Effect of clopidogrel on bleeding after coronary artery bypass surgery.

OBJECTIVE: Platelet dysfunction is a common cause of bleeding after coronary artery bypass graft surgery. This study explores the effects of clopidogrel on bleeding complications after coronary artery bypass graft surgery. DESIGN: Prospective observational study of patients undergoing coronary artery bypass graft. SETTING: Tertiary care center. PATIENTS: A total of 247 patients undergoing coronary artery bypass graft surgery. INTERVENTIONS: None. MEASUREMENTS: Primary end point was need for reexploration secondary to bleeding. Secondary end points included need for transfusion of blood products and chest tube output. MAIN RESULTS: Eight (3.3%) of 247 patients required reexploration secondary to bleeding. Clopidogrel recipients had higher incidence of reexploration for bleeding (9.8 vs. 1.6, p =.01) with an odds ratio of 6.9 (95% confidence interval, 1.6-30). Clopidogrel also increased the percentage of patients receiving packed red blood cell transfusion (72.6 vs. 51.6%, p =.007), the number of packed red blood cell units (3 vs. 1.6, p =0.0004), and the number of cryoprecipitate units (2.4 vs. 1.2, p =.04) transfused after coronary artery bypass graft surgery. Among clopidogrel recipients, a trend for increased transfusion of platelet units (4.3 vs. 1.7, p =.05) and fresh frozen plasma units (1.1 vs. 0.6, p =.08) also was found. CONCLUSIONS: Preoperative use of clopidogrel in combination with aspirin is associated with increased need for surgical reexploration as well as risk of packed red blood cell and cryoprecipitate transfusions after coronary artery bypass graft surgery.     

Myocardial infarction following coronary artery bypass graft surgery increases healthcare resource utilization

OBJECTIVE: To assess the health economic impact of perioperative myocardial infarction in a cohort of patients undergoing coronary artery bypass graft surgery. DESIGN: Retrospective cohort analysis using data from hospital bills and uniform billing forms. SETTING: A total of 147 geographically diverse hospitals in the United States. PATIENTS: The study population consisted of 2,102 coronary artery bypass graft surgery patients enrolled in the PRIMO-CABG trial at U.S. sites between January 2002 and February 2003. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Resource utilization and costs during the index hospitalization and during a 6-month follow-up period were compared between patients who had a myocardial infarction by postoperative day 4 and those who did not. Linear regression was used to examine whether myocardial infarction by day 4 was associated with index hospitalization costs, after adjusting for baseline characteristics. Myocardial infarction occurred in 191 (9.1%) patients undergoing coronary artery bypass graft surgery. Myocardial infarction was associated with a doubling of intensive care unit time (3.5 days among patients with no myocardial infarction and 7.1 days among patients with myocardial infarction, p < .01) and a 48% increase in hospital length of stay. Myocardial infarction by day 4 was associated with a 43% increase in hospital costs, a 29% increase in physician service costs, a 41% increase in total costs during the index hospitalization, and a 38% increase in cumulative 6-month costs. After baseline adjustment, myocardial infarction continued to be associated with higher index hospitalization costs. CONCLUSIONS: Myocardial infarction following coronary artery bypass graft surgery was associated with a significant increase in intensive care unit time, hospital length of stay, and overall costs, which contributed to greater hospital and physician service costs. Healthcare resource utilization is increased in patients sustaining a myocardial infarction following coronary artery bypass graft surgery.     

Determinants of red cell, platelet, plasma, and cryoprecipitate transfusions during coronary artery bypass graft surgery: the Collaborative Hospital Transfusion Study

