Biochemical markers of myocardial injury in the pericardial fluid of patients undergoing heart surgery

The purpose of this study was to compare cardiac markers in the pericardial fluid and serum in order to evaluate preoperative myocardial injury. Thirty patients were divided into three groups. The first group (AVR; n=10) received an aortic valve replacement. The second group (SA; n=10) included patients with stable angina who underwent elective coronary artery bypass grafting (CABG). The third group (ACS; n=10) included patients with acute coronary syndrome who underwent urgent CABG. Pericardial fluid and venous samples were taken after opening the pericardium and 24 h postoperatively. Serum and pericardial concentration of troponin I (cTnI), creatine kinase (CK), its MB isoenzyme (CK-MB) and myoglobin were determined. Preoperative pericardial cTnI was significantly (P<0.01) higher than in serum in all groups. Preoperative pericardial CK, CK-MB and myoglobin were significantly (P<0.01) lower than in serum in groups AVR and SA. Preoperative pericardial and serum cTnI were significantly higher in the ACS than in AVR and SA groups (P<0.01). Postoperative pericardial concentration of all markers was significantly higher (P<0.01) than in serum in all groups. We conclude that preoperative pericardial accumulation of cTnI may reflect subclinical injury which may not be demonstrated by the usual laboratory tests.     

Intraoperative Angiography During Minimally Invasive Direct Coronary Artery Bypass Operations

Background. The technical demands of beating heart operations raise concerns about anastomotic patency. This feasibility study tested the usefulness of intraoperative angiography during minimally invasive direct coronary artery bypass grafting (MIDCABG).

Methods. Ten patients underwent intraoperative angiography of the internal thoracic artery (ITA) after MIDCABG. Minimally invasive direct coronary artery bypass grafting was performed on a beating heart through the fourth or fifth intercostal space. Angiography was performed through the right or left femoral artery with a 7F introducer system placed before the operation. Views were obtained in the right and left anterior oblique and straight anterior projections.

Results. There were no deaths or intraoperative morbidities related to MIDCABG or angiography. Seven patients demonstrated widely patent MIDCABG anastomoses with obliteration of all intercostals, widely patent ITA pedicles, good distal runoff, and placement of the ITA into the proper native coronary artery. Two patients had revisions of their ITA pedicles, which on repeated angiography showed correction. One patient’s procedure was converted to a sternotomy because of poor distal runoff and haziness at the level of the MIDCABG anastomosis.

Conclusions. This feasibility study demonstrates the utility of intraoperative ITA angiography in identifying problems after MIDCABG. Intraoperative angiography may facilitate MIDCABG by documenting proper placement of conduits, obliteration of intercostal vessels, and patency of the MIDCABG anastomosis and ITA pedicle.     

Cardiac troponin I release after open heart surgery: a marker of myocardial protection?

Background. Unlike creatine kinase MB isoenzyme, cardiac troponin I (cTnI) is a highly specific marker of myocardial injury. Its release has recently been studied after coronary artery bypass grafting operation. However, its significance after open heart surgery (OHS) remains to be determined. This protein release could be a marker of myocardial protection. We sought to study cTnI release after OHS in patients with normal coronary arteries and to compare it with cTnI release in patients after coronary artery bypass graft (CABG) surgery.

Methods. Eighty-five patients undergoing OHS and 86 patients undergoing CABG were enrolled in the study. CTnI concentrations were measured in serial venous blood samples drawn before surgery and immediately, 12 hours, 24 hours, 48 hours, and 5 days after aortic unclamping.

Results. In the OHS group and in the CABG group without acute myocardial infarction (AMI), cTnI peaked at 12 hours postoperatively (6.35 ± 6.5 and 5.38 ± 8.55 ng/mL, respectively) and normalized on day 5 postoperatively (0.57 ± 2 and 0.72 ± 1.62 ng/mL, respectively). CTnI concentration did not differ significantly between the OHS group and the CABG group in the absence of AMI for any samples considered. In the CABG group, 2 patients had AMI. In the OHS group, cTnI levels at 12 hours postoperatively were found to correlate closely with CPB and aortic cross-clamping (ACC) times, contrary to the CABG group, which correlated only with occurrence of AMI. CTnI release was independent of age and ejection fraction in either group.

