Overweight and Aging Increase the Risk of Atrial Fibrillation After Cardiac Surgery Independently of Left Atrial Size and Left Ventricular Ejection Fraction

Abstract

Background: Body mass index (BMI), age, left atrium (LA) dimensions and left ventricular ejection fraction (LVEF) have been linked to post-operative atrial fibrillation (POAF) after cardiac surgery. The aim was to better define the role of these risk factors. Methods: This study evaluated 249 patients (without prior atrial dysrhythmia) undergoing cardiac or aortic surgery . Prior to surgery the following data were collected: age (yrs), BMI (kg/m2), LA diameter (cm), LA area (cm2), LVEF (%), the presence of arterial hypertension (AH) and of diabetes, tyroid stimulating hormone (TSH, mU/L) and, creatinine (mg/dL). Results: Patients with (n. 127, 51%) and without POAF (n. 122, 49%) were compared. No difference was observed for sex, LA diameter, LA area, LVEF, TSH and diabetes. Instead, patients with PoAF had higher values of age, BMI, creatinine and a greater prevalence of AH and Bentall procedures. Multivariable analysis showed that the only independent predictors of PoAF were: age (OR = 1,05, CI 95% 1,025-1,076, p= 0,0001) and BMI (OR=1,095, CI 95% 1,015-1,182, p= 0,019). Conclusions: Results suggest that advanced age and a higher value of BMI are strong risk factors for POAF in patients without previous AF. This even in the presence of comparable LA dimensions and LVEF.

Determinants of atrial fibrillation after cardiac surgery

“…Advancing age is the most widely proven major predictor in the occurrence of POAF [27][28][29][30][31]. In patients aged 72 years or older, the risk of POAF is approximately five times greater than in patients who are aged 55 or younger [2].…”

“…Altered expression of micro-RNA 199a and increased levels of cardiac SIRT1 protein are associated with the occurrence of atrial fibrillation after coronary artery bypass graft surgery [39] miRNA-199a was lowered in 29 In patients with POAF the mtDNA copy number was drastically higher (n = 101, 21%) than in those who remained in sinus following CABG procedure (p < 0.001) [40] Single nucleotide polymorphisms (SNPs)…”

“…In the case of POAF, modifiable predictors include diseases such as obesity and a high BMI [29,42,43]. A metaanalysis by Phan et al [43] found that patients who were obese were significantly more likely to develop POAF than the non-obese patients they were compared to (p = 0.006).…”