Alpha‐2 adrenergic agonists for the prevention of cardiac complications among patients undergoing surgery
Referencias
References to studies included in this review
References to studies excluded from this review
Additional references
References to other published versions of this review
Characteristics of studies
Characteristics of included studies [ordered by study ID]
Ir a:
| Methods | Clonidine versus placebo. | |
| Participants | 24 patients who were undergoing coronary artery bypass graft surgery. | |
| Interventions | Clonidine was given as 5 μg/kg orally 2 hours before surgery. | |
| Outcomes | Myocardial infarction, ischaemia (ST depression > 0.1 mV for > 3 min before cardiopulmonary bypass), hypotension (requiring drug treatment), congestive heart failure. | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Blinding (performance bias and detection bias) | Unclear risk | The authors described the study as 'double‐blinded'. They reported the use of a placebo in the control arm, and described that 'management was double blind throughout the study period'. No other details were reported. |
| Methods | 3 treatment arms (clonidine, enoximine, enalaprilat) and 1 placebo arm. | |
| Participants | 44 patients who were undergoing coronary artery bypass graft surgery. | |
| Interventions | Clonidine was given as 0.05 μg/kg/min IV from induction of anaesthesia to initiation of cardiopulmonary bypass. | |
| Outcomes | Myocardial infarction (new persistent Q‐wave on ECG and CK‐MB > 12 U/L), ischaemia (ST depression > 0.1 mV or elevation > 0.2 mV for > 1 min on first postoperative day), bradycardia (requiring pacing), hypotension (requiring inotropic support after cardiopulmonary bypass). | |
| Notes | Data from the enoximine and enalaprilat arms were excluded from the analyses. | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Blinding (performance bias and detection bias) | Low risk | The authors reported that all clinical care, study data entry, and analyses were performed by individuals who were 'blinded to the patient's study group'. |
| Methods | Dexmedetomidine versus propofol. | |
| Participants | 89 patients who had undergone non‐emergent coronary artery bypass graft surgery with an expected length of intubation < 24 hours. | |
| Interventions | Dexmedetomidine was given as a 1 μg/kg IV loading dose followed by a 0.4 μg/kg/min infusion, beginning immediately after surgery. Propofol was given as a 0.2‐0.7 μg/kg/min IV infusion. | |
| Outcomes | All‐cause mortality, supraventricular tachyarrhythmia. | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | The authors described the use of a random‐number table. |
| Blinding (performance bias and detection bias) | High risk | |
| Methods | Clonidine versus placebo. | |
| Participants | 43 patients who were undergoing coronary artery bypass graft surgery. | |
| Interventions | Clonidine was given as 5 μg/kg orally 90 min before surgery, followed by 5 μg/kg via nasogastric tube 10 min before initiation of cardiopulmonary bypass. | |
| Outcomes | Ischaemia (use of nitrates for ischaemic ECG changes), bradycardia (requiring intraoperative pacing). | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Blinding (performance bias and detection bias) | Low risk | The authors described their study as 'double‐blind'. They reported the use of a placebo in the control arm, but no other details about blinding. |
| Methods | Dexmedetomidine versus control. | |
| Participants | 50 patients who were undergoing off‐pump coronary artery bypass graft surgery. | |
| Interventions | Dexmedetomidine was given as a 1 μg/kg IV loading dose followed by a 0.15 μg/kg/min infusion, beginning 30 min before surgery. The infusion was continued until 2 hr after extubation (maximum duration 24 hr). | |
| Outcomes | Ischaemia (ST depression or elevation > 0.1 mV for > 1 min after surgery). | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Allocation concealment (selection bias) | High risk | |
| Blinding (performance bias and detection bias) | High risk | |
| Methods | Clonidine versus placebo. The study was terminated early at 61 patients due to low incidence of ischaemia. It was originally designed to recruit 160 patients in 2 arms. | |
| Participants | 61 patients, with a diagnosis or risk factors of coronary artery disease, who were undergoing major non‐cardiac surgery (82% vascular). | |
| Interventions | Clonidine was given as a transdermal patch (200 μg/day) for 72 hours from the night before surgery. In addition, clonidine was given as 300 μg orally 60 to 90 min before surgery. | |
| Outcomes | All‐cause mortality, myocardial infarction (persistent new Q‐wave on ECG, or CK‐MB > 40 IU), ischaemia (ST depression > 0.1 mV or elevation > 0.2 mV for > 1 min), congestive heart failure. | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | The authors reported the use of computer‐generated random numbers. |
| Allocation concealment (selection bias) | Low risk | Sealed envelopes. |
| Blinding (performance bias and detection bias) | Low risk | The authors reported that all patients and clinicians were blinded to treatment assignment throughout the study. |
| Other bias | High risk | The study terminated early because of a lower than expected rate of myocardial ischemia ‐ it was unclear whether this unblinded interim analysis was pre‐specified. |
| Methods | Clonidine versus placebo. | |
| Participants | 24 patients with hypertension who were undergoing coronary artery bypass graft surgery. | |
| Interventions | Clonidine was given as 5 μg/kg orally 90 min before surgery. | |
| Outcomes | Ischaemia. | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Blinding (performance bias and detection bias) | High risk | |
| Methods | Clonidine versus placebo. | |
| Participants | 30 patients with hypertension who were undergoing non‐cardiac surgery (abdominal, head and neck, orthopedic). | |
| Interventions | Clonidine was given as 5 μg/kg orally 90 min before surgery. | |
| Outcomes | Ischaemia, hypotension (requiring drug treatment). | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Blinding (performance bias and detection bias) | High risk | |
| Methods | Clonidine versus control. | |
| Participants | 40 patients who were undergoing coronary artery bypass graft surgery. | |
| Interventions | Clonidine was given as 4 μg/kg IV 10 min before skin incision, 2 μg/kg IV 30 min after CPB, and 1 μg/kg IV after skin suture. | |
| Outcomes | Death, myocardial infarction. | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | The authors described the use of 'stratified randomization'. |
| Blinding (performance bias and detection bias) | High risk | |
| Methods | Dexmedetomidine versus propofol. Analyses were performed on an intention‐to‐treat basis. | |
| Participants | 295 patients who had undergone coronary artery bypass graft surgery. | |
| Interventions | Dexmedetomidine was given as 1 μg/kg IV bolus, followed by a 0.4 μg/kg/hr infusion, beginning immediately after surgery. Propofol was given based on institutional protocols. | |
