Subclavian artery reconstruction in patients undergoing coronary artery bypass grafting.

The presence of occlusive disease of the subclavian artery (SCA) proximal to the origin of the internal thoracic artery (ITA) influences the operative strategy and the outcome of coronary artery bypass grafting (CABG). Of 780 patients who underwent CABG, concomitant SCA occlusive lesions were reconstructed in 13 patients (nine males, four females). The affected SCAs were left-sided in 11 patients, and right-sided and bilateral in one, each. An aortoaxillary bypass utilizing an 8-mm PTFE graft was constructed in nine patients and a carotid-subclavian (C-S) transposition in two, simultaneously with CABG. Percutaneous balloon angioplasty with a stent was performed in two patients prior to CABG. With follow-up periods ranging from 4 to 8.4 years (mean, 6.3 years), aortoaxillary bypass grafts were patent in all patients. Other reconstructive procedures, including a C-S transposition and balloon angioplasty, were performed safely and effectively in off-pump CABG patients. In six patients, the left internal thoracic artery (LITA) could be used as a graft to the coronary artery after SCA reconstruction. Aortoaxillary bypass using an 8-mm PTFE graft is a safe and effective way for simultaneous subclavian reconstruction in patients undergoing CABG. Mid-term patency of the graft is satisfactory. The LITA can be used as a graft to the coronary arteries in selected patients. Preoperative brachial angiography is mandatory in these patients.     

Plasma levels and vascular effects of endothelin and big endothelin in patients with stable and unstable angina pectoris undergoing coronary bypass grafting.

OBJECTIVES: The aim of this study was to determine the plasma and pericardial levels of endothelin-1 (ET-1) and its precursor big endothelin-1 (Big ET-1) in patients with unstable and stable angina prior to and following coronary bypass surgery. To further investigate the content of ET-1, tissue levels were studied in the internal mammary artery (IMA) in patients with stable and unstable angina pectoris. Finally, the difference in reactivity of the IMA to ET-1 and Big ET-1 in stable and unstable patients was evaluated. METHODS: Plasma and pericardial levels of ET-1 and Big ET-1 were determined with radioimmunoassay in 81 patients (33 unstable) immediately before coronary bypass surgery, and at 6, 14, 40 and 64 h following the procedure. Specimens of the distal IMA from 12 patients (six unstable) were collected at the beginning of surgery for determination of tissue levels of ET-1. Additionally, distal internal mammary arteries were obtained from another 24 patients (12 unstable). These vessels were mounted in organ baths for functional studies on vascular reactivity to ET-1 and Big ET-1. RESULTS: The peripheral plasma levels of ET-1 in unstable patients were significantly lower in patients with unstable angina compared with patients with stable angina pectoris at all points of measurement. The levels of Big ET-1 were significantly higher pre-operatively in the unstable group, but decreased to similar levels to those of stable patients following coronary bypass grafting. There was no difference in ET-1 tissue content in the IMA between the patients. ET-1 and Big ET-1 caused an endothelin(A) (ET(A))-receptor blocker sensitive, concentration-dependent contraction of the IMA obtained from stable as well as unstable patients. CONCLUSIONS: It is concluded that unstable angina pectoris is associated with an increased ET-1 turnover. This increased turnover may participate in the local regulation of coronary vascular tone with subsequent influence of the condition of the patients. The present investigation also implies that ET(A)-blockade may be useful as an additional pharmacological principal in the treatment of unstable angina pectoris prior to revascularization, as well as to prevent post-operative arterial graft spasm.     

Gastrointestinal complications in patients undergoing coronary artery bypass grafting.

PURPOSE: Gastrointestinal complications (GICs) such as gastroduodenal ulcer, enterocolitis, and ischemic colitis after coronary artery bypass grafting (CABG) are rare, but are associated with high mortality and morbidity. The present study was performed to detect risk factors and to investigate outcomes following GICs after CABG. METHODS: Between January 1992 and December 2001, 17 of 549 patients (3.1%) developed GICs after CABG with cardiopulmonary bypass, presenting with gastrointestinal bleeding due to gastroduodenal ulcer, enterocolitis, or ischemic colitis. We conducted a retrospective analysis of these patients. RESULTS: All patients required emergent treatment for hemorrhage by means of blood transfusion and endoscopic ablation and/or clipping. The following possible predictors of GICs were identified by logistic multivariate analysis: age over 70, diabetes mellitus (particularly insulin-dependent diabetes), history of cerebrovascular disease or history of renal failure and postoperative low output syndrome (LOS). CONCLUSION: Our results suggested that GICs after CABG with cardiopulmonary bypass are rare but can be lethal. Early diagnosis and prompt intervention can be difficult but are potentially life saving for patients in whom GICs develop.     

