Correlation between Preoperative Pulmonary Artery Pressure and Postoperative Atrial Fibrillation in Patients Undergoing Cardiac Surgery

Atrial fibrillation (AF) is the most common arrhythmia to occur after cardiac surgery. The incidence of post-operative atrial fibrillation (POAF) has been reported to range from 10 to 65%. It is associated with increased morbidity, mortality, longer hospital stay and increased costs. A number of studies have examined the predictors of POAF. There have never been any studies evaluating the correlation between pre-operative pulmonary artery pressure (PAP) and the incidence of POAF. Objective : This study aims to prospectively assess pre-operative mean PAP as a predictor of POAF. Methods : One hundred and nine consecutive elective cardiac surgery patients were enrolled. Baseline demographic data were obtained. A Swan-Ganz catheter was inserted before beginning the cardiac operation. The PAP was recorded before induction of general anesthesia. Holter-monitoring was performed for 72 hours after the cardiac surgery. The primary endpoint was the overall occurrence of POAF. Results : Overall POAF occurred in 29 (26.6%) of the 109 patients. Compared to patients with no POAF, the patients who developed POAF had larger left atrial sizes (4.2 ± 0.4 versus 3.7 ± 0.4 cm, p<0.001). There were no differences in baseline characteristics. Mean PAP levels in POAF patients were significantly higher than those in non-POAF patients (21.84 ± 6.71 versus 18.6 ± 5.46 mmHg, p = 0.012). The patients who had mean PAP levels in the highest quartiles (mean PAP ≥ 22.5 mmHg) were five times more likely to have POAF, compared to those with the lowest quartiles (mean PAP < 15 mmHg) (p = 0.012). The length of stay and total costs of treatment were significantly higher in POAF patients (12 ± 4 versus 10 ± 3 days, p < 0.001; 199,215 ± 31,435 versus 169,176 ± 17,272 baht; p < 0.001) Conclusions : Preoperative PAP level is a good predictor of POAF. Measurement of mean PAP levels in patients undergoing cardiac surgery is useful in identifying patients at risk for POAF.