Efficacy of clonidine for prevention of perioperative myocardial ischemia: a critical appraisal and meta-analysis of the literature.
BACKGROUND
There is a belief that clonidine may be effective in reducing perioperative myocardial ischemic events, although the results of several trials are conflicting. The aim of the current study was to provide a systematic review of randomized controlled trials that tested the efficacy of clonidine in this regard.


METHODS
Data was collected from a MEDLINE search of English-language studies published from 1980 to 1999 and a manual search of bibliographies from retrieved articles. A total of 28 studies were assessed. According to the selection criteria (study design, population, intervention, and outcome) and a quality scoring system, seven studies were finally included in the meta-analysis. After homogeneity was established by Q value, the data were then combined using the fixed-effects model. The pooled odds ratio was calculated. A subgroup analysis based on the types of surgery and administration route was also performed to qualify the results. The results were expressed as odds ratio and 95% confidence interval.


RESULTS
Heterogeneity of outcome data was negative in the trials. The pooled odds ratio was 0.49 (95% confidence interval 0.34-0.71). In the subgroup analysis, clonidine reduced the incidence of myocardial ischemia in patients undergoing cardiac and noncardiac surgery. Rates of bradycardia were similar in clonidine and placebo groups.


CONCLUSIONS
The meta-analysis suggests that perioperative clonidine reduces cardiac ischemic episodes in patients with known, or at risk of, coronary arterial disease without increasing the incidence of bradycardia. Therefore, these findings strongly justify planning and execution of a definitive study seeking the benefits of clonidine.
Nishina
Kahoru
K
Department of Anesthesia and Perioperative Medicine, Faculty of Medical Sciences, Kobe University Graduate School of Medicine, Kobe, Japan.
Mikawa
Katsuya
K
Uesugi
Takanobu
T
Obara
Hidefumi
H
Maekawa
Munetaka
M
Kamae
Isao
I
Nishi
Nobuo
N
D000316:Adrenergic alpha-Agonists / Q000009:adverse effects / Q000627:therapeutic use*; D002986:Clinical Trials as Topic; D003000:Clonidine / Q000009:adverse effects / Q000627:therapeutic use*; D006801:Humans; D007431:Intraoperative Complications / Q000517:prevention & control*; D017202:Myocardial Ischemia / Q000517:prevention & control*; D015203:Reproducibility of Results; D012107:Research Design
D000316:Adrenergic alpha-Agonists; D003000:Clonidine