| Outcomes | Myocardial infarction, supraventricular tachyarrhythmia, congestive heart failure, hypotension, bradycardia. | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | The authors described the use of blocked randomization. |
| Allocation concealment (selection bias) | Low risk | Sealed envelopes. |
| Blinding (performance bias and detection bias) | High risk | |
| Incomplete outcome data (attrition bias) | Low risk | |
| Methods | Dexmedetomidine versus placebo. | |
| Participants | 80 patients who were undergoing coronary artery bypass graft surgery. | |
| Interventions | Dexmedetomidine was given as 50 ng/kg/min IV before surgery for 30 min, followed by 7 ng/kg/min IV intraoperatively. | |
| Outcomes | All‐cause mortality, myocardial infarction (new persistent Q‐waves on ECG and CK‐MB > 70 U/L), ischaemia (ST depression > 0.1 mV or elevation > 0.2 mV for > 1 min), supraventricular tachyarrhythmia, congestive heart failure, hypotension (systolic blood pressure < 80 mmHg after surgery), bradycardia (heart rate < 50 beats/min after surgery). | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | The authors described the use of permuted block randomization. |
| Blinding (performance bias and detection bias) | Low risk | The authors described their study as 'double‐blind'. They reported the use a placebo in the control arm. In addition, all ECGs were interpreted by a clinician who was blinded to the patients' treatment assignments. No other details of blinding were provided. |
| Methods | Clonidine versus placebo. | |
| Participants | 40 patients who were undergoing vascular (carotid artery) surgery. | |
| Interventions | Clonidine was given as 4 μg/kg orally 90 min before surgery. | |
| Outcomes | Ischaemia (ST depression > 0.1 mV for > 1 min). | |
| Notes | Published as an abstract. | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Blinding (performance bias and detection bias) | Unclear risk | The authors described their study as 'double‐blind', but provided no other details about this blinding. |
| Methods | 2 treatment arms (thoracic epidural anaesthesia, clonidine) and 1 control arm. | |
| Participants | 45 patients who were undergoing coronary artery bypass graft surgery. | |
| Interventions | Clonidine was given as 5 μg/kg orally 90 min before surgery, followed by 5 μg/kg via nasogastric tube 10 min before initiation of cardiopulmonary bypass. | |
| Outcomes | All‐cause mortality, myocardial infarction (troponin T > 0.1 ng/mL), ischaemia (ST depression > 0.1 mV or ST elevation > 0.2 mV), bradycardia (requiring pacing). | |
| Notes | Only patients in clonidine and control arms were included in analyses. Data on ischaemia were available for only 29 patients. | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Blinding (performance bias and detection bias) | High risk | |
| Incomplete outcome data (attrition bias) | High risk | 2 patients in control arm were excluded because of repeat thoracotomy for bleeding. |
| Methods | Dexmedetomidine versus placebo. Analyses were performed on an intention‐to‐treat basis. | |
| Participants | 401 patients who had undergone major surgery and needed postoperative ventilation (45% cardiac surgery). | |
| Interventions | Dexmedetomidine was given as a 1 μg/kg IV bolus, followed by a 0.4 μg/kg/hr infusion, beginning after arrival in the intensive care unit. | |
| Outcomes | All‐cause mortality, hypotension, bradycardia, supraventricular tachyarrhythmia. | |
| Notes | Patients receiving epidural or spinal analgesia were excluded. | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Allocation concealment (selection bias) | Low risk | Allocation by an independent pharmacist. |
| Blinding (performance bias and detection bias) | Low risk | The authors described their study as 'double‐blind'. They reported the use of a placebo in the control arm. In addition, they reported that all individuals performing data collection, laboratory test analysis, and statistical analysis were blinded to treatment assignment. |
| Methods | Clonidine versus placebo. | |
| Participants | 36 patients who were undergoing microlaryngoscopy and rigid bronchoscopy under general anaesthesia. | |
| Interventions | Clonidine was given as 300 μg orally 90 min prior to surgery. | |
| Outcomes | Ischaemia (ST depression > 0.1 mV or elevation > 0.2 mV for > 1 min), hypotension (requiring drug treatment), congestive heart failure. | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Blinding (performance bias and detection bias) | Low risk | The authors described their study as 'double‐blind'. They reported the use of a placebo in the control arm. In addition, the clinician who analyzed ECGs was blinded to treatment assignment. No other details of blinding were provided. |
| Methods | Mivazerol (2 different doses) versus placebo. | |
| Participants | 317 patients (17 were excluded) with coronary artery disease who were undergoing vascular surgery under general anaesthesia for > 1 hour. | |
| Interventions | Mivazerol was given as either low‐dose (2 μg/kg IV bolus and 0.75 μg/kg/hr infusion) or high‐dose (4 μg/kg IV bolus and 1.5 μg/kg/hr infusion). The bolus was given 20 min before induction of anaesthesia and continued for 72 hr after surgery. | |
| Outcomes | All‐cause mortality, cardiac mortality, myocardial infarction (persistent new Q‐wave or CK‐MB > 100 ng/mL), ischaemia (ST depression > 0.1 mV or ST elevation > 0.2 mV for > 1 min during first 24 postoperative hours), congestive heart failure, bradycardia (requiring drug treatment), hypotension (requiring drug treatment). | |
| Notes | The dexmedetomidine arms were combined in analyses. | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | The authors described the use of blocked stratified randomization. |
| Blinding (performance bias and detection bias) | Low risk | The authors described their study as 'double‐blind'. They reported the use of placebo in the control arm. They also reported that the individuals who undertook clinical care, interpreted the ECG recordings, diagnosed myocardial infarction by ECG criteria, and performed statistical analyses were blinded to treatment assignment. |
| Incomplete outcome data (attrition bias) | Low risk | |
| Methods | Clonidine versus placebo. | |
| Participants | 156 patients (6 were excluded) who were undergoing coronary artery bypass graft surgery. | |
| Interventions | Clonidine was given as 5 μg/kg orally 90 min before surgery, followed by 5 μg/kg via nasogastric tube before cardiopulmonary bypass. | |
| Outcomes | All‐cause mortality, myocardial infarction (CK‐MB fraction > 5%), ischaemia (intraoperative ST depression > 0.1 mV or ST elevation > 0.2 mV for > 2 min), bradycardia (heart rate < 50 beats/min requiring drug therapy), hypotension (mean blood pressure < 65 mmHg requiring drug therapy). | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | The authors described the use of stratified randomization. |
