Feasibility and Safety of Delivering Xenon to Patients Undergoing Coronary Artery Bypass Graft Surgery While on Cardiopulmonary Bypass: Phase I Study

Background: Postoperative neurocognitive deficit is prevalent after cardiac surgery. Xenon may prevent or ameliorate acute neuronal injury, but it also may aggravate injury during cardiac surgery by increasing bubble embolism. Before embarking on a randomized clinical trial to test the safety and efficacy of xenon for postoperative neurocognitive deficit, we undertook a phase I study to investigate the safety of administering xenon to patients undergoing coronary artery bypass grafting while on cardiopulmonary bypass and to assess the practicability of our xenon delivery system.

Methods: Sixteen patients scheduled for coronary artery bypass grafting surgery with hypothermic cardiopulmonary bypass gave their informed consent to participate in an open-label dose-escalation study (0, 20, 35, 50% xenon in oxygen and air). Xenon was delivered throughout surgery using both a standard anesthetic breathing circuit and the oxygenator. Gaseous and blood xenon partial pressures were measured five times before, during, and after cardiopulmonary bypass. Middle cerebral artery Doppler was used to assess embolic load, and major organ system function was assessed before and after surgery.

Results: Middle cerebral artery Doppler showed no evidence of increased emboli with xenon. Patients receiving xenon had no major organ dysfunction: Troponin I and S100[beta] levels tended to be lower in patients receiving xenon. Up to 25 l xenon was used per patient. Xenon partial pressure in the blood tracked the delivered concentration throughout.     

Combined use of off-pump techniques and a sutureless proximal aortic anastomotic device reduces cerebral microemboli generation during coronary artery bypass grafting

OBJECTIVE: Intraoperative cerebral microemboli are associated with the development of postoperative stroke and neurocognitive decline in patients undergoing coronary artery bypass grafting. Although cardiopulmonary bypass is responsible for the generation of a significant number of such emboli, the elimination of cardiopulmonary bypass alone has not been conclusively shown to improve neurocognitive outcome. The current study was performed to determine the effects of combined off-pump coronary artery bypass grafting and sutureless proximal aortic anastomotic techniques on the generation of intraoperative cerebral microemboli compared with standard coronary artery bypass grafting techniques of cardiopulmonary bypass and hand-sewn proximal anastomoses. METHODS: Fifty-three patients underwent off-pump coronary artery bypass grafting by using the sutureless Symmetry aortic connector device (St Jude Medical, St Paul, Minn) for all proximal anastomoses. Eighteen of these patients received intraoperative transcranial Doppler ultrasonography to determine right- and left-sided cerebral microembolic counts. These results were compared with those obtained from a similar group of 17 patients undergoing standard coronary artery bypass grafting, in whom cardiopulmonary bypass and hand-sewn proximal anastomoses were used. RESULTS: Our use of the proximal anastomotic device in patients undergoing coronary artery bypass grafting was safe, with no aortic complications, postoperative strokes, or in-hospital deaths. Microembolic counts to both the right and left cerebral circulation were significantly reduced in the patients undergoing off-pump coronary artery bypass grafting (right = 21.9 +/- 20.7 emboli, left = 24.9 +/- 19.2 emboli) compared with those in patients undergoing standard coronary artery bypass grafting (right = 181.6 +/- 85.3, left = 189.9 +/- 60.401, P <.0001). CONCLUSIONS: Our use of a sutureless proximal anastomotic device during off-pump coronary artery bypass grafting is safe and significantly decreases cerebral microembolism when compared with standard coronary artery bypass grafting with cardiopulmonary bypass and hand-sewn anastomoses. Long-term follow-up is needed to determine the effects of this technical strategy on neurocognitive outcome.     

