七氟醚和异丙酚对冠状动脉旁路移植术患者心肌保护作用比较的Meta分析

目的 采用Meta分析法比较七氟醚和异丙酚对冠状动脉旁路移植术患者心肌的保护作用.方法 通过电子数据库检索比较冠状动脉旁路移植术患者七氟醚和异丙酚心肌保护作用的临床随机对照研究,文献检索至2008年9月.由两位作者分别对研究质量进行评估,并提取有关资料,主要包括患者术前情况、术中情况、体外循环后心脏指数、术后心肌肌钙蛋白Ⅰ水平、机械通气时间、正性肌力药物使用情况、ICU停留时间、住院时间、术后死亡、心肌梗死、心肌缺血和房颤的发生情况,采用RevMan 5.0软件进行Meta分析.结果 共纳入13项前瞻性临床随机对照研究,包括696例患者,其中七氟醚组402例,异丙酚组294例.两组患者术后机械通气时间、正性肌力药物使用率、术后病死率、心肌梗死和房颤的发生率差异无统计学意义(P>0.05).与异丙酚组相比,七氟醚组患者体外循环后心脏指数升高,术后心肌肌钙蛋白Ⅰ水平和心肌缺血发生率降低,ICU停留时间和住院时间缩短(P<0.05).结论 冠状动脉旁路移植术患者七氟醚的心肌保护作用优于异丙酚.     

Induced preconditioning of cardiac performance in coronary bypass surgery--sevoflurane vs propofol

Twenty ASA III and IV adult patients scheduled for elective coronary artery surgery were included in the study. Anesthesia was induced and maintained with either sevoflurane (sevoflurane group; n = 10) or propofol (propofol group; n = 10). All preoperative cardiac medications were continued until the morning of surgery. There were significant decreases in mean arterial blood pressure, cardiac index and ejection fraction after CPB in propofol group compared with sevoflurane. Further, the plasma creatine kinase myocardial isoenzyme concentrations were significantly higher in propofol group but did not approach the critical values needed for diagnosis of myocardial infarction. Conclusion: It is concluded that, sevoflurane appears to be associated with better hemodynamic stability before and after CPB than propofol. This could be attributed to cardioprotective effect of sevoflurane during ischemia and reperfusion.     

Sevoflurane but not propofol preserves myocardial function in coronary surgery patients

BACKGROUND: Sevoflurane has been shown to protect against myocardial ischemia and reperfusion injury in animals. The present study investigated whether these effects were clinically relevant and would protect left ventricular (LV) function during coronary surgery. METHODS: Twenty coronary surgery patients were randomly assigned to receive either target-controlled infusion of propofol or inhalational anesthesia with sevoflurane. Except for this, anesthetic and surgical management was the same in all patients. A high-fidelity pressure catheter was positioned in the left ventricle and the left atrium. LV response to increased cardiac load, obtained by leg elevation, was assessed before and after cardiopulmonary bypass (CPB). Effects on contraction were evaluated by analysis of changes in dP/dt(max). Effects on relaxation were assessed by analysis of the load dependence of myocardial relaxation (R = slope of the relation between time constant tau of isovolumic relaxation and end-systolic pressure). Postoperative concentrations of cardiac troponin I were followed during 36 h. RESULTS: Before CPB, leg elevation slightly increased dP/dt(max) in the sevoflurane group (5 +/- 3%), whereas it remained unchanged in the propofol group (1 +/- 6%). After CPB, leg elevation resulted in a decrease in dP/dt(max) in the propofol group (-5 +/- 4%), whereas the response in the sevoflurane group was comparable to the response before CPB (5 +/- 4%). Load dependence of LV pressure fall (R) was similar in both groups before CPB. After CPB, R was increased in the propofol group but not in the sevoflurane group. Troponin I concentrations were significantly lower in the sevoflurane than in the propofol group. CONCLUSIONS: Sevoflurane preserved LV function after CPB with less evidence of myocardial damage in the first 36 h postoperatively. These data suggest a cardioprotective effect of sevoflurane during coronary artery surgery.     