| Allocation concealment (selection bias) | Low risk | Independant randomization by research pharmacy |
| Blinding (performance bias and detection bias) | Low risk | The authors described their study as 'double‐blind'. They reported the use of a placebo. In addition, they described that 'investigators and patients' were blinded to treatment assignment. The diagnosis of myocardial infarction by ECG and biochemical criteria was made by a blinded clinician. Statistical analyses were also performed by individuals blinded to treatment assignment. |
| Incomplete outcome data (attrition bias) | Low risk | |
| Methods | Mivazerol versus placebo. Analyses were performed in an intention‐to‐treat basis. | |
| Participants | 2854 patients with a diagnosis or risk factors for coronary artery disease who were undergoing vascular, abdominal, thoracic, or orthopedic surgery. | |
| Interventions | Mivazerol was given as a 4 μg/kg IV bolus 20 min before induction of anaesthesia, and a 72 hr IV infusion at 1.5 μg/kg/hr. | |
| Outcomes | 30‐day mortality, myocardial infarction (persistent new Q‐wave with clinical syndrome or troponin‐T > 1 μg/L), hypotension (requiring drug treatment), bradycardia (requiring drug treatment). | |
| Notes | 2857 patients were recruited in total, but only the results for the 1897 patients with coronary artery disease were reported. Adverse event data were however reported for all 2854 patients. | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | The authors described the use of a computer‐generated randomization schedule. |
| Allocation concealment (selection bias) | Low risk | Sealed envelopes. |
| Blinding (performance bias and detection bias) | Low risk | The authors described their study as 'double‐blind'. They reported the use of a placebo in the control arm. In addition, they reported that all outcomes were adjudicated by individuals who were blinded to treatment assignment. |
| Incomplete outcome data (attrition bias) | Low risk | |
| Other bias | High risk | Study inclusion criteria were modified after monitoring of blinded data (1304 participants recruited). Since the event rate in patients with risk factors for coronary artery disease were lower than expected, the trial protocol was ammended to focus only on patients with pre‐existing coronary artery disease. |
| Methods | Clonidine versus placebo. | |
| Participants | 30 patients with a diagnosis of obstructive sleep apnoea who were undergoing head‐and‐neck surgery. | |
| Interventions | Clonidine was given as 2 μg/kg orally on the night before surgery and on the morning of surgery. | |
| Outcomes | Ischaemia, hypotension (heart rate < 40 beats/min and requirement for atropine). | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | The authors described the use of a computer program to perform randomization. |
| Allocation concealment (selection bias) | High risk | |
| Blinding (performance bias and detection bias) | Unclear risk | The authors described their study as 'double‐blind'. They reported the use of a placebo in the control arm, but provided no other details on blinding. |
| Incomplete outcome data (attrition bias) | High risk | 1 patient excluded from haemodynamic analysis because of an angiotensin‐converting enzyme inhibitor overdose on ward. |
| Methods | Clonidine versus placebo. | |
| Participants | 30 patients (1 was excluded) who were undergoing vascular (carotid artery) surgery. | |
| Interventions | Clonidine was given as 300 μg orally 90 min before surgery. | |
| Outcomes | Myocardial infarction, bradycardia (intraoperative heart rate < 45 beats/min), hypotension (intraoperative systolic pressure < 100 mmHg for > 3 min and requiring drug treatment). | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | The authors described the use of a random number table. |
| Allocation concealment (selection bias) | Low risk | Sealed envelopes. |
| Blinding (performance bias and detection bias) | Unclear risk | The authors described their study as 'double‐blind'. They reported the use of an identical placebo in the control arm, but provided no other details on blinding. |
| Incomplete outcome data (attrition bias) | High risk | 1 patient excluded after randomization after a thrombosis in the carotid artery was discovered intraoperatively. |
| Methods | Clonidine versus placebo. | |
| Participants | 26 patients who were undergoing coronary artery bypass graft surgery. | |
| Interventions | Clonidine was given as 2.5 μg/kg orally before induction of anaesthesia. | |
| Outcomes | Ischaemia (ST deviation > 0.1 mV for > 5 min before cardiopulmonary bypass). | |
| Notes | Published as a letter to the editor. | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Blinding (performance bias and detection bias) | Unclear risk | The authors described their study as 'double‐blind'. They reported the use of a placebo in the control arm, but provided no other details on blinding. |
| Methods | Clonidine versus placebo. | |
| Participants | 24 patients (3 were excluded) with hypertension who were undergoing vascular (aortic) surgery. | |
| Interventions | Clonidine was given as 6 μg/kg orally 120 minutes before induction of anaesthesia, followed by a 3 μg/kg IV infusion over 60 min after aortic declamping. | |
| Outcomes | All‐cause mortality, bradycardia (intraoperative requiring drug treatment), hypotension (intraoperative). | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Blinding (performance bias and detection bias) | Unclear risk | The authors described their study as 'double‐blind'. They reported the use of a placebo in the control arm, but provided no other details on blinding. |
| Incomplete outcome data (attrition bias) | High risk | Three patients excluded for surgical (n=2) or inadequate data collection (n=1) reasons. |
| Methods | Clonidine versus placebo. Analyses were performed on an intention‐to‐treat basis. | |
| Participants | 297 patients who were undergoing vascular surgery. | |
| Interventions | Clonidine was given as 2 μg/kg orally 90 min before induction of anaesthesia. | |
| Outcomes | Cardiac mortality, myocardial infarction (new persistent Q‐waves on ECG, or CK‐MB elevation > 40 U/L or 10%), ischaemia (intraoperative ST deviation > 0.1 mV for > 1 min), bradycardia (requiring drug treatment). | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | The authors described the use of a random number table. |
| Blinding (performance bias and detection bias) | Low risk | The authors described their study as 'double‐blind'. They reported the use of an identical placebo in the control arm. In addition, the clinicians that evaluated all ECG recordings were blinded to treatment assignment. No other details on blinding were provided. |
| Incomplete outcome data (attrition bias) | High risk | 47 patients excluded from outcome analysis (from 297 total) because of transfers to other hospitals/departments within 4 days after surgery (n=24), repeat surgery within 1 week (n=8), and missing outcome data (n=7). |
