Complete revascularization in coronary artery bypass grafting with and without cardiopulmonary bypass

BACKGROUND: The feasibility of complete revascularization on the beating heart without cardiopulmonary bypass (CPB) as compared with the standard operation with CPB in elective low-risk patients with multivessel disease has not been clearly demonstrated in a prospective trial. METHODS: Eighty selected low-risk patients were enrolled. In preoperative study with coronary angiography, the decision was made whether complete revascularization without CPB could be performed. Patients were randomly assigned to receive CABG either with (n = 40) or without CPB (n = 40). Randomization criteria were age, sex, and left ventricular ejection fraction. Completeness of revascularization as well as short- and mid-term clinical outcome in a 13.4 +/- 6.5 month follow-up period were monitored. RESULTS: Twenty-six of 40 (65%) patients undergoing CABG without CPB underwent complete revascularization. In 5 of these patients (12.5%) suitable vessels were discarded for technical reasons and 9 patients (22.5%) were switched to CABG with CPB owing to the deeply intramyocardial course of target vessels (n = 5) or to hemodynamic instability (n = 4). In the group of patients operated on with CPB, 34 of 40 patients (85%) received complete revascularization. In 6 patients (15%) suitable vessels were discarded for technical reasons. Mean number of bypass grafts was 3.1 +/- 0.8 with CPB and 2.6 +/- 0.5 without CPB (p = 0.043). Clinical outcome and hospital stay were comparable in both groups. No patient died during the study period. No myocardial infarction was observed. Three patients undergoing CABG without CPB underwent successful PTCA 3 months after surgery. CONCLUSIONS: CABG without the use of CPB is effective for complete revascularization in the majority of selected low-risk patients. Nevertheless, it has to be stated that the rate of incomplete revascularization in this early series of CABG without CPB is higher, and compromises the basic principle of complete revascularization.     

Vacuum assisted cardiopulmonary bypass in minimally invasive cardiac surgery: its feasibility and effects on hemolysis

The present study describes a cardiopulmonary bypass (CPB) technique that incorporates vacuum assisted venous drainage and arterial return using a centrifugal pump in minimally invasive cardiac surgery (MICS). The technique was performed on 40 patients scheduled to undergo MICS. The proposed CPB technique enables a good operative field to be obtained even through a limited incision through the use of peripheral cannulation using small cannulae. Vacuum pressure was applied to the venous reservoir (-43 +/- 14 mm Hg) to maintain adequate CPB flow (>2.4 L x min-1 x M-2). The effects of CPB on hemolysis were subsequently compared between patients who underwent the proposed procedure (MICS group; n = 6) and a control group who underwent coronary arterial bypass grafting (CABG group; n = 6) with conventional CPB. Plasma free hemoglobin (FHb) increased and plasma haptoglobin (Hp) decreased during CPB in both groups, with no significant difference between the groups. By the next day, FHb had returned to pre-CPB levels whereas Hp remained lower in both groups. Again, these values did not differ significantly between groups. Thus, we conclude that the proposed CPB technique is useful in MICS with acceptable effects on hemolysis.     

Does off-pump coronary artery bypass (OPCAB) surgery improve the outcome in high-risk patients?: a comparative study of 1398 high-risk patients.