Fenoldopam: renal and splanchnic effects in patients undergoing coronary artery bypass grafting

Impairment of renal and splanchnic perfusion during and after cardiopulmonary bypass may be responsible for acute renal failure and endotoxin-mediated systemic inflammation, respectively. We hypothesised that fenoldopam, a selective dopamine receptor agonist, would preserve renal function after cardiopulmonary bypass through its selective renal vasodilatory and natriuretic effects, and increase gastrointestinal mucosal perfusion by selective splanchnic vasodilation. We examined the effects of fenoldopam on haemodynamic parameters, creatinine clearance, fractional excretion of sodium, urine output, free water clearance and gastric mucosal pH in 31 patients undergoing elective coronary revascularisation. Patients were randomly assigned to receive continuous infusions of fenoldopam 0.1 microg x kg(-1) x min(-1) (n = 16) or placebo (n = 15). Renal parameters were measured: during a 24-h period before hospital admission, during cardiopulmonary bypass, from completion of cardiopulmonary bypass until 4 h later, from 4 to 8 h after cardiopulmonary bypass, and from 8 to 14 h after cardiopulmonary bypass. Gastric intramucosal pH was measured using a gastric tonometer before, during and after cardiopulmonary bypass. In the placebo group, but not the fenoldopam group, mean (SD) creatinine clearance decreased after separation from cardiopulmonary bypass, from 107 (36) to 71 (22) ml x min(-1) (p < 0.01) and from 107 (36) to 79 (26) ml x min(-1) (p < 0.01) for the 0-4 h and 4-8 h intervals after cardiopulmonary bypass, respectively. Changes in intramucosal pH were similar in both groups. The findings are consistent with the hypothesis that fenoldopam possesses a renoprotective effect in patients undergoing cardiopulmonary bypass.     

The protective effects of preconditioning decline in aged patients undergoing coronary artery bypass grafting.

OBJECTIVE: We sought to investigate the effects of myocardial ischemic preconditioning in adult and aged patients undergoing coronary artery bypass grafting. METHODS: Eighty patients with 3-vessel disease undergoing coronary artery bypass grafting were randomized into one of the following groups: adult ischemic preconditioning, adult control, aged ischemic preconditioning, and aged control. Hemodynamic data and cardiac troponin I values were compared between the groups. The ischemic preconditioning groups received 2 periods of 2 minutes of ischemia, followed by 3 minutes of reperfusion. The Student t test, chi(2) test, and analysis of variance for repeated measures were used for the statistical analysis. RESULTS: The baseline for right ventricular ejection fraction and cardiac index was similar. Right ventricular ejection fraction was depressed after the operation in all groups. Ischemic preconditioning significantly improved the recovery of right ventricular ejection fraction and cardiac index after the operation in adult patients (P =.013 and.001, respectively), but in the aged group there was no difference in the changes of ejection fraction and cardiac index (P =.232 and.889, respectively). The cardiac troponin I value in the adult patients subjected to ischemic preconditioning was lower than that in the adult control subjects (P =.046), but in aged patients undergoing ischemic preconditioning, the value was similar to that in aged control subjects (P =.897). Ischemic preconditioning also resulted in a shorter postoperative mechanical ventilation time and in less inotropic use in the adult group. CONCLUSION: Ischemic preconditioning protects the heart from ischemic reperfusion injury in adult patients undergoing coronary artery bypass grafting. The beneficial effects of ischemic preconditioning are manifested as a better recovery of right ventricular and global hemodynamic function, cellular viability, and surgical outcome. The protective effect of ischemic preconditioning is diminished in aged patients undergoing coronary bypass.     