BACKGROUND: Very little is known about the determinants of blood transfusions in patients undergoing coronary artery bypass graft surgery. STUDY DESIGN AND METHODS: To identify factors that influenced the transfusion of red cells, platelets, plasma, and cryoprecipitate, statistical methods were used to study 2476 consecutive diagnosis- related group 106 and 107 patients in five teaching hospitals who underwent coronary artery bypass surgery between January 1, 1992, and June 30, 1993. RESULTS: The likelihood of red cell transfusion was significantly associated with 10 preoperative factors: 1) admission hematocrit, 2) the patient's age, 3) the patient's gender, 4) previous coronary artery bypass surgery, 5) active tobacco use, 6) catheterization during the same admission, 7) coagulation defects, 8) insulin-dependent diabetes with renal or circulatory manifestations, 9) first treatment of new episode of transmural myocardial infarction, and 10) severe clinical complications. Platelet and/or plasma transfusions were strongly associated with the dose of red cells transfused. Transfusion requirements and other in-hospital outcomes were associated with patient characteristics, surgical procedure (reoperation vs. primary procedure), and the conduits used for revascularization (venous graft only, venous and internal mammary artery graft, or internal mammary artery graft only). Blood resource use and donor exposures were evaluated with respect to the risk to patients of contracting hepatitis C virus and human immunodeficiency virus infections. CONCLUSION: The classification of coronary artery bypass graft patients on the basis of attributes known preoperatively and by conduits used yields subsets of patients with distinctly different transfusion requirements and in- hospital outcomes.     

Possible interaction of platelets and adrenaline in the early phase of myocardial infarction

It is known that in most cases of transmural acute myocardial infarction a platelet clot originates within a coronary artery. In acute myocardial infarction patients increased levels of the plasma catecholamines adrenaline and noradrenaline as well as the platelet release proteins platelet factor 4 and beta-thromboglobulin have been reported. In this study, significantly higher values were found of platelet factor 4 (P less than 0.0001) and beta-thromboglobulin (P less than 0.002) in 17 acute myocardial infarction patients as compared to 17 control patients (on intensive care due to non-cardiac disorders), while the plasma levels of adrenaline and noradrenaline were not different. Positive correlations were obtained between the two catecholamines and the platelet products in the control group and between adrenaline and both platelet factor 4 (r = 0.715, P less than 0.01) and beta-thromboglobulin (r = 0.547, P less than 0.05) in the acute myocardial infarction patients. The data suggest that a stimulation of the platelets by adrenaline may facilitate in vitro activation during sampling in patients with high catecholamine load. On the other hand, a "preactivation" of the platelets by an increase of adrenaline might be of significance for thrombus formation in acute myocardial infarction.     

The prostacyclin-thromboxane system and platelet hemostasis following aortocoronary bypass with an uncomplicated postoperative course]

Prostacyclin-thromboxane system and platelet hemostasis have been studied in 56 patients upon aortocoronary bypass surgery with uncomplicated early postoperative period. It has been established that cardiopulmonary bypass surgery leads to a considerable increase in 6-keto-PGF1 alpha and TXB2 levels per platelet, as compared to preoperative values. By hour 18 postoperatively 6-keto-PGF1 alpha to platelet number ratio returns to baseline, while TXB2 to platelet number ratio remains higher than preoperative values, which determines a shift in 6-keto-PGF1 alpha to TXB2 ratio towards TXB2, thus ensuring, probably, enhanced platelet aggregation properties. Thrombocytopenia, a decrease in platelet aggregation properties and elevated blood plasma level of beta-thromboglobulin were observed upon aortocoronary bypass surgery. By hour 18 postoperatively the number of platelets increased significantly, their aggregation properties were enhanced, beta-thromboglobulin blood plasma level was reduced, however, the parameters under study did not reach normal values at that time. Increased levels of 6-keto-PGF1 alpha and TXB2 per platelet in the early postoperative period are considered an important component of compensatory-adaptive body reactions directed to normalization of the damaged body functions, namely hemostasis and microcirculation.     