OBJECTIVE: Although there has been some evidence supporting the theoretical and practical advantages of off-pump coronary artery bypass (OPCAB) over the conventional coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB), it has not yet been determined which group of patients would benefit most from it. It has been advocated recently that high-risk patients could benefit most from avoidance of CPB. The aim of this retrospective study is to assess the efficacy of the OPCAB technique in multi-vessel myocardial revascularization in a large series of high-risk patients. METHODS: The records of 1398 consecutive high-risk patients who underwent primary isolated CABG at Harefield Hospital between August 1996 and December 2001 were reviewed retrospectively. Patients were considered as high-risk and included in the study if they had a preoperative EuroSCORE of > or =5. Two hundred and eighty-six patients were operated on using the OPCAB technique while 1112 patients were operated on using the conventional CABG technique with CPB. The OPCAB patients were significantly older than the CPB patients (68.1+/-8.3 vs. 63.7+/-9.9 years, respectively, P<0.001). The OPCAB group included significantly more patients with poor left ventricular (LV) function (ejection fraction (EF) < or =30%) (P<0.001) and more patients with renal problems (P<0.001). RESULTS: There was no significant difference in the number of grafts between the groups. The CPB patients received 2.8+/-1.2 grafts per patient while OPCAB patients received 2.8+/-0.5 grafts per patient (P=1). Twenty-one (7.3%) OPCAB patients had one or more major complications, while 158 (14.2%) CPB patients (P=0.008) developed major complications. Thirty-eight (3.4%) CPB patients developed peri-operative myocardial infarction (MI) while only two (0.7%) OPCAB patients developed peri-operative MI (P=0.024). The intensive therapy unit (ITU) stay for OPCAB patients was 29.3+/-15.4 h while for CPB patients it was 63.6+/-167.1 h (P<0.001). There were ten (3.5%) deaths in the OPCAB patients compared to 78 (7%) deaths in the CPB patients (P=0.041) within 30 days postoperatively. CONCLUSIONS: This retrospective study shows that using the OPCAB technique for multi-vessel myocardial revascularization in high-risk patients significantly reduces the incidence of peri-operative MI and other major complications, ITU stay and mortality. Even though the OPCAB group included a significantly higher proportion of older patients with poor LV function (EF < or =30%) and renal problems, the beneficial effect of OPCAB was evident.     

Elective intraaortic balloon counterpulsation in high-risk off-pump coronary artery bypass grafting

The beneficial effects of intraaortic balloon pump (IABP) in CABG with cardiopulmonary bypass (CPB) have been reported. However, the benefits of insertion of IABP electively in high-risk off-pump coronary artery bypass grafting (OPCAB) have not been established. Six hundred and twenty-five patients who underwent OPCAB form the study group. High-risk patients fulfilling two or more of the following: left main stem stenosis >70%, unstable angina, and poor left ventricular function, who had elective insertion of IABP preoperatively by the open technique (group I; n = 20) were compared with a similar high-risk group that did not (group II; n = 25). There were no significant differences in risk factors between the two groups (Euroscore 5.68). The mean number of grafts was similar. Postoperatively, there were no significant differences in the need for inotropes, duration of ventilation, arrhythmias, cerebrovascular, gastrointestinal, and infective complications (p = NS). There were no IABP-related complications. Acute renal failure requiring hemofiltration was higher in group II (n = 5; p < 0.05). Four patients (16%) in group II required postoperative IABP. Although intensive care stay was longer in group I (27.6 +/- 15.3 vs. 18.6 +/- 9.1 hours; p < 0.05), patients in group I were discharged earlier from hospital. There was no difference in mortality between the two groups (n = 1 in each group). In high-risk patients undergoing OPCAB, routine preoperative insertion of IABP electively reduces the incidence of acute renal failure. In addition it avoids the need for emergency insertion postoperatively and may result in earlier discharge.     

High myocardial lactate concentration is associated with poor myocardial function prior to cardiopulmonary bypass

AIM: This study was designed to analyse the relationship between myocardial lactate--determined by microdialysis--and hemodynamics during coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB). METHODS: Twenty consecutive patients with coronary artery disease were enrolled for this prospective, observational study. Microdialysis measurements were performed in the apical region of the heart during periods of 15 to 20 min before, during, and after CPB; hemodynamics and plasma lactate concentrations were determined correspondingly. Correlation analysis revealed a relationship between myocardial lactate concentration and right ventricular ejection fraction at baseline (Spearman's r: 0.6; P=0.02). Patients were thus grouped according to the myocardial lactate concentration at baseline into a high-lactate group (2.5+/-0.7 mmol.l(-1), n=10) and low-lactate group (0.9+/-0.5 mmol.l(-1), n=10). RESULTS: Preoperative left ventricular ejection fraction was not different between the groups (high-lactate group: 53+/-16%; low-lactate group: 57+/-15%; P=n.s.) Patients in the high-lactate-group had a lower stroke volume index (P=0.005) and right ventricular ejection fraction (P=0.04) before, and higher central venous and pulmonary artery pressures (P<0.01) after CPB. Plasma lactate was significantly higher during CPB in the high-lactate-group (P<0.05). No correlation was observed between myocardial and plasma lactate. Six patients in the high-lactate but none in the low-lactate-group needed inotropic support after weaning from CPB (P=0.01). CONCLUSIONS: These data are suggestive of an association between subtle myocardial ischemia--detected by microdialysis--and perioperative myocardial dysfunction in patients undergoing CABG. The microdialysis technique may be a valuable adjunct for monitoring myocardial metabolism during cardiac surgery.     