Conclusions. cTnI release in patients after OHS with normal coronary arteries has the same profile as cTnI release in patients after CABG in the absence of AMI. However, its peak at 12 hours postoperatively is only correlated to ACC and CPB times, which is contrary to cTnI release after CABG surgery. This observation suggests that cTnI could be a marker of myocardial ischemia after OHS.     

不同循环方式对老年患者冠状动脉旁路移植术预后的影响

目的 比较老年冠状动脉粥样硬化性心脏病(冠心病)患者接受不同循环方式下冠状动脉旁路移植术(CABG)后围手术期的心肌损伤程度,分析其对预后的影响.方法 2008年7月至2009年6月,我院收治的125例老年冠心病患者分别在非体外循环(A组,70例)、心肺转流(CPB)不停跳(B组,33例)、CPB停跳(C组,22例)下行CABG.分别于术前,术后0、24、72和168 h取静脉血标本,分别测定心肌肌钙蛋白Ⅰ(cTnI)和肌酸激酶同工酶-MB(CK-MB)的水平,另外记录并发症及病死率.结果 三组术前、术后168 h的cTnI和CK-MB差异无统计学意义(P>0.05).术后0、24、72 h的cTnI和CK-MB值A组低于B、C组(P<0.05).术后0、24、72 h的cTnI和CK-MB值B组低于C组(P<0.05).A组并发症发生率低于B、C组(P<0.05),A组病死率低于B组(P<0.05),但与C组的差异无统计学意义.B组与C组的并发症发生率和病死率差异无统计学意义.结论 对于老年冠心病患者,非体外循环CABG造成的心肌损伤小于CPB不停跳和CPB停跳.非体外循环CABG能够减少老年冠心病患者围手术期并发症的发生.     

Role of troponin I, myoglobin, and creatine kinase for the detection of early graft failure following coronary artery bypass grafting.

OBJECTIVE: The detection of early graft failure following coronary artery bypass grafting (CABG) enables immediate reintervention and may significantly limit myocardial damage, thus potentially improving outcome. To date, non-invasive indicators of early graft failure following coronary surgery are still of uncertain diagnostic value. METHODS: In a prospective study, patients following isolated CABG with a postoperative serum cardiac troponin I (cTnI) above 20 ng/ml or significant ECG-changes underwent acute repeat angiography. cTnI, myoglobin (Myo), and creatine kinase (CK) were measured preoperatively and at 1, 6, 12, and 24 h after aortic unclamping. Peak values of cTnI, Myo, CK and isoenzyme CK-MB were determined postoperatively. Receiver operating curves (ROC) for cTnI, Myo and CK/CK-MB were constructed at 6, 12, and 24 h after aortic unclamping to differentiate between patients with and without early graft failure. Based on these curves, the area under curve+/-standard deviation (AUC+/-SD), the sensitivity and specificity were calculated. RESULTS: Out of 2078 consecutive patients having undergone isolated CABG from January 2001 to April 2003, 55 fulfilled the inclusion criteria and underwent acute repeat angiography. Early graft failure was found in 35 patients (group 1), whereas 20 patients did not show graft failure (group 2). CTnI and Myo, but not CK and CK-MB levels were significantly increased in group 1 compared to group 2 at 12 and 24 h after aortic unclamping. ROC analysis of cTnI, Myo and CK/CK-MB indicated cTnI as the best discriminator between the groups with 21.5 ng/ml at 12 h (AUC, 0.82+/-0.06; sensitivity, 82%; specificity, 66%) and 33.4 ng/ml at 24 h (AUC, 0.95+/-0.03; sensitivity, 98%; specificity, 82%) and Myo with 887 microg/ml at 12 h (AUC, 0.72+/-0.07; sensitivity, 73%; specificity, 57%) after aortic unclamping. In contrast, CK/CK-MB as well as the appearance of ECG-changes could not separate between the groups. CONCLUSIONS: cTnI, but not Myo and CK served as a reliable marker for the identification of patients with early graft failure following CABG.     