Sevoflurane provides greater protection of the myocardium than propofol in patients undergoing off-pump coronary artery bypass surgery

BACKGROUND: Sevoflurane, like other halogenated anesthetics, has been shown to have a protective effect on the myocardium at risk after an ischemic injury. The current study tested the hypothesis that such beneficial effects, so far mainly seen in the laboratory, are reproducible in humans. METHODS: After institutional review board approval, 20 patients scheduled to undergo elective off-pump coronary artery bypass surgery were randomized to receive general anesthesia with either sevoflurane or propofol. Except for this, anesthetic and surgical management was the same in both groups. For assessing myocardial injury, troponin I and myocardial fraction of creatine kinase were determined during the first 24 postoperative hours. Systemic hemodynamic variables were measured before, during, and after completion of coronary artery bypass. RESULTS: Troponin I concentrations increased significantly more in propofol-anesthetized patients than in patients anesthetized with sevoflurane. CONCLUSION: Patients receiving sevoflurane for off-pump coronary artery surgery had less myocardial injury during the first 24 postoperative hours than patients receiving propofol. The results further support cardioprotective effects of sevoflurane.     

MYOCARDIAL INFARCT IMAGING AFTER CARDIAC SURGERY*

One hundred and nineteen patients undergoing cardiac surgery had postoperative myocardial imaging performed with technetium pyrophosphate in order to assess the incidence of perioperative myocardial infarction. Fifty-six patients had only coronary artery bypass graft (CABG) surgery, of whom 13 (23%) had a positive scintigram. Thirteen patients had CABG with other cardiac surgery and six (46%) had a positive scintigram. Fifty patients had other cardiac surgery but no CABG, and of these eight (16%) had a positive scintigram. The overall incidence of positive scintigrams was 23%, whereas definite or probable ECG diagnosis of infarction was present in 14 patients (12%). Serum levels of cardiac enzymes were higher in patients with positive scintigrams, but this finding did not consistently reach statistical significance. The use of a left ventricular vent during surgery did not correlate with a positive scintigram, nor did the total time on cardiopulmonary bypass or aortic cross-clamping. Patients having cardiac surgery, including CABG and valve replacement, have a 23% overall incidence of positive scintigrams. This suggests that the incidence of infarction after cardiac surgery is higher than can be recognized from the conventional criteria of ECG and enzyme changes.     

Myocardial infarct imaging after cardiac surgery.

One hundred and nineteen patients undergoing cardiac surgery had postoperative myocardial imaging performed with technetium pyrophosphate in order to assess the incidence of perioperative myocardial infarction. Fifty-six patients had only coronary artery bypass graft (CABG) surgery, of whom 13(23%) had a positive scintigram. Thirteen patients had CABG with other cardiac surgery and six (46%) had a positive scintigram. Fifty patients had other cardiac surgery but no CABG, and of these eight (16%) had a positive scintigram. The overall incidence of positive scintigrams was 23%, whereas definite or probable ECG diagnosis of infarction was present in 14 patients (12%). Serum levels of cardiac enzymes were higher in patients with positive scintigrams, but this finding did not consistently reach statistical significance. The use of a left ventricular vent during surgery did not correlate with a positive scintigram, nor did the total time on cardiopulmonary bypass or aortic cross-clamping. Patients having cardiac surgery, including CABG and valve replacement, have a 23% overall incidence of positive scintigrams. This suggests that the incidence of infarction after cardiac surgery is higher than can be recognized from the conventional criteria of ECG and enzyme changes.     

Effects of propofol,desflurane, and sevoflurane on recovery of myocardial function after coronary surgery in elderly high-risk patients

BACKGROUND: The present study investigated the effects of propofol, desflurane, and sevoflurane on recovery of myocardial function in high-risk coronary surgery patients. High-risk patients were defined as those older than 70 yr with three-vessel disease and an ejection fraction less than 50% with impaired length-dependent regulation of myocardial function. METHODS: Coronary surgery patients (n = 45) were randomly assigned to receive either target-controlled infusion of propofol or inhalational anesthesia with desflurane or sevoflurane. Cardiac function was assessed perioperatively and during 24 h postoperatively using a Swan-Ganz catheter. Perioperatively, a high-fidelity pressure catheter was positioned in the left and right atrium and ventricle. Response to increased cardiac load, obtained by leg elevation, was assessed before and after cardiopulmonary bypass (CPB). Effects on contraction were evaluated by analysis of changes in dP/dt(max). Effects on relaxation were assessed by analysis of the load-dependence of myocardial relaxation. Postoperative levels of cardiac troponin I were followed for 36 h. RESULTS: After CPB, cardiac index and dP/dt(max) were significantly lower in patients under propofol anesthesia. Post-CPB, leg elevation resulted in a significantly greater decrease in dP/dt(max) in the propofol group, whereas the responses in the desflurane and sevoflurane groups were comparable with the responses before CPB. After CPB, load dependence of left ventricular pressure drop was significantly higher in the propofol group than in the desflurane and sevoflurane group. Troponin I levels were significantly higher in the propofol group. CONCLUSIONS: Sevoflurane and desflurane but not propofol preserved left ventricular function after CPB in high-risk coronary surgery patients with less evidence of myocardial damage postoperatively.     