冠状动脉搭桥术患者的围术期护理

目的探讨冠状动脉搭桥术患者的围术期护理。方法总结行冠状动脉搭桥术的154例患者的临床护理资料,重点关注患者的术前护理、术后病情观察、并发症的观察和护理、康复护理。结果 154例行冠状动脉搭桥术的患者中,153例手术后经治疗护理顺利康复出院,1例死亡。结论冠状动脉搭桥术的围术期护理十分重要。精心的围术期护理可以帮助患者顺利度过危险期,减少和预防并发症的发生,促进患者全面康复。     

Antiplatelet therapy in acute coronary syndromes: the emergency physician's perspective

The platelet plays a central role in the pathogenesis of coronary thrombosis after atherosclerotic plaque rupture, and its active inhibition forms a cornerstone of the management of acute coronary syndromes (ACS). Early treatment with clopidogrel in addition to aspirin is more effective than aspirin alone in reducing recurrent ischemic events in patients presenting with ACS, and is a useful adjunct to percutaneous coronary intervention, especially with stenting. There is a potential for increased bleeding complications in patients on clopidogrel therapy who subsequently undergo urgent coronary artery bypass graft surgery. Consequently, many emergency physicians withhold clopidogrel treatment until it is clear that urgent coronary artery bypass graft surgery will not be required. The potential untoward effects seem to be minimized by withholding antiplatelet therapy 3-5 days before surgery. Intravenous glycoprotein (GP) IIb/IIIa receptors inhibitors are also particularly useful in patients who undergo percutaneous coronary intervention, and may have some utility in the medical management of patients with high-risk non-ST-segment elevation ACS, starting in the emergency department. For patients presenting to the emergency department with ACS, the benefits and risks of initiating clopidogrel or GP IIb/IIIa inhibitor therapy need to be considered on an individual basis.     

Left main coronary artery rotational atherectomy and stenting

BACKGROUND: Coronary artery bypass surgery is a difficult option in patients who are not candidates for bypass surgery and high-risk patients with critical left main coronary artery (LMCA) disease. We report outcomes and short-term follow-up of patients who had LMCA rotational atherectomy and/or stenting, assess the role of these interventions in protected and unprotected significant LMCA stenosis, and review the literature. METHODS: We reviewed the cases of seven men with critical LMCA stenosis for whom coronary artery bypass surgery was considered a high risk. Five patients had rotational atherectomy, one had coronary artery stenting, and one had both. RESULTS: In all cases, angiographic success was achieved, and symptoms were relieved. Six patients were discharged from the hospital in 3 to 6 days. One patient who had cardiogenic shock, respiratory failure, and acute renal failure before the procedure died of arrhythmia 4 days afterward. Another patient had elective coronary artery bypass graft surgery 3 weeks later for recurrent angina. Cardiac catheterization was repeated in 1 month for chest pain in three patients at 4 to 7 months follow-up, and none had progression of residual stenosis in the LMCA. CONCLUSIONS: Our study suggests that LMCA rotational atherectomy and stenting are safe and effective revascularization procedures in high-risk patients and patients who are not candidates for bypass surgery.     

急性心肌梗死后非体外循环冠状动脉搭桥术临床研究

目的:探讨冠心病急性心肌梗死30 d内非体外循环冠状动脉搭桥手术的可行性和安全性。方法:回顾性分析130例急性心机梗死患者30 d内非体外循环冠状动脉搭桥术患者的临床资料,分析冠状动脉病变、冠状动脉搭桥支数、血液动力学参数、心肌损伤指标等因素的变化。结果:130例急性心机梗死患者30 d内非体外循环冠状动脉搭桥手术后死亡4例(3.1%),心力衰竭9例(6.9%),心律失常20例(15.4%)。结论:急性心肌梗死30 d内冠状动脉搭桥手术具有可行性和安全性,但术前肌钙蛋白I应尽量接近或达到正常,急性期手术其术后并发症发生率高于非急性期手术。     

Serum cardiac troponin I after conventional and minimal invasive coronary artery bypass surgery.

We evaluated myocardial release of cardiac troponin I (cTnI) in patients treated with conventional coronary artery bypass grafting (CABG), which employs extracorporeal circulation, and different kinds of minimal invasive coronary artery bypass grafting (MICABG), a surgical technique where the operation is performed without extra-corporeal circulation. Furthermore, we evaluated the usefulness of serum cTnI measurement to detect perioperative myocardial infarction (PMI) after coronary artery bypass surgery. Thirty-one patients were included: sixteen underwent CABG, fifteen underwent different MICABG and five patients had PMI. Blood specimens for cTnI measurements were collected up to 72 hours after opening the graft. Aortic cross-clamping time was a minor determinant of myocardial damage; on the other side, the trauma during surgery correlated with the number of involved arteries and with the manoeuvre employed to obtain heart dislocation, and appeared a more important determinant of myocardial damage. In patients with PMI, the cumulative release of cTnI was higher than in patients free from PMI; however, only after 24-72 hours we observed significant differences in serum cTnI values, because the increased perioperative values of cTnI complicated the interpretation of the myocardial status and a single cut-off could not be used to exclude PMI.     