老年人非体外循环冠状动脉旁路移植术的心肌保护作用

目的比较70岁以上老年人非体外循环冠状动脉旁路移植术(OPCAB)和体外循环冠状动脉旁路移植术(CABG)围术期心肌损伤程度,探讨OPCAB的心肌保护效果。方法30例老年患者分为两组,A组15例,为CABG组,B组15例,为OPCAB组。分别于术前、术中30min、术中1h、术后6h、12h、24h、72h、120h取静脉血标本,分别测定心肌肌钙蛋白I(cTnI)水平和CKMB活性;另外记录围手术期各项临床指标。结果OPCAB组术后辅助呼吸时间较CABG组短(P<0.01),而且主动脉球囊反搏和输血例数较低(P<0.05)。CABG组与OPCAB组cTnI、CKMB的术前水平相,术后6hcTnI即有升高而后下降,术后30min至72h均较OPCAB组明显升高(P<0.05或0.01)。结论与CABG相比,OPCAB的心肌损伤较轻,心肌保护效果较好。     

Respiratory dysfunction after cardiac surgery: effects of avoiding cardiopulmonary bypass and the use of bilateral internal mammary arteries.

BACKGROUND: The quantitative contribution of cardiopulmonary bypass (CPB) to respiratory dysfunction after cardiac surgery is not documented and the effect of the use of bilateral internal mammary artery (IMA) grafts is not clear. METHODS: One hundred and seventy-five patients undergoing CABG with (CPB, n=150) and without (NOCPB, n=25) CPB were studied. PMN elastase (as a marker of the systemic inflammatory response) and serial arterial oxygen (paO(2)) and carbon dioxide (paCO(2)) tension, alveolar arterial oxygen (AaO(2)) gradient and percent saturation were measured. The CPB group was subdivided into three groups by the number of IMA grafts used: 0IMA (n=12), 1IMA (n=82) and 2IMA (n=51). RESULTS: The NOCPB group was younger, had significantly better preoperative blood gases, received fewer grafts and had lower PMN elastase levels than the CPB group. In both groups maximum respiratory dysfunction occurred at 48 h (paO(2), percentage saturation and Aa gradient all P<0.001 versus baseline) with partial recovery by 5 days. The percentage decline and subsequent recovery in all blood gas parameters was near identical in the CPB and NOCPB groups. Amongst the three IMA groups the percentage changes in all blood gas parameters were similar, as was the duration of postoperative ventilation and time to discharge. There was no correlation between blood gas parameters at 48 h with age, CPB time, blood loss, duration of ventilation or peak PMN elastase level. CONCLUSIONS: Changes in postoperative gas exchange are similar in patients undergoing CABG with and without CPB even although PMN elastase levels indicate that CPB produces a more marked inflammatory response. The use of 2IMA compared with 1IMA does not increase respiratory dysfunction.     

Inflammatory response after coronary revascularization with or without cardiopulmonary bypass

BACKGROUND: We sought to investigate the effect of multiple coronary artery bypass grafting (CABG) with or without cardiopulmonary bypass (CPB) on the perioperative inflammatory response. METHODS: Sixty patients undergoing CABG were randomly assigned to one of two groups: (A) on pump with conventional CPB and cardioplegic arrest, and (B) off pump on the beating heart. Serum samples were collected for estimation of neutrophil elastase, interleukin 8 (IL-8), C3a, and C5a preoperatively and at 1, 4, 12, and 24 hours postoperatively. Furthermore, white blood cell (WBC), neutrophil, and monocyte counts were carried out preoperatively and at 1, 12, 36 and 60 hours postoperatively. Overall incidence of infection and perioperative clinical outcome were also recorded. RESULTS: The groups were similar in terms of age, weight, gender ratio, extent of coronary disease, left ventricular function, and number of grafts per patient. Neutrophil elastase concentration peaked early after CPB in the on-pump group, with a decline with time. Repeated-measures analysis of variance between groups and comparisons at each time point (modified Bonferroni) showed elastase concentrations were significantly higher in the on-pump than the off-pump group (both p < 0.0001). IL-8 increased significantly after surgery in the on-pump group, with no decline during the observation period (p = 0.01 vs off pump). C3a and C5a rose early after surgery in both groups when compared with baseline values. Postoperative WBC, neutrophil, and monocyte counts were significantly higher in the on-pump than the off-pump group (p < 0.01). Finally, the incidence of postoperative overall infections was significantly higher in the on-pump group (p < 0.0001 vs off pump). CONCLUSIONS: CABG on the beating heart is associated with a significant reduction in inflammatory response and postoperative infection when compared with conventional revascularization with CPB and cardioplegic arrest.     