The Efficacy of Medical Stabilization Prior to Myocardial Revascularization in Early Refractory Postinfarction Angina

The timing of coronary artery bypass graft (CABG) surgery in patients with persistent, severe myocardial ischemia after an acute myocardial infarction is controversial. Based on the previous disappointing clinical experience with urgent surgery, a period of medical stabilization (mean ten days, range two to 28) prior to surgery was employed in a prospective nonrandomized clinical trial. The frequent use of intravenous nitroglycerin and intra-aortic balloon pumping was important in allowing preoperative clinical stabilization in these patients who were refractory to conventional medical therapy. The combined medical-surgical treatment protocol was associated with no early or late mortality in 20 patients who suffered preoperative myocardial infarction and demonstrated refractory post-infarction angina. Although these patients were considered to be high-risk surgical candidates, the incidence of perioperative myocardial damage in this selected group was comparable with that observed in patients undergoing elective CABG surgery at this institution without recent preoperative myocardial infarction. In order to determine the hemodynamic effectiveness of this selected patient management process, perioperative changes in left ventricular performance were determined by multigated cardiac blood pool imaging. Computer-based analysis of this radionuclide-related data allowed the accurate determination of ejection fraction (EF). Those patients with preoperative subendocardial infarction (N = 12) had no decrease in global EF 24 hours after operation and significant increases in EF seven days and eight months after operation. This pattern is analogous to that observed in patients without preoperative myocardial necrosis undergoing elective CABG surgery at this institution. Those patients with recent preoperative transmural myocardial infarction (N = 8) showed a decrease in EF 24 hours after operation, but recovered to preoperative levels seven days and eight months after operation. There was, however, no increase in EF in this subgroup of patients. On the basis of this study, the authors tentatively recommend a concerted effort at preoperative medical stabilization prior to CABG surgery in patients with persistent refractory myocardial ischemia soon after acute myocardial necrosis. A prospective, randomized study comparing urgent and delayed surgery, as well as nonsurgical treatment, will be necessary to define more precisely optimal management of this subgroup of cardiac patients.     

Cardioprotective properties of sevoflurane in patients undergoing aortic valve replacement with cardiopulmonary bypass

In coronary surgery patients the use of a volatile anesthetic regimen with sevoflurane was associated with a better recovery of myocardial function and less postoperative release of troponin I. In the present study we investigated whether these cardioprotective properties were also apparent in the cardiac surgical setting of aortic valve replacement (AVR) surgery for the correction of aortic stenosis. Thirty AVR surgery patients were randomly assigned to receive either target-controlled infusion of propofol or inhaled anesthesia with sevoflurane. Cardiac function was assessed perioperatively using a pulmonary artery catheter. Perioperatively, a high-fidelity pressure catheter was positioned in the left ventricle. Postoperative concentrations of cardiac troponin I were followed for 48 h. After cardiopulmonary bypass (CPB), stroke volume and dP/dt(max) were significantly higher in the patients with sevoflurane. Post-CPB, the effects of an increase in cardiac load on dP/dt(max) were similar to pre-CPB in the sevoflurane group (1.0 % +/- 5.4% post-CPB versus 1.3% +/- 8.6% pre-CPB) but more depressed in the propofol group (-8.2% +/- 4.4% post-CPB versus 0.1% +/- 4.9% pre-CPB). The rate of relaxation was significantly slower post-CPB in the propofol group. Postoperative levels of troponin I were significantly lower in the sevoflurane group. Our data indicate that the use of a volatile anesthetic regimen in AVR surgery was associated with better preservation of myocardial function and a reduced postoperative release of troponin I.     

