On-pump versus off-pump coronary revascularization: evaluation of renal function.

BACKGROUND: Coronary revascularization with cardiopulmonary bypass has the potential risk of renal dysfunction related to the nonphysiologic nature of cardiopulmonary bypass. Recently, there has been a revival of interest in performing myocardial revascularization on the beating heart and we investigated whether this prevents renal compromise. METHODS: A prospective, randomized, controlled trial was performed in 50 patients (45 males, mean age 61+/-3.7 years) undergoing elective coronary artery bypass grafting. Patients were randomly assigned to conventional revascularization with cardiopulmonary bypass (on pump) or beating heart revascularization (off pump). Glomerular and tubular function were assessed up to 48 hours postoperatively. RESULTS: There were no deaths, myocardial infarctions or acute renal failure in either group. Glomerular filtration as assessed by creatinine clearance and the urinary microalbumin/creatinine ratio was significantly worse in the on pump group (p < 0.0004 and 0.0083, respectively). Renal tubular function was also impaired in the on pump group as assessed by increased N-acetyl glucosaminidase activity (p < 0.0272). CONCLUSIONS: These results suggest that off pump coronary revascularization offers a superior renal protection when compared with conventional coronary revascularization with cardiopulmonary bypass and cardioplegic arrest in first time coronary bypass patients.     

Emergent off-pump complete myocardial revascularization in dextrocardia

Dextrocardia is a rare condition not spared by coronary artery disease. We report the case of a 72-year-old patient with dextrocardia associated with situs inversus totalis who presented to our Institution with acute myocardial infarction complicated by congestive heart failure. Due to the severe general conditions of the patient, an emergent off-pump complete myocardial revascularization was undertaken. The patient tolerated the procedure well and was asymptomatic at discharge. The technical aspects encountered in the setting of mirror-image anatomy and the advantages of off-pump myocardial revascularization in the critically ill patient are discussed.     

Beating heart off-pump myocardial revascularization in an infant

A 6-week-old patient weighing 4 kg was admitted for surgical correction of anomalous left coronary artery from the pulmonary artery. Reimplantation of the coronary artery with cardiopulmonary bypass was impossible because the patient also had hereditary spherocytosis, which put him at risk for hemolytic anemia. Thus, closure of the left main stem and left internal mammary artery-left anterior descending coronary artery bypass grafting were performed successfully with the heart beating.     

Concomitant off-pump myocardial revascularization and pheochromocytoma resection

Surgical management of patients with coexisting ischemic heart disease and pheochromocytoma remains challenging. We present one such case in which hybrid myocardial revascularization (angioplasty with stenting and off-pump coronary artery bypass grafting) and resection of pheochromocytoma were undertaken. Unusual features included simultaneous coronary artery surgery and tumor resection and, in particular, coronary artery surgery being performed without cardiopulmonary bypass.     

Left thoracotomy approach in reoperative off-pump coronary revascularization

Objective: Reoperative coronary bypass grafting is at high risk. Particularly in redo cases where the patent graft is running near the midline of the sternum, the graft may be exposed to injury by a median sternotomy and subsequent dissection. Whereas, off-pump bypass grafting from the left axillary artery or descending thoracic artery by a left thoracotomy approach is safe for preventing graft damage.Methods: From March 1998 to February 2002, we performed off-pump coronary artery bypass grafting by a left thoracotomy approach in 9 patients. The left axillary artery was used as the inflow vessel in 4 cases, and the descending thoracic, aorta in 5.Results: The radial artery was anastomosed proximally to the axillary artery in 4 cases and the descending thoracic aorta in one case. The saphenous vein graft was anastomosed, proximally to the descending thoracic aorta in 4 cases. Transdiaphragmatic minimally invasive bypass grafting for the right coronary artery was simultaneously performed in 3 cases. Postoperative cardiac events were ventricular arrhythmia in 6 cases and supraventricular arrhythmia in 3 cases. There was no damage to the patent grafts. Postoperative coronary angiography performed, in 8 cases revealed all the grafts to be patent without stenosis. Cardiac symptoms were not found after the operation in any of the cases.Conclusions: These procedures can prevent the injury to patent grafts caused by a median sternotomy, and will be one of the useful strategies for reoperative off-pump coronary artery bypass grafting.     

