非体外循环冠状动脉搭桥手术的麻醉方法及血液动力学和氧代谢的变化

目的 观察非体外循环冠状动脉搭桥手术的麻醉方法、术中病人血液动力学和氧代谢的变化以及术后病人的早期.非体外循环冠状动脉搭桥手术闰人20例，麻醉用咪唑安定0.1-0.2mg/kg、芬太尼15－30μg/kg及0.5%-2%的吸入麻醉药等，在切皮前、开心包后、心脏操作中、操作完成后10min及术毕观察血液动力学指标及脑氧饱和度，同时采集桡动脉和肺动脉血，测定血气及动脉血乳酸（ABL），计算氧供DO2）、氧耗（VO2）和氧摄取率（ERO2）。术后早期观察术后拔除气管插管、ICU停留及术后住院时间、并发症及死亡等情况。结果 心脏操作中MAP、SV、SI下降，HR、CVP升高，MAP下降以搭回旋支时最明显（P＜0.01），HR升高以搭右冠时最明显（P＜0.01）；心脏操作中DO2降低（P＜0.05），VO2无变化，ERO2升高（P＜0.01）；操作后DO2、ERO2恢复至操作前水平；操作后ABL升高（P＜0.01）。结论 本组麻醉方法使病人完全度过非体外循环搭桥术，在心脏操作期易出现血压、每搏量、心指数下降，伴心率、静脉压升高，但时间短暂无严重后果，氧代谢紊乱及缺氧程度较轻。     

Hemodynamic collapse during off-pump coronary artery bypass grafting

Background. The causes of hemodynamic collapse during off-pump coronary artery bypass (OPCAB) remain scarcely defined. We present an analysis of 23 cases of sustained hemodynamic collapse during elective off- pump CABG.

Methods. During a 54-month period, we performed 1420 elective OPCAB procedures through a sternotomy, constituting 71.2% of the total CABG procedures performed. Twenty-three patients (1.6%) experienced hemodynamic collapse intra-operatively requiring immediate cardiopulmonary bypass. Preoperative characteristics, intraoperative data, and postoperative outcome were retrospectively reviewed in each patient.

Results. In all cases, improvements in intra-operative technique and/or judgment could be made retrospectively. Twenty (20/23) of these patients had an uneventful postoperative course and three (3/23) patients had an unstable course with two deaths.

Conclusions. The causes of hemodynamic collapse during elective OPCAB were ischemic, mechanical, or a combination of both. A detailed review of our five and a half year experience has revealed a number of suggestions for improving the conduct of the operation.     

Mild or moderate ischemic mitral regurgitation in patients undergoing off-pump coronary artery bypass grafting

BACKGROUND: There has been a debate, whether mild or moderate ischemic mitral regurgitation (IMR) should be repaired at the time of coronary bypass surgery. We assessed the early and midterm outcomes of patients with mild or moderate IMR who underwent isolated off-pump coronary artery bypass grafting (OPCAB). METHODS: We retrospectively reviewed records of 602 patients who underwent OPCAB between April 2001 and July 2004. Of those, 96 patients had mild or moderate MR (IMR group), and 506 had none or trivial MR (no IMR group). Preoperative and postoperative characteristics were compared between the groups. Furthermore, fates of grade of MR and functional status were investigated in patients with IMR. RESULTS: The preoperative mean New York Heart Association (NYHA) classes were 2.7 +/- 1.0 and 2.4 +/- 0.9 in the IMR and no IMR groups, respectively (p < 0.01). Operative mortality was similar between groups (1.0% in the IMR group and 0.4% in no IMR group, p = 0.41). The cumulative survival rate for the IMR group was 93.7% at 1 year and 90.1% at 4 years. The mean NYHA class was 1.1 +/- 0.4 (p < 0.0001) at 28.8 +/- 11.4 months after operation for the IMR group. The mean grade of mitral regurgitation diminished (from 2.2 +/- 0.4 to 1.1 +/- 0.6, p < 0.0001) soon after operation in patients with IMR, and remained so (1.1 +/- 0.8, p < 0.0001) during the follow-up period. CONCLUSIONS: Mild or moderate IMR could be improved with isolated OPCAB. The early and midterm functional outcomes of these patients were favorable.     