Blood use in patients undergoing repeat coronary artery bypass graft procedures: multivariate analysis

BACKGROUND : The prevailing clinical opinion is that patients undergoing repeat coronary artery bypass graft (CABG) operation require more blood transfusions than do patients undergoing primary CABG operation. To determine the extent of this increased demand and the variables responsible for it, the cases of 196 patients who had undergone primary procedures and 65 patients who had had repeat procedures at the same institution were reviewed. STUDY DESIGN AND METHODS : To analyze the differences in transfusion requirements for these two groups, the following data were obtained: number of transfusions given between the time of surgery and the time of hospital discharge; preoperative hemoglobin (Hb), hematocrit (Hct), prothrombin time, and platelet count; Hb and Hct at hospital discharge; time the patient was on cardiopulmonary bypass; number and type of grafts; estimates of intraoperative blood loss; and chest-tube blood shed during the first 48 hours after surgery. RESULTS : The groups were comparable with respect to age, body weight, preoperative Hb and Hct, number of grafts, and aspirin exposure. Patients in the repeat group had 35-percent greater blood loss and required 75-percent more blood components than did the patients undergoing primary procedures. The mean number of blood components transfused per patient was as follows: red cells, 3.8 +/? 0.5 units in repeat patients and 2.2 +/? 0.2 units in primary patients (p = 0.002); platelets, 2.9 +/? 0.9 vs. 1.1 +/? 0.2 (p = 0.043); fresh-frozen plasma, 1.6 +/? 0.4 vs. 0.8 +/? 0.1 (p = 0.044). Analysis of variables by regression method for repeat patients showed a predictive effect of blood loss (p < 0.0001), prolonged time on cardiopulmonary bypass (p < 0.0001), preoperative Hb (p = 0.0003), and aspirin exposure (p = 0.0094) on red cell transfusion rate in repeat patients (R-square = 0.7778, Prob > f = 0.0001). CONCLUSION : Repeat CABG patients have higher transfusion rates. These findings may be attributed to the increased microvascular bleeding, prolonged time on cardiopulmonary bypass, lower preoperative Hb, and the use of preoperative antiplatelet medications.     

CT血管造影分析体外循环与非体外循环冠状动脉旁路移植后的桥血管通畅率

背景：近年来,非体外循环冠状动脉旁路移植后桥血管通畅率是否与传统的体外循环冠状动脉旁路移植相同存在争议。目的：探讨体外循环与非体外循环冠状动脉旁路移植后桥血管时间通畅率的差异性。方法：选取同一操作者行体外循环冠状动脉旁路移植患者100例,按其临床特征及桥血管病变危险因素匹配抽取非体外循环冠状动脉旁路移植患者137例。采用64排多螺旋CT血管造影分析冠脉搭桥后1个月,1年,2年,3年,4年的桥血管通畅情况。结果与结论：共对641条桥血管进行评价,两组中左侧乳内动脉桥血管时间通畅率均高于大隐静脉桥,两组左侧乳内动脉桥和大隐静脉桥血管时间通畅率比较差异均无显著性意义。说明非体外循环与体外循环冠状动脉旁路移植后患者桥血管时间通畅率相似,对于某些适当的患者来说,非体外循环冠状动脉旁路移植不失为一个良好的选择。     

Influence of aspirin or heparin on platelet function and postoperative blood loss after coronary artery bypass surgery