Inflammatory response and myocardial injury following coronary artery bypass grafting with or without cardiopulmonary bypass

Objective: In coronary artery bypass grafting (CABG) without cardiopulmonary bypass (CPB) the inflammatory response is suggested to be minimized. Coronary anastomoses are performed during temporary coronary occlusion. Inflammatory response and myocardial ischaemia need to be studied in a randomized study comparing CABG in multivessel disease with versus without CPB. Methods: Following randomization 30 consecutive patients received CABG either with (n=16) or without CPB (n=14). Primary study endpoints were parameters of the inflammatory response (interleukin (IL)-6, interleukin-10, ICAM-1, P-selectin) and of myocardial injury (myoglobin, creatine kinase-MB (CK-MB), troponin I) (intraoperatively, 4, 8, 16, 24 and 48 h after surgery). The secondary endpoint was clinical outcome. Results: The incidence of major (death: CABG with CPB n=1, not significant (n.s.)) and minor adverse events (wound infection: with CPB n=2, without CPB n=1, n.s.; atrial fibrillation: with CPB n=3, without CPB n=2, n.s.) was comparable between both groups. The release of IL-6 was comparable during 8 h of observation (n.s.). Immediately postoperatively IL-10 levels were higher in the operated group with CPB (211.7±181.9 ng/ml) than in operated patients without CPB (104.6±40.3 ng/ml, P=0.0017). Thereafter no differences were found between both groups. A similar pattern of release was observed in serial measures of ICAM-1 and P-selectin, with no difference between both study groups (n.s.). Eight hours postoperatively the cumulative release of myoglobin was lower in operated patients without CPB (1829.7±1374.5 μg/l) than in operated patients with CPB (4469.8±4525.7 μg/l, P=0.0152). Troponin I release was 300.7±470.5 μg/l (48 h postoperatively) in patients without CPB and 552.9±527.8 μg/l (P=0.0213). CK-MB mass release was 323.5±221.2 μg/l (24 h postoperatively) in operated patients without CPB and 1030.4±1410.3 μg/l in operated patients with CPB (P=0.0003). Conclusions: This prospective randomized study suggests that in low-risk patients the impact of surgical access on inflammatory response may mimic the influence of long cross-clamp and perfusion times on inflammatory response. Our findings indicate that multiregional warm ischaemia, caused by snaring of the diseased coronary artery, causes considerably less myocardial injury than global cold ischaemia induced by cardioplegic cardiac arrest.     

Beta-blockade versus Buckberg blood-cardioplegia in coronary bypass operation.

OBJECTIVE: Continuous perfusion of the coronary arteries with beta-blocker (esmolol)-enriched normothermic blood during cardiac surgery has been suggested as an alternative technique for myocardial protection. The aim of the present study was to compare the beta-blocker technique to Buckberg's blood cardioplegia during coronary artery bypass grafting (CABG). METHODS: Sixty patients with coronary artery disease were randomly assigned to either the esmolol group (ES, n = 30) or the blood cardioplegia group (BC, n = 30). During aortic crossclamp ES patients received continuous normothermic coronary perfusion with esmolol-enriched blood. Hearts of the BC group were protected by antegrade cold blood cardioplegia according to Buckberg. We measured left ventricular (LV) contractility using TEE (fractional area of contraction, FAC) and hemodynamic parameters prior to cannulation for cardiopulmonary bypass (CPB), after decannulation, and 4 h postoperatively. Myocardial lactate release was measured prior to aortic cross-clamp, during cross-clamp, and after decannulation. LV biopsies for determination of heat-shock protein (HSP-70), actin pattern and intercellular adhesion-molecule (ICAM-I) as indicators for structural changes were collected prior CPB, at the end of the aortic cross-clamp period, and prior to weaning off CPB. RESULTS: There was no significant difference between both groups with respect to grafts and cross-clamp time. ES hearts did not release lactate during cross-clamp. In contrast, BC hearts released significant amounts of lactate. Post CPB FAC and hemodynamics under similar inotropic stimulation showed no difference between groups, whereas at 4 h post CPB measurements showed slightly better values in the ES group: cardiac index: ES: 2.9+/-0.1 (SEM) versus BC: 2.6+/-0.1 L/min per m2 (P < 0.05); FAC: ES: 55+/-3 versus BC: 48+/-3% (P < 0.05). HSP-70 and actin pattern showed no difference between groups; however, ICAM-I showed a significantly higher degree of structural changes in BC hearts: 18+/-2 versus ES: 11+/-1% (P < 0.05). CONCLUSION: Our data demonstrate that application of the beta-blocker technique during routine CABG was associated with slightly better functional recovery and less structural myocardial alteration as compared with intermittent cold blood cardioplegia, however, both techniques provided equivalent myocardial protection in terms of patient outcome. Future studies are required to investigate if myocardial ischemia minimization by use of the beta-blocker technique may be beneficial in compromized hearts.     