Neurologic outcomes after coronary artery bypass grafting with and without cardiopulmonary bypass

Neurologic injury, in the form of either stroke or more subtle neurocognitive impairment, is a frequent and potentially devastating complication of coronary artery bypass grafting (CABG). The etiology of CABG-associated neurologic injury is likely multifactorial, with the phenomena of cerebral hypoperfusion and embolism being the major contributors. Several perioperative strategies have been developed in an effort to reduce the incidence of CABG-associated neurologic complications. Hypothermic cerebral perfusion, alpha stat acid-base management, and slow patient rewarming have been shown by several investigators to minimize adverse neurologic sequelae associated with the use of cardiopulmonary bypass. Performing CABG without cardiopulmonary bypass (off-pump CABG), meanwhile, has been shown to reduce the risk of perioperative stroke, especially in high-risk patients such as the elderly. Whether off-pump CABG reduces the incidence of less severe neurocognitive impairment has not yet been clearly established and merits further investigation in the form of large, multicenter, randomized trials. Other technical innovations, such as the use of sutureless and clampless aortic anastomotic devices, also may be able to further minimize the neurologic complications associated with CABG.     

The cerebral complications of coronary artery bypass surgery.

A prospective study of 79 coronary artery bypass surgery patients has been undertaken to determine the cerebral consequences of this form of surgery. Thirty comparative major vascular and thoracic non-cardiopulmonary bypass patients have also been studied. Detailed neurological, neuropsychological and cerebral blood flow investigations were undertaken preoperatively and at 8 days and 8 weeks postoperatively. Whilst stroke was rare following coronary artery bypass surgery, only one case in 76 being found (less than 1%), moderate or severe neuropsychological deficit was common, occurring in 49 of 67 patients (73%) 8 days after surgery and in 25 of 67 patients (37%) 8 weeks after surgery. However, the non-cardiopulmonary bypass patients also showed comparative levels of neuropsychological deficit. Cerebral blood flow was significantly reduced 8 days following coronary artery bypass surgery but not at 8 weeks and not in the comparative group. Significant cerebral blood flow reduction 8 days after coronary artery bypass graft surgery was not related to neuropsychological deficit found at a similar time. A greater neuropsychological deficit was found with longer cardiopulmonary bypass times but increased length of cardiopulmonary bypass appeared not to be related to an increased cerebral blood flow reduction.     

Solid and gaseous cerebral microembolization during off-pump, on-pump, and open cardiac surgery procedures

BACKGROUND: Neurocognitive dysfunction remains a limitation of cardiac surgery with cardiopulmonary bypass. Intraoperative cerebral microembolization is believed to be one of the most important etiologic factors. Using a new generation of transcranial Doppler ultrasonography, we compared the number and nature of intraoperative microemboli in patients undergoing on-pump and off-pump cardiac surgery procedures. METHODS: Bilateral continuous transcranial Doppler monitoring of the middle cerebral arteries was performed in 45 patients (15 off-pump coronary artery bypass grafting, 15 on-pump coronary artery bypass grafting, and 15 open cardiac procedures). All recordings were performed using a multi-range, multifrequency system to allow both measurement of the number and discrimination of the nature of microemboli in the 3 different groups. RESULTS: The median number (interquartile range) of microemboli in the off-pump coronary artery bypass grafting, on-pump coronary artery bypass grafting, and open procedure groups were 40 (28-80), 275 (199-472), and 860 (393-1321), respectively (P <.01). Twelve percent of microemboli in the off-pump coronary artery bypass grafting group were solid compared with 28% and 22% in the on-pump coronary artery bypass grafting and open procedure groups, respectively (P <.05). In the on-pump groups, 24% of microemboli occurred during cardiopulmonary bypass, and 56% occurred during aortic manipulation (cannulation, decannulation, application, and removal of crossclamp or sideclamp). CONCLUSIONS: Cerebral microembolization is significantly reduced with avoidance of cardiopulmonary bypass. The majority of microemboli occurring during cardiac surgery are gaseous, with a higher proportion of solid microemboli in the on-pump group, and may have a different significance for cerebral injury than solid microemboli. The ability to reliably discriminate gas and solid microemboli may have an important role in the implementation of neuroprotective strategies.     

