and HFD + VD. Serum levels of lipid profile parameters, liver enzymes, insulin, glucose, C-reactive protein (CRP), tumor necrosis factor alpha (TNF-α), and hepatic levels of malondialdehyde (MDA), total antioxidant capacity (TAC), and reactive oxygen species (ROS) were measured. BMI and HOMA-IR were calculated, and liver tissues were processed for histopathological and immunohistochemical studies. The present study found that 1,25-(OH)₂ D3 significantly decreased BMI, HOMA-IR, serum levels of glucose, insulin, liver enzymes, lipid profile parameters, CRP, TNF-α, hepatic levels of MDA, ROS, hepatic expression of MPST, TNF-α, 8-hydroxy-2'-deoxyguanosine (8-OHdG), and caspase-3; and significantly increased hepatic TAC in both HFD-fed groups. In conclusion: Administration of 1,25-(OH)₂ D3 with HFD abolished the NAFLD changes associated with HFD in 4-week group, and markedly attenuated the changes in 12-week group. The anti-apoptotic effect via decrement of caspase-3 and MPST expression are novel mechanisms suggested to be implicated in the protective effect of 1,25-(OH)₂ D3.

Vitamin D supplementation and cardiac tissue inflammation in obese rats

OBJECTIVE

The current study was aimed to evaluate the effects of active form of vitamin D on TGF- β, NF-κB and MCP-1 in heart tissue of obese rats.

METHODS

Forty rats were allocated into groups of normal diet and high fat diet for sixteen weeks; then each group was divided into two groups that received either 500 IU/kg vitamin D or placebo for five weeks. Biochemical parameters were assessed by ELISA kits.

RESULTS

Vitamin D reduced TGF-β in obese rats supplemented with vitamin D compared with other groups (P = 0.03). Moreover, vitamin D reduced MCP-1 concentrations in the heart tissues of both vitamin D administered groups compared to placebo one (P = 0.002). NF-κB in the heart of HFD + vitamin D group was significantly lower (P = 0.03). Current study also showed that vitamin D improves glycemic status and reduce insulin resistance significantly in HFD group (P = 0.008).

CONCLUSION

Vitamin D was a potential anti- inflammatory mediator of cardiovascular disease and markers of glycemic status in obese rats. Further investigations are needed to better identify the therapeutic role of this vitamin in CVD and to elucidate the underlying mechanisms.

Vitamin D supplementation and postoperative atrial fibrillation

Vitamin D is an important vitamin that has hormone-like effects in the human body. 1,25-dihydroxy vitamin D (1,25(OH)2 D) is known as the active form of vitamin D. Activated vitamin D can affect cellular proliferation, apoptosis, cellular membrane transport, immune system, and aging through genes. Postoperative atrial fibrillation (PoAF) is an important problem that increases mortality and morbidity rates after cardiac surgery operations. Various studies have been conducted on the relationship between vitamin D and PoAF. Although there are studies in the literature showing that vitamin D supplementation reduces cardiovascular mortality and morbidity in different study types (randomized vs. observational), there are also studies showing that it has no effect on clinical outcomes. Since the subject is atrial fibrillation, the conditions of the study groups such as age, the prevalence of coronary artery disease, degree of hypertension, and lung disease should be analyzed well. On the other hand, vitamin D supplementation should be carefully determined for which patient, for how long, and at what dose.

Association Between the Circulating Level of 25-Hydroxyvitamin D and Clinical Results After Cardiac Surgery: A Meta-Analysis and Systematic Review

Background: Vitamin D (VitD) is an important pleiotropic hormone for organ systems. Studies have focused on the level of VitD, especially that of 25-hydroxyvitamin D (25-(OH)-VitD), in patients after cardiac surgery and the relationship between VitD deficiency and adverse outcomes, but the results have been inconsistent. We carried out a meta-analysis to evaluate differences in the 25-(OH)-VitD level before and after cardiac surgery, and evaluated the predictive value of 25-(OH)-VitD level in the clinical outcomes of patients undergoing cardiac surgery.

