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Published on: February 26, 2013
Preoperative hemoglobin A1c predicts atrial fibrillation after off-pump coronary bypass surgery
Takeshi Kinoshita1, Tohru Asai, Tomoaki Suzuki
1Division of Cardiovascular Surgery, Shiga University of Medical Science, Otsu, Japan. kinotake@belle.shiga-med.ac.jp
Insights
Preoperative hemoglobin A1c levels independently predict atrial fibrillation (AF) after coronary bypass grafting. Lower A1c levels are associated with a higher risk of developing AF post-surgery.
Area of Science:
- Cardiovascular Surgery
- Endocrinology
- Clinical Research
Background:
- Diabetes mellitus is a known risk factor for adverse outcomes after coronary bypass grafting.
- The association between diabetes, specifically preoperative hemoglobin A1c levels, and postoperative atrial fibrillation (AF) requires further investigation.
Purpose of the Study:
- To examine the relationship between preoperative hemoglobin A1c levels and the incidence of AF following isolated off-pump coronary artery bypass grafting (CABG).
Main Methods:
- Retrospective analysis of 805 patients undergoing isolated off-pump CABG.
- Patients were categorized into tertiles based on preoperative hemoglobin A1c levels.
- Both group and continuous analyses were performed to assess the association between A1c and postoperative AF.
Main Results:
- Postoperative AF occurred in 19.8% of patients.
- Lower preoperative hemoglobin A1c levels were significantly associated with a higher incidence of AF.
- Hemoglobin A1c independently predicted AF occurrence, with an AUC of 0.70.
Conclusions:
- Preoperative hemoglobin A1c is an independent predictor of postoperative atrial fibrillation after isolated off-pump coronary bypass grafting.
- This finding highlights the importance of glycemic control in managing patients undergoing cardiac surgery.
Objective:
Diabetes mellitus has been recognized as a risk factor for mortality and morbidity after coronary bypass grafting, but a significant association between diabetes mellitus and postoperative atrial fibrillation (AF) has not been found. Although a recent study demonstrated a potential link between preoperative hemoglobin A1c level and risk of postoperative AF, there has not been sufficient examination of this relationship. We aimed to investigate the association between preoperative hemoglobin A1c and AF after isolated off-pump coronary bypass grafting.
Methods:
Of 912 consecutive patients undergoing isolated coronary bypass surgery, 805 were retrospectively analyzed for AF after excluding the following 107 cases: emergency (n=81), chronic AF (n=18), and pacemaker rhythm (n=8). We performed a group analysis with hemoglobin A1c levels categorized into tertiles of the baseline distribution and a continuous analysis based on 1% increments in hemoglobin A1c levels. The cutoff points for the tertiles were as follows: lower, 3.8-5.6% (n=283); middle, 5.7-6.7% (n=282); upper, 6.8-11.4% (n=240).
Results:
AF occurred in 159 patients (19.8%) after surgery. The median value (25th-75th percentile) of preoperative hemoglobin A1c was significantly lower in patients who developed AF than in those who did not (5.8 (5.4-6.3) vs 6.1 (5.5-7.2), p=0.01). The incidence of postoperative AF was 28.3% (80/283) in the lower tertile, 17.4% (49/282) in the middle tertile, and 12.5% (30/240) in the upper tertile (p for trend=0.01). The unadjusted odds ratio (95% confidence interval) for the association between hemoglobin A1c and postoperative AF was 0.70 (0.61-0.83) per 1% increase and 0.42 (0.29-0.70) for the upper versus the lower tertile. This association persisted after adjustment for the univariate predictors (0.74 (0.60-0.92) per 1% increase; 0.54 (0.31-0.90) for upper vs lower tertile) and the known risk factors (0.78 (0.63-0.95) per 1% increase; 0.55 (0.35-0.88) for upper vs lower tertile). The area under the receiver operator characteristic curve (95% confidence interval) for preoperative hemoglobin A1c as a predictor of postoperative AF was 0.70 (0.65-0.75) (p=0.01).
Conclusions:
Preoperative hemoglobin A1c independently predicts the occurrence of AF after isolated off-pump coronary bypass grafting.
