Wider perioperative glycemic fluctuations increase risk of postoperative atrial fibrillation and ICU length of stay

Abstract

IntroductionPostoperative atrial fibrillation (POAF) is a common complication following cardiac surgery associated with increased morbidity and mortality. Although sustained hyperglycemia is a known risk factor of AF and poor ICU outcomes, emerging in-vitro studies reveal acute glycemic fluctuations to be an additional independent predictor of AF. The effect of acute glycemic fluctuations on the incidence of POAF in the clinical setting remains unclear. We aim to investigate the effect of the magnitude of acute perioperative glycemic fluctuations on the incidence of POAF in a multi-ethnic Southeast-Asian population.MethodsWe obtained data from1743 patients who underwent elective CABG in a tertiary heart centre from 2009–2011. Patients were kept to a tight baseline glycemic control in accordance with hospital protocol. The magnitude of the difference between the highest and lowest perioperative glucose levels up till the first 48 postoperative hours was employed as a measure of glycemic fluctuation. Patients were divided into 4 groups for analysis based on the magnitude of glycemic fluctuation:A)0-2mmol/L(N = 147); B)>2-4mmol/L(N = 426); C)>4-6mmol/L(N = 513); D)>6mmol/L(N = 657).Our primary outcome was the incidence of POAF. Secondary outcomes included ICU and 30-day mortality and length of stay.ResultsThe overall incidence of POAF was 14.7%. This increased as the magnitude of glycemic fluctuation increased, and was statistically highest in Group D(16.4%) as compared with the other 3 sub-groups. Multivariate logistic regression revealed the magnitude of perioperative glycemic fluctuation to be an independent risk factor of POAF(O.R.1.06, 95% C.I.1.01–1.11, p = 0.014).ICU length of stay was statistically highest in Group D(63.1 hours, p = < .001). However, ICU and 30 day mortality rates were similar among the 4 groups.ConclusionIncreased magnitudes of acute perioperative glycemic fluctuations are associated with a significantly increased risk of POAF and length of ICU stay; and should therefore be minimised but balanced against the risks of hypoglycemia so as to avoid POAF and optimise patient outcomes.

Increased glucose variability is associated with atrial fibrillation after coronary artery bypass

“…Two studies demonstrated that elevated 24‐hour postoperative GV increased the risk of major adverse events after CABG, but not following isolated cardiac valvular surgery . In addition, a recent single‐center study from Singapore found that increased GV was an independent risk factor for POAF and increased intensive care unit length of stay in elective CABG patients . These retrospective studies align well with the results from two animal models which demonstrate that hyperglycemia and glucose fluctuations induce atrial fibrillation and aggravate arrhythmias …”

“…The results of this present study are consistent with prior reports that postoperative hyperglycemia and increased GV increase the risk of POAF . Sim et al performed a single‐center study of 1743 elective CABG patients in Singapore and demonstrated that wider postoperative glycemic fluctuation in the first 48 hours was an independent risk factor for POAF and increased ICU length of stay. Similar to the present study, they also reported that increased age and increased intraoperative blood transfusions were significant factors associated with PAOF in their univariate analysis.…”

“…Increased postoperative glucose variability (GV) may contribute to atrial fibrillation and major adverse events after CABG and may be a feasible therapeutic target to reduce these poor outcomes . GV refers to swings in glucose levels throughout the day, including hypoglycemic episodes, hyperglycemic episodes, and postprandial changes .…”

Atrial fibrillation and type 2 diabetes: Prevalence, etiology, pathophysiology and effect of anti‐diabetic therapies

“… A meta‐analysis of studies with a long follow‐up period did show an increase in the incidence of AF that was proportional to the HbA1c . However, a study of type 2 diabetic patients who had undergone cardiac surgery did not show an association between HbA1c and post‐operative AF, although peri‐operative glycaemic fluctuations appear to increase the risk of post‐operative AF . In the ACCORD study, aggressive diabetes management with a target HbA1c of less than 6% failed to reduce the incidence of NAF compared to a target of 7.0% to 7.9% .…”

Determinants of left intra‐atrial electromechanical delay as evaluated by tissue Doppler imaging in candidates for coronary artery bypass graft surgery

“…In addition, one‐fifth of patients with CAD are affected by AF . The prevalence of AF after CABGS in patients with CAD has been reported to be about 15% …”