冠状动脉旁路移植术后血清肌钙蛋白T的动态变化

目的研究冠状动脉旁路移植术(CABG)后血清肌钙蛋白T(TnT)的动态变化及临床意义。方法采用双抗体夹心酶联免疫吸附测定法(ELISA),测定37例患者CABG后血清TnT的浓度变化,并与肌酸激酶(CK)和肌酸激酶同工酶(CK-MB)进行比较。结果TnT在CABG后4～12小时达到峰值,术后6～8天恢复正常。CK-MB于术后4～16小时升至峰值,术后48小时即恢复正常。CABG后TnT峰值与主动脉阻断时间呈正相关(r=0.55,P＜0.05)。结论TnT在CABG后对于诊断微小心肌损伤、判断预后具有高特异性、高敏感性。     

Human cytokine responses to coronary artery bypass grafting with and without cardiopulmonary bypass.

BACKGROUND: Coronary artery bypass grafting (CABG) is associated with a systemic inflammatory response. This has been attributed to cytokine release caused by extracorporeal circulation and myocardial ischemia. This study compares the inflammatory response after CABG with cardiopulmonary bypass and after minimally invasive direct coronary artery bypass grafting (MIDCABG) without cardiopulmonary bypass. METHODS: Cytokine release and complement activation (interleukin-6 and interleukin-8, soluble tumor necrosis factor receptors 1 and 2, complement factor C3a, and C1 esterase inhibitor) were determined in 24 patients before and after CABG or MIDCABG. The maximum body temperature, chest drainage, and fluid balance were recorded for 24 hours after operation. RESULTS: Release of interleukin-6, interleukin-8, and tumor necrosis factor receptors 1 and 2 was significantly higher (p < or = 0.005) in the CABG group than the MIDCABG group just after operation. After 24 hours, a significant increase in interleukin-6 was also found in the MIDCABG group (p = 0.001) compared with preoperative value. Body temperature and fluid balance were significantly higher after CABG (p < or = 0.001). CONCLUSIONS: Minimally invasive direct coronary artery bypass grafting represents a less traumatizing technique of surgical revascularization. The reduction in the inflammatory response may be advantageous for patients with a high degree of comorbidity.     

Cardiac troponin I versus creatine kinase-MB in the detection of postoperative cardiac events after coronary artery bypass grafting surgery

AIM: Several studies suggest that postoperarive concentrations of cardiac troponin-I (cTnI) may increase in patients undergoing aorto-coronary bypass grafting (CABG). The degree and pattern of release appears to be associated with perioperative myocardial damage. METHODS: This was a prospective observational study with serial sampling conducted at the Departments of Cardiothoracic Surgery and Anesthesiology, University Hospital of Ioannina, Ioannina, Greece. The levels of cTnI and creatine kinase-MB (CK-MB) preoperatively, upon admission to the intensive care unit and at 12, 24, 36 and 48 hours after surgery, as well as daily from postoperative days 3-7 were determined in 41 consecutive patients (33 males and 8 females, aged 64.8+/-6.1 years) who underwent CABG with cardiopulmonary bypass. The Authors compared the patterns and variation of cTnI and creatine kinase (CK)-MB after CABG in patients with or without postoperative cardiac events (PCEs). RESULTS: Eleven patients experienced a PCE (postoperative ventricular and supraventricular arrhythmia, need for intra-aortic balloon pump (IABP) for >12 hours, or postoperative myocardial infarction, [MI]). In patients without PCE the elevation of cTnI peaked at 24 hours after surgery, while in patients with PCE maximal values of cTnI occurred after 36 hours. CTnI levels correlated with CK-MB after the procedure. Receiver-operating characteristic (ROC) curve analysis indicated that cTnI is superior to CK-MB with regard to PCE diagnosis following CABG (area under the ROC curve, 0.73, 95% CI (0.53-0.93) versus 0.54, 95% CI, (0.25-0.83). CONCLUSION: CTnI seems to be more valuable compared to CK-MB in the detection of PCEs in patients undergoing coronary surgery.     