Thrombogenic side-effects of recombinant factor VIIa after use in coronary artery bypass surgery

Recombinant activated factor VII (rFVIIa) has been used 'off licence' to successfully treat bleeding and reduce transfusion requirements in complex cardiac surgery. However; concerns over thrombogenic side-effects have limited but not excluded its use in patients undergoing coronary artery bypass surgery (CABG). We present two cases of CABG (one 'on pump' and one 'off pump') which were complicated by intraoperative aortic dissection and severe bleeding. In both cases the bleeding was successfully treated with rFVIIa. However the first case suffered from severe postoperative arrhythmias, myocardial infarction, cardiac arrest and worsening left ventricular dysfunction, suggesting graft patency may have been impaired, whereas the second case remained symptom-free suggesting graft patency was unaffected by the use of rFVIIa. If rFVIIa is needed to treat bleeding during CABG surgery, it may be more appropriate to administer smaller, repeated doses to minimize the risk of thrombosis and early graft failure.     

Antiarrhythmic Effect of Ischemic Preconditioning in Recent Unstable Angina Patients Undergoing Coronary Artery Bypass Grafting

Coronary artery bypass grafting (CABG) for unstable angina pectoris patients results in a higher incidence of arrhythmia and higher arrhythmic cardiac mortality. Ischemic preconditioning (IP) has proved effective in suppressing ischemia reperfusion arrhythmias in animals and in humans. The purpose of the present study was to investigate whether IP protects against postoperative arrhythmias in recent unstable angina patients undergoing urgent CABG. Forty-one patients with recent unstable angina and three-vessel coronary artery disease admitted for CABG were randomized into an IP group and a control group. The IP protocol involved twice occluding the ascending aorta with a cross-clamp for 2 minutes, followed by 3 minutes of reperfusion. Twenty-four-hour continuous electrocardiography (24-h ECG) was recorded from the preoperative day to the 2nd postoperative day. The incidences of supraventricular extrasystole (SVES), ventricular extrasystole (VES), supraventricular tachycardia (SVT), and ventricular tachycardia (VT) were 95.2%, 85.7%, 26.2%, and 26.2%, respectively, before surgery and 100.0%, 100.0%, 88.1%, and 76.2%, respectively, after surgery. IP significantly reduced the incidence of VT and the severity of SVES, VES, SVT, and VT after surgery. The period of mechanical ventilation and the length of stay in the intensive care unit were significantly shorter in the IP group. In summary, rhythm disturbances are common in CABG patients with recent unstable angina. IP significantly reduces rhythm disturbances, including SVES, VES, SVT, and VT after CABG. The findings indicate that IP could constitute an additional myocardial protective strategy in recently unstable angina patients undergoing CABG.     

Postoperative nausea and vomiting after sevoflurane with or without ondansetron compared with propofol in female patients undergoing breast surgery

Implications: We studied 180 female patients undergoing breast surgery. The patients were randomly allocated to receive one of three anesthetic techniques. Compared with either propofol or sevoflurane alone, sevoflurane with ondansetron resulted in a decreased incidence of postoperative nausea and vomiting. Sevoflurane with ondansetron prophylaxis is a good alternative to propofol with respect to avoiding postoperative nausea and vomiting.     

Changes in plasma creatinine concentration after cardiac anesthesia with isoflurane, propofol, or sevoflurane: a randomized clinical trial

BACKGROUND: Renal impairment often follows cardiac surgery. The authors investigated whether sevoflurane produces greater increases in plasma creatinine concentration than isoflurane or propofol after elective coronary artery surgery. METHODS: As part of maintenance anesthesia, including during cardiopulmonary bypass, patients were randomly allocated to receive one of three agents: isoflurane (n = 118), sevoflurane (n = 118), or propofol (n = 118). Fresh gas flows were 3 l/min. The preoperative plasma creatinine concentration was subtracted from the highest creatinine concentration in the first 3 postoperative days. A median maximum increase greater than 44 microM (0.5 mg/dl) was regarded as clinically important. Data were analyzed on an intention-to-treat basis. Subgroup analyses were performed on per-protocol patients and those with preoperative renal impairment (creatinine concentration > 130 microM [1.47 mg/dl] or urea > 7.7 mM [blood urea nitrogen, 21.6 mg/dl]). RESULTS: The differences between the groups were small, clinically unimportant, and not statistically significant for the primary analysis and subgroups. The proportions of patients with creatinine increases greater than 44 microM were 15% in the isoflurane group, 17% in the sevoflurane group, and 11% in the propofol group (P = 0.45). The median increases were 8 microM in the isoflurane group, 4 microM in the sevoflurane group, and 6 microM in the propofol group. The differences between the three median maximum increases were 1-4 microM (P > 0.45). In the subgroup with preoperative renal impairment, the median increases were 10 microM in the isoflurane group, 15 microM in the sevoflurane group, and 5 microM in the propofol group (P = 0.72). CONCLUSIONS: Sevoflurane did not produce greater increases in creatinine than isoflurane or propofol after elective coronary artery surgery.     