Methods: Studies related to VitD level and cardiac surgery were searched from PubMed, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials databases from inception to October 2020. We applied the Newcastle–Ottawa Scale to assess the risk of a bias in individual studies. We examined the heterogeneity and publication bias and performed subgroup analyses and sensitivity analyses.

Results: Fifteen studies were included in our analysis. The 25-(OH)-VitD level was significantly lower immediately after surgery [stand mean difference (SMD), 0.69; 95%CI (0.1, 1.28), P = 0.023] and 24-h after surgery [0.84; (0.47, 1.21), 0.000] compared with that before surgery. A higher prevalence of 25-(OH)-VitD deficiency was recorded 24 h after surgery [RR, 0.59; 95%CI (0.47, 0.73), P = 0.00]. Pooled results demonstrated a significant relationship between the preoperative 25-(OH)-VitD level and vasoactive-inotropic score (VIS) [SMD, −3.71; 95%CI (−6.32, −1.10); P = 0.005], and patients with 25-(OH)-VitD deficiency revealed a comparatively poor prognosis and severe condition after cardiac surgery [−0.80; (−1.41, −0.19), 0.01]. However, 25-(OH)-VitD deficiency was not associated with the duration of stay in the intensive care unit.

Conclusions: Cardiac surgery would leads to deficiency of 25-(OH)-VitD. And the preoperative and postoperative levels of 25-(OH)-VitD are associated with adverse events, which is eligible to work as an indicator to demonstrate clinical outcomes.

Vitamin D and Cardiovascular Disease: Current Evidence and Future Perspectives

Vitamin D deficiency is a prevalent condition, occurring in about 30–50% of the population, observed across all ethnicities and among all age groups. Besides the established role of vitamin D in calcium homeostasis, its deficiency is emerging as a new risk factor for cardiovascular disease (CVD). In particular, several epidemiological and clinical studies have reported a close association between low vitamin D levels and major CVDs, such as coronary artery disease, heart failure, and atrial fibrillation. Moreover, in all these clinical settings, vitamin deficiency seems to predispose to increased morbidity, mortality, and recurrent cardiovascular events. Despite this growing evidence, interventional trials with supplementation of vitamin D in patients at risk of or with established CVD are still controversial. In this review, we aimed to summarize the currently available evidence supporting the link between vitamin D deficiency and major CVDs in terms of its prevalence, clinical relevance, prognostic impact, and potential therapeutic implications.

Health implication of vitamin D on the cardiovascular and the renal system

Vitamin D regulates the calcium and phosphorus balance in the body. The activated form of vitamin D (1 α,25-dihydroxyvitamin D) binds to vitamin D receptor which regulates genes that control cell proliferation, differentiation and apoptosis. In the cardiovascular system, the vitamin D receptor is present in cardiomyocytes and the arterial wall. A clear correlation between vitamin D level and cardiovascular diseases is established. Vitamin D deficiency affects the renin-angiotensin system leading to ventricular hypertrophy and eventually to stroke. While clinical trials highlighted the positive effects of vitamin D supplements on cardiovascular disease these still need to be confirmed. This review outlines the association between vitamin D and cardiovascular and renal disease summarising the experimental data of selective cardiovascular disorders.

The relationship between preoperative serum vitamin D deficiency and postoperative atrial fibrillation: A systematic review and meta-analysis