Atrial fibrillation after coronary artery bypass grafting without cardiopulmonary bypass.

OBJECTIVE: Atrial fibrillation is the most common complication after heart surgery. It rarely has a fatal outcome but causes patient instability, prolongs hospital stay, or even is the reason for perioperative infarction. Although conventional coronary artery bypass grafting (CABG) with cardiopulmonary bypass has excellent short-term and long-term results, the number of coronary operations on a beating heart without cardiopulmonary bypass is still growing. To reduce surgical trauma, off-pump coronary artery bypass grafting via sternotomy (OPCABG) or minimally invasive direct vision coronary artery bypass grafting (MIDCABG) via small thoracotomy are performed. The aim of this study was to estimate the frequency of atrial fibrillation in patients after myocardial revascularization without cardiopulmonary bypass. METHODS: A retrospective analysis of 48 patients undergoing myocardial revascularization without cardiopulmonary bypass was performed. Twenty-four patients underwent OPCABG and 24 were operated using the MIDCABG technique. The incidence of cardiac arrhythmias was analyzed since operation to the fourth postoperative day. Each patient had continuous ECG monitoring with option of arrhythmia analysis during ICU stay. After discharge from ICU 24-h ECG monitor studies were carried out. Surface 12-lead ECG was accomplished once a day, and additionally each time symptoms of cardiac arrhythmia occurred. Risk factors of atrial fibrillation were estimated. RESULTS: Atrial fibrillation occurred in 25% of patients after MIDCABG, in 29% after OPCABG, and in 18% after CABG with cardiopulmonary bypass. This difference has no statistical significance. Risk factors and incidence of postoperative complications were comparable in all groups. CONCLUSIONS: Atrial fibrillation is a common complication after procedures of myocardial revascularization, performed with or without cardiopulmonary bypass. The occurrence is not dependent on the type of operation.     

Strict thermoregulation attenuates myocardial injury during coronary artery bypass graft surgery as reflected by reduced levels of cardiac-specific troponin I

We assessed the cardioprotective effects of perioperative maintenance of normothermia by determining the perioperative profile of troponin I, a highly cardiac-specific protein important in risk stratification of patients with acute ischemic events. Candidates for their primary coronary artery bypass grafting (CABG) were randomized into a new thermoregulation system group, Allon( thermoregulation (AT; n = 30), and a routine thermal care (RTC; n = 30) group. Anesthetic and operative techniques were similar in both groups. Intraoperative warming was applied before and after cardiopulmonary bypass (CPB) and up to 4 h after surgery. Perioperative temperature and hemodynamic data were recorded. Blood samples for creatine kinase (CK) and its isoform, MB (CK-MB), and for cardiac-specific troponin I (cTnI) were obtained at predetermined intervals throughout the entire operation. Core and skin temperatures were higher in the AT group at all time points. The systemic vascular resistance was lower and the cardiac index higher in the AT group at all intra- and postoperative time points. Increases in CK, CK-MB, and cTnI levels indicated intraoperative ischemic insult in all patients. The respective CK levels for the AT and RTC groups were 53.3 +/- 22.7 IU/L and 47.9 +/- 17.86 IU/L at the time of anesthesia and 64.7 +/- 45.6 IU/L and 47.8 +/- 19.4 IU/L 30 min after the onset of surgery, demonstrating thereafter a steep increase before the discontinuation of CPB. CK-MB mass concentrations in both groups behaved almost identically. Pre-CPB cTnI levels at anesthesia induction were 0.3 +/- 0 ng/mL in both groups, followed by a distinctive profile observed after separation from CPB: 28.1 +/- 11.4 ng/mL, 26.05 +/- 9.20 ng/mL, and 22.3 +/- 8.9 ng/mL at discontinuation from CPB, chest closure, and 2 h after surgery, respectively, in the RTC group, versus 0.6 +/- 4.6 ng/mL, 6.6 +/- 5.5 ng/mL, and 7.9 +/- 4.76 ng/mL at these three time points, respectively, in the AT group (P < 0.01 between groups at the specified time points). Contrary to conventional thinking about the benefits of hypothermia, maintenance of normothermia throughout the non-CPB phases during CABG was demonstrated to be important in attenuating myocardial ischemic injury. Insofar as troponin I was more sensitive than other tested markers, it may provide important data on possible protection from myocardial insult and on other cardioprotective measures.     

