Date Published: March 1, 2018
Publisher: Public Library of Science
Author(s): Xiaoyan Ling, Hongmei Zhou, Yunjian Ni, Cheng Wu, Caijun Zhang, Zhipeng Zhu, Katriina Aalto-Setala.
Cardiac surgery patients often experience several types of tachyarrhythmias after admission to the intensive care unit (ICU), which increases mortality and morbidity. Dexmedetomidine (DEX) is a popular medicine used for sedation in the ICU, and its other pharmacological characteristics are gradually being uncovered.
To determine whether DEX has an antiarrhythmic effect after cardiac surgery.
The three primary databases MEDLINE, Embase (OVID SP) and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched, and all English-language and randomized control-designed clinical publications comparing DEX to control medicines for sedation after elective cardiac surgery were included. Two colleagues independently extracted the data and performed other quality assessments. A subgroup analysis was performed according to the different medicines used and whether cardiopulmonary bypass (CPB) was applied. All tachyarrhythmias that occurred in the atria and ventricles were analyzed.
A total of 1295 patients in 9 studies met the selection criteria among 2587 studies that were screened. After quantitative synthesis, our results revealed that the DEX group was associated with a lower incidence of ventricular arrhythmia (VA, OR 0.24, 95% CI 0.09–0.64, I2 = 0%, P = 0.005) than the control group. Subgroup analysis did not reveal a significant difference between the DEX and propofol subgroups (OR 0.13, 95% CI 0.03–0.56, I2 = 0%, P = 0.007). Additionally, no difference in the incidence of atrial fibrillation (AF) was observed regardless of the different control medicines (OR 0.82, 95% CI 0.60–1.10, I2 = 25%, P = 0.19) or whether CPB was applied.
This meta-analysis revealed that DEX has an antiarrhythmic effect that decreases the incidence of VA compared to other drugs used for sedation following cardiac surgery. DEX may not have an effect on AF, but cautious interpretation should be exercised due to high heterogeneity.
The incidence of complications has decisive significance for overall mortality in patients following cardiac operations. A high incidence of complications is directly correlated with increased hospitalization and economic costs as well as with the quality of life of the patients. Postoperative arrhythmia (POA) is a type of complication that can occur following cardiac surgery. Atrial tachyarrhythmia is a common postoperative heart rhythm disorder and includes the so-called postoperative atrial fibrillation (POAF). Ventricular arrhythmia (VA) is also a major complication with lower frequency and less clarity.
With the popularity of DEX sedation for ICU patients, an increasing number of functions and shortcomings for this drug have been reported. Moreover, the controversial reports urgently need to be resolved. Our current meta-analysis indicates that infusion with DEX following cardiac surgery may decrease the incidence of VT but not AF compared with control drugs. Currently, the pathogenesis of POAs is largely understood. The proposed risk factors for POAs include hypoxia, ischemia, trauma, inflammation, catecholamines and electrolyte abnormalities, but some patients have different characteristics . It is well known that tachyarrhythmias can lead to reduced diastolic filling time and cardiac output, which can result in myocardial ischemia and hypotension. Related research has indicated that the excitation of sympathetic nerves is the primary pathogenesis of tachyarrhythmia following cardiac surgery . AF following cardiac surgery is a thoroughly studied postoperative tachyarrhythmia [38–42]. Specifically, new-onset AF is the focus of current research studies . According to Banach’s meta-analysis, the incidence of AF among patients after cardiac surgery doubles the risk of death . The ACCP Guidelines for the Prevention and Management of Postoperative Atrial Fibrillation After Cardiac Surgery were proposed by The American College of Chest Physicians in 2005 . The recommendations for the management of POAF were subsequently updated in 2016 . The potential mechanism underlying POAF may be activation of a systemic proinflammatory state, myocardial irritation, and heightened sympathetic tone. Although various functional drugs are recommended, it remains unclear whether these drugs have definitive effects. Another arrhythmia that can lead to sudden cardiac death in the cardiac ICU is VT or VF, which has an incidence of 5–8% . It has been reported that VT or VF after cardiac surgery not only worsens long-term prognosis but also increases in-hospital mortality [47–48]. There are many risk factors for VT/VF, including ischemia, sympathetic stimulation, and electrolyte abnormalities . However, there are not many medications available for the treatment and prevention of VT or VF nor many related clinical research studies. Amiodarone may currently be the most effective drug , but clinical research for the development of new drugs is urgently required.
Based on this meta-analysis, we conclude that DEX elicits antiarrhythmic effects by decreasing the incidence of VA compared with control drugs following cardiac surgery. No statistically significant difference in AF incidence was observed between the DEX and control groups, but cautious interpretation should be exercised when CPB is utilized. Additional larger-scale prospective studies or further subgroup analyses are warranted in the future.