Postoperative metabolic acidosis following the minimally invasive radiofrequency maze procedure.

ABSTRACT

PURPOSE: Atrial fibrillation (AF) is the most common arrhythmia treated in the world. While medical treatment with antiarrhythmic drugs remains the primary treatment modality, symptomatic refractory AF often requires treatment with a catheter or surgical ablation. One minimally invasive therapy is the Mini-Maze procedure, which utilizes epicardial radiofrequency ablation via a subxiphoid approach to rid the heart of arrhythmogenic atrial foci without a median sternotomy or cardiopulmonary bypass. The goal of this retrospective cohort study was to identify clinical factors associated with metabolic acidosis following the Mini-Maze procedure. MATERIALS AND METHODS: After Institutional Review Board approval, we studied patients undergoing the Mini-Maze procedure, off-pump coronary artery bypass grafting or patients conventional Cox-Maze on cardiopulmonary bypass. The first base deficit value obtained in the Intensive Care Unit was used as a measure of metabolic acidosis. Using logistic regression with Akaike information criteria, we analyzed preoperative, intraoperative, and postoperative data to determine the factors associated with changes in base deficit. RESULTS: A multivariable model using stepwise selection demonstrated that diabetes mellitus and weight were associated with a decrease in the base deficit by 2.87 mEq/L (95% CI -5.55--0.19) and 0.04 mEq/L (95%CI -0.08, 0.004), respectively. Furthermore, creatinine was associated with a 1.57 mEq/L (95% CI 0.14, 2.99) increase in the base deficit. CONCLUSION: The Mini-Maze procedure was not associated with postoperative metabolic acidosis. Instead, nondiabetic patients and patients with higher creatinine were associated with greater base deficits after undergoing cardiac surgery.