七氟醚预处理对体外循环冠状动脉旁路移植术病人围术期心肌的保护作用

目的探讨七氟醚预处理对体外循环(CPB)下冠状动脉旁路移植术(CABG)病人心肌的保护作用。方法择期CPB下CABG病人40例,ASAⅡ级或Ⅲ级,随机分为2组(n=20):七氟醚组(S组)或异丙酚组(P组)。麻醉维持:P组靶控输注异丙酚,血浆靶浓度2～3μg/L,静脉输注芬太尼2～3μg·kg~(-1)·h~(-1);S组夹闭主动脉前,吸入0.5%～2%七氟醚,静脉输注芬太尼2～3μg·kg~(-1)·h~(-1),夹闭主动脉后靶控输注异丙酚,血浆靶浓度2～3μg/L,静脉输注芬太尼2～3μg·kg~(-1)·h~(-1)。于切皮前即刻、CPB前即刻、CPB后即刻、回ICU后即刻、6、12h记录心率(HR)、平均动脉压(MAP)、肺动脉楔压(PCWP)、中心静脉压(CVP)、心脏指数(CI)、体循环血管阻力指数(SVRI)。于麻醉诱导前、回ICU后即刻、6、12、24h采集静脉血,测定血清心肌肌钙蛋白I(cTnI)浓度。记录术后不良事件的发生情况。结果2组各时点MAP、PCWP、CVP、HR和SVRI比较差异无统计学意义(P>0.05);与切皮前即刻和P组比较,S组回ICU后各时点CI升高(P<0.05)。与P组比较,S组回ICU后各时点cTnI浓度降低(P<0.05)。2组病人术后均无死亡;2组心肌梗塞、房颤和心肌缺血的发生率差异无统计学意义(P>0.05);S组cTnI浓度>2ng/ml的发生率低于P组(P<0.05)。结论七氟醚预处理对体外循环下冠状动脉旁路移植术病人围术期心肌具有一定的保护作用。     

地尔硫(艹卓)在非体外循环下冠状动脉搭桥术围术期的心肌保护作用

目的 探讨非体外循环下冠状动脉搭桥术(OPCABG)围术期输注地尔硫(艹卓)对心肌的保护作用.方法 40例择期手术患者,随机分为地尔硫(艹卓)组(D组)与硝酸甘油组(C组),每组20例.D组静脉给予地尔硫(艹卓)0.1 mg·kg-1·h-1至术后24 h,C组常规给予硝酸甘油0.1μg·kg-1·h-1至术后24 h.分别在术毕、术后1、3、6、12和24 h记录血流动力学参数,并采集血样测定血清肌钙蛋白Ⅰ(cTnI).结果 与C组比较,D组的心率术后1、3、6、12、24 h均较慢(P＜0.05).C组房颤4例,D组1例;C组室上性心动过速5例,D组1例.术后6 h的cTnI,D组显著低于C组(P＜0.05).结论 OPCABG围术期持续输注地尔硫(艹卓)有比硝酸甘油更好的抗缺血和抗心律失常的保护作用.     

Intraaortic balloon pumping in patients undergoing coronary artery bypass grafting

Beneficial effect of preoperative intraaortic balloon pumping (IABP) treatment in high-risk patients who had open heart surgery have been demonstrated. The purpose of this study is to determine the impact of preoperative IABP use on survival in high-risk patients undergoing coronary artery bypass grafting (CABG). METHODS: Two hundred seventy-seven consecutive patients having CABG at our institution were reviewed. Patients having an IABP were identified retrospectively and grouped into one of 3 groups as follows. Group A (n = 14): preoperative IABP for high-risk urgent or elective cases. Group B (n = 26): preoperative IABP for emergency cases. Group C (n = 6): unplanned intraoperative or postoperative IABP. RESULTS: Forty-six patients had an IABP (16.6% of total). Parsonnet score in group B was significantly higher (p < 0.05). Length of operation for group C was significantly longer (p < 0.05). Overall hospital mortality in the total group of 277 cases was 4.2%. Hospital mortality was 7.1% in group A, 7.7% in group B, and 50% in group C. Hospital mortality in group C was significantly higher (p < 0.01). CONCLUSIONS: The beneficial effect of preoperative treatment with IABP in high-risk patients undergoing CABG was confirmed. This approach resulted in a significantly lower hospital mortality.     