| Methods | Three dexmedetomidine arms (low, medium and high doses), and 1 placebo arm. | |
| Participants | 25 patients, with a diagnosis or risk factors of coronary artery disease, who were undergoing vascular surgery. | |
| Interventions | Dexmedetomidine was given as an IV infusion intraoperatively until 48 hours after surgery with total doses 2.64 μg/kg (low dose), 5.31 μg/kg (medium dose), and 8.03 μg/kg (high dose). | |
| Outcomes | All‐cause mortality, myocardial infarction, ischaemia, supraventricular tachyarrhythmia, bradycardia (requiring drug treatment), hypotension (requiring drug treatment), congestive heart failure. | |
| Notes | Dexmedetomidine arms were combined for the purpose of analyses. | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Blinding (performance bias and detection bias) | Low risk | The authors described their study was 'double‐blinded'. They reported the use of a placebo in the control arm. In addition, all individual who analysed ECG recordings were blinded to treatment assignment. No other details of blinding were reported. |
| Incomplete outcome data (attrition bias) | High risk | 1 patient in the dexmedetomidine arm was excluded because of emergent re‐operation. |
| Methods | Dexmedetomidine versus placebo. Analyses were performed on an intention‐to‐treat basis. | |
| Participants | 41 patients who were undergoing vascular surgery. | |
| Interventions | Starting 20 min before surgery, dexmedetomidine was given as 1.2 μg/min IV for 20 min, 0.8 μg/min IV for 40 min, 0.35 μg/min IV for 240 min, and then 0.15 μg/min IV until 48 hours postoperatively. | |
| Outcomes | All‐cause mortality. | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | The authors described the use of random permuted blocks with stratificaton by centre. |
| Blinding (performance bias and detection bias) | Unclear risk | The authors described their study as 'double‐blind'. They reported the use of a placebo in the control arm. No other details on blinding were reported. |
| Methods | Dexmedetomidine versus placebo. | |
| Participants | 30 patients who had undergone cardiac (53%), vascular noncardiac (13%), and non‐vascular noncardiac (33%) surgery, and who needed > 6 hr of sedation and mechanical ventilation after surgery. | |
| Interventions | Dexmedetomidine was given within 6 hr after surgery as a 1.0 μg/kg IV loading dose and a 0.4 μg/kg/hr infusion for 72 hr. | |
| Outcomes | All‐cause mortality, bradycardia, hypotension, congestive heart failure. | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Blinding (performance bias and detection bias) | Unclear risk | The authors described their study as 'double‐blind'. They reported the use of a placebo in the control arm. No other details on blinding were reported. |
| Incomplete outcome data (attrition bias) | High risk | 2 patients in control arm were excluded because of protocol deviations during the study. |
| Methods | Dexmedetomidine versus placebo. | |
| Participants | 105 patients (7 were excluded) who had undergone cardiac (83%) and non‐cardiac (17%) surgery, and needed > 6 hr of mechanical ventilation and sedation after surgery. | |
| Interventions | Dexmedetomidine was given, within 1 hr of arrival in the intensive care unit, as a 1 μg/kg IV loading dose and a 0.2‐0.7 μg/kg/hr infusion for 6 to 24 hr. | |
| Outcomes | All‐cause mortality, myocardial infarction, ischaemia, supraventricular tachyarrhythmia, bradycardia (requiring drug treatment), hypotension (requiring drug treatment). | |
| Notes | Patients receiving epidural or spinal anaesthesia were excluded. | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Blinding (performance bias and detection bias) | Unclear risk | The authors described their study as 'double‐blind'. They reported the use of a placebo in the control arm. No other details on blinding were reported. |
| Incomplete outcome data (attrition bias) | Low risk | |
| Methods | Dexmedetomidine versus propofol. | |
| Participants | 20 patients who had undergone non‐vascular noncardiac surgery and required > 8 hr of mechanical ventilation after surgery. | |
| Interventions | Dexmedetomidine was given upon arrival in the intensive care unit as a 2.5 μg/kg/hr IV loading dose and a 0.2‐0.5 μg/kg/hr infusion. Propofol was given upon arrival in the intensive care unit as a 1 mg/kg IV loading dose, and a 1‐3 mg/kg/hr infusion. | |
| Outcomes | All‐cause mortality, bradycardia (requiring drug treatment), hypotension (requiring drug treatment). | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Allocation concealment (selection bias) | Low risk | Sealed envelopes. |
| Blinding (performance bias and detection bias) | High risk | |
| Methods | Dexmedetomidine versus placebo. Analyses were performed on an intention‐to‐treat basis. | |
| Participants | 28 patients who were undergoing thoracotomy with epidural analgesia. | |
| Interventions | Dexmedetomidine was given as a 0.5 μg/kg IV loading dose and 0.4 μg/kg/hr infusion starting immediately after surgery. | |
| Outcomes | All‐cause mortality, myocardial infarction, atrial fibrillation, hypotension (mean blood pressure < 60 mmHg), bradycardia (heart rate < 50/min requiring treatment) . | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Allocation concealment (selection bias) | Low risk | Allocation by an independent pharmacist. |
| Blinding (performance bias and detection bias) | Low risk | The authors described their study as 'double‐blind'. They reported the use of a placebo in the control arm. In addition, they described that the patients, study investigators, and responsible clinicians were blinded to treatment assignment. |
| Incomplete outcome data (attrition bias) | Low risk | |
| Methods | Clonidine versus placebo. Analyses were performed on an intention‐to‐treat basis. | |
| Participants | 190 patients, with a diagnosis or risk factors of coronary artery disease, who were undergoing elective noncardiac surgery (18% vascular, 21% abdominal, 6% thoracic). | |
| Interventions | Clonidine was given as 200 μg orally on the night before surgery and on the morning of surgery. A 200 μg/day transdermal patch was applied on the night before surgery, and removed on postoperative day 4. | |
| Outcomes | All‐cause 30‐day mortality, myocardial infarction (ECG changes and CK‐MB elevation), ischaemia (ST deviation > 0.1 mV for > 1 min on Holter monitoring), congestive heart failure, hypotension (systolic blood pressure < 80 mmHg), bradycardia (heart rate < 40/min). | |
| Notes | 10.5% prevalence of epidural use. | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | The authors described the use of a computer‐generated randomization schedule. |
| Allocation concealment (selection bias) | Low risk | Allocation by an independent pharmacist. |