Postoperative hyperthermia following off-pump versus on-pump coronary artery bypass surgery

OBJECTIVE: Hyperthermia is common in the first 24 hours following coronary artery bypass graft surgery (CABG) with cardiopulmonary bypass (CPB). An inflammatory response to CPB is often implicated in the pathophysiology of this fever. Unlike CABG with CPB, the temperature pattern after off-pump CABG (OPCAB), where CPB is avoided, has not yet been described. The purpose of this study was to describe the postoperative temperature pattern following OPCAB and to compare it with that following on-pump cardiac surgery. DESIGN: Retrospective, observational study. SETTING: Tertiary care university hospital. PARTICIPANTS: Consenting patients undergoing CABG or OPCAB procedures. INTERVENTIONS: Observational. MEASUREMENTS AND MAIN RESULTS: Of the CABG patients, 89% had temperature elevations above 38 degrees C, versus 44% of the OPCAB patients (P = 0.04). Peak body temperature was higher in the on-pump patients (CABG 38.5 degrees C +/- 0.4 degrees C versus OPCAB 37.9 degrees C +/- 0.5 degrees C; P = 0.002), as was the area under the curve for temperatures greater than 38 degrees C (CABG 1.6 +/- 1.7 degrees C/hr versus OPCAB 0.4 +/- 1.2 degrees C/hr; P = 0.02). CONCLUSIONS: Off-pump CABG surgery patients experience less hyperthermia compared with on-pump CABG patients. The reasons for a lower incidence and severity of hyperthermia after OPCAB surgery are not known, but may be related to a reduced inflammatory response.     

Preliminary experience with the mini-extracorporeal circulation system (Medtronic resting heart system)

A compact cardiopulmonary bypass (CPB) utilized by closed circuit system with minimized priming volume can be a solution to reduce adverse effects of CPB, and the Resting Heart System (RHS; Medtronic, Inc, Minneapolis, MN, USA) is the newest one on the market. We performed CABG with RHS in 10 patients, and report here our preliminary experiences with RHS in comparison with conventional CPB. Twenty patients who underwent isolated CABG were randomized into two groups; RHS group (n=10) with the use of RHS and Conventional group (n=10) with the use of a conventional CPB. There were no significant differences of preoperative patient characteristics in both groups. The mean number of grafts was 2.7+/-0.6 and 2.7+/-0.8 (P=0.38), the mean aortic clamp was 32+/-11 and 35+/-11 min (P=0.35), and CPB times were 68+/-25 and 72+/-24 min (P=0.82) in RHS and Conventional group, respectively. All patients but one had no complications and survived in both groups. One patient in RHS group died suddenly on the 5th postoperative day after uneventful postoperative course. Postoperative leukocyte count at 6 h after the operation and value of the C-reactive protein were 11200+/-2310 and 13300+/-3990/mm(3) (P=0.10) and 44.4+/-9.7 and 65.3+/-18.5 mg/l (P=0.045) in RHS and Conventional group, respectively. CABG operations could be safely performed using the RHS with a comfort level similar to standard CPB.     