The effect of halothane, isoflurane, sevoflurane and propofol infusion on renal function after coronary artery bypass surgery

Renal insufficiency after cardiac surgery is associated with increased mortality, morbidity, and length of stay in the intensive care unit. We investigated the effect of isoflurane, halothane, sevoflurane and propofol anesthesia on perioperative renal function following elective coronary artery surgery. The medical records of 224 patients, in the Hacettepe University Medical Faculty Hospital who had undergone cardiac surgery in one year, were retrospectively reviewed. 65 (29%) patients received isoflurane, 68 (30%) patients received halothane, 64 (29%) patients received sevoflurane, and 27 (12%) patients received propofol infusion as part of maintenance anesthesia for coronary artery bypass surgery. Patient characteristics (age, sex, preoperative ejection fraction), operative data (duration of CPB, duration of operation, number of distal anastomoses, usage of diuretic, intraoperative crystalloid and blood transfusion), intraoperative urinary output, preoperative and postoperative (6th hours and 24th hours) BUN and plasma creatinine levels, were not statistically significant between and within groups. Intraoperative inotropic agent (dopamine) was used in 8 (12.3%) patients in the isoflurane group, in 10 (14.7%) patients in the halothane group, in 11 (17.2%) patients in sevoflurane group and in 9 (33.3%) patients in the propofol group. Postoperatively fluid and blood transfusion, postoperative drainage, urinary output, diuretic usage were smiliar between the four groups (p>0,05). Inotropic agent was used in 8 (12.3%) patients in the isoflurane group, in 9 (13.2%) patients in the halothane group, in 16 (25%) patients in the sevoflurane group and in 7 (25.9%) patients in the propofol group. It is concluded that, halothane, isoflurane, sevoflurane and propofol infusion anesthesia as part of anesthesia maintenance for elective coronary artery bypass surgery does not affect early postoperative renal functions.     

Perioperative morbidity and mortality in combined vs. staged approaches to carotid and coronary revascularization

Between 1986 and 1994 we identified 57 patients who underwent carotid endarterectomy (CEA) and coronary artery bypass grafting (CABG) during the same hospitalization. Simultaneous CABG and CEA was performed in 28 patients (mean age 70.5 years, 58% male). Indications for CABG in these patients were myocardial infarction in two, crescendo angina in 19, congestive heart failure in two and left main or triple-vessel coronary artery disease noted during carotid preoperative evaluation in five. Indications for CEA were transient ischemic attack (TIA) in 12, crescendo TIA in six, cerebrovascular accident (CVA) in five, and asymptomatic stenosis in five. There were no postoperative myocardial infarctions or perioperative deaths. Two patients developed atrial fibrillation, and four patients had CVAs (two were ipsilateral to the side of CEA). Twenty-nine patients underwent staged procedures (i.e., not performed concomitantly but during the same hospitalization). Indications for CABG and CEA were comparable to those in the group undergoing simultaneous procedures. In 17 patients CEA was performed before CABG. There was a single CVA, the result of an intracerebral hemorrhage. Five of the 17 patients had a myocardial infarction and two died; one patient had first-degree heart block requiring a pacemaker. Four additional patients developed atrial fibrillation, one of whom required cardioversion. The remaining 12 patients had CABG followed by CEA. There were no CVAs, myocardial infarctions, arrhythmias, or deaths in this subgroup. These data demonstrate that the performance of simultaneous CABG and CEA procedures is associated with increased neurologic morbidity (14.3%), both ipsilateral and contralateral to the side of carotid surgery in contrast to staged CABG and CEA (3.4%). In addition, when staged carotid surgery preceded coronary revascularization in those with severe coronary artery disease, the combined cardiac complication and mortality rate was significantly higher than when coronary revascularization preceded CEA. This evidence suggests that when CABG and CEA must be performed during the same hospitalization, the procedures should be staged with CABG preceding CEA. Presented at the Twentieth Annual Meeting of the Peripheral Vascular Surgery Society, New Orleans, La., June 10, 1995.     