Efficacy of continuous intraoperative administration of low-dose milrinone during the circumflex artery anastomosis of off-pump coronary artery bypass

BACKGROUND : We have experienced instability of hemodynamic state during off-pump coronary artery bypass (OPCAB), especially, circumflex (Cx) artery anastomosis. Although some reports have implied the efficacy of mirlinone in OPCAB anastomosis due to its characteristic inotropic effect without increasing myocardial oxygen consumption, we examined the effect of smaller doses of mirlinone during Cx anastomosis. METHODS : Fourteen patients received milrinone (M group) continuously at a rate of 0.15-0.30 microg x kg(-1) min(-1) after sternotomy until the end of operation. Sixteen patients in the control group (C group) received saline. Norepinephrine was concomitantly administered for maintaining systolic blood pressure above 100 mmHg. We measured hemodynamic parameters during Cx anastomosis and postoperative myocardial isozymes, and examined arrhythmias. RESULTS : In the M group mean pulmonary arterial pressure (MPAP) decreased significantly and cardiac index (CI) and SvO2 increased significantly, compared with C group. M group showed lower incidence of atrial fibrillation for 2 days. CONCLUSIONS : We conclude that low-dose milrinone has a good influence on intraoperative and postoperative managements of OPCAB surgery.     

Unexpected hemodynamic deterioration and mitral regurgitation due to a tissue stabilizer during left anterior descending coronary anastomosis in off-pump coronary artery bypass graft surgery.

We have experienced three rare cases of hemodynamic deterioration and transient mitral regurgitation (MR) induced by a suction-type tissue stabilizer during the left internal thoracic artery (LITA)-to-LAD (left anterior descending) coronary artery anastomosis. Transesophageal echocardiogram (TEE) showed new or worsening MR during the placement of a tissue stabilizer. In all three cases, the positioning of the stabilizer was difficult to secure a good surgical field, because the LAD coronary artery migrated deep into the myocardium. This anatomical variation seemed to require a stronger fixation of the stabilizer to the heart. We concluded that compression of the left ventricular (LV) wall may have possibly caused morphologic changes of the LV and the distortion of the annulus of the mitral valve. These changes are thought to have caused decreased LV filling and the MR, which led to an unexpected hemodynamic deterioration.     

非体外循环冠状动脉旁路移植术对右心室血流动力学的影响

目的应用连续心排血量测定的方法,观察在进行非体外循环冠状动脉旁路移植术(OPCABG)中右心功能的变化. 方法冠状动脉粥硬化性心脏病178例,均为2～3支血管病变需行冠状动脉旁路移植术.术前心功能Ⅱ级72例,Ⅲ级84例,Ⅳ级22例.左心室射血分数0.35～0.82,平均搭桥数3.3根.所有病人均行Swan-Ganz漂浮导管,用连续心输出量监测仪连续监测血流动力学指标,包括心率(HR),平均动脉压(MAP),中心静脉压(CVP),平均肺动脉压(MPAP),右房压(RAP),肺毛细血管楔压(PCWP),心输出量(CO),心脏指数(CI),每搏容量指数(SVI),体循环阻力指数(SVRI),肺循环阻力指数(PVRI),混合静脉血饱和度(SvO2),右室射血分数(RVEF),右室收缩末容量(RVESV),右室舒张末容量(RVEDV),右室收缩末容量指数(RVESVI),右室舒张末容量指数(RVEDVI).设定时间点观察血流动力学指标:麻醉诱导后血流动力学稳定后,准备搬动心脏前(T1),吻合前降支前(T2),吻合回旋支或对角支前(T3),吻合右冠状动脉或后降支前(T4),心脏回位后,关胸前(T5).结果 4例死亡,其中2例为术前急性心肌梗死急诊手术,术后3天死于严重低心排血量综合征,1例术后7天死于严重呼吸衰竭,1例于术后4天死于急性肺栓塞.与T1相比,T2时,MPAP,PCWP,RAP和PVRI明显增加而SvO2明显降低;T3时,血流动力学变化明显,MPAP,PCWP,RAP和PVRI明显增加,SvO2明显降低,CI,SVI,RVEF明显下降,SVRI明显增加;T4时,HR,RAP明显增加而SvO2明显降低;T5时未恢复正常水平. 结论在进行纯缘支吻合时,右心功能有所下降,主要是CI及RVEF有明显的变化,而在前降支及右冠状动脉的吻合时,对右心血流动力学影响不大,因此,在OPCABG中监护右心功能具有重要意义,尤其是对右心功能受到损害的患者.     