Perioperative melatonin secretion in patients undergoing coronary artery bypass grafting

Melatonin, a neurohormone, plays an important role in adjusting the "biological clock" in humans. We sought to describe perioperative patterns of melatonin secretion in patients undergoing coronary artery bypass grafting surgery with cardiopulmonary bypass (CPB). After IRB approval and written informed consent, 12 male patients scheduled for elective coronary artery bypass grafting under hypothermic CPB were enrolled in the study. During anesthesia, patients' eyes were carefully covered to prevent light effects. Blood samples were taken at specific time points during surgery, every 3 h in the immediate postoperative period, and for 24 h from 6:00 PM of Postoperative Day 2 until 6:00 PM of Postoperative Day 3. Plasma melatonin and cortisol concentrations were measured by radioimmunoassay and enzyme-linked immunosorbent assay, respectively. During surgery, plasma melatonin concentrations were below the minimum sensitivity concentration, yet small concentrations, without circadian variation, were detected during the immediate postoperative period. During Postoperative Days 2 and 3, circadian secretion patterns of melatonin were present in 10 patients and showed an inverse correlation with light intensity (r = 0.480; P < 0.01). Plasma cortisol concentrations in the immediate postoperative period were significantly larger than those before the induction of anesthesia (P < 0.01). Only three patients regained circadian secretion of cortisol. We concluded that melatonin and cortisol secretion was disrupted during cardiac surgery with CPB and in the immediate postoperative period. However, circadian rhythms of melatonin were present in most patients from Postoperative Day 2. Only 30% of the patients regained circadian rhythm of cortisol secretion. IMPLICATIONS: Melatonin is a hormone that plays an important role in adjusting the biological clock in humans and that regulates secretion of various other hormones. We studied melatonin secretion in patients undergoing cardiac surgery with cardiopulmonary bypass. Melatonin secretion was disturbed during and immediately after surgery but had recovered a circadian rhythm 24 h later, raising the question of whether melatonin should be supplemented before cardiac surgery.     

Graft selection in elderly patients undergoing coronary artery bypass grafting

Purpose  

This study aimed to assess the clinical and angiographic outcomes after coronary artery bypass grafting (CABG) in elderly patients (≥75 years).     

Autologous platelet sequestration in patients undergoing coronary artery bypass grafting

OBJECTIVES: Blood conservation remains an important issue for patients undergoing cardiac surgery with cardiopulmonary bypass. Platelet sequestration (PSQ) is an aggressive autologous blood conservation method, whose effectiveness is still debated. The main objective of the present study was to evaluate whether PSQ reduces postoperative blood transfusion requirements in patients undergoing coronary artery bypass grafting (CABG) and to determine if PSQ is a cost-effective blood conservation method. MATERIAL AND METHODS: All adult patients admitted for CABG entered the study. Exclusion criteria were: recent blood transfusion (<7 days), a platelet count of 150x10(3)/microl or less, hematocrit less than 35% and body weight 50 kg or less. The sequestration was aim 20% or more of the total platelet plasma volume. The sequestration protocol was three sequestration cycles performed just prior to surgery. The concentrated platelet portion was reinfused after weaning from the cardiopulmonary bypass. Hundred seven parameters/patients were recorded. Sixty patients entered the study; 30 in the PSQ group and 30 controls (CTR). RESULTS: Patient characteristics, operation data, preoperative hematology and coagulation parameters did not differ between the groups. In the PSQ group a mean of 433+/-34 ml concentrated platelet portion was collected. The mean platelet count in the concentrated platelet portion was 749+/-157x10(3)/microl, resulting in a platelet yield of 28+/-6% (2040%). The average total chest tube blood loss was 423 ml (PSQ) compared to 858 ml (CTR), p<0.001. A greater number of CTR patients required blood transfusion postoperatively (23) compared to PSQ (3), P<0.001, and fluid requirements were also significantly increased in the control group, P<0.001. No statistical differences in hematology and coagulation parameters between the groups were observed. The hospital mortality was low and the incidence of postoperative complications was few and without group differences. Post-extubation gas exchange was better in PSQ patients compared to CTR. CONCLUSIONS: A preoperative PSQ of a minimum 20% of the total platelet plasma volume resulted in significantly lower postoperative blood loss and fluid and blood transfusion requirements compared to controls. Post-extubation gas exchange was also better after PSQ. Only one patient did not tolerate the sequestration. No other adverse effects of the procedure were observed.     