Preoperative statin therapy does not reduce cognitive dysfunction after cardiopulmonary bypass

OBJECTIVE: The purpose of this study was to determine if patients receiving statin therapy before coronary artery bypass grafting surgery would have less cognitive dysfunction after cardiopulmonary bypass as a consequence of a diminished inflammatory response. DESIGN: Retrospective observational study of patients undergoing coronary artery bypass grafting surgery. SETTING: Referral center for cardiothoracic surgery at a university hospital. PARTICIPANTS: Four hundred forty patients undergoing coronary artery bypass grafting surgery with cardiopulmonary bypass. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Thirty-five percent of patients received statins in the preoperative period. Multivariable analysis revealed no effect of preoperative statin therapy on cognitive function (p = 0.67). Post hoc analysis revealed that statin therapy at hospital discharge was associated with less improvement in cognitive performance at 6 weeks after surgery (p = 0.011). No significant differences were found between statin therapy groups in either range or maximum value of any of the cytokines (p > 0.05). CONCLUSIONS: Preoperative statin therapy did not decrease the inflammatory response to cardiopulmonary bypass or the cognitive dysfunction commonly seen after cardiac surgery.     

Cerebral embolisation during modern cardiopulmonary bypass

Objectives: Cerebral microembolisation still occurs during cardiopulmonary bypass and may cause both stroke and postoperative cognitive impairment. We investigated the frequency of cerebral embolisation during coronary artery bypass surgery with modern cardiopulmonary bypass and related these to ascending aortic atherosclerosis. Methods: Transcranial Doppler monitoring for cerebral embolisation to both middle cerebral arteries was performed in 65 patients undergoing coronary artery surgery with non-pulsatile alpha-stat hypothermic bypass. Epicardial ultrasound imaging of ascending aortic atherosclerosis was performed in 14 patients. Results: Thirty patients (56.9%) had more than 200 emboli entering the middle cerebral artery territories during surgery; most at the start of bypass and during defibrillation. Readjustment of aortic clamps and aortic cannulation also caused a large number of emboli which were probably particulate. Aortic disease was mild (mean plaque thickness 1 mm, interquartile range 0.9–1.2 mm) and did not relate to the number of cerebral emboli produced by aortic manipulation. Conclusions: Cerebral embolisation remains common during coronary surgery despite advances in filter and bypass pump technology. Aortic manipulation and clamping was associated with emboli but epicardial ultrasound imaging was of little help in its prediction.     

Effects of extreme hemodilution during cardiac surgery on cognitive function in the elderly

BACKGROUND: Strategies for neuroprotection including hypothermia and hemodilution have been routinely practiced since the inception of cardiopulmonary bypass. Yet postoperative neurocognitive deficits that diminish the quality of life of cardiac surgery patients are frequent. Because there is uncertainty regarding the impact of hemodilution on perioperative organ function, the authors hypothesized that extreme hemodilution during cardiac surgery would increase the frequency and severity of postoperative neurocognitive deficits. METHODS: Patients undergoing coronary artery bypass grafting surgery were randomly assigned to either moderate hemodilution (hematocrit on cardiopulmonary bypass >or=27%) or profound hemodilution (hematocrit on cardiopulmonary bypass of 15-18%). Cognitive function was measured preoperatively and 6 weeks postoperatively. The effect of hemodilution on postoperative cognition was tested using multivariable modeling accounting for age, years of education, and baseline levels of cognition. RESULTS: After randomization of 108 patients, the trial was terminated by the Data Safety and Monitoring Board due to the significant occurrence of adverse events, which primarily involved pulmonary complications in the moderate hemodilution group. Multivariable analysis revealed an interaction between hemodilution and age wherein older patients in the profound hemodilution group experienced greater neurocognitive decline (P = 0.03). CONCLUSIONS: In this prospective, randomized study of hemodilution during cardiac surgery with cardiopulmonary bypass in adults, the authors report an early termination of the study because of an increase in adverse events. They also observed greater neurocognitive impairment among older patients receiving extreme hemodilution.     