常规与非体外循环冠状动脉旁路移植术炎症因子比较

目的：比较多支冠状动脉（冠脉）病变行常规体外循环冠状动脉旁路移植术（CABG）和非体外循环冠状动脉旁路移植术（OPCAB）围术期心肌损伤和炎症因子的变化情况。方法：CABG组（A组，13例），OPCAB组（B组，22例）。分别于麻醉诱导后、手术结束后即刻、术后24h和48h进行血样检测，分别测定TNF－α、IL-1β、IL-8和IL－10水平。另外记录围手术期各项临床指标如引流量、输血量、呼吸机使用时间和发热时间等。结果：两组在年龄、冠脉病变程度、心功能和血管旁路移植数目上相似。术后IL－8水平OPCAB组相对稍高，但两组无显著差异。围术期CABG组IL－1、TNF较OPCAB明显为高（P＜0．05）。但炎症因子IL－10 OPCAB组却较CABG组明显升高（P＜0．05），术后24h达高峰。最后，CABG较OPCAB病人呼吸机使用时间延长且发热时间延长。结论：与CABG组相比，OPCAB组围术期炎症反应和术后并发发症明显降低。     

Emergency myocardial revascularization for acute myocardial infarction: survival benefits of avoiding cardiopulmonary bypass.

OBJECTIVE: Emergency coronary artery bypass grafting (CABG) for acute myocardial infarction (AMI) is associated with increased operative mortality. It has been suggested that this mortality might be reduced by performing the operation without cardiopulmonary bypass (CPB). METHODS: Between January 1992 and April 1998, 77 patients underwent emergency CABG within 48 h of AMI. Thirty seven were operated on with CPB, and 40 without CPB. The two groups were similar regarding age, gender, left-ventricular ejection fraction (EF) and preoperative use of intra-aortic balloon pump (IABP; 50%). The mean number of grafts/patient was 3 in the CPB group, and 1.9 in the No-CPB group (P<0.0001). RESULTS: Operative mortality in the CPB group was 24% (nine of 37) compared to 5% (two of 40) without CPB (P=0.015). Follow-up ranged between 6 and 66 months. There were no late deaths in the CPB group compared to nine (22%) in the No-CPB group (P<0.0066). Patients operated on with CPB had lower rates of recurrent angina (0 versus 15%; P=0.04) and re-interventions (0 versus 15%; P=0.04). CONCLUSIONS: Our experience suggests that CABG without CPB is the preferred method of myocardial revascularization, due to the fact that it carries lower mortality than CABG with CPB. The trade-off includes increased rates of recurrent angina, re-interventions and late mortality.     

Influence of combined zero-balanced and modified ultrafiltration on the systemic inflammatory response during coronary artery bypass grafting.

OBJECTIVE: To evaluate whether combined zero-balanced and modified ultrafiltration affects the systemic inflammatory response in coronary artery bypass graft (CABG) patients. DESIGN: Randomized and controlled. SETTING: University-affiliated heart center. PARTICIPANTS: Forty-three patients scheduled for elective CABG. INTERVENTIONS: In the ultrafiltration group (UF group; n = 21), zero-balanced ultrafiltration was performed during rewarming and modified ultrafiltration immediately after the end of cardiopulmonary bypass (CPB). A control group of patients (n = 22) was treated identically to the treatment group except no ultrafiltration process was performed. MEASUREMENTS AND MAIN RESULTS: Immediately after CPB (ie, after zero-balanced ultrafiltration), and again after the modified ultrafiltration, the concentrations of interleukin-6 and interleukin-8 were significantly less (p < 0.05) in the UF group compared with the control group. Both proinflammatory cytokine levels peaked at 2 and 4 hours after CPB, at which time no difference between the two groups could be observed. The levels of measured anti-inflammatory mediators (interleukin-10 and interleukin-1 receptor antagonist) did not show any difference between the two groups. Intrapulmonary shunt fraction decreased in the course of the modified ultrafiltration from 31% +/- 1.2% to 25% +/- 1.3% (p < 0.01), whereas mean arterial pressure increased (69 +/- 1.8 to 80 +/- 2.8 mmHg; p < 0.01); neither parameter changed in the control group. Time to extubation was shorter in the UF group (6.1 +/- 0.5 v 8.6 +/- 0.7 hours; p < 0.05). CONCLUSION: It was concluded that the use of ultrafiltration diminished inflammatory response in a very limited time period immediately after CPB and, probably as a consequence, slightly improved clinical parameters.     