| Blinding (performance bias and detection bias) | Low risk | The authors described their study as 'double‐blind'. They reported the use of an identical‐appearing placebo in the control arm. The responsible clinicians were described as being blinded to treatment assignment. In addition, interpretation of ECG tracings and diagnosis of myocardial infarction were made by individuals who were blinded to treatment assignment. |
| Incomplete outcome data (attrition bias) | Low risk | |
| Methods | Clonidine versus placebo. | |
| Participants | 60 patients with coronary artery disease undergoing non‐cardiac surgery (10% vascular, 50% intra‐peritoneal, 27% orthopedic) | |
| Interventions | Clonidine was given as 3 μg/kg orally 90 min before surgery. | |
| Outcomes | Ischaemia (ST deviation > 0.1 mV for > 3 min during first 24 postoperative hours). | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Blinding (performance bias and detection bias) | Low risk | The authors described their study as 'double‐blind'. They reported the use of a placebo in the control arm. The authors described that the 'anesthesia providers in the study were blind to all research information'. The interpretation of all ECGs was also performed by individuals blinded to treatment assignment. |
Characteristics of excluded studies [ordered by study ID]
Ir a:
| Study | Reason for exclusion |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| Quasi‐randomized trial design (patients divided into 2 groups based on order in which they were admitted to the intensive care unit). | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| Participants did not undergo surgery. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. | |
| No required outcomes were reported. |
Data and analyses
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 All‐Cause Mortality Show forest plot | 18 | 3828 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.66 [0.44, 0.98] |
| Analysis 1.1  Comparison 1 Alpha‐2 agonists versus control in all surgery, Outcome 1 All‐Cause Mortality. | ||||
| 2 Cardiac Mortality Show forest plot | 6 | 2590 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.53 [0.30, 0.95] |
| Analysis 1.2  Comparison 1 Alpha‐2 agonists versus control in all surgery, Outcome 2 Cardiac Mortality. | ||||
| 3 Myocardial Infarction Show forest plot | 16 | 3603 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.85 [0.65, 1.10] |
| Analysis 1.3  Comparison 1 Alpha‐2 agonists versus control in all surgery, Outcome 3 Myocardial Infarction. | ||||
| 4 Myocardial Ischaemia Show forest plot | 20 | 1650 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.68 [0.57, 0.81] |
| Analysis 1.4  Comparison 1 Alpha‐2 agonists versus control in all surgery, Outcome 4 Myocardial Ischaemia. | ||||
| 5 Supraventricular Tachyarrhythmia Show forest plot | 8 | 1056 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.02 [0.65, 1.58] |
| Analysis 1.5  Comparison 1 Alpha‐2 agonists versus control in all surgery, Outcome 5 Supraventricular Tachyarrhythmia. | ||||
| 6 Congestive Heart Failure Show forest plot | 11 | 1203 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.74 [0.47, 1.19] |
| Analysis 1.6  Comparison 1 Alpha‐2 agonists versus control in all surgery, Outcome 6 Congestive Heart Failure. | ||||
| 7 Hypotension Show forest plot | 17 | 3600 | Risk Ratio (M‐H, Random, 95% CI) | 1.32 [1.07, 1.62] |
| Analysis 1.7  Comparison 1 Alpha‐2 agonists versus control in all surgery, Outcome 7 Hypotension. | ||||
| 8 Bradycardia Show forest plot | 18 | 3933 | Risk Ratio (M‐H, Random, 95% CI) | 1.66 [1.14, 2.41] |
| Analysis 1.8  Comparison 1 Alpha‐2 agonists versus control in all surgery, Outcome 8 Bradycardia. | ||||
| 9 Acute Stroke Show forest plot | 5 | 713 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.68 [0.31, 1.52] |
| Analysis 1.9  Comparison 1 Alpha‐2 agonists versus control in all surgery, Outcome 9 Acute Stroke. | ||||
| 10 Preoperative Beta‐Blocker Use Show forest plot | 17 | 3338 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.11 [1.01, 1.22] |
| Analysis 1.10  Comparison 1 Alpha‐2 agonists versus control in all surgery, Outcome 10 Preoperative Beta‐Blocker Use. | ||||
| 11 Preoperative Calcium Channel Blocker Use Show forest plot | 16 | 3293 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.96 [0.89, 1.03] |
| Analysis 1.11  Comparison 1 Alpha‐2 agonists versus control in all surgery, Outcome 11 Preoperative Calcium Channel Blocker Use. | ||||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 All‐Cause Mortality Show forest plot | 18 | Risk Ratio (M‐H, Fixed, 95% CI) | Subtotals only | |
| Analysis 2.1  Comparison 2 Alpha‐2 agonist (stratified by drug) versus control in all surgery, Outcome 1 All‐Cause Mortality. | ||||
| 1.1 Clonidine | 8 | 848 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.34 [0.13, 0.94] |
| 1.2 Dexmedetomidine | 8 | 783 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.00 [0.40, 2.54] |
| 1.3 Mivazerol | 2 | 2197 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.69 [0.42, 1.15] |
| 2 Cardiac Mortality Show forest plot | 5 | Risk Ratio (M‐H, Fixed, 95% CI) | Subtotals only | |
| Analysis 2.2  Comparison 2 Alpha‐2 agonist (stratified by drug) versus control in all surgery, Outcome 2 Cardiac Mortality. | ||||
| 2.1 Clonidine | 3 | 363 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.75 [0.17, 3.37] |
| 2.2 Mivazerol | 2 | 2197 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.51 [0.27, 0.98] |
| 3 Myocardial Infarction Show forest plot | 16 | Risk Ratio (M‐H, Fixed, 95% CI) | Subtotals only | |
| Analysis 2.3  Comparison 2 Alpha‐2 agonist (stratified by drug) versus control in all surgery, Outcome 3 Myocardial Infarction. | ||||
| 3.1 Clonidine | 9 | 881 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.59 [0.26, 1.33] |
| 3.2 Dexmedetomidine | 5 | 525 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.68 [0.24, 1.87] |
| 3.3 Mivazerol | 2 | 2197 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.91 [0.68, 1.21] |
| 4 Myocardial Ischaemia Show forest plot | 19 | Risk Ratio (M‐H, Fixed, 95% CI) | Subtotals only | |
| Analysis 2.4  Comparison 2 Alpha‐2 agonist (stratified by drug) versus control in all surgery, Outcome 4 Myocardial Ischaemia. | ||||
| 4.1 Clonidine | 15 | 1077 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.62 [0.51, 0.76] |
| 4.2 Dexmedetomidine | 4 | 273 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.71 [0.48, 1.05] |
| 5 Hypotension Show forest plot | 17 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| Analysis 2.5  Comparison 2 Alpha‐2 agonist (stratified by drug) versus control in all surgery, Outcome 5 Hypotension. | ||||
| 5.1 Clonidine | 8 | 525 | Risk Ratio (M‐H, Random, 95% CI) | 1.51 [1.11, 2.04] |
| 5.2 Dexmedetomidine | 7 | 878 | Risk Ratio (M‐H, Random, 95% CI) | 1.57 [1.16, 2.12] |
| 5.3 Mivazerol | 2 | 2197 | Risk Ratio (M‐H, Random, 95% CI) | 0.95 [0.82, 1.10] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 All‐Cause Mortality Show forest plot | 7 | 546 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.70 [0.21, 2.31] |
