Postoperative Atrial Fibrillation Is Associated With Late Mortality After Coronary Surgery, but Not After Valvular Surgery

Abstract Funding Acknowledgements Type of funding sources: None. Background. Postoperative atrial fibrillation (POAF) is the most common arrhythmic complication following cardiac surgery. It may occur between the second and fourth postoperative days as acute POAF, or within 30 days as subacute POAF (sPOAF). The incidence varies from 15% to 60%, with the highest rates observed in patients undergoing valvular surgery. POAF is associated with longer hospital stay and higher thromboembolic risk, which consistently increase patients’ morbidity and mortality. Identification of high-risk categories may allow optimization of in-hospital prevention and treatment, possibly improving clinical outcomes. Aim of the study. The aim of this study was to assess the incidence of sPOAF and to identify possible predictors in patients performing Cardiovascular Rehabilitation (CR) after Cardiac Surgery (CS). Methods. A single-centre retrospective study was performed on 383 post-cardiac surgery patients hospitalised in our CR Unit for inpatient rehabilitation. The entire population was on sinus rhythm at the admission in CR and continuous monitoring with 12-lead ECG telemetry was performed during the hospital stay. We calculated the incidence of sPOAF and then evaluated the predictive value of the following variables: anamnestic data, type of cardiac intervention, clinical course in both CS and CR Unit, laboratory parameters including baseline neutrophil-to-lymphocyte ratio (NLR). Results. Median age was 65 years (63% male). sPOAF was documented in 122 cases (31.9%). Patients developing sPOAF were older [median age 69 (63-76) vs. 61 (51-70); p < 0.001)], more frequently underwent complex surgical procedures (50% vs. 36%; p = 0.009) and were known for previous episodes of atrial fibrillation (27.9% vs. 11.2%; p < 0.001). On the first day after surgery (T1), sPOAF group showed higher values of glycemia [median 155 (126.5–186.8) vs. 129 (106.5–164); p < 0.001] and troponin T [median 721.5 (470.1–1084.3) vs. 488 (301.6-776.2); p < 0.001]. The multivariate analysis identified advanced age (OR 1.04, 95% CI 1.01-1.08; p = 0.023), acute POAF in the Cardiac Surgery Unit (OR 3.51, 95% CI 1.62-7.59; p = 0.001), baseline NLR (OR 1.46, 95% CI 1.10-1.93; p = 0.008) and T1-troponin > 552 ng/L (OR 4.16 95% CI 1.50-11.53; p = 0.006) as independent risk predictors of sPOAF during the CR period. Conclusions. sPOAF is common after cardiac surgery occurring in 31.9% of patients during CR. Age, acute POAF, baseline NLR and elevated troponin T on the first postoperative day were shown predictors of increased sPOAF risk. Recognition of new predictors of POAF could be helpful to better stratify patients, improving management strategies and outcomes.

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Abstract 4102: Preoperative Angiotensin Blocking Drug Therapy Does Not Reduce Atrial Fibrillation After Cardiac Surgery

Circulation ◽

10.1161/circ.118.suppl_18.s_829 ◽

2008 ◽

Vol 118 (suppl_18) ◽

Author(s):

Florian Rader ◽

Eugene H Blackstone

Keyword(s):

Atrial Fibrillation ◽

Cardiac Surgery ◽

Drug Therapy ◽

Propensity Score ◽

Ace Inhibitors ◽

Postoperative Atrial Fibrillation ◽

Consecutive Series ◽

Blocking Drug ◽

Valvular Surgery ◽

Co Morbidity

Introduction: Postoperative atrial fibrillation (POAF) is a common complication after cardiac surgery. Angiotensin blocking drug therapy (ABDT) with Angiotensin converting enzyme (ACE) inhibitors and Angiotensin II receptor blockers (ARBs) has been shown to have anti-arrhythmic effects in animal models. However, data from small observational studies of ABDT use in patients undergoing cardiac surgery had discordant results and did not sufficiently adjust for selection bias. Therefore, we performed the largest study to date examining the association between preoperative use of ABDT and postoperative atrial fibrillation. Methods and Results: A consecutive series of 10,552 patients underwent coronary artery bypass graft (CABG) surgery with or without valvular surgery at Cleveland Clinic between 1997 through 2002. Of these 4,795 (45%) patients were on ABDT within 30 days prior to surgery and 3,633 (34%) patients developed POAF prior to discharge. Without adjusting for patient co-morbidities, ABDT had an Odds Ratio (OR) of 1.13 (95% Confidence Interval (CI) 1.05–1.25, p<0.01). A propensity score matched sample was developed, adjusting for 68 potential confounders. In the 6874 matched patients, who had a well balanced co-morbidity profile, ABDT was not associated with POAF (OR 1.03, CI 0.93–1.12, p=0.67). A subsequent propensity score matched analysis of 3227 patients, who underwent isolated valvular surgery in the same timeframe, also demonstrated ineffectiveness of preoperative ABDT (OR 0.91, CI 0.74 –1.09, p=0.33), irrespective of valve location. Stratified analysis by linear propensity score quintiles and propensity-adjusted logistic multivariable regression analysis of all patients in the CABG and the valvular surgery cohort confirmed these findings. Conclusions: In this large observational study preoperative use of ACE inhibitors or ARBs did not reduce postoperative occurrence of atrial fibrillation in patients undergoing cardiac surgery. Although withdrawal from ABDT prior to surgery is common practice and could account for this result, we cannot recommend such therapy for primary prophylaxis without larger randomized controlled trials.

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