The impact of abdominal aortic aneurysm on muscle mass and energy expenditure: A novel preliminary investigation

Genetically predicted basal metabolic rate and venous thromboembolism risk: a Mendelian randomization study

Background

Basal metabolic rate (BMR) is the minimum amount of energy needed by the body to carry out essential physiological functions. The goal of this study was to evaluate whether BMR causally influences venous thromboembolism (VTE) and its subtypes in European individuals.

Methods

A two-sample Mendelian randomization (MR) was performed. Within a genome-wide association study (GWAS) involving 454,874 people, genetic variants were chosen as instrumental variables based on their significant associations (p < 5 × 10-8) with BMR and their limited linkage disequilibrium (r2 < 0.001). The FinnGen project served as sources for summary statistics of VTE, encompassing different subtypes.

Results

Using the multiplicative random-effect inverse variance weighted method, our investigation revealed that one standard deviation higher BMR was associated with VTE (odds ratio [OR] = 1.684, 95% confidence interval [CI]: 1.465-1.936, p = 2.339 × 10-13), PE (OR = 1.824, 95% CI: 1.512-2.200, p = 3.399 × 10-10), and DVT of lower extremities (OR = 1.887, 95% CI: 1.562-2.280, p = 4.778 × 10-11). The consistency of these associations was observed in sensitivity analyses using various MR techniques like Mendelian randomization pleiotropy residual sum and outlier, MR-Egger, weighted median, and contamination mixture method. In addition, multivariable MR revealed direct effects of BMR on VTE and its subtypes when taking body mass index and current tobacco smoking into account.

Conclusion

Higher BMR may increase the risk of VTE and its subtypes including PE and DVT of lower extremities.

Causal association between basal metabolic rate and risk of cardiovascular diseases: a univariable and multivariable Mendelian randomization study

Basal metabolic rate (BMR) is associated with cardiovascular health; however, the causal relationship between BMR and the risk of cardiovascular diseases (CVDs) remains unclear. This study aimed to investigate the potential causal relationship of BMR on common CVDs including aortic aneurysm (AA), atrial fibrillation and flutter (AFF), calcific aortic valvular stenosis (CAVS), heart failure (HF), and myocardial infarction (MI) by Mendelian randomization (MR). The univariable MR analysis using inverse variance weighted (IVW) model as the primary analysis method revealed that genetically predicted higher BMR causally increased the risk of AA [IVW odds ratio (OR) = 1.34, 95% confidence interval CI  1.09-1.65, p = 0.00527], AFF (IVW OR = 1.87, 95% CI  1.65-2.12, p = 1.697 × E-22), and HF (IVW OR = 1.35, 95% CI  1.20-1.51, p = 2.364 × E-07), while causally decreasing the risk of MI (IVW OR = 0.83, 95% CI  0.73-0.93, p = 0.00255). In the multivariable MR analysis, which controlled for common cardiovascular risk factors, direct effects of BMR on an increased risk of AA and AFF, as well as a decreased risk of MI, but an attenuated causal effect on HF, were observed. In conclusion, the current MR study provides evidence for a causal relationship between BMR and the risk of AA, AFF, HF, and MI.

Management of Abdominal Aortic Aneurysm Disease: Similarities and Differences Among Cardiovascular Guidelines and NICE Guidance

The development of endovascular techniques has improved abdominal aortic aneurysm (AAA) management over the past 2 decades. Different cardiovascular societies worldwide have recommended the endovascular approach as the standard of care in their currently available guidelines. While endovascular treatment has established its role in daily clinical practice, a new debate has arisen regarding the indications, appropriateness, limitations, and role of open surgery. To inform this debate, the MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials databases were searched from 2010 to May 2020; the systematic search identified 5 articles published between 2011 and 2020 by 4 cardiovascular societies and the National Institute of Health and Care Excellence (NICE). Four debatable domains were assessed and analyzed: diagnostic methods and screening, preoperative management, indications and treatment modalities, and postoperative follow-up and endoleak management. The review addresses controversial proposals as well as widely accepted recommendations and "gray zone" issues that need to be further investigated and analyzed, such as screening in women, medical management, and follow-up imaging. While the recommendations for AAA management have significant overlap and agreement among international cardiovascular societies, the NICE guidelines diverge regarding the role of open repair in aortic disease, recommending conventional surgery in most elective cases.

Preoperative Evaluation of the Renal Function before the Treatment of Abdominal Aortic Aneurysms

BACKGROUND

Chronic impaired renal function constitutes a major risk factor of morbi-mortality during the treatment of an abdominal aortic aneurism (AAA). The inflammatory state due to the AAA could result in a reduction in the muscular mass and an overestimation of the glomerular filtration rate (GFR) with the usual formulas. The objective of this study was to determine if the formulas used to evaluate the estimated GFR were adapted in patients with AAA.

MATERIALS AND METHODS

Between August 2013 and November 2014, we conducted an exploratory study to evaluate the renal function before surgery for AAA in 28 patients. The renal function was evaluated by (1) the dosage of plasmatic creatinine, (2) the GFR estimated with the Cockroft-Gault, Modification of Diet in Renal Disease (MDRD), and chronic kidney disease epidemiology collaboration (CKD-EPI) formulas, (3) the creatinine clearance (CC), and (4) the direct measurement of the GFR with a reference method (iohexol clearance). Statistical analysis was carried out to compare and correlate the GFR estimated by the various formulas with the GFR measured by the reference technique.

RESULTS

The study included 21 men (75%) and 7 women (25%), with a median age of 76 years (58-89). The measured GFR was correlated with the GFR estimated from the CKD-EPI (rho = 0.78, P < 0.0001), the MDRD (rho = 0.78, P < 0.0001), the Cockroft-Gault (rho = 0.65, P = 0.0002), and CC (rho = 0.86, P < 0.0001). However, there were important individual variations between estimated and measured GFR. As regards the detection of the patients presenting a GFR <60 mL/min/1.73 m², the sensitivities of the CKD-EPI, MDRD, Cockroft-Gault formulas and CC were 64%, 64%, 71%, and 70%, respectively. Specificities were 71%, 79%, 57%, and 100%, respectively. The estimation of the GFR by the CKD-EPI formula had the lowest bias (-3.0). Bland-Altman plots indicated that the estimation of the GFR by the CKD-EPI formula had the best performance in comparison with the other methods.

CONCLUSIONS

This study found a statistical correlation between the measurement of the GFR and the various formulas available to estimation the GFR among AAA patients. The CKD-EPI formula is most appropriate. However, there were important individual variations between the measurement and the estimations of the GFR. A larger scale study is necessary to determine the profile of the patients with a risk of error in the estimation of the GFR. The French recommendations on the evaluation of the renal function before AAA treatment remain based on serum creatinine and should be revalued.