Postoperative atrial fibrillation (POAF) is the most common arrhythmia seen in the first days following cardiac surgeries. Recently, there is a growing discussion regarding the link between vitamin D deficiency and POAF development. This systematic review and meta-analysis of the observational studies aimed at evaluating the association between preoperative vitamin D deficiency and Postoperative atrial fibrillation. In this study, using PubMed, Scopus, Google Scholar, EMBASE, Web of Science, and Cochrane Libraries, we searched for records published before July 2020. Two reviewers screened for studies that examined the relationship between preoperative vitamin D levels and the generation of POAF. Data regarding study design, patient characteristics, definition of atrial fibrillation (AF), type of surgery, vitamin D levels, and measurement methods were extracted. Five studies were included in the meta-analysis. Our primary analysis showed a significant relationship between preoperative levels of vitamin D and POAF development (mean differences (MD) = -2.851, 95% confidence interval (CI) =-5.506 to -0.195; P value 0.035). Our meta-analysis suggested serum vitamin D deficiency is associated with an increased risk of POAF development. Further large scale interventional studies are needed to explore whether vitamin D supplementation will prevent POAF.

Postoperative complications associated with coronary artery bypass graft surgery and their therapeutic interventions

Coronary artery disease is one of the commonest surgery demanding cardiovascular diseases. Coronary artery bypass graft surgery is practiced all over the world for the treatment of coronary artery disease. Systemic trauma during the surgery is associated with a wide range of complications, some of which are fatal. Preoperative risk factors such as age, previous illness and obesity are common predictors of these adverse events. Advances in therapeutic medicine have allowed timely treatment of these adverse events and co-morbidities. This review summarizes some of the most occurring complications associated with coronary artery bypass graft and corresponding treatment options.

Atrial fibrillation after cardiac surgery and preoperative vitamin D levels: A systematic review and meta-analysis

Background

In this meta-analysis, we aimed to investigate the possible relationship between atrial fibrillation development after cardiac surgery and preoperative vitamin D levels.

Methods

Literature review was carried out in the PubMed, ScienceDirect and Ovid electronic databases without any limitation of time frame. Published studies which recorded the preoperative levels of vitamin D and atrial fibrillation after cardiac surgery in the English language were included. The results of the studies were evaluated based on either random or fixed effect model according to the presence of heterogeneity (I²>25%).

Results

A total of 1,865 articles were screened. After the article titles and abstracts were analyzed, six articles involving 769 patients which met the inclusion criteria were included. The results indicated that there was a relationship between preoperative vitamin D levels and postoperative atrial fibrillation (SMD: -0.46, 95% CI: -0.79 to -0.12; p<0.007). Heterogeneity was observed for studies conducted (I² =76.1%).

Conclusion

We concluded that low preoperative vitamin D levels were associated with the development of atrial fibrillation after cardiac surgery. However, there is a need for large-scale, randomized-controlled trials for preventing the heterogeneity of the results.

Role of Vitamin D in Patients with Heart Failure with Reduced Ejection Fraction

Heart failure (HF) with reduced ejection fraction (HFrEF) presents as the severest phenotype on the spectrum of HF. Although great progress has been made with respect to its treatment over the past 3 decades, morbidity and mortality remain high, posing a big burden on human health. Recent evidence suggests vitamin D has a critical role in maintaining heart health through activation of the vitamin D receptor expressed in cardiomyocytes, and vitamin D deficiency may be implicated in the pathophysiology of HFrEF through activation of the renin-angiotensin system, impaired calcium handling, exaggerated inflammation, secondary hyperparathyroidism, pro-fibrotic properties, and proatherogenic potential. Additionally, epidemiological data disclosed that vitamin D deficiency is highly prevalent in patients with HFrEF and is associated with poor clinical outcomes. However, randomized control trials of vitamin D supplementation in HF, especially in HFrEF, have shown inconsistent results. Thus, this article aims to review the epidemiology, pathophysiology, and prognostic value of vitamin D deficiency in HF, with a special focus on randomized control trials associated with vitamin D supplementation in patients with HFrEF.

The Status and Research Progress on Vitamin D Deficiency and Atrial Fibrillation

Atrial fibrillation is a common type of arrhythmia and is an important cause of stroke and heart failure. vitamin D is an emerging risk factor of AF, and is implicated in the pathophysiology of atrial fibrillation. It has been established that this vitamin is extensively involved in the regulation of both the renin angiotensin aldosterone system and the immune system. Epidemiological studies have not yet reached a consensus on the possible association between vitamin D deficiency and atrial fibrillation. Better research designs and methods can further clarify the relationship between the two.