Isoflurane preconditioning-induced cardio-protection in patients undergoing coronary artery bypass grafting

BACKGROUND AND OBJECTIVES: Ischaemic preconditioning is commonly regarded as one of the most powerful protective mechanisms against a subsequent lethal ischaemic injury during coronary artery bypass graft surgery but is not practiced routinely. Experimentally, isoflurane, a commonly used volatile anaesthetic agent, provides myocardial protection through a signal transduction cascade that is remarkably similar to the pathways identified in ischaemic preconditioning. The aim of our study was to investigate whether pre-ischaemic administration of isoflurane exerted protection against prolonged ischaemia with functional recovery and reduced necrosis among patients undergoing coronary artery bypass graft surgery. METHODS: Forty patients scheduled for elective coronary artery bypass graft operations were prospectively randomized into the control or isoflurane groups. In the isoflurane group, isoflurane 2.5 minimum alveolar concentration was administered for 15 min followed by a 5-min washout period before aortic cross-clamping. The control group received a time-matched period of isoflurane-free cardiopulmonary bypass. The conduction of anaesthesia and surgery were standardized in all patients. Haemodynamic data, troponin I release and inotropic support were measured and recorded perioperatively. RESULTS: There were no adverse effects related to isoflurane administration. In the isoflurane group, the mean cardiac index after cardiopulmonary bypass was significantly higher than the pre-bypass value (P < 0.05), whereas no difference was found in the control group. At 15 min after cardiopulmonary bypass and 6 h after surgery, the changes in cardiac index and stroke volume index were significantly higher in the isoflurane group than in the control group (P < 0.05). There was a consistently lower release of troponin I in the isoflurane group compared to the control group. Compared to the controls, the mean troponin I level was significantly reduced in the isoflurane group at 24 h after surgery (P = 0.042). CONCLUSIONS: The present results support the preconditioning effect of isoflurane in patients undergoing coronary artery bypass graft surgery as clinically feasible and providing optimal cardiac protection.     

Anesthesia in patients undergoing valvular replacement and coronary artery bypass grafting

We investigated the intraoperative hemodynamic changes in patients who underwent combined valvular replacement (VR) and coronary artery bypass grafting (CABG). The data of 8 patients who under went VR + CABG were compared with those of 50 patients who underwent VR during the same period (1986). Heart rate before the institution of cardiopulmonary bypass (CPB) was not different between these two group, but blood pressure of VR + CABG cases was significantly higher than that of VR cases. This required a higher dosage of fentanyl in VR + CABG cases.     

Clopidogrel and bleeding in patients undergoing elective coronary artery bypass grafting

Objective

In an effort to minimize transfusions in patients undergoing elective coronary artery bypass grafting operations after recent clopidogrel exposure, we studied laboratory tests predictive of platelet dysfunction and used a strict algorithm-driven treatment of bleeding.

Methods

Forty-five patients receiving clopidogrel within 6 days of the operation and 45 control subjects were studied. Prothrombin time, activated partial thromboplastin time, platelet count, and platelet function test results were measured before heparinization, after protamine administration, and then every 2 hours. No transfusions were administered unless a patient met both laboratory and clinical criteria.

Results

Algorithm-driven treatment of bleeding significantly reduced the mean units of all blood components transfused by about one third, as shown by comparison with current control and historical data. Compared with current control subjects, clopidogrel recipients required significantly more transfusions of platelets (9.0 ± 1.7 vs 1.2 ± 0.5 U; P < .0001) and packed red blood cells (4.3 ± 0.6 vs 2.3 ± 0.5 U; P = .01) and required longer periods of controlled ventilation (12.4 ± 1.3 vs 8.6 ± 0.8 hours; P = .02). Preoperative platelet dysfunction before heparin administration for cardiopulmonary bypass, as measured by using adenosine diphosphate aggregometry (response <40%), predicted all but 1 case of severe coagulopathy requiring multiple transfusions (16.6 ± 2.8 U of platelets and 5.8 ± 1.0 U of packed red blood cells).