The aim of the study was to assess the effect of aspirin or heparin pretreatment on platelet function and bleeding in the early postoperative period after coronary artery bypass grafting (CABG) surgery. Seventy-five male patients with coronary artery disease who underwent CABG with cardiopulmonary bypass (CPB) were studied. The patients were divided into three groups: Group 1 (n=25) included patients receiving aspirin pretreatment, Group 2 (n=22) received heparin pretreatment, and Group 3 (n=28) included patients who received no antiplatelet or anticoagulant pretreatment. Twenty-four hours after surgery, all patients were administered aspirin therapy that was continued throughout their hospitalization period. We assessed the following preoperative blood coagulation indices: activated partial thromboplastin time (aPTT), international normalized ratio (INR), and fibrinogen. We compared platelet count and platelet aggregation induced by adenosinediphosphate (ADP) before surgery, 1 h after surgery, 20 h after surgery and on the seventh postoperative day. We assessed drained blood loss within 20 postoperative hours. Preoperative blood coagulation indices did not differ among the groups. Platelet count was also similar. One hour after surgery, platelet count significantly decreased in all groups (p<0.001), after 20 postoperative hours it did not undergo any marked changes, and on the seventh postoperative day, it significantly increased in all groups (p<0.001). Before surgery, the lowest index of ADP-induced platelet aggregation was found in Group 1 (p<0.05). One hour after surgery, platelet aggregation significantly decreased in all groups, most markedly in Group 3 (p<0.001), yet after 20 h, its restitution tendency and a significant increase in all groups was noted. On the seventh day, a further increase in the statistical mean platelet aggregation value was noted in Groups 2 and 3. Comparison of platelet aggregation after 20 postoperative hours and on the seventh day after surgery revealed a significantly higher than 10% increase of the index in 32% of patients in Group 1 (p<0.05), 27.3% of patients in Group 2 (p<0.05) and in 35.7% of patients in Group 3 (p<0.001). The lowest statistically significant value of postoperative blood loss was noted in Group 2 (p<0.01). Our study has shown that aspirin or heparin pretreatment had no impact on the dynamics of platelet function in the early postoperative period after CABG. The lowest postoperative blood loss was noted in patients pretreated with heparin.     

Perioperative risk of patients undergoing noncardiac surgery after coronary artery bypass surgery

BACKGROUND: Most data suggesting that noncardiac surgery early after coronary artery bypass surgery carries low risk are derived from post hoc analyses of randomized controlled trials, with only limited data derived from contemporary, nonselected, and nontrial patients. METHODS: We retrospectively reviewed the medical records of patients who underwent coronary artery bypass surgery at our institution between January 1999 and October 2006 to determine whether they subsequently had major noncardiac surgery and what the outcomes of the noncardiac surgery were. RESULTS: During the study period, 1065 patients underwent coronary artery bypass surgery, and 272 (26%) subsequently underwent 467 major noncardiac surgeries. The mean interval from coronary artery bypass to noncardiac surgery was 1.9 +/- 1.9 years (range, 0-7.8 years). A major complication occurred in 3 surgeries (0.6% [95% confidence interval, 0.1%-1.9%]). Two patients died (both from respiratory arrest during the postoperative period: 1 patient had a tongue cancer excision, and the other patient had polycythemia vera), and the third patient had a perioperative arrhythmia. CONCLUSIONS: Noncardiac surgery is often required early after coronary artery bypass surgery and carries very low risk for cardiac complications, suggesting that preoperative cardiac evaluation may not be required in most such patients.     

非体外循环冠状动脉旁路移植手术的护理配合

[目的]总结非体外循环冠状动脉旁路移植（OPCAB）手术的护理配合.[方法]对31例病人行OPCAB手术,同时加强术前准备及术中护理配合.[结果]31例病人手术均顺利,病人均康复出院,手术效果满意.[结论]加强 OPCAB手术的护理配合是手术成功的保证.     

Elevated beta-thromboglobulin in patients with chronic renal failure: effect of hemodialysis

Elevated plasma concentrations of beta-thromboglobulin were observed in 25 consecutive patients with chronic renal failure. Further increases in this platelet protein were observed during hemodialysis but not during peritoneal dialysis. The hemodialysis-induced increases were not prevented by either aspirin or dipyridamole, a fact which suggested that release of this protein was not dependent on platelet functional activity. Measurement of beta-thromboglobulin provides a sensitive indicator of platelet disruption during hemodialysis.     