The relationship between vitamin D and risk of atrial fibrillation: a dose-response analysis of observational studies

Background

The relationship between serum vitamin D and atrial fibrillation (AF) or postoperative atrial fibrillation (POAF) in patients undergoing coronary artery bypass graft (CABG) is still debated. It is also unclear whether there is a dose-response relationship between circulating vitamin D and the risk of AF or POAF.

Methods

The Cochrane Library, PubMed, and Embase databases were searched for relevant studies. We used a “one-stage approach” with a restricted cubic spline model to summarize the dose-specific relationships between serum vitamin D and AF. Relative risk (RR) was used to measure the effects in this meta-analysis.

Results

In total, 13 studies were included with a total of 6519 cases of AF among 74,885 participants. Vitamin D deficiency (< 20 ng/ml) was associated with increased risks of AF (RR: 1.23, 95% CI: 1.05–1.43). In the dose-response analysis, the summary RR for a 10 ng/ml increased in vitamin D was 0.88 (95% CI: 0.78–0.98) and there was no evidence of a non-linear association, P_{non-linearity} = 0.86. In the age subgroup, high vitamin D (per 10 ng/ml increase) reduced the risk of AF in the older group (> 65 years) (RR = 0.68, 95% CI = 0.52–0.89) but not among young individuals (< 65 years) (RR = 0.87, 95% CI = 0.72–1.06). In addition, a strong association was found between a 10 ng/ml increased in vitamin D and POAF incident in the patient after CABG (RR: 0.44, 95% CI: 0.24–0.82).

Conclusion

Our dose-response meta-analysis suggested serum vitamin D deficiency was associated with an increased risk of AF in the general population and POAF in patients after CABG. Further studies are needed to explore the age difference in the association between serum vitamin D level and the risk of AF and whether vitamin D supplements will prevent AF.

Trial registration

This study has been registered with PROSPERO (International prospective register of systematic reviews)-registration number-CRD42019119258.

CARDIO-RENAL METABOLIC SYNDROME AND PRO-INFLAMMATORY FACTORS: THE DIFFERENTIAL EFFECTS OF DIETARY CARBOHYDRATE AND FAT

BACKGROUND

We aimed to evaluate whether a high carbohydrate or a high fat diet differs in alteration of the inflammatory and metabolic risk factors in cardio-renal metabolic syndrome in rats.

METHODS

Twelve male Wister rats were randomly divided into two groups: one received diet 1 standard pellet rat diet (D1) containing 10% fat, 50% carbohydrate, 25% protein and another group received diet 2 (D2) containing 59% fat, 30% carbohydrate and 11% protein for 16 weeks. Weight was recorded weekly. FSG and insulin levels were measured using an enzymatic spectrophotometric and a standard ELISA kit respectively. Inflammatory parameters including TGF-β, MCP-1, TNF-α, IL-1β, IL-6 in the renal and cardiac tissues of rats were evaluated by ELISA technique.

RESULT

Food intake in D1 and D2 groups increased in the study period, however food intake in D2 group was significantly higher compared with D1 group. FSG, HOMA and TG concentrations in D2 group were significantly higher compared to D1 group. Moreover, TGF-β and MCP-1 concentrations in the renal tissues of D2 group and TNF-α in the cardiac tissues of D1 group were significantly higher compared with D1 group (P<0.05). Positive associations between IL-1β and TG and between HOMA, FSG with TGF-β and MCP-1 in the renal tissue of animals were also identified.

Effects of high-dose vitamin D supplementation on the occurrence of post-operative atrial fibrillation after coronary artery bypass grafting: randomized controlled trial

OBJECTIVE

This study aimed to investigate the preventive effects of a high-dose vitamin D administered preoperatively on the post-operative atrial fibrillation (POAF) occurrence in patients with insufficient or deficient serum vitamin D levels who underwent coronary artery bypass grafting (CABG) surgery.