Sevoflurane-remifentanil versus propofol-remifentanil anesthesia at a similar bispectral level for off-pump coronary artery surgery: no evidence of reduced myocardial ischemia

OBJECTIVE: Sevoflurane could decrease myocardial ischemic injury in patients undergoing off-pump coronary artery bypass surgery. This study was designed to compare postoperative troponin I (cTnI) concentrations after sevoflurane-remifentanil versus propofol-remifentanil anesthesia. DESIGN: Prospective, randomized single-blind clinical study. SETTING: University hospital. PARTICIPANTS: Eighteen patients. INTERVENTIONS: General anesthesia was conducted with sevoflurane-remifentanil (n = 9) or propofol-remifentanil (n = 9). Administration of sevoflurane and propofol was adjusted to maintain the bispectral index (BIS) between 40 and 60. MEASUREMENTS AND MAIN RESULTS: Groups were comparable regarding the patients' characteristics. The objective of BIS was maintained in both groups except during the period of coronary artery grafts (p < 0.001) when the BIS number in the propofol group fell below 40 and was significantly lower than in the sevoflurane group. Intraoperative hemodynamic variables were similar between groups. No patient required cardiopulmonary bypass. Need for inotropic and vasoactive support during the first graft was not necessary in the propofol group and occurred in 4 patients in the sevoflurane group (not significant). During the second graft, 2 patients in the propofol group and 3 in the sevoflurane group needed hemodynamic support. Postoperative hemodynamic variables were comparable between groups. Areas under the curve of postoperative increases in cTnI were 27.0 +/- 38.6 and 17.4 +/- 14.6 ng/mL/hour in the sevoflurane and propofol groups, respectively (not significant). CONCLUSION: This study does not support cardioprotective effects of sevoflurane. The particularly short total cumulative duration of ischemia and the relatively low administered end-tidal sevoflurane concentrations may explain this result.     

Factors affecting post minimally invasive direct coronary artery bypass grafting incidence of myocardial infarction, percutaneous transluminal coronary angioplasty, coronary artery bypass grafting and mortality of cardiac origin

In the present study we identify parameters which influence the incidence of myocardial infarction (MI), need for percutaneous coronary intervention (PCI), coronary artery bypass grafting (CABG) and cardiac mortality after minimal invasive coronary artery bypass grafting (MIDCABG). With a mean follow-up of 30+/-11.2 months, 390 patients were assessed with Wald test-corrected chi(2) analysis to identify preoperative factors which correlate with a higher incidence of post-MIDCABG MI, PCI, CABG and mortality from cardiac causes. We found an increased incidence of postoperative MI in patients with 2-vessel (8.7%) and 3-vessel (7.7%) vs. 1.3% 1-vessel coronary artery disease (CAD) (P=0.023), and in patients with preceding cardiac procedure (CABG and PCI: 8.4% vs. 2.0% without, P=0.023). Also diabetes was associated with higher post-MIDCABG frequency of MI (P=0.035). Severity of angina was associated with lesser post-MIDCAB-PCI (P=0.011) while preceding CABG predicted a higher incidence (P=0.012). Preoperative low ejection fraction (EF) (multivariate, P<0.001), preoperative MI (P=0.007) and extent of CAD (P=0.001) were associated with a higher post-MIDCABG mortality. None of the parameters correlated with subsequent CABG MIDCABG. The extent and history of CAD, history of cardiac interventions and low EF seem to influence the outcome adversely and should be considered deciding pro or against the MIDCAB-option.     

Silent myocardial ischemia is not predictive of myocardial infarction in peripheral vascular surgery patients