Influence of diabetes on mortality and morbidity: off-pump coronary artery bypass grafting versus coronary artery bypass grafting with cardiopulmonary bypass

BACKGROUND: Myocardial revascularization in diabetic patients is challenging with no established optimum treatment strategy. We reviewed our coronary artery bypass grafting experience to determine the impact of eliminating cardiopulmonary bypass on outcomes in diabetic patients relative to nondiabetic patients. METHODS: From January 1995 through December 1999, 9,965 patients, of whom 2,891 (29%) had diabetes, underwent isolated coronary artery bypass grafting. Diabetic and nondiabetic patients were further divided into groups on the basis of cardiopulmonary bypass use. Twelve percent (346 of 2,891) of diabetic patients and 12% (829 of 7,074) of nondiabetic patients underwent coronary artery bypass grafting without cardiopulmonary bypass; the remainder had coronary artery bypass grafting with cardiopulmonary bypass. Nineteen preoperative variables were compared among treatment groups by univariate analysis. RESULTS: Patients undergoing coronary artery bypass grafting without cardiopulmonary bypass compared with those having coronary artery bypass grafting with cardiopulmonary bypass had higher mean predicted mortalities (diabetic, 3.96% versus 3.72%, p = 0.83; nondiabetic, 3.03% versus 2.86%, p = 0.79). In nondiabetic patients, coronary artery bypass grafting without cardiopulmonary bypass provides an actual and risk-adjusted survival advantage over coronary artery bypass grafting with cardiopulmonary bypass (1.81% versus 3.44%, p = 0.0127; risk-adjusted mortality, 1.79% versus 3.61%, p = 0.007). This survival benefit of coronary artery bypass grafting without cardiopulmonary bypass was not seen in diabetic patients (2.89% versus 3.69%, p = 0.452; risk-adjusted mortality, 2.19% versus 2.98%, p = 0.42). Diabetic patients undergoing coronary artery bypass grafting without cardiopulmonary bypass had fewer complications, including decreased blood product use (34.39% versus 58.4%, p = 0.001), and reduced incidence of prolonged ventilation (6.94% versus 12.10%, p = 0.005), atrial fibrillation (15.90% versus 23.26%, p = 0.002), and renal failure requiring dialysis (0.87% versus 2.75%, p = 0.036). CONCLUSIONS: The survival advantage in nondiabetic patients treated with coronary artery bypass grafting without cardiopulmonary bypass is not apparent in diabetic patients. Coronary artery bypass grafting without cardiopulmonary bypass in diabetic patients is nevertheless associated with a significant reduction in morbidity.     

Drew-Anderson technique attenuates systemic inflammatory response syndrome and improves respiratory function after coronary artery bypass grafting

BACKGROUND: Cardiopulmonary bypass causes inflammatory reactions leading to organ dysfunction postoperatively. This study was undertaken to determine whether using patients' own lungs as oxygenator in a bilateral circuit (Drew-Anderson Technique) could reduce systemic inflammatory response to cardiopulmonary bypass, improving patients clinical outcome following coronary artery bypass grafting. METHODS: A prospective randomized controlled trial involving 30 patients, divided in two groups of 15 patients each, undergoing elective coronary artery bypass grafting, was undertaken. In the Drew-group bilateral extracorporeal circulation using patient's lung as oxygenator was performed. The other patients served as control group, where standard cardiopulmonary bypass procedure was used. RESULTS: Pro-inflammatory and anti-inflammatory mediators were measured. Peak concentrations of proinflammatory interleukin-6, interleukin-8, were significantly lower in 15 patients undergoing Drew-Anderson Technique compared with the concentrations measured in 15 patients treated with standard cardiopulmonary bypass technique. Differences in patient recovery were analyzed with respect to time of intubation, blood loss, intrapulmonary shunting, oxygenation, and respiratory index. In patients undergoing uncomplicated coronary artery bypass grafting procedures bilateral extracorporeal circulation using the patients' own lung as oxygenator provided significant biochemical and clinical benefit in comparison to the standard cardiopulmonary bypass procedure. CONCLUSIONS: This prospective randomized clinical study has demonstrated that exclusion of an artificial oxygenator from cardiopulmonary bypass circuit significantly decreases the activation of inflammatory reaction, and that interventions that attenuate this response may result in more favorable clinical outcome.     