Standard coronary artery bypass grafting and beating heart bypass. Indications and long-term results.

OBJECTIVES AND METHOD: We have performed 225 cases of coronary artery bypass grafting (CABG), between October 15 1995 and September 8 1999. We have evaluated the operative results of 121 cases (53.8%) of conventional CABG and 104 cases (46.2%) of minimally invasive coronary artery bypass grafting performed during this period. The average numbers of bypassed grafts was 3.45 for conventional CABG, and 1.41 for minimally invasive coronary artery bypass grafting. Sixty-seven right internal thoracic arteries, 145 left internal thoracic arteries, 71 gastroepiploic arteries, 38 radial arteries and 12 saphenous veins were used for conventional CABG, and 29 right internal thoracic arteries, 81 left internal thoracic arteries, 18 gastroepiploic arteries, 3 radial arteries, 10 saphenous veins and 2 inferior epigastric arteries were used for minimally invasive coronary artery bypass grafting. The total number of 303 grafts were anastomosed to 417 coronary arteries for conventional CABG, and 143 grafts were anastomosed to 147 coronary arteries for minimally invasive coronary artery bypass grafting. RESULTS: Although two saphenous veins were occluded, the early postoperative patency rate was 100% for conventional CABG using right internal thoracic arteries, left internal thoracic arteries, gastroepiploic arteries and radial arteries. Three site of stenosis in 18 left internal thoracic arteries and 2 in 16 right internal thoracic arteries were recognized in minimally invasive coronary artery bypass grafting without the use of stabilizers. One site of stenosis in 63 left internal thoracic arteries was recognized in minimally invasive coronary artery bypass grafting with the use of stabilizers. CONCLUSION: The use of stabilizers enables adaptation of the minimally invasive coronary artery bypass grafting procedure to a wider range of coronary artery bypass procedures, and a higher graft patency can be expected.     

缺血预处理与温-冷-温技术在冠状动脉旁路移植术中对心肌的保护作用

目的通过监测血浆肌酸激酶同工酶(CK-MB)、心肌肌钙蛋白I(cTnI) 的水平,评价三种不同的心肌保护方法在冠状动脉旁路移植术(CABG)中的应用. 方法将36例均为稳定型心绞痛、3支血管病变、首次施行CABG患者随机分成3组缺血预处理组、温血组、对照组, 观察临床结果和术后应用血管活性药情况,并于转流前、术毕、术后6～12 、24 、72小时和第6天分别抽静脉血测定 CK-MB、cTnI. 结果缺血预处理组和温血组的自动复跳率均为100%,明显高于对照组(58%); cTnI 和CK-MB的水平从术后6～12小时开始升高(P<0.05),在24小时达到峰值,在术后第6天恢复.与对照组比较缺血预处理组和温血组在术后6～12、24、72小时时cTnI 和CK-MB的水平明显低(P<0.01). 结论多次短时间的缺血预处理和"温-冷-温"技术在低危CABG患者中较常规方法更有利于对缺血心肌的保护.     