Increased plasminogen activator inhibitor activity and diabetes predict subsequent coronary events in patients with angina pectoris

BACKGROUND: Plasminogen activator inhibitor (PAI) is a marker of recurrence of myocardial infarction. Diabetes mellitus is also an important risk factor of coronary artery disease, including myocardial infarction and angina pectoris. AIM: We examined baseline plasma PAI activity levels, clinical variables, and angiographic findings and assessed them as prospective values for subsequent coronary events, such as sudden death, nonfatal myocardial infarction and coronary revascularization by percutaneous transluminal coronary angioplasty or coronary artery bypass surgery during the follow-up period. METHODS: We conducted a prospective study for 4 years of 249 consecutive patients admitted with angina pectoris. Blood samples for PAI were drawn at discharge. RESULTS: In the multivariate Cox proportional hazard model, PAI activity and diabetes mellitus were significant and independent risk factors (the risk increased by 10% in those with a higher PAI concentration and by 70% in diabetic patients). Event-free survival was reduced by higher PAI activity (> or = 8.4 IU/mL) and the presence of diabetes. The patients with higher PAI activity and diabetes had a 4.2-fold risk in comparison with the patients with lower PAI activity and no diabetes. However, patients with lower PAI activity were less likely to have coronary events even when they had diabetes. CONCLUSIONS: Higher PAI activity and diabetes predict subsequent coronary events in patients with angina pectoris. Diabetes has less prognostic value for subsequent coronary events in patients with lower PAI activity.     

Access to coronary artery bypass surgery by race/ethnicity and gender among patients who are appropriate for surgery.

OBJECTIVE: The study sought to determine if there were race/ethnicity or gender differences in access to coronary artery bypass graft (CABG) surgery among patients who have been designated as appropriate and as necessary for that surgery according to the RAND methodology. METHODS: RAND appropriateness and necessity criteria were used to identify a race/gender stratified sample of postangiography patients who would benefit from coronary artery bypass graft surgery. These patients were tracked for 3 months to determine if they had undergone coronary artery bypass graft surgery in New York State. Subjects were a total of 1,261 postangiography patients in eight New York hospitals in 1994 to 1996. Measures included percentages of patients for whom coronary artery bypass graft surgery was appropriate and necessary undergoing surgery by race/ethnicity and gender, as well as multivariate odds ratios for race/ethnicity and gender. RESULTS: After controlling for age, payer, number of vessels diseased, and presence of left main disease, African-American and Hispanic patients were found to be significantly less likely to undergo coronary artery bypass graft surgery than white non-Hispanic patients (respective odds ratios 0.64 and 0.60). When "necessity" was used as a criterion instead of "appropriateness," significant differences in access for African-American patients remained. The gatekeeper physician recommended surgery only 10% of the time that patients did not undergo "appropriate" coronary artery bypass graft surgery, and this percentage did not vary significantly by race/ethnicity or gender of the patient. CONCLUSIONS: Even after controlling for appropriateness and necessity for coronary artery bypass graft surgery in a prospective study, African-American patients had significant access problems in obtaining coronary artery bypass graft surgery. These problems appeared not to be related to patient refusals.     

冠状动脉旁路移植术中红外监测导航技术初探

目的应用自主研发的心脏红外长波摄像监测系统,对冠状动脉旁路移植手术行术中监测,通过对红外热图分析,探讨该技术在心肌缺血诊断,心脏搭桥效果判断及不良事件应急处理方面的应用价值。方法随机选取行胸骨正中开胸心脏停跳下冠状动脉旁路移植手术患者20例,术中全程行红外摄像实时监控,采集并分析热图,并与术前信息比对,发现不良信息,指导手术操作。结果红外摄像获取的心脏热图能够准确判断心肌缺血部位,同时能够判断桥血管及吻合口是否通畅、可对搭桥术后缺血心肌血供恢复状况加以判断并推测手术效果。结论红外摄像监控技术对冠状动脉旁路移植手术具有术中指导意义和临床推广价值。