Conclusions

A strict transfusion algorithm can reduce the transfusion requirement for all blood components. Preheparin testing of platelet function with adenosine diphosphate aggregometry can identify patients at highest risk for perioperative bleeding and transfusions and might further reduce the perioperative transfusion requirement.     

尼卡地平或乌拉地尔在冠状动脉旁路移植术转流中控制血压效果的研究

目的　比较尼卡地平或乌拉地尔在体外循环中控制血压的效果及其对血液动力学的影响。方法　 60例冠状动脉旁路移植术 ( CABG)病人在体外循环 ( CPB)中平均动脉压 ( MAP)升至80 mm Hg( 1k Pa=7.5 mm Hg)时接受尼卡地平或乌拉地尔治疗。60例病人随机分为尼卡地平组或乌拉地尔组 ,每组 3 0例 ;另设同时期同类病人 3 0例作为对照组。观察两药起效时间 ,维持 MAP在 ( 70±5 ) mm Hg所需剂量 ,降压期间对人工肺血面的影响 ,停机后的血液动力学及混合静脉血氧饱和度( SvO2 )变化。结果　将 MAP从 80 m m Hg降至 70 m m Hg,应用尼卡地平 4μg· kg- 1 · min- 1 所需时间为 ( 2 .4± 1.1)分 ,维持 MAP在 ( 70± 5 ) m m Hg所需剂量为 ( 1.1± 0 .5 ) μg·kg- 1· m in- 1。应用乌拉地尔 90 μg· kg- 1· min- 1所需时间为 ( 2 .8± 1.0 )分 ,维持 MAP在 ( 70± 5 ) mm Hg所需剂量为 ( 5 0 .8±14 .4 ) μg· kg- 1· min- 1 ,但有 2例耐药 ,需不断增加剂量方能控制血压。尼卡地平组 19例 ( 63 % ) ,乌拉地尔组 2 2例 ( 73 % )心脏自动复跳 ,两组的自动复跳率均高于对照组 ( 4 6.2 % ) ( P<0 .0 5 ) ,但两组之间无差异 ( P>0 .0 5 )。停机后两组外周阻力 ( SVR)较 CPB前均明显下降 ( P<0 .0 1) ,每搏量 ( SV)     

Angiographic coronary diffuseness and outcomes in dialysis patients undergoing coronary artery bypass grafting surgery.

OBJECTIVE: Pre-operative dialysis-dependent renal failure (DDRF) is a predictor of morbidity and mortality following coronary artery bypass grafting surgery (CABG). Whether this is due in part to a more diffuse coronary atherosclerotic burden in these patients is unknown. The purpose of this study was to compare coronary atherosclerotic disease burden in patients with and without pre-existing DDRF undergoing CABG. METHODS: From a retrospective analysis of a single-centre cardiac surgical database, consecutive DDRF patients undergoing isolated CABG (n=35) were matched to 70 non-dialysis-dependent (NDD) patients without renal failure by procedure, age, sex, functional status, ejection fraction, number of diseased vessels, and diabetes. Pre-operative angiograms were analyzed by a single, blinded adjudicator using a modification of a previously published coronary diffuseness score (range: 0-45). Angiographic scores and baseline and outcome characteristics were compared using chi(2) tests, Fisher's Exact tests, and t-tests as appropriate. RESULTS: No statistical differences were found among pre-operative characteristics between the two groups. The mean angiographic coronary diffuseness scores for the dialysis and non-dialysis groups were 18.2 and 20.6, respectively (p=0.13). Transfusion was more frequent (77 vs. 23%, p<0.0001) and median length of stay longer (9 vs. 7 days, p=0.02) in the DDRF group. There were no differences in the number of distal anastomoses performed in the two groups. Low rates of peri-operative myocardial infarction, stroke, re-operation, and in-hospital mortality were observed in both groups. CONCLUSIONS: Objective quantification revealed that patients with DDRF undergoing CABG did not have a greater coronary artery atherosclerosis disease burden than matched controls who did not have pre-operative DDRF. This may be due to pre-operative patient selection bias. The increased morbidity and mortality of CABG in patients with DDRF is more likely to be due to the multiple adverse systemic effects of renal failure and dialysis on the cardiovascular system as opposed to diffuseness of distal coronary disease.