Minimally invasive direct coronary bypass versus cardiopulmonary technique: angiographic comparison

BACKGROUND: Studies comparing minimally invasive direct coronary artery bypass grafting (MIDCABG) with techniques using cardiopulmonary bypass (CPB) are needed. METHODS: Sixteen patients underwent single-vessel left internal thoracic artery-left anterior descending (LITA-LAD) MIDCABG through a left anterior thoracotomy, and 10 underwent multivessel bypass grafting that included a LITA-LAD, using CPB. Intraoperative completion angiography was performed on all LITA-LAD bypasses, and graded. One point each was given for: anastomotic patency, pedicle patency, intercostal obliteration, proper placement into the correct native coronary artery, and Thrombosis In Myocardial Ischemia grade III flow. RESULTS: There were no intraoperative deaths or morbidities. LITA takedown averaged 49 +/- 18.6 minutes for MIDCABG and 16 +/- 2.0 minutes for CPB CABG (p < 0.05). LITA length did not differ between groups (15.3 +/- 1.2 cm for MIDCABG, 14.3 +/- 1.08 cm for CPB CABG). Ischemic arrest time was significantly less for the CPB group (13.3 +/- 8.3 minutes versus 24.5 +/- 9.6 minutes; p < 0.05). Average grade for MIDCABG LITA-LAD was 4.06 +/- 0.98 points versus 4.77 +/- 0.98 points for CPB LITA-LAD bypass (p = not significant). CONCLUSIONS: Intraoperative completion angiography is feasible and, when combined with a grading system, may facilitate the comparison of MIDCABG with standard techniques.     

Different CABG methods in patients with chronic obstructive pulmonary disease

BACKGROUND: Pulmonary dysfunction is still a major problem in coronary artery bypass grafting (CABG). The purpose of this randomized study was to determine the effect of different CABG techniques on pulmonary function. METHODS: Fifty eight patients with severe obstructive pulmonary disease had elective isolated coronary surgery. The surgical methods for the patients with chronic obstructive pulmonary disease (COPD) were standard CABG in 18 patients (group 1), beating heart surgery in 19 patients (group 2), and minimally invasive direct coronary artery bypass grafting (MIDCABG) in 21 patients (group 3). RESULTS: The earliest extubation time was from group 3 (p < 0.001). The average stay in the intensive care unit was significantly longer in group 1 (2.6 +/- 1.5 days) than in groups 2 (1.4 +/- 0.8 days) and 3 (1.1 +/- 0.8 days) (p < 0.05). The most prevalent respiratory morbidity was atelectasis that developed in 6 patients from group 1, in 2 patients from group 2, and in 3 patients from group 3. Forced expiratory volumes in 1 second (FEV1) obtained in the second postoperative month were significantly lower than preoperative values only in group 1 (p < 0.05). Forced vital capacity (FVC) values were significantly lower than the preoperative values in all three groups (p < 0.05). CONCLUSIONS: Off-pump bypass surgical procedures are more advantageous than on-pump methods for patients with COPD. These patients can be operated on using the beating heart technique or by using MIDCABG to prevent side effects of CPB on pulmonary function and effects of sternotomy.     