METHODS

The study was a randomized controlled, blinded and parallel-arm trial conducted on 116 who had vitamin D deficiency or insufficiency during the pre-operative evaluation were included in the study conducted between January 2018 and January 2019. Patients were divided into those who received oral vitamin D (treatment group; n = 58) and those who did not (control group; n = 58) 48 h before CABG surgery. In the treatment group, patients with vitamin D deficiency were administered 300.000 IU vitamin D orally and those with vitamin D insufficiency 150.000 IU 48 h preoperatively. Patients were followed up during hospitalisation process with respect to POAF.

RESULTS

Both groups showed no significant differences with regard to age, gender, body mass index, creatine level, left atrial diameter, pre-operative drug use, calcium level, ejection fraction, diabetes mellitus and hypertension. The ratio of POAF occurrence found in the treatment and control groups were 12.07% and 27.59%, respectively. Vitamin D treatment was found to reduce the risk of POAF development by 0.24 times (p = 0.034).

CONCLUSION

In this study with sufficient sample size, preoperative short-term high-dose vitamin D supplementation was found to be significantly preventive to the occurrence of POAF in patients with vitamin D insufficiency and deficiency who underwent CABG surgery.

Effect of Plasma Level of Vitamin D on Postoperative Atrial Fibrillation in Patients Undergoing Isolated Coronary Artery Bypass Grafting

Objective

Postoperative atrial fibrillation (PoAF) is a common complication after coronary artery bypass grafting (CABG). The aim of the present study was to evaluate the association between development of PoAF and vitamin D levels in patients undergoing isolated CABG.

Methods

This prospective randomized clinical trial was conducted on the patients with isolated CABG. The study was terminated when 50 patients in both PoAF(+) group and PoAF(-) group were reached. Development of AF until discharge period was assessed. Vitamin D level was measured immediately after AF; it was measured on the discharge day for the patients without PoAF. Predictive values of the independent variables were measured for the development of PoAF.

Results

The groups were separated as PoAF(-) group (66% male, mean age 58.18±10.98 years) and PoAF(+) group (74% male, mean age 61.94±10.88 years). 25(OH) vitamin D level (OR=0.855, 95% CI: 0.780-0.938, P=0.001) and > 65 years (OR=3.525, 95% CI: 1.310-9.483, P=0.013) were identified as an independent predictor of postoperative AF after CABG surgery in multivariate analysis. The cut-off level for 25(OH) vitamin D level in receiver-operating characteristic curve analysis was determined as 7.65 with sensitivity of 60% and specificity of 64% for predicting PoAF (area under the curve: 0.679, P=0.002).

Conclusion

Vitamin D level is considered an independent predictor for development of PoAF. Lower vitamin D levels may be one of the reasons for PoAF.

Preventive Effect of Preoperative Vitamin D Supplementation on Postoperative Atrial Fibrillation

Objective

To assess the relationship between preoperative vitamin D (vitD) supplementation and the development of postoperative atrial fibrillation (POAF).

Methods

The study group consisted of 328 consecutive patients. The ınfluence of preoperative vitD supplementation on POAF was reviewed in 136 patients who underwent coronary artery bypass graft surgery with vitD insufficiency (n=80) and vitD deficiency (n=56). Patients were assigned to receive either oral vitD (50.000 U) (treatment group, n=68) or not (control group, n=68) 48 hours before surgery. Patients were followed up during hospitalisation process with respect to POAF.

Results

There was no significant difference between treatment and control groups with regards to age, gender, diabetes mellitus, smoking history, chronic obstructive pulmonary disease, left atrial diameter, and biochemical parameters. Also, there was no significant difference between these groups with regards to mean vitD level on both insufficiency and deficiency patients (24.6±3.7 vs. 24.9±3.9 ng/ml P=0.837, 11.4±4.9 vs. 10.9±5.2 ng/ml P=0.681, respectively). Although the occurrence of POAF was not significantly different among treatment and control groups in patients with vitD insufficiency (31% vs. 33% P=0.538), there was a significant difference between the two groups regarding to POAF in patients with vitD deficiency (18% vs. 29% P=0.02).