| Analysis 3.1  Comparison 3 Alpha‐2 agonist versus control in cardiac surgery, Outcome 1 All‐Cause Mortality. | ||||
| 2 Myocardial Infarction Show forest plot | 8 | 776 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.01 [0.46, 2.21] |
| Analysis 3.2  Comparison 3 Alpha‐2 agonist versus control in cardiac surgery, Outcome 2 Myocardial Infarction. | ||||
| 3 Myocardial Ischaemia Show forest plot | 10 | 589 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.65 [0.50, 0.85] |
| Analysis 3.3  Comparison 3 Alpha‐2 agonist versus control in cardiac surgery, Outcome 3 Myocardial Ischaemia. | ||||
| 4 Supraventricular Tachyarrhythmia Show forest plot | 4 | 583 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.06 [0.65, 1.71] |
| Analysis 3.4  Comparison 3 Alpha‐2 agonist versus control in cardiac surgery, Outcome 4 Supraventricular Tachyarrhythmia. | ||||
| 5 Bradycardia Show forest plot | 6 | 657 | Risk Ratio (M‐H, Random, 95% CI) | 1.91 [1.11, 3.29] |
| Analysis 3.5  Comparison 3 Alpha‐2 agonist versus control in cardiac surgery, Outcome 5 Bradycardia. | ||||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 All‐Cause Mortality Show forest plot | 9 | 2851 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.61 [0.39, 0.96] |
| Analysis 4.1  Comparison 4 Alpha‐2 agonist versus control in non‐cardiac surgery, Outcome 1 All‐Cause Mortality. | ||||
| 2 Cardiac Mortality Show forest plot | 4 | 2515 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.51 [0.27, 0.93] |
| Analysis 4.2  Comparison 4 Alpha‐2 agonist versus control in non‐cardiac surgery, Outcome 2 Cardiac Mortality. | ||||
| 3 Myocardial Infarction Show forest plot | 8 | 2817 | Risk Ratio (M‐H, Random, 95% CI) | 0.49 [0.22, 1.09] |
| Analysis 4.3  Comparison 4 Alpha‐2 agonist versus control in non‐cardiac surgery, Outcome 3 Myocardial Infarction. | ||||
| 4 Myocardial Ischaemia Show forest plot | 10 | 1061 | Risk Ratio (M‐H, Random, 95% CI) | 0.73 [0.54, 1.00] |
| Analysis 4.4  Comparison 4 Alpha‐2 agonist versus control in non‐cardiac surgery, Outcome 4 Myocardial Ischaemia. | ||||
| 5 Bradycardia Show forest plot | 10 | 2845 | Risk Ratio (M‐H, Random, 95% CI) | 1.44 [0.89, 2.31] |
| Analysis 4.5  Comparison 4 Alpha‐2 agonist versus control in non‐cardiac surgery, Outcome 5 Bradycardia. | ||||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 All‐Cause Mortality Show forest plot | 7 | 1648 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.47 [0.25, 0.90] |
| Analysis 5.1  Comparison 5 Alpha‐2 agonist versus control in vascular surgery, Outcome 1 All‐Cause Mortality. | ||||
| 2 Cardiac Mortality Show forest plot | 4 | 1522 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.36 [0.16, 0.79] |
| Analysis 5.2  Comparison 5 Alpha‐2 agonist versus control in vascular surgery, Outcome 2 Cardiac Mortality. | ||||
| 3 Myocardial Infarction Show forest plot | 6 | 1616 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.66 [0.46, 0.94] |
| Analysis 5.3  Comparison 5 Alpha‐2 agonist versus control in vascular surgery, Outcome 3 Myocardial Infarction. | ||||
| 4 Myocardial Ischaemia Show forest plot | 5 | 715 | Risk Ratio (M‐H, Random, 95% CI) | 0.92 [0.64, 1.34] |
| Analysis 5.4  Comparison 5 Alpha‐2 agonist versus control in vascular surgery, Outcome 4 Myocardial Ischaemia. | ||||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 All‐Cause Mortality Show forest plot | 2 | 1013 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.05 [0.52, 2.09] |
| Analysis 6.1  Comparison 6 Alpha‐2 agonist versus control in non‐vascular, non‐cardiac surgery, Outcome 1 All‐Cause Mortality. | ||||
| 2 Myocardial Infarction Show forest plot | 2 | 1021 | Risk Ratio (M‐H, Random, 95% CI) | 0.92 [0.20, 4.16] |
| Analysis 6.2  Comparison 6 Alpha‐2 agonist versus control in non‐vascular, non‐cardiac surgery, Outcome 2 Myocardial Infarction. | ||||
| 3 Myocardial Ischaemia Show forest plot | 3 | 96 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.23 [0.04, 1.30] |
| Analysis 6.3  Comparison 6 Alpha‐2 agonist versus control in non‐vascular, non‐cardiac surgery, Outcome 3 Myocardial Ischaemia. | ||||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Myocardial infarction Show forest plot | 2 | 526 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.72 [0.29, 1.81] |
| Analysis 7.1  Comparison 7 Alpha‐2 agonist versus control in patients receiving epidural or spinal anaesthesia, Outcome 1 Myocardial infarction. | ||||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 All‐Cause Mortality Show forest plot | 5 | 2699 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.59 [0.37, 0.95] |
| Analysis 8.1  Comparison 8 Alpha‐2 agonists versus control in studies with blinding and concealed allocation, Outcome 1 All‐Cause Mortality. | ||||
| 2 Myocardial Infarction Show forest plot | 5 | 2326 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.90 [0.68, 1.21] |
| Analysis 8.2  Comparison 8 Alpha‐2 agonists versus control in studies with blinding and concealed allocation, Outcome 2 Myocardial Infarction. | ||||
| 3 Myocardial Ischaemia Show forest plot | 3 | 394 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.59 [0.41, 0.85] |
| Analysis 8.3  Comparison 8 Alpha‐2 agonists versus control in studies with blinding and concealed allocation, Outcome 3 Myocardial Ischaemia. | ||||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Myocardial Infarction Show forest plot | 9 | 3064 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.84 [0.64, 1.11] |
| Analysis 9.1  Comparison 9 Alpha‐2 agonists versus control in studies that used strict definitions of myocardial infarction or ischaemia, Outcome 1 Myocardial Infarction. | ||||
| 2 Myocardial Ischaemia Show forest plot | 13 | 1340 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.65 [0.54, 0.79] |
| Analysis 9.2  Comparison 9 Alpha‐2 agonists versus control in studies that used strict definitions of myocardial infarction or ischaemia, Outcome 2 Myocardial Ischaemia. | ||||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 All‐Cause Mortality Show forest plot | 17 | 1931 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.69 [0.37, 1.28] |
| Analysis 10.1  Comparison 10 Alpha‐2 agonists versus control in all surgery, excluding Oliver 1999, Outcome 1 All‐Cause Mortality. | ||||
| 2 Cardiac Mortality Show forest plot | 5 | 693 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.61 [0.18, 2.04] |
| Analysis 10.2  Comparison 10 Alpha‐2 agonists versus control in all surgery, excluding Oliver 1999, Outcome 2 Cardiac Mortality. | ||||
| 3 Myocardial Infarction Show forest plot | 15 | 1706 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.53 [0.30, 0.94] |
| Analysis 10.3  Comparison 10 Alpha‐2 agonists versus control in all surgery, excluding Oliver 1999, Outcome 3 Myocardial Infarction. | ||||
Searching results
Funnel plot of comparison: Alpha‐2 agonists versus control in all surgery (outcome: all‐cause mortality).