Sevoflurane but not propofol preserves myocardial function in coronary surgery patients

BACKGROUND: Sevoflurane has been shown to protect against myocardial ischemia and reperfusion injury in animals. The present study investigated whether these effects were clinically relevant and would protect left ventricular (LV) function during coronary surgery. METHODS: Twenty coronary surgery patients were randomly assigned to receive either target-controlled infusion of propofol or inhalational anesthesia with sevoflurane. Except for this, anesthetic and surgical management was the same in all patients. A high-fidelity pressure catheter was positioned in the left ventricle and the left atrium. LV response to increased cardiac load, obtained by leg elevation, was assessed before and after cardiopulmonary bypass (CPB). Effects on contraction were evaluated by analysis of changes in dP/dt(max). Effects on relaxation were assessed by analysis of the load dependence of myocardial relaxation (R = slope of the relation between time constant tau of isovolumic relaxation and end-systolic pressure). Postoperative concentrations of cardiac troponin I were followed during 36 h. RESULTS: Before CPB, leg elevation slightly increased dP/dt(max) in the sevoflurane group (5 +/- 3%), whereas it remained unchanged in the propofol group (1 +/- 6%). After CPB, leg elevation resulted in a decrease in dP/dt(max) in the propofol group (-5 +/- 4%), whereas the response in the sevoflurane group was comparable to the response before CPB (5 +/- 4%). Load dependence of LV pressure fall (R) was similar in both groups before CPB. After CPB, R was increased in the propofol group but not in the sevoflurane group. Troponin I concentrations were significantly lower in the sevoflurane than in the propofol group. CONCLUSIONS: Sevoflurane preserved LV function after CPB with less evidence of myocardial damage in the first 36 h postoperatively. These data suggest a cardioprotective effect of sevoflurane during coronary artery surgery.     

Experimental off-pump coronary artery revascularization with adenosine-enhanced reperfusion

OBJECTIVE: Although beating heart coronary artery bypass grafting has recently gained popularity, it eliminates the protective strategies (ie, cardioplegia) developed for use in conventional cardiac operations. We recently introduced the technique of perfusion-assisted direct coronary artery bypass to perfuse the grafted vessels during multivessel off-pump coronary artery bypass grafting. In the present study we tested the hypothesis that intracoronary reperfusion with the cardioprotective agent adenosine during simulated perfusion-assisted direct coronary artery bypass attenuates reperfusion injury. METHODS: In anesthetized dogs the heart was exposed, and the left anterior descending coronary artery was ligated for 75 minutes. Reperfusion was achieved through a catheter in the left anterior descending coronary artery by means of a computer-controlled pump. Intracoronary left anterior descending coronary artery perfusion pressure was continuously matched to mean arterial blood pressure. In one group (adenosine group) 10 micromol/L adenosine was added to the blood during the first 30 minutes of reperfusion, whereas another group (vehicle group) received a comparable volume of saline solution. RESULTS: During the first 30 minutes of reperfusion, blood flow through the left anterior descending coronary artery was significantly greater (P <.05) in the adenosine group than in the vehicle group (150.6 +/- 21.9 vs 50.2 +/- 11.3 mL/min at 15 minutes of reperfusion). Although there were no group differences in postischemic wall motion, infarct size was significantly smaller in the adenosine group than in the vehicle group (11.1% +/- 3.0% vs. 28.0% +/- 4.0% of area at risk, P <.05). Myeloperoxidase activity in the necrotic tissue, an index of neutrophil accumulation, tended to be lower in the adenosine group than in the vehicle group (58.6 +/- 14.2 vs. 91.0 +/- 21.6 DeltaAbs Units x min(-1) x g(-1) tissue). In isolated postischemic left anterior descending coronary artery rings, the maximal relaxation response to the endothelium-dependent vasodilator acetylcholine was significantly greater in the adenosine group than in the vehicle group (97.9% +/- 5.6% vs. 64.7% +/- 6.5%, P<.05). CONCLUSION: This novel reperfusion strategy for off-pump coronary artery bypass grafting can be used not only in cases requiring multiple grafting but also to attenuate necrosis and endothelial dysfunction in acute evolving infarction.     