Conclusion

Although preoperative vitD supplementation was not found to be associated with prevention of POAF in patients with vitD insufficiency, it was found to be strongly associated with prevention of POAF in those with vitD deficiency.

Relationship between Vitamin D Levels and the Incidence of Post Coronary Artery Bypass Graft Surgery Atrial Fibrillation

Background: Postoperative atrial fibrillation (POAF) is probably a consequence of inflammation. Vitamin D is known for its anti-inflammatory properties. The aim of this study was to evaluate the effects of vitamin D levels on the incidence of POAF. Methods: In a prospective cohort study, patients were monitored for the occurrence of POAF during the first 5 days after coronary artery bypass grafting surgery in Tehran Heart Center. Those with concomitant valvular surgeries were excluded. Thereafter, they were divided into 2 groups: with or without POAF. Vitamin D levels were assessed in all the patients. The relationship between the vitamin D level and the incidence of POAF was evaluated and compared between the groups using the Mann-Whitney U test. Results: The study population comprised of 156 patients. The mean age was 62.8±8.6 years, and 105 (67.3%) patients were male. Of the 156 patients, 29 (19%) developed POAF. The median preoperative vitamin D level was 15.3 in the group with POAF and 25.3 in the group without POAF (P=0.07). Conclusion: Our results demonstrated no significant relationship between vitamin D levels and the occurrence of POAF.

Adipose Tissue Inflammation and Oxidative Stress: the Ameliorative Effects of Vitamin D

Obesity is a low-grade inflammatory disease and is associated with numerous comorbidities. The current study was aimed to evaluate the effects of vitamin D administrations on markers of inflammation and oxidative stress in adipose tissue of high-fat diet-induced obese rats. In the beginning of the study, 40 rats were divided into two groups: normal diet and high-fat diet (HFD) for 16 weeks; then, each group was subdivided into two groups including ND, ND + vitamin D, HFD, and HFD + vitamin D. Vitamin D supplementation was done for 5 weeks at 500 IU/kg dosage. Tumor necrosis factor (TNF)-α, interleukin (IL)-1β, monocyte chemoattractant protein (MCP)-1, transforming growth factor (TGF)-β and IL-6 concentrations and markers of oxidative stress including glutathione peroxidase (GPx), superoxide dismutase (SOD), malondialdehyde (MDA), and catalase (CAT) concentrations in adipose tissue of rats were determined using ELISA kits and spectrophotometry methods, respectively. Vitamin D treatment led to a significant reduction in adipose tissue TNF-α concentrations in both ND + vitamin D and HFD + vitamin D groups (P < 0.05). Adipose tissue MCP-1 concentration also reduced in HFD + vitamin D group compared with HFD group. Among markers of oxidative stress in adipose tissue, SOD and GPx concentrations significantly increased in adipose tissue of HFD + vitamin D treated group compared with other groups (P < 0.05). Reduced food intake and weight gain was also occurred after vitamin D treatment. Vitamin D improved adipose tissue oxidative stress and inflammatory parameters in obese rats. Vitamin D treatment was also associated with decreased food intake and decreased weight gain in animals under a high-fat diet. Further studies are needed to better clarify the underlying mechanisms.

Clinical Risk Factors for Postoperative Atrial Fibrillation among Patients after Cardiac Surgery

BACKGROUND

Postoperative atrial fibrillation (POAF) is a common arrhythmia following cardiac surgery and is associated with increased health-care costs, complications, and mortality. The etiology of POAF is incompletely understood and its prediction remains suboptimal. Using data from published studies, we performed a systemic review and meta-analysis to identify preoperative clinical risk factors associated with patients at increased risk of POAF.