Continuous ambulatory ECG (CAECG) monitoring has been advocated as an effective low-cost preoperative method for detecting silent myocardial ischemia in patients undergoing peripheral vascular surgery. In addition, silent ischemic events are associated with an increased incidence of postoperative myocardial infarctions. Ninety-six patients (mean age 73 years) admitted for elective aortic (24) or infrainguinal (72) operations over a 2-year period underwent 24-hour two- or three-lead CAECG monitoring. Results were reviewed by a single cardiologist blinded to the study. The criterion for ischemia was ST segment depressions of 1 mm or greater for 40 seconds or more 60 msec after the J point. Postoperative myocardial infarction was determined by ECG changes and/or elevated serum creatinine phosphokinase with positive MB isoenzymes. Risk factors included hypertension (71%), history of coronary artery disease (66%), smoking (61%), and diabetes mellitus (47%). Nine out of 96 patients (9.4%) had a positive CAECG test for silent myocardial ischemia. Only one patient (11.1%) developed postoperative myocardial infarction and there were no deaths in this group. The incidence of postoperative myocardial infarction in the nonischemic group was 16.1% (14/87). However, the mortality in this group was 6.9% (6/87). New and malignant arrhythmias requiring preoperative medical intervention were observed in seven patients (7.4%): two cases of ventricular tachycardia and five cases of atrial flutter/fibrillation. Contrary to previous reports, CAECG monitoring for silent ischemia was not a significant predictor of postoperative myocardial infarction or mortality in our patient population. However, we continue to recommend the preoperative use of CAECG monitoring as a diagnostic tool for unsuspected malignant arrhythmias.Presented at the Seventeenth Annual Meeting of the Peripheral Vascular Surgery Society, Chicago, Ill., June 7, 1992.     

The effects of volatile anesthetics on cardiac ischemic complications and mortality in CABG: a meta-analysis

PURPOSE: Coronary artery bypass graft surgery (CABG) is associated with cardiac complications, including ischemia, acute myocardial infarction (AMI), and death. Volatile anesthetics have been shown to have a preconditioning-like effect. This systematic review assesses the effects of volatile anesthetics on cardiac ischemic complications and morbidity after CABG. METHODS: Data were obtained, without language restriction, from searches of MEDLINE, Science Citation Index, PubMed, and reference lists. We included only prospective randomized controlled trials evaluating volatile anesthetics during CABG. Two reviewers independently abstracted data on myocardial ischemia, acute myocardial infarction (AMI), and death. Treatment effects were calculated as odds ratio (OR) with 95% confidence intervals (CI) for binary data, and weighted mean difference (WMD) with 95% CI for continuous data. PRINCIPAL FINDINGS: Thirty-two studies (2,841 patients) were included. In comparison with iv anesthesia, volatile anesthetics were associated with reduced all-cause mortality (OR, 0.65; 95% CI, 0.36-1.18; P = 0.16). Enflurane was associated with increased AMI (OR, 1.34; 95% CI, 0.68-2.64; P = 0.40), whereas sevoflurane and desflurane reduced cardiac troponin I (cTnI) at six hours, 12 hr, 24 hr [WMD, -1.45; 95% CI (-1.73, -1.16); P < 0.00001], and 48 hr after operation. CONCLUSION: This meta-analysis demonstrates sevoflurane and desflurane reduce the postoperative rise in cTnI. Sevoflurane-mediated reduction in cardiac troponin was associated with improved long-term outcomes in one study. This meta-analysis was not able to show that these positive effects on troponin were translated into improved clinical outcomes. Well-designed large randomized control trials are needed to further elucidate the differential cardio-protective effects of volatile anesthetics.     

Cardiac arrhythmias and myocardial ischemia after thoracotomy for lung cancer.

The records of 598 patients undergoing a thoracic surgical procedure for lung cancer from 1975 through 1989 were reviewed for occurrence of cardiac arrhythmias and myocardial ischemic events. Atrial tachycardias occurred in 16% (94/598); atrial fibrillation was preponderant (87%), followed by supraventricular tachycardia and atrial flutter. Patients with recurrent episodes of dysrhythmias had a significantly higher mortality rate than those without episodes or with a single episode only (17% versus 2.4%; p less than 0.01). Transient ischemic electrocardiographic changes were documented in 23 patients (3.8%) and myocardial infarction in 7 (1.2%). An abnormal preoperative exercise test result and intraoperative hypotension were strongly associated with both dysrhythmia and ischemia (p less than 0.01). Pneumonectomy, ischemic changes on the electrocardiogram, and cardiac enlargement were also associated with arrhythmias (p less than 0.01). A weaker association (p less than 0.05) was found between postoperative arrhythmias and old myocardial infarction (greater than 6 months), arterial hypertension, and heart failure. Pulmonary function had no predictive value in this respect. A history of angina or old myocardial infarction was predictive of transient postoperative myocardial ischemia but not myocardial infarction. Despite improved anesthetic and monitoring techniques and more frequent use of the intensive care unit postoperatively in the last decade, the incidence of arrhythmias after thoracotomy has not decreased. More effective prevention is needed, particularly for patients with defined preoperative and perioperative risk factors.