非体外循环冠状动脉旁路移植术的血流动力学研究

目的：分析非体外循环冠状动脉旁路移植术中血流动力学的变化。方法：2000年6月至2001年1月，连续32例病人接受非体外循环冠状动脉旁路移植术，术中、术后对各吻合血管的血流动力学指标进行持续监测。全组完成前降支吻合32例、右冠状动脉26例、回旋支28例、对角支8例。结果：本组死亡例。行前降支冠状动脉吻合时血流动力学指标无明显变化。右冠状动脉吻合时影响右心功能。回旋支及对角支冠状动脉吻合时对血流动力学有明显的影响，导致平均肺动脉压（MPAP）、肺毛细血管楔压（PAWP）、中心静脉压（CVP）明显升高，每搏指数（SVI）及左室每搏功指数（LVSWI）有明显下降；心排指数（CI）有一定的下降趋势。行主动脉近心端吻合时尽管已无心脏搬动，但MPAP、SVRI及肺循环阻力指数（PVRI）仍较诱导后有明显升高，CI有明显下降。术毕及术的2、6、16h各血流动力学指标趋于正常，CI有明显改善。结论：非体外循环冠状动脉旁路移植行前降支及右冠状动脉吻合时对血流动力学影响较小，回旋支及对角支冠状动脉吻合时对血流动力学有明显的影响，术毕及术后2、6、16h各血流动力学指标趋于正常，心脏功能有明显改善。     

Mechanisms of hemodynamic changes during off-pump coronary artery bypass surgery

PURPOSE: To describe the mechanisms of hemodynamic changes during off-pump coronary artery bypass graft surgery (OP-CABG). SOURCE: Pertinent medical literature in the English and French languages was identified through a Medline computerized literature search and a manual search of selected articles, using off-pump coronary artery surgery, beating heart surgery, hemodynamic, and transesophageal echocardiography as key words. Human and animal studies were included. PRINCIPAL FINDING: Hemodynamic variations in OP-CABG may be due to mobilization and stabilization of the heart, or myocardial ischemia occurring during coronary occlusion. Suction type and compression type stabilizers produce hemodynamic effects through different mechanisms. Heart dislocation (90 degrees anterior displacement) and compression of the right ventricle to a greater extent than the left ventricle are responsible for hemodynamic alterations when using suction type stabilizers. Compression of the left ventricular outflow tract and abnormal diastolic expansion secondary to direct deformation of the left ventricular geometry are proposed mechanisms for hemodynamic derangements with compression type stabilizer. Coronary occlusion during the anastomosis can have additional effects on left ventricular function, depending on the status of collateral flow. The value and limitations of electrocardiographic (ECG), hemodynamic and echocardiographic monitoring modalities during OP-CABG are reviewed. CONCLUSIONS: In summary, hemodynamic changes which can either be secondary to the stabilization technique or to transient ischemia represent an important diagnostic challenge during off-bypass procedures. The mechanism can vary according to the stabilization system. Current monitoring such as ECG and hemodynamic monitoring are used but remain limited in establishing the cause of hemodynamic instability. Transesophageal echocardiography is used in selected patients to diagnose the etiology of hemodynamic instability and can direct therapy, particularly in those with severe myocardial systolic and diastolic dysfunction, mild to moderate mitral regurgitation, or for patients who are unstable during the procedure.     

Three-dimensional mitral valve structure in predicting moderate ischemic mitral regurgitation improvement after coronary artery bypass grafting

Objective

Focusing on 3-dimensional mitral valve structure, this study investigated predictors for moderate ischemic mitral regurgitation (IMR) improvement after off-pump coronary artery bypass grafting (OPCAB).

The degree of newly emerging mitral regurgitation during off-pump coronary artery bypass is predicted by preoperative left ventricular function

Purpose During off-pump coronary artery bypass (OPCAB), the displacement of the heart causes mitral regurgitation. We hypothesized that patients with impaired left ventricle (LV) function would be more prone to develop mitral regurgitation, due to further LV end-diastolic pressure elevation and mitral annulus distortion. Therefore, in this study, we examined the relationship between LV function and the severity of mitral regurgitation. Methods We studied 41 patients undergoing elective OPCAB. LV function was evaluated by LV ejection fraction (LVEF), serum brain natriuretic peptide (BNP) levels, the Tei index (myocardial performance index) and mitral inflow propagation velocity (Vp). Results Among all of the anastomoses performed mitral regurgitation was most severe during anastomosis of the left circumflex artery (LCX) territory (P < 0.001). Twenty-five patients (61%) had no to mild mitral regurgitation during anastomosis of the LCX territory (M-MR group) and 16 patients (39%) had moderate to severe mitral regurgitation during anastomosis of the LCX territory (S-MR group). There were significant differences between these groups in preoperative serum BNP levels (median, 26 pg·ml⁻¹ interquartile range [IQR, 14 to 75 pg·ml⁻¹] versus median, 173 pg·ml⁻¹ [IQR, 91 to 296 pg·ml⁻¹]; P < 0.001), Tei index values (median, 0.35; [IQR, 0.27 to 0.41] versus median, 0.53 [IQR, 0.47 to 0.57]; P < 0.001), and Vp (median, 63 cm·s⁻¹; [IQR, 57 to 72 cm·s⁻¹] versus median, 47 cm·s⁻¹; [IQR, 40 to 57 cm·c⁻¹]; P = 0.008), while there was no significant difference in LVEF between the patients in the M-MR group and those in the S-MR group. Conclusion Preoperative LV dysfunction is a predictor of severe mitral regurgitation during OPCAB. When poor LV function is suggested, it is necessary to be prepared for further hemodynamic deterioration caused by mitral regurgitation.     