Xenon and the inflammatory response to cardiopulmonary bypass in the rat

OBJECTIVE: The purpose of this study was to investigate the effect of xenon on the inflammatory response to cardiopulmonary bypass. DESIGN: Prospective, randomized experimental study. SETTING: University research laboratory. PARTICIPANTS: Sprague-Dawley rats. INTERVENTIONS: After surgical preparation, rats were randomly divided into 4 groups: (1) SHAM rats were cannulated but did not undergo cardiopulmonary bypass; (2) cardiopulmonary bypass rats were subjected to 60 minutes of cardiopulmonary bypass using an oxygenator receiving a 30% O(2), 65% N(2), and 5% CO(2) gas mixture; (3) MK801 rats received MK801 (0.15 mg/kg intravenous) 15 minutes before 60 minutes of cardiopulmonary bypass with the same gas mixture; and (4) xenon rats underwent 60 minutes of cardiopulmonary bypass receiving a 30% O(2), 60% xenon, 5% N(2), and 5% CO(2) gas mixture. MEASUREMENTS AND MAIN RESULTS: All bypass groups showed elevations in both cytokines compared with the SHAM-operated group. However, the inflammatory response to cardiopulmonary bypass in the group receiving xenon was no different from the other bypass groups. CONCLUSIONS: Xenon appears to have no effect on the inflammatory response to cardiopulmonary bypass, making its previously described neuroprotective effect during cardiopulmonary bypass likely independent of any inflammation modulation.     

Intraoperative echocardiographic imaging of coronary arteries and graft anastomoses during coronary artery bypass grafting without cardiopulmonary bypass.

BACKGROUND: No accepted approach exists for the intraoperative evaluation of the quality of coronary arteries and the technical adequacy of graft anastomoses during coronary artery bypass grafting without cardiopulmonary bypass. METHODS AND RESULTS: We assessed the accuracy of high-frequency epicardial echocardiography and power Doppler imaging in evaluating coronary arteries during coronary artery bypass grafting without cardiopulmonary bypass. To validate measurements of coronary arteries and graft anastomoses by high-frequency epicardial echocardiography and power Doppler imaging, we compared luminal diameters determined by these methods with diameters determined histologically in a study of off-pump coronary artery bypass grafting in 20 dogs. Technical errors were deliberately created in 10 grafts (stenosis group). The results of these animal validation studies showed that the maximum luminal diameters of coronary arteries and graft anastomoses measured by high-frequency epicardial echocardiography (HEE) and power Doppler imaging (PDI) correlated well with the histologic measurements: HEE = 1.027 x Histologic measurements + 0.005 (P <.0001); PDI = 0.886 x Histologic measurements + 0.0453 (P =.0001). Similar results were found in the evaluation of the stenosis group: PDI = 0.991 x Histologic measurements + 0.074 (P <.0001). Subsequently, we demonstrated the clinical applicability of this approach in 12 patients who underwent minimally invasive or off-pump coronary artery bypass grafting. Twenty graft anastomoses were examined intraoperatively by high-frequency epicardial echocardiography and power Doppler imaging, and luminal diameters determined by power Doppler imaging were compared with those determined by postoperative coronary angiography. The results demonstrated that graft anastomosis by power Doppler imaging correlated well with the angiographic measurements: PDI = 1.018 x Angiographic measurements - 0.106 (P <.0001). CONCLUSION: High-frequency epicardial echocardiography can provide meaningful information on the target coronary artery, and power Doppler imaging can accurately measure graft anastomoses and can detect technical errors and inadequacies during coronary artery bypass grafting without cardiopulmonary bypass.     