Funnel plot of comparison: Alpha‐2 agonists versus control in all surgery (outcome: cardiac mortality).
Funnel plot of comparison: Alpha‐2 agonists versus control in all surgery (outcome: myocardial infarction).
Funnel plot of comparison: Alpha‐2 agonists versus control in all surgery (outcome: myocardial ischaemia).
Comparison 1 Alpha‐2 agonists versus control in all surgery, Outcome 1 All‐Cause Mortality.
Comparison 1 Alpha‐2 agonists versus control in all surgery, Outcome 2 Cardiac Mortality.
Comparison 1 Alpha‐2 agonists versus control in all surgery, Outcome 3 Myocardial Infarction.
Comparison 1 Alpha‐2 agonists versus control in all surgery, Outcome 4 Myocardial Ischaemia.
Comparison 1 Alpha‐2 agonists versus control in all surgery, Outcome 5 Supraventricular Tachyarrhythmia.
Comparison 1 Alpha‐2 agonists versus control in all surgery, Outcome 6 Congestive Heart Failure.
Comparison 1 Alpha‐2 agonists versus control in all surgery, Outcome 7 Hypotension.
Comparison 1 Alpha‐2 agonists versus control in all surgery, Outcome 8 Bradycardia.
Comparison 1 Alpha‐2 agonists versus control in all surgery, Outcome 9 Acute Stroke.
Comparison 1 Alpha‐2 agonists versus control in all surgery, Outcome 10 Preoperative Beta‐Blocker Use.
Comparison 1 Alpha‐2 agonists versus control in all surgery, Outcome 11 Preoperative Calcium Channel Blocker Use.
Comparison 2 Alpha‐2 agonist (stratified by drug) versus control in all surgery, Outcome 1 All‐Cause Mortality.
Comparison 2 Alpha‐2 agonist (stratified by drug) versus control in all surgery, Outcome 2 Cardiac Mortality.
Comparison 2 Alpha‐2 agonist (stratified by drug) versus control in all surgery, Outcome 3 Myocardial Infarction.
Comparison 2 Alpha‐2 agonist (stratified by drug) versus control in all surgery, Outcome 4 Myocardial Ischaemia.
Comparison 2 Alpha‐2 agonist (stratified by drug) versus control in all surgery, Outcome 5 Hypotension.
Comparison 3 Alpha‐2 agonist versus control in cardiac surgery, Outcome 1 All‐Cause Mortality.
Comparison 3 Alpha‐2 agonist versus control in cardiac surgery, Outcome 2 Myocardial Infarction.
Comparison 3 Alpha‐2 agonist versus control in cardiac surgery, Outcome 3 Myocardial Ischaemia.
Comparison 3 Alpha‐2 agonist versus control in cardiac surgery, Outcome 4 Supraventricular Tachyarrhythmia.
Comparison 3 Alpha‐2 agonist versus control in cardiac surgery, Outcome 5 Bradycardia.
Comparison 4 Alpha‐2 agonist versus control in non‐cardiac surgery, Outcome 1 All‐Cause Mortality.
Comparison 4 Alpha‐2 agonist versus control in non‐cardiac surgery, Outcome 2 Cardiac Mortality.
Comparison 4 Alpha‐2 agonist versus control in non‐cardiac surgery, Outcome 3 Myocardial Infarction.
Comparison 4 Alpha‐2 agonist versus control in non‐cardiac surgery, Outcome 4 Myocardial Ischaemia.
Comparison 4 Alpha‐2 agonist versus control in non‐cardiac surgery, Outcome 5 Bradycardia.
Comparison 5 Alpha‐2 agonist versus control in vascular surgery, Outcome 1 All‐Cause Mortality.
Comparison 5 Alpha‐2 agonist versus control in vascular surgery, Outcome 2 Cardiac Mortality.
Comparison 5 Alpha‐2 agonist versus control in vascular surgery, Outcome 3 Myocardial Infarction.
Comparison 5 Alpha‐2 agonist versus control in vascular surgery, Outcome 4 Myocardial Ischaemia.
Comparison 6 Alpha‐2 agonist versus control in non‐vascular, non‐cardiac surgery, Outcome 1 All‐Cause Mortality.
Comparison 6 Alpha‐2 agonist versus control in non‐vascular, non‐cardiac surgery, Outcome 2 Myocardial Infarction.
Comparison 6 Alpha‐2 agonist versus control in non‐vascular, non‐cardiac surgery, Outcome 3 Myocardial Ischaemia.
Comparison 7 Alpha‐2 agonist versus control in patients receiving epidural or spinal anaesthesia, Outcome 1 Myocardial infarction.
Comparison 8 Alpha‐2 agonists versus control in studies with blinding and concealed allocation, Outcome 1 All‐Cause Mortality.
Comparison 8 Alpha‐2 agonists versus control in studies with blinding and concealed allocation, Outcome 2 Myocardial Infarction.
Comparison 8 Alpha‐2 agonists versus control in studies with blinding and concealed allocation, Outcome 3 Myocardial Ischaemia.
Comparison 9 Alpha‐2 agonists versus control in studies that used strict definitions of myocardial infarction or ischaemia, Outcome 1 Myocardial Infarction.
Comparison 9 Alpha‐2 agonists versus control in studies that used strict definitions of myocardial infarction or ischaemia, Outcome 2 Myocardial Ischaemia.
Comparison 10 Alpha‐2 agonists versus control in all surgery, excluding Oliver 1999, Outcome 1 All‐Cause Mortality.
Comparison 10 Alpha‐2 agonists versus control in all surgery, excluding Oliver 1999, Outcome 2 Cardiac Mortality.
Comparison 10 Alpha‐2 agonists versus control in all surgery, excluding Oliver 1999, Outcome 3 Myocardial Infarction.