Hemodynamic changes during displacement of the beating heart using epicardial stabilization for off-pump coronary artery bypass graft surgery

OBJECTIVE: To evaluate the hemodynamic alterations during off-pump coronary artery bypass graft surgery to determine the degree of impairment caused and the techniques to rectify them. DESIGN: Prospective, observational cohort study performed from January 2000 through September 2000. PARTICIPANTS: Patients (n = 500) with coronary artery disease undergoing multivessel off-pump coronary artery bypass graft surgery using the Octopus tissue stabilizer (Medtronic, Inc, Minneapolis, MN). Unstable patients with ongoing ischemia were excluded from the study. INTERVENTIONS: All patients were monitored with radial artery and pulmonary artery catheters and continuous transesophageal echocardiography monitoring with a multiplane transducer. The perioperative requirement of an intracoronary shunt, inotropes, or an intra-aortic balloon pump was noted. The effect of the Trendelenburg position and fluids on hemodynamics was observed. The need for defibrillation and institution of emergency cardiopulmonary bypass were major endpoints to determine the inability of the patient to tolerate displacement of the heart. MEASUREMENTS AND MAIN RESULTS: Mean patient age was 59.3 +/- 11.6 years. There were 204 (40%) patients in the high-risk category; 54 (10.8%) patients had left ventricular ejection fraction <25%. The mean number of grafts was 2.7 +/- 0.8. Vertical displacement of the heart to access the lateral and inferior walls decreased the mean arterial pressure by 18 +/- 4% (p < 0.01), with a concomitant increase in central venous pressure of 66 +/- 18% (p < 0.001). The stroke volume and the cardiac index were reduced by 35.7 +/- 11% (p < 0.001) and 45 +/- 13% (p < 0.001). On transesophageal echocardiography, there was development of new regional wall motion abnormalities in 59.2% and a decrease in global left ventricular functions in 61.2%. The use of inotropes was highest during anastomosis on the posterior wall-78.4% compared with 21.9% for the anterior wall. An intra-aortic balloon pump was used in 55 (11.2%) patients, and 7 (0.71 %) patients had to be put on emergency CPB. The in-hospital mortality was 1.2%. CONCLUSION: Most patients had hemodynamic changes easily correctable by fluids and inotropes. Monitoring of left ventricular and right ventricular function by transesophageal echocardiography enhances safety of the procedure and is recommended. The use of the Octopus II tissue stabilizer proved to be a safe and versatile means to stabilize the heart during off-pump coronary artery bypass procedures, especially in high-risk patients.     

Off-pump coronary artery bypasssurgery in patients with mitral regurgitation

Introduction of off-pump coronary artery bypass grafting (off-pump CABG : OPCAB) makes it possible to shorten the bypass time and cardiac arrest time in patients with both ischemic heart disease and valvular disease. This may be beneficial in patients with poor cardiac function and renal dysfunction. However, it is unclear whether such patients can tolerate the changes of hemodynamics during vertical displacement of the heart. In 3 patients who had ischemic heart disease with non-ischemic mitral regurgitation, we performed OPCAB prior to mitral valve plasty. The changes of mitral regurgitation observed by transesophageal echocardiography and several hemodynamic parameters were monitored as the heart was moved to various positions during OPCAB. When a heart positioner (Starfish) was used, hemodynamic deterioration was not observed, and there was also no aggravation of mitral regurgitation. Based on these results, we conclude that it may be possible to carry out OPCAB safely in patients with associated mitral regurgitation.     

Hemodynamic changes during posterior vessel off-pump coronary artery bypass: comparison between deep pericardial sutures and vacuum-assisted apical suction device

Background

Displacement of the heart to expose posterior vessels during off-pump coronary artery bypass may cause hemodynamic derangement. The aims of this study were (1) to elucidate the hemodynamic changes during off-pump coronary artery bypass for the obtuse marginal branch (OM) of the left circumflex artery; and (2) to compare the hemodynamic changes caused by a deep pericardial suture technique with those caused by a vacuum-assisted apical suction device for displacement of the heart.