体外循环旁路洗入七氟醚对冠状动脉旁路移植术患者心肌损伤的影响

目的 评价体外循环(CPB)旁路洗入七氟醚对冠状动脉旁路移植术(CABG)患者心肌损伤的影响.方法 择期CPB下行CABG的患者40例,年龄50 ～ 64岁,体重53～90 kg,ASA分级Ⅱ或Ⅲ级,采用随机数字表法,将患者随机分为2组(n=20):对照组(C组)和七氟醚组(S组).S组于CPB开始即刻通过体外循环机洗入1.0％ ～2.0％七氟醚,持续到CPB结束,C组不给予七氟醚.于麻醉诱导后5 min(T0)、术后6 h(T1)、12 h(T2)及24 h(T3)时采集血样,测定血浆心肌肌钙蛋白I(cTnI)浓度和磷酸肌酸激酶同工酶(CK-MB)活性.于主动脉阻断前和CPB结束时取右心耳组织,电镜下观察心肌超微结构,并行心肌细胞线粒体损伤评分.结果 与C组比较,S组T2和T3时血浆cTnI浓度,CPB结束时心肌细胞线粒体损伤评分降低(P＜0.05),血浆CK-MB活性差异无统计学意义(P＞0.05).S组心肌病理学损伤较C组减轻.结论 CPB旁路洗入七氟醚可减轻CABG术患者的心肌损伤.     

Cerebral oxygenation is better during mild hypothermic than normothermic cardiopulmonary bypass

PURPOSE: Normothermic cardiopulmonary bypass (CPB) has been recently used in cardiac surgery. However, there is a controversy whether there is a difference in incidence of neurological disorder after coronary artery bypass graft (CABG) surgery between normothermic CPB and mild hypothermic CPB. In this study, we assessed the effects of normothermia and mild hypothermia (32 degrees C) during CPB on jugular oxygen saturation (SjvO2). METHODS: Twenty patients scheduled for elective CABG surgery were divided into two groups. Group 1 (n = 10) underwent normothermic (>35 degrees C) CPB, and Group 2 (n = 10) underwent mild hypothermic (32 degrees C) CPB. Alpha-stat blood gas regulation was applied. After inducing anesthesia, a 4.0 French fibre optic oximetry oxygen saturation catheter was inserted into the right jugular bulb to monitor SjvO2 continuously throughout anesthesia and surgery. RESULTS: The SjvO2 in the normothermic group was decreased at 20 (41.5+/-2.4%) and 40 min (43.8+/-2.8%) after the onset of CPB compared with control (53.9+/-5.4%, P<0.05). However, there was no change in SjvO2 in the mild hypothermic group during the study. No changes in jugular venous-arterial differences of lactate or creatine phosphokinase isoenzyme BB were observed in two groups during the study. CONCLUSIONS: Cerebral oxygenation, as assessed by SjvO2 was increased during mild hypothermic CPB than during normothermic CPB.     

Off-pump coronary artery bypass grafting attenuates proinflammatory markers

Objective: Cardiac surgery with cardiopulmonary bypass (CPB) has been considered the main causative factors of postoperative inflammatory reactions. The aim of this study was to compare surrogate markers of the proinflammatory response in patients who underwent coronary artery bypass grafting (CABG) with or without CPB. Methods and Results: Twenty patients undergoing first-time CABG were enrolled in the study, 10 with and 10 without CPB. Blood samples were drawn at the following times: at the anesthetic induction, the end of surgery, and thereafter at 12 and 24 hours postoperatively. Neutrophil elastase, interleukin (IL)-6 , and serum soluble Fas were chosen to evaluate the extent of the systemic inflammatory response. The groups were similar in terms of age, gender ratio, number of grafts per patient. There were no operative mortality or serious postoperative complications. Two of each group received blood transfusion postoperatively. Neutrophil elastase showed a significantly higher value in the on-pump group compared with the off-pump group at the end of surgery. Soluble Fas level showed a higher value at the end of surgery compared with baseline, while it had no significant changes in the off-pump patients. IL-6 levels in the on-pump group were consistently higher compared to the off-pump group but showed no statistically significant differences between the groups. Conclusion: Compared with off-pump CABG, on pump CABG induced higher serum levels of proinflammatory markers including neutrophil elastase and soluble Fas.     

Normothermic cardiopulmonary bypass is beneficial for cognitive brain function after coronary artery bypass grafting--a prospective randomized trial.