METHODS

A systematic search of PubMed, MEDLINE, and EMBASE databases was performed.

RESULTS

Twenty-four studies that reported univariate analysis results regarding POAF risk factors, published from 2001 to May 2017, were included in this meta-analysis with a total number of 36,834 subjects. Eighteen studies were performed in the United States and Europe and 16 studies were prospective cohort studies. The standardized mean difference (SMD) between POAF and non-POAF groups was significantly different (reported as [SMD: 95% confidence interval, CI]) for age (0.55: 0.47-0.63), left atrial diameter (0.45: 0.15-0.75), and left ventricular ejection fraction (0.30: 0.14-0.47). The pooled odds ratios (ORs) (reported as [OR: 95% CI]) demonstrated that heart failure (1.56: 1.31-1.96), chronic obstructive pulmonary disease (1.36: 1.13-1.64), hypertension (1.29: 1.12-1.48), and myocardial infarction (1.18: 1.05-1.34) were significant predictors of POAF incidence, while diabetes was marginally significant (1.06: 1.00-1.13).

CONCLUSION

The present analysis suggested that older age and history of heart failure were significant risk factors for POAF consistently whether the included studies were prospective or retrospective datasets.

The effects of vitamin D administration on brain inflammatory markers in high fat diet induced obese rats

Background

Obesity induced brain inflammation is associated with cognitive disorders. We aimed to investigate the influence of vitamin D on hypothalamus and hippocampus inflammatory response in high-fat diet induced obese rats.

Methods

In the beginning of the study, 40 rats were divided into two groups: control diet and high fat diet (HFD) for 16 weeks; then each group subdivided into two groups including: N, ND + vitamin D, HFD and HFD + vitamin D. Vitamin D supplementation was done for 5 weeks at 500 IU/kg dosage. IL-6, IL-1β, NF-Kβ and acetylcholine (ACH) and brain derived neurotropic factor (BDNF) concentrations in hippocampus and hypothalamus homogenate samples were measured by commercial ELISA kits.

Results

Vitamin D administration, reduced food intake and weight gain in studied groups (P < 0.001). Vitamin D reduced hippocampus acetylcholine concentrations in ND + vitamin D group (P < 0.001). High fat diet increased hippocampus IL-6 concentrations significantly (P < 0.05) compared with normal diet receiving groups. Vitamin D could not have significant effects on IL-6 concentrations. Vitamin D administrations reduced IL-1β, NF-Kβ and acetylcholine concentration and BDNF concentrations in ND + vitamin D compared with ND group. These reductions were not significant in HFD + vitamin D versus HFD group.

Conclusion

According to our results, vitamin D reduced food intake and weight gain and modulated the HFD induced inflammatory response in hippocampus and hypothalamus of high fat diet induced obesity. Therefore, this neurosteroid, can be suggested as a supplemental therapeutic tool in prevention of obesity related cognitive and neurodegenerative problems.

Vitamin D and new-onset atrial fibrillation: A meta-analysis of randomized controlled trials

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, which affects 1.5% to 2% of the general population. More than six million Europeans suffer from AF. To research vitamin D levels in the prevention of new-onset atrial fibrillation (AF), we conducted a systematic review of randomized controlled trials (RCTs). We focused on the vitamin D levels in the prevention of new-onset AF. The outcomes assessed were vitamin D levels, left ventricular ejection fraction (LVEF), and left atrium diameter. Six RCTs ultimately met the inclusion criteria in the meta-analysis. The outcomes of Vitamin D levels (MD = -4.27, 95% CI = -5.20 to-3.34, P = 0.30) in the new-onset AF showed no significant difference. The left atrium diameter (MD = 1.96, 95% CI = 1.48 to 2.60, P < 0.01) between new-onset AF and LVEF (MD = -0.92, 95% CI = -1.59 to -0.26, P < 0.01) showed significant difference. Our study shows that circulating vitamin D levels may not play a major role in the development of new-onset AF.