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 All‐Cause Mortality Show forest plot | 18 | 3828 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.66 [0.44, 0.98] |
| 2 Cardiac Mortality Show forest plot | 6 | 2590 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.53 [0.30, 0.95] |
| 3 Myocardial Infarction Show forest plot | 16 | 3603 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.85 [0.65, 1.10] |
| 4 Myocardial Ischaemia Show forest plot | 20 | 1650 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.68 [0.57, 0.81] |
| 5 Supraventricular Tachyarrhythmia Show forest plot | 8 | 1056 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.02 [0.65, 1.58] |
| 6 Congestive Heart Failure Show forest plot | 11 | 1203 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.74 [0.47, 1.19] |
| 7 Hypotension Show forest plot | 17 | 3600 | Risk Ratio (M‐H, Random, 95% CI) | 1.32 [1.07, 1.62] |
| 8 Bradycardia Show forest plot | 18 | 3933 | Risk Ratio (M‐H, Random, 95% CI) | 1.66 [1.14, 2.41] |
| 9 Acute Stroke Show forest plot | 5 | 713 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.68 [0.31, 1.52] |
| 10 Preoperative Beta‐Blocker Use Show forest plot | 17 | 3338 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.11 [1.01, 1.22] |
| 11 Preoperative Calcium Channel Blocker Use Show forest plot | 16 | 3293 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.96 [0.89, 1.03] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 All‐Cause Mortality Show forest plot | 18 | Risk Ratio (M‐H, Fixed, 95% CI) | Subtotals only | |
| 1.1 Clonidine | 8 | 848 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.34 [0.13, 0.94] |
| 1.2 Dexmedetomidine | 8 | 783 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.00 [0.40, 2.54] |
| 1.3 Mivazerol | 2 | 2197 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.69 [0.42, 1.15] |
| 2 Cardiac Mortality Show forest plot | 5 | Risk Ratio (M‐H, Fixed, 95% CI) | Subtotals only | |
| 2.1 Clonidine | 3 | 363 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.75 [0.17, 3.37] |
| 2.2 Mivazerol | 2 | 2197 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.51 [0.27, 0.98] |
| 3 Myocardial Infarction Show forest plot | 16 | Risk Ratio (M‐H, Fixed, 95% CI) | Subtotals only | |
| 3.1 Clonidine | 9 | 881 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.59 [0.26, 1.33] |
| 3.2 Dexmedetomidine | 5 | 525 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.68 [0.24, 1.87] |
| 3.3 Mivazerol | 2 | 2197 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.91 [0.68, 1.21] |
| 4 Myocardial Ischaemia Show forest plot | 19 | Risk Ratio (M‐H, Fixed, 95% CI) | Subtotals only | |
| 4.1 Clonidine | 15 | 1077 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.62 [0.51, 0.76] |
| 4.2 Dexmedetomidine | 4 | 273 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.71 [0.48, 1.05] |
| 5 Hypotension Show forest plot | 17 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 5.1 Clonidine | 8 | 525 | Risk Ratio (M‐H, Random, 95% CI) | 1.51 [1.11, 2.04] |
| 5.2 Dexmedetomidine | 7 | 878 | Risk Ratio (M‐H, Random, 95% CI) | 1.57 [1.16, 2.12] |
| 5.3 Mivazerol | 2 | 2197 | Risk Ratio (M‐H, Random, 95% CI) | 0.95 [0.82, 1.10] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 All‐Cause Mortality Show forest plot | 7 | 546 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.70 [0.21, 2.31] |
| 2 Myocardial Infarction Show forest plot | 8 | 776 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.01 [0.46, 2.21] |
| 3 Myocardial Ischaemia Show forest plot | 10 | 589 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.65 [0.50, 0.85] |
| 4 Supraventricular Tachyarrhythmia Show forest plot | 4 | 583 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.06 [0.65, 1.71] |
| 5 Bradycardia Show forest plot | 6 | 657 | Risk Ratio (M‐H, Random, 95% CI) | 1.91 [1.11, 3.29] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 All‐Cause Mortality Show forest plot | 9 | 2851 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.61 [0.39, 0.96] |
| 2 Cardiac Mortality Show forest plot | 4 | 2515 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.51 [0.27, 0.93] |
| 3 Myocardial Infarction Show forest plot | 8 | 2817 | Risk Ratio (M‐H, Random, 95% CI) | 0.49 [0.22, 1.09] |
| 4 Myocardial Ischaemia Show forest plot | 10 | 1061 | Risk Ratio (M‐H, Random, 95% CI) | 0.73 [0.54, 1.00] |
| 5 Bradycardia Show forest plot | 10 | 2845 | Risk Ratio (M‐H, Random, 95% CI) | 1.44 [0.89, 2.31] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 All‐Cause Mortality Show forest plot | 7 | 1648 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.47 [0.25, 0.90] |
| 2 Cardiac Mortality Show forest plot | 4 | 1522 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.36 [0.16, 0.79] |
| 3 Myocardial Infarction Show forest plot | 6 | 1616 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.66 [0.46, 0.94] |
| 4 Myocardial Ischaemia Show forest plot | 5 | 715 | Risk Ratio (M‐H, Random, 95% CI) | 0.92 [0.64, 1.34] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 All‐Cause Mortality Show forest plot | 2 | 1013 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.05 [0.52, 2.09] |
| 2 Myocardial Infarction Show forest plot | 2 | 1021 | Risk Ratio (M‐H, Random, 95% CI) | 0.92 [0.20, 4.16] |
| 3 Myocardial Ischaemia Show forest plot | 3 | 96 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.23 [0.04, 1.30] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Myocardial infarction Show forest plot | 2 | 526 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.72 [0.29, 1.81] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 All‐Cause Mortality Show forest plot | 5 | 2699 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.59 [0.37, 0.95] |
| 2 Myocardial Infarction Show forest plot | 5 | 2326 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.90 [0.68, 1.21] |
| 3 Myocardial Ischaemia Show forest plot | 3 | 394 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.59 [0.41, 0.85] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Myocardial Infarction Show forest plot | 9 | 3064 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.84 [0.64, 1.11] |
| 2 Myocardial Ischaemia Show forest plot | 13 | 1340 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.65 [0.54, 0.79] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 All‐Cause Mortality Show forest plot | 17 | 1931 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.69 [0.37, 1.28] |
| 2 Cardiac Mortality Show forest plot | 5 | 693 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.61 [0.18, 2.04] |
| 3 Myocardial Infarction Show forest plot | 15 | 1706 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.53 [0.30, 0.94] |