BACKGROUND: Hypothermic and normothermic cardiopulmonary bypass (CPB) have resulted in apparently contradictionary cardiac and neurologic outcome. Cerebrovascular risk and cognitive dysfunction associated with normothermic CPB still remain uncertain. MATERIALS AND METHODS: In a prospective randomized study, we measured the effects of mildly hypothermic (32 degrees C, n=72) vs. normothermic (37 degrees C, n=72) CPB on cognitive brain function. All patients received elective coronary artery bypass grafting (mean age 62.1+/-6.3 years, mean ejection fraction 60.4+/-13%). Cognitive brain function was objectively measured by cognitive P300 auditory-evoked potentials before surgery, 1 week and 4 months after surgery, respectively. Additionally, standard psychometric tests ('trailmaking test A', 'mini-mental state') were performed and clinical outcome was monitored. RESULTS: Patients, operated with mild hypothermia, showed a marked impairment of cognitive brain function. As compared with before surgery (370+/-45 ms), P300 evoked potentials were prolonged at 1 week (385+/-37 ms; P<0.001) and even at 4 months (378+/-34 ms, P<0.001) after surgery, respectively. In contrast, patients operated with normothermic CPB, did not show an impairment of P300 peak latencies (before surgery 369+/-36 ms, 1 week after surgery 376+/-38 ms, n.s.; 4 months after surgery 371+/-32 ms, n.s.). Group comparison revealed a trend towards prolonged P300 peak latencies in the patient group undergoing mildly hypothermic CPB (P=0.0634) 1 week after surgery. Four months postoperatively, no difference between the two groups could be shown (P=n.s.) Trailmaking test A and mini mental state test failed to discriminate any difference. Five patients died (mild hypothermia n=3, normothermia n=2) postoperatively (cardiac related n=3, sepsis n=2). None of the patients experienced major adverse cerebrovascular events. CONCLUSIONS: Objective cognitive P300 auditory evoked potential measurements indicate, that subclinical impairment of cognitive brain function is more pronounced in patients undergoing mildly hypothermic CPB as compared with normothermic CPB for CABG.     

Precardiopulmonary bypass right ventricular function is associated with poor outcome after coronary artery bypass grafting in patients with severe left ventricular systolic dysfunction

Patients with severe left ventricular systolic dysfunction (LVSD) undergoing coronary artery bypass grafting (CABG) have an increased risk for morbidity and mortality. The purpose of this study was to assess the association of pre-CABG right ventricular (RV) function with outcome for patients with severe LVSD. We performed a retrospective evaluation of 41 patients with severe LVSD (left ventricular ejection fraction [LVEF] < or =25%) scheduled for nonemergent CABG. Data were obtained from review of medical records, transesophageal echocardiography tapes, and phone interview. The pre- and post-cardiopulmonary bypass (CPB) LVEF and the RV fractional area of contraction (RVFAC) were calculated by using intraoperative transesophageal echocardiography. Group 1 patients had an RVFAC < or =35% (n = 7), whereas Group 2 patients had RVFAC >35% (n = 34). The durations of mechanical ventilation and of intensive care unit and hospital stays are presented as the median. Pre-CABG LVEF was similar between Groups 1 and 2 (15.8% +/- 3.3% versus 17.8% +/- 3.9%). Compared with Group 2, Group 1 patients required greater duration of mechanical ventilation (12 days versus 1 day; P < 0.01), longer intensive care unit (14 versus 2 days; P < 0.01) and hospital (14 versus 7 days; P = 0.02) stays, had a more frequent incidence and severity of LV diastolic dysfunction, and had a smaller change in LVEF immediately after CPB (4.1% +/- 8.3% versus 12.5% +/- 9.2%; P = 0.03). All Group 1 patients died of cardiac causes within 2 yr of surgery; five died during the same hospital admission. Three Group 2 patients died: one of colon cancer at 18 mo after CABG and two of cardiac causes 24 and 48 mo after surgery. A fourth patient was awaiting cardiac transplantation 4 yr after surgery. The remaining Group 2 patients were New York Heart Association Classification I or II. For patients with severe LVSD undergoing CABG, pre-CPB RV dysfunction was associated with poor outcome. Patients with RVFAC >35% had a relatively uneventful perioperative course and good long-term survival, whereas patients with RVFAC < or =35% had a poor early and late outcome. Assessment of RV function is useful to further assess the risk of CABG. IMPLICATIONS: Right ventricular function before cardiopulmonary bypass is associated with poor outcome after coronary artery surgery in patients with poor left ventricular function.