Framingham risk score for estimation of 10-years of cardiovascular diseases risk in patients with metabolic syndrome

BACKGROUND

There are a few studies evaluating the predictive value of Framingham risk score (FRS) for cardiovascular disease (CVD) risk assessment in patients with metabolic syndrome in Iran. Because of the emerging high prevalence of CVD among Iranian population, it is important to predict its risk among populations with potential predictive tools. Therefore, the aim of the current study is to evaluate the FRS and its determinants in patients with metabolic syndrome.

METHODS

In the current cross-sectional study, 160 patients with metabolic syndrome diagnosed according to the National Cholesterol Education Adult Treatment Panel (ATP) III criteria were enrolled. The FRS was calculated using a computer program by a previously suggested algorithm.

RESULTS

Totally, 77.5, 16.3, and 6.3% of patients with metabolic syndrome were at low, intermediate, and high risk of CVD according to FRS categorization. The highest prevalence of all of metabolic syndrome components were in low CVD risk according to the FRS grouping (P < 0.05), while the lowest prevalence of these components was in high CVD risk group (P < 0.05). According to multiple logistic regression analysis, high systolic blood pressure (SBP) and fasting serum glucose (FSG) were potent determinants of intermediate and high risk CVD risk of FRS scoring compared with low risk group (P < 0.05).

CONCLUSION

In the current study, significant associations between components of metabolic syndrome and different FRS categorization among patients with metabolic syndrome were identified. High SBP and FSG were associated with meaningfully increased risk of CVD compared with other parameters.

TRIAL REGISTRATIONS

The study is not a trial; the registration number is not applicable.

The Role of Toll-Like Receptors and Vitamin D in Cardiovascular Diseases-A Review

Cardiovascular diseases are the leading cause of mortality worldwide. Therefore, a better understanding of their pathomechanisms and the subsequent implementation of optimal prophylactic and therapeutic strategies are of utmost importance. A growing body of evidence states that low-grade inflammation is a common feature for most of the cardiovascular diseases in which the contributing factors are the activation of toll-like receptors (TLRs) and vitamin D deficiency. In this article, available data concerning the association of cardiovascular diseases with TLRs and vitamin D status are reviewed, followed by a discussion of new possible approaches to cardiovascular disease management.

Cardiac tissue oxidative stress and inflammation after vitamin D administrations in high fat- diet induced obese rats

BACKGROUND

Obesity is associated with numerous metabolic and inflammatory disorders. The current study was aimed to evaluate the effects of vitamin D administration on the markers of oxidative stress and inflammation in the cardiac tissue of high-fat diet induced obese rats.

METHODS

In the beginning of the study, 40 male Wistar rats were divided into two groups: normal diet (ND) and high fat diet (HFD) for 16 weeks; then each group subdivided into two groups including: ND, ND + vitamin D, HFD and HFD + vitamin D. Vitamin D supplementation was done for 5 weeks at 500 IU/kg dosage. Tumor necrosis factor (TNF)-α concentration and markers of oxidative stress including glutathione peroxidase (GPx), superoxide dismutase (SOD), malondialdehyde (MDA) and catalase (CAT) concentrations in the cardiac tissue and serum concentrations of lipids in rats were determined using ELISA kits and spectrophotometry methods respectively.

RESULTS

According to our results, GPx activity in ND and ND + vitamin D group was significantly higher compared with HFD group. Similarly, SOD activity was also significantly increased in ND + vitamin D group compared with ND and HFD groups. Moreover, vitamin D administration, significantly reduced catalase activity in ND + vitamin D and HFD + vitamin D groups (P < 0.05). TNF-α concentration in heart tissue in ND + vitamin D group significantly reduced compared with ND group. Cardiac tissue MDA concentration in baseline or after vitamin D administration did not changed significantly.

CONCLUSION

Vitamin D improved cardiac oxidative stress and inflammatory markers in HFD induced obese rats. Further studies in human models are needed to further confirm the use of this nutrient in daily clinical practice.