Impact of off-pump coronary artery surgery on myocardial performance and beta-adrenoceptor function

OBJECTIVE: To determine the hemodynamic changes during beating heart revascularization of the left anterior descending artery, the circumflex artery, and the right coronary artery as well as cardiovascular beta-adrenoceptor function before and after off-pump coronary artery bypass surgery. DESIGN: Prospective study. SETTING: University department of cardiothoracic anesthesia. PARTICIPANTS: Twenty patients scheduled for off-pump coronary artery bypass surgery using the Octopus 2 stabilizer system. INTERVENTIONS: Isoproterenol, 4 microg, was administered intravenously after induction of anesthesia and again after surgery to monitor cardiac beta-receptor function. MEASUREMENTS AND MAIN RESULTS: The hemodynamic responses to isoproterenol and cardiovascular variables were monitored before, during, and after immobilization of the target coronary artery with catheters in the radial and pulmonary arteries. During surgery on the left anterior descending artery (n = 23), stroke volume and cardiac index decreased 17 mL (21%) and 400 mL (17%). During revascularization of the circumflex artery (n = 9), stroke volume and cardiac index decreased 19 mL (28%) and 300 mL (17%). During surgery on the posterior aspect of the heart (n = 13), stroke volume and cardiac index decreased 22 mL (29%) and 400 mL (17%). All the cardiovascular variables had returned to baseline values 5 minutes after releasing the heart. The hemodynamic responses to isoproterenol were equal before and after surgery. CONCLUSION: This study provides evidence that the hemodynamic changes associated with off-pump surgery on the 3 major coronary arteries are similar and of short duration. No desensitization of cardiovascular beta-adrenoceptors was found. This finding is in contrast to the deterioration in beta-adrenoceptor function seen after surgery with cardiopulmonary bypass.     

Simultaneous off-pump coronary revascularization with pulmonary resection or vascular surgery

Patients who require coronary artery bypass grafting and who also have vascular disease or lung malignancy constitute a high-risk group, and their management remains controversial. Combining off-pump coronary surgery (OPCAB) with peripheral artery revascularization or lung resection is an attractive proposition, as it avoids the risks associated with cardiopulmonary bypass. This paper presents the results of 26 such combined procedures consisting of simultaneous OPCAB and peripheral revascularization or lung resection, between April 2001 and March 2003. Twenty underwent concomitant carotid endarterectomy and OPCAB, four underwent aortobifemoral bypass and OPCAB, and two underwent pneumonectomy and OPCAB. There was no in-hospital mortality. Prolonged ventilatory support was necessary in one patient who had a lung resection. The median postoperative length of stay in the Intensive Care Unit was 1.3 days (range 1 to 6) and the median length of hospital stay was 5.7 days (range 4 to 16 days). Off-pump coronary surgery clearly has a place for patients with peripheral vascular disease or pulmonary malignancy who additionally require myocardial revascularization.     

Percutaneous ventricular assist device support during off-pump surgical coronary revascularization

Intraaortic balloon pump counterpulsation has been used for mechanical circulatory support in cardiogenic shock patients, but percutaneous left ventricular assist devices can provide superior circulatory support in the same group of patients. We describe the case of a patient in cardiogenic shock after a myocardial infarction. A percutaneous ventricular assist device was used to provide immediate active hemodynamic support, and, because the patient's condition necessitated surgical revascularization, percutaneous left ventricular assist device support was continued during off-pump coronary artery bypass.     

Safety and efficacy of off-pump coronary revascularization in severe left ventricular dysfunction

Background  

Myocardial revascularization in presence of severe Left Ventricular Dysfunction (LVD) presents a challenging surgical scenario. To improve the results of this high risk procedure, off-pump revascularization is being increasingly used; yet without conclusive evidence of definite benefit. Present study aims to assess the early outcome of coronary revascularization in presence of severe Left Ventricle (LV) dysfunction by off pump method as against conventional on- pump technique.     

Combined off-pump coronary revascularization: ascending aorta to carotid bypass

A 76-year-old man with symptomatic cerebral vascular disease and coronary artery disease was treated with simultaneous off-pump bypass and cerebral revascularization. With the emergence of off-pump coronary artery operation as a viable option for coronary revascularization we believe that this procedure will become our method of choice for combined cerebral and coronary artery disease.