Methods

Hemodynamic changes during posterior vessel off-pump coronary artery bypass were studied in a prospective randomized manner. A deep pericardial suture technique (group 1, n = 10) or a vacuum-assisted apical suction device (group 2, n = 10) was used to facilitate the exposure of the OM. Hemodynamic variables such as cardiac index, stroke volume index (SVI), mean arterial pressure, mean pulmonary artery pressure, central venous pressure, pulmonary capillary wedge pressure, heart rate, systemic vascular resistance, pulmonary vascular resistance, left ventricular stroke work index, and right ventricular stroke work index were monitored during off-pump coronary artery bypass. Hemodynamic data were obtained before revascularization of the left anterior descending coronary artery at a baseline (T0), 3 minutes after heart displacement for revascularization of OM (T1), 3 minutes after the beginning of OM grafting (T2), and 3 minutes after the completion of OM grafting and heart repositioning (T3).

Results

There were no significant differences in the baseline hemodynamic variables (T0) between the two groups. In group 1, SVI, cardiac index, left ventricular stroke work index, and right ventricular stroke work index decreased significantly, and central venous pressure and pulmonary capillary wedge pressure increased significantly, during displacement of the heart (T1, p < 0.05). In group 2, SVI decreased significantly, and central venous pressure, pulmonary capillary wedge pressure, and mean pulmonary artery pressure increased significantly during displacement of the heart (T1, p < 0.05). The percent changes of cardiac index, SVI, and right ventricular stroke work index during OM grafting (T2) in comparison with baseline values (T0) were significantly larger in group 1 than in group 2 (cardiac index, 73% ± 12% versus 90% ± 11%; SVI, 69% ± 12% versus 86% ± 8%; right ventricular stroke work index, 30% ± 17% versus 71% ± 25%, in groups 1 versus 2, respectively; p < 0.05).

Conclusions

Displacement of the heart using either a deep pericardial suture technique or a vacuum-assisted apical suction device caused a significant decrease in SVI. The hemodynamic changes during OM grafting were smaller when using a vacuum-assisted apical suction device.     

心肌特异性脂肪酸结合蛋白在不停跳冠状动脉搭桥术中的变化

Objective To appraise the sensitivity of hFABP for myocardial ischemia in patients undergoing off-pump coronary artery bypass grafting among cardiac markers. Methods Thirty-eight consecutive patients undergoing OPCABG were included in a randomized study using standardized operative procedures and myocardial protection. Serial blood samples were taken preoperatively, during anastomoses, at the end of operation, 6 h, 18 h and 36 h postoperatively and tested for hFABF,Troponin Ⅰ （cTnⅠ） ,sCD40L,creatine kinase isoenzyme （CK-MB）. Results Six cases （16.7%） were found myocardial injury during the OPCABG by ECG or PAP. Their serial serum hFABP,cTnⅠ,sCD40L, CK-MB were higher than those without myocardial injury. The peak serum level of hFABP was higher and occurred earlier than those of cTnⅠ, sCD40L,CK-MB. Conclusion These results suggest that serum hFABP is an early and sensitive biochemical marker for the diagnosis of myocardial injury in patients undergoing OPCABG.     

Graft-to-coronary-artery shunt during off-pump coronary artery bypass grafting

We have developed a simple technique for temporary shunt from the saphenous vein graft to the coronary artery during off-pump coronary anastomosis. The ends of a 2-mm diameter tube were inserted into the distal end of the saphenous vein graft in which proximal anastomosis had been established and into the right coronary artery crux. Blood flow sufficient to maintain adequate hemodynamics was obtained through the shunt tube while suturing around the tube. We successfully employed this technique in 5 patients with acute coronary syndrome. We suggest that this technique may represent an addition to the armamentarium for off-pump anastomosis to the right coronary artery.     

Intrathecal morphine for off-pump coronary artery bypass patients

Due to the fact that patients have increased mental alertness following off-pump coronary artery bypass (OPCAB), pain management in the immediate postoperative period is a major concern. Thirty-two patients underwent OPCAB grafting, 20 received 5 mcg/kg morphine sulfate intrathecally. This group was compared with 12 patients who did not receive intrathecal morphine. All patients were verbally evaluated for pain using the Wong-Baker Visual Analog Scale at eight, 12 and 24 hours. All the scores were highly statistically significant in favor of the intrathecal group. No significant complications were seen in this group of patients. It is concluded that intrathecal morphine at 5 mcg/kg is effective and safe in maintaining comfort for OPCAB patients in the immediate postoperative period.