Advantages and limitations in minimally invasive cardiac surgery

The introduction of endoscopic technology to cardiovascular surgery was significantly delayed compared to abdominal and lung surgery, although it has been gradually introduced in this field during the past decade in closure of patent ductus arteriosus, repair of the vascular ring, implantation of pacemaker leads or AICD, and pericardectomy. Endoscopic technology also started to be used in harvesting saphenous vein grafts (SVG) and the left internal thoracic artery for coronary artery bypass grafting(CABG) from the mid-1990s. Although complete endoscopic surgery has not yet been established in the major field of standard cardiovascular surgery, many cardiac surgeons attempt to minimize the size of chest wounds with 6- to 8-cm skin incisions, which is called minimally invasive cardiac surgery (MICS) or minimally invasive direct coronary artery bypass (MIDCAB). Complete endoscopic cardiac surgeries were performed utilizing the Zeus system and Da Vinci system at the end of the 20th century. Another method to minimize the invasiveness of CABG is to perform it without cardiopulmonary bypass, so-called off-pump coronary artery bypass (OPCAB). Currently, less-invasive procedures are mainly applied for relatively simple cardiac surgeries, although these procedures are also potentially effective to avoid postoperative cerebral or respiratory complications in high-risk patients. MICS is effective in reducing the size of surgical wounds and in decreasing intraoperative blood loss. On the other hand, the duration of anesthesia and surgery can be prolonged due to technical difficulty, and the risk of unsatisfactory anastomosis or incomplete revascularization can also be increased. The cardiopulmonary bypass circuit utilized for MICS requires a more complicated system including negative pressure venous drainage. The detection of accidental trouble during surgery, which is related to the extracorporeal circulation or the MICS procedure itself, can be delayed due to the limited surgical view. MICS procedures carry additional risks related to the more complicated cardiopulmonary bypass system and small surgical wound. We must be deliberate in determining the indications for MICS and obtain complete informed consent from patients when we perform MICS, including informing them of the additional risks related to the MICS procedure itself and the possibility of conversion to standard open-heart 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。     

Levels of Troponin I and Cardiac Enzymes After Reinfusion of Shed Blood in Coronary Operations

Background. Reinfusion of shed blood after coronary artery bypass grafting might increase the levels of cardiac enzymes with consequent difficulties in the diagnosis of perioperative myocardial infarction.

Methods. Thirty consecutive patients undergoing coronary artery bypass grafting who bled at least 400 mL within the first 4 hours after operation underwent reinfusion of shed blood. Thirty consecutive patients who were not autotransfused served as control. All patients underwent enzyme determination (total creatine kinase, MB fraction, lactate dehydrogenase, and troponin I) in the shed blood and in circulating blood preoperatively, at arrival in the intensive care unit, and 6, 24, and 48 hours after operation.

Results. The shed blood contained significantly higher concentration of cardiac enzymes than the circulating blood at all time intervals (p = 0.0001). The levels of creatine kinase, its MB fraction, and lactate dehydrogenase in circulating blood were significantly elevated in patients receiving autotransfusion up to 24 hours after autotransfusion. The blood levels of troponin I were not significantly different between the two group of patients at all time points. The percent fraction of MB did not increase after autotransfusion.

Conclusions. The measurement of cardiac troponin I is a useful marker for the diagnosis of perioperative myocardial infarction in patients undergoing transfusion of shed blood after coronary operation.     

Myocardial and lung injury after cardiopulmonary bypass: role of interleukin (IL)-10

BACKGROUND: Proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-6, and IL-8 play a key role in the inflammatory cascade after cardiopulmonary bypass (CPB) and may induce cardiac and lung dysfunction. Antiinflammatory cytokines such as IL-10 may also significantly limit these complications. Corticosteroid administration before CPB increases blood IL-10 levels and prevents proinflammatory cytokine release. This study examined the association of increased release of IL-10, stimulated by steroid pretreatment, with reduced myocardial and lung injury after CPB. METHODS: Twenty patients undergoing coronary artery bypass grafting (CABG) received either preoperative steroid (n = 10, protocol group) or no steroid (n = 10, control group). Perioperative care was standardized, and all caregivers were blinded to treatment group. Seven intervals of blood samples were obtained and assayed for TNF-alpha, IL-6, IL-8, and IL-10. Various hemodynamic and pulmonary measurements were obtained perioperatively. Levels of MB isoenzyme creatine kinase (CK-MB) were also measured. RESULTS: In the protocol group, proinflammatory cytokines were significantly reduced while IL-10 levels were much higher after CPB. The protocol group had a lower alveolar-arterial oxygen gradient and higher ratio of arterial oxygen pressure to fraction of inspired oxygen after CPB. Creatine kinase (CK) and CK-MB were reduced in the patients treated with steroid. Correlations were found between plasma cytokines levels and cardiac index, and CK-MB. CONCLUSIONS: This study confirms that corticosteroids abolish proinflammatory cytokines release and increase blood IL-10 levels after CPB. Our findings demonstrate a greater release of IL-10 induced by steroid pretreatment, and better heart and lung protection after CPB.     

