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Atrioventricular block in coronary artery bypass surgery: perioperative predictors and impact on mortality
Ricardo Medeiros Piantá1, Andres Di Leoni Ferrari2, Aline Almeida Heck2
1Sao Lucas Hospital, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
Insights
Postoperative atrioventricular block after coronary artery bypass surgery is often transient but linked to increased mortality and longer hospital stays. Key risk factors include advanced age, female gender, kidney disease, and atrial fibrillation.
Area of Science:
- Cardiology
- Cardiac Surgery
Background:
- Cardiac conduction disturbances are common post-coronary artery bypass surgery (CABG).
- These issues often stem from ischemic heart disease or perioperative factors.
- Understanding these factors is crucial for patient outcomes.
Purpose of the Study:
- To investigate the association between perioperative factors and atrioventricular block (AVB) post-CABG.
- To determine the need for temporary pacing and permanent pacemakers.
- To assess the impact of AVB on hospital stay and mortality.
Main Methods:
- Retrospective cohort analysis of 3532 patients undergoing CABG.
- Logistic regression was used to identify significant associations.
- Data sourced from the Postoperative Heart Surgery Unit database.
Main Results:
- AVB occurred in 8.15% of patients, requiring temporary pacing.
- Significant risk factors for AVB included age >60, female gender, chronic kidney disease, atrial fibrillation, NYHA class III/IV, perioperative myocardial infarction, and intra-aortic balloon use.
- AVB was associated with increased mortality (17.9% vs 7.3%) and longer hospital stays (12.75 vs 10.53 days).
Conclusions:
- AVB post-CABG is frequently transient but associated with specific perioperative factors.
- Identified risk factors necessitate careful monitoring and management.
- AVB significantly increases mortality risk and prolongs hospitalization.
Introduction:
Disturbances of the cardiac conduction system are frequent in the postoperative period of coronary artery bypass surgery. They are mostly reversible and associated with some injury of the conduction tissue, caused by the ischemic heart disease itself or by perioperative factors.
Objective:
Primary: investigate the association between perioperative factors and the emergence of atrioventricular block in the postoperative period of coronary artery bypass surgery. Secondary: determine the need for temporary pacing and of a permanent pacemaker in the postoperative period of coronary artery bypass surgery and the impact on hospital stay and hospital mortality.
Methods:
Analysis of a retrospective cohort of patients submitted to coronary artery bypass surgery from the database of the Postoperative Heart Surgery Unit of the Sao Lucas Hospital of the Pontifical Catholic University of Rio Grande do Sul, using the logistic regression method.
Results:
In the period from January 1996 to December 2012, 3532 coronary artery bypass surgery were carried out. Two hundred and eighty-eight (8.15% of the total sample) patients had atrioventricular block during the postoperative period of coronary artery bypass surgery, requiring temporary pacing. Eight of those who had atrioventricular block progressed to implantation of a permanent pacemaker (0.23% of the total sample). Multivariate analysis revealed a significant association of atrioventricular block with age above 60 years (OR=2.34; CI 95% 1.75-3.12; P<0.0001), female gender (OR=1.37; CI 95% 1.06-1.77; P=0.015), chronic kidney disease (OR=2.05; CI 95% 1.49-2.81; P<0.0001), atrial fibrillation (OR=2.06; CI 95% 1.16-3.66; P=0.014), functional class III and IV of the New York Heart Association (OR=1.43; CI 95% 1.03-1.98; P=0.031), perioperative acute myocardial infarction (OR=1.70; CI 95% 1.26-2.29; P<0.0001) and with the use of the intra-aortic balloon in the postoperative period of coronary artery bypass surgery (OR=1.92; CI 95% 1.21-3.05; P=0.006). The presence of atrioventricular block resulted in a significant increase in mortality (17.9% vs. 7.3% in those who did not develop atrioventricular block) (OR=2.09; CI 95% 1.46-2.99; P<0.0001) and a longer hospital stay (12.75 days x 10.53 days for those who didn't develop atrioventricular block) (OR=1.01; CI 95% 1.00-1.02; P=0.01).
Conclusions:
In most cases, atrioventricular block in the postoperative period of coronary artery bypass surgery is transient and associated with several perioperative factors: age above 60 years, female sex, chronic kidney disease, atrial fibrillation, New York Heart Association functional class III or IV, perioperative acute myocardial infarction and use of an intra-aortic balloon. Its occurrence prolongs hospitalization and, above all, doubles the risk of mortality.