Do we still need CK-MB in coronary artery bypass grafting surgery?

AIM: The aim of this study was to evaluate the role of cardiac Troponin I (cTnI) and CK-MB for early prediction of outcome of patients undergoing coronary artery bypass grafting (CABG) surgery. METHODS: In 134 consecutive patients undergoing CABG-surgery blood samples were analyzed for cTnI concentration and CK-MB activity. ECG, hemodynamic parameters and the need for inotropic support, were continuously registered. Patients were divided into group A (uneventful course), group B (ischemia by ECG, hemodynamic stability) and group C (ischemia by ECG and IABP). RESULTS: After removal of X-clamp an increase cTnI and CK-MB was observed in all patients. Five hrs after stop of CPB group A (8.3+/-4.2 microg/L) had lower cTnI values compared to group B (14.8+/-5.3 microg/L) (p=0.035) and C (54+/-22.8 microg/L) (p=0.023). The cut off value was 14.8 microg/L. Sensitivity and specificity (99%/97%) was higher for cTnI than for CK-MB (90%/30%). The positive predictive value of outcome was better for cTnI (86%) than for CK-MB (33%). CONCLUSION: CTnI is a specific and sensitive marker for evaluation of perioperative myocardial ischemia (PMI). Additional determination of CK-MB activity does not provide further clinical information. CTnI should be the marker of first choice in CABG surgery.     

Minimally invasive coronary artery bypass grafting via a small thoracotomy versus off-pump: a case-matched study

Objective: The minimally invasive coronary artery bypass grafting (MICS CABG) operation performed via a small thoracotomy has not previously been examined in a direct comparison to sternotomy off-pump coronary artery bypass grafting (OPCAB). Methods: We matched, according to age, gender, left ventricular function, and median number of distal anastomoses, 150 patients who underwent MICS CABG via small left thoracotomy, and 150 patients who received sternotomy OPCAB. All operations were performed by the same surgeon. Results: There was no perioperative mortality (0/300). In the MICS CABG group, pump assistance was used in 28/150 (19%) patients, and conversion to sternotomy occurred in 10/150 (6.7%) patients. In the OPCAB group, conversion to on-pump occurred in 3/150 (2.0%) patients. There were four (2.7%) reoperations for bleeding and one (0.7%) for anastomotic revision in each group. The median hospital length of stay was 5 days for MICS CABG (average 5.4), and 6 days for OPCAB (average 7.2) (P = 0.02). New-onset atrial fibrillation occurred in 35 (23%) MICS CABG patients and in 42 (28%) OPCAB patients (P = 0.3). No wound infection occurred with MICS CABG versus six (4.0%) with OPCAB (P = 0.03). A self-limiting left pleural effusion developed in 22 (15%) MICS CABG patients and in six (4.0%) OPCAB patients (P = 0.002). The median time to return to full physical activity was 12 days in MICS CABG patients versus >5 weeks in OPCAB patients (P < 0.001). Conclusions: MICS CABG is a valuable alternative for patients in need of multivessel CABG. The operation appears at least as safe as OPCAB, and associated with shorter hospital length of stay, less wound infections, and faster postoperative recovery than OPCAB.