Staged coronary artery bypass grafting after percutaneous angioplasty for intracranial vascular stenosis

OBJECTIVE: Cerebrovascular disease is commonly associated with coronary artery disease and is a major risk factor for cardiac surgery. Concomitant coronary artery bypass grafting and carotid endarterectomy may reduce the risk of stroke; however, this staged operation is effective only for extracranial lesions. The strategy for on-pump coronary artery bypass grafting for patients with intracranial vascular stenosis is still controversial. METHODS: The subjects were 157 consecutive candidates for coronary artery bypass grafting who underwent computed tomography and digital subtraction cerebral angiography preoperatively to check for cerebrovascular disease. Additional single-photon emission computed tomography was performed to evaluate cerebral ischemia, according to the neurologist's request. Patients with diffuse intracranial vascular stenosis impossible to treat with percutaneous transluminal angioplasty underwent off-pump coronary artery bypass grafting. Patients with a circumflex coronary artery lesion first underwent percutaneous transluminal angioplasty for cerebral vascular stenosis followed by secondary on-pump coronary artery bypass grafting. RESULTS: Three patients were selected for staged operations. Percutaneous transluminal angioplasty was performed for 4 intracranial stenotic lesions. All lesions were dilated successfully, and no complications developed during or after the procedure. All patients tolerated staged coronary artery bypass grafting and were extubated within 1 day without any mental disturbance. No further neurologic complication occurred, and computed tomography performed postoperatively revealed no significant changes. CONCLUSION: Staged on-pump coronary bypass after percutaneous transluminal angioplasty for cerebrovascular disease may reduce the risk of stroke during cardiopulmonary bypass, and it is useful especially in patients with intracranial cerebrovascular disease.     

Pulmonary abnormalities after coronary arterial bypass grafting operation: cardiopulmonary bypass versus mechanical stabilization

BACKGROUND: Cardiopulmonary bypass has been implicated in causing poor pulmonary gas exchange postoperatively in patients undergoing coronary artery bypass grafting procedures. This randomized prospective study was conducted to determine whether patients undergoing coronary artery bypass grafting operations using cardiac stabilization and thereby avoiding cardiopulmonary bypass will have improved pulmonary function postoperatively. METHODS: Fifty-eight patients were randomized to one of two groups: coronary artery bypass grafting operation with stabilization or coronary artery bypass grafting operation with cardiopulmonary bypass. Preoperative and postoperative pulmonary gas exchange measurements were performed on intubated patients, including the arterial partial pressure of oxygen on 100% inspired oxygen, the alveolar-arterial oxygen gradient, and pulmonary shunt. Static and dynamic lung compliance measurements were performed postoperatively. Hemodynamic variables (including creatine kinase-MB and troponin levels), intubation time, postoperative bleeding, and blood transfusions were compared. RESULTS: Both study groups had a large decrease in arterial partial pressure of oxygen on 100% inspired oxygen (p < 0.0001) and a significant postoperative increase in the alveolar-arterial oxygen gradient (p < 0.0001). There was no statistical difference in the postoperative gas exchange between the two groups; however, the postoperative pulmonary shunt was significantly better in the stabilization group (24% versus 31%, p = 0.03). The patients were extubated in the intensive care unit earlier in the stabilization group (8.2 hours versus 9.2 hours, not significant). The mean static and dynamic lung compliance postoperatively was lower in the stabilization group, although not statistically significant (p = 0.06). CONCLUSIONS: Coronary artery bypass grafting operation using cardiac stabilization technique is safe and avoids the risk of cardiopulmonary bypass. The pulmonary gas exchange postoperatively is comparable to standard cardiopulmonary bypass procedures, but a reduced postoperative pulmonary shunt was seen in the stabilization group.     

Propensity case-matched analysis of off-pump coronary artery bypass grafting in patients with atheromatous aortic disease

OBJECTIVE: Atheromatous aortic disease is a risk factor for excessive mortality and stroke in patients undergoing coronary artery bypass grafting. Outcomes of off-pump coronary artery bypass grafting and coronary artery bypass grafting with cardiopulmonary bypass in patients with severe atheromatous aortic disease were compared by propensity case-match methods. METHODS: Routine intraoperative transesophageal echocardiography identified 985 patients undergoing isolated coronary artery bypass grafting with severe atheromatous disease in the aortic arch or ascending aorta. Off-pump coronary artery bypass grafting was performed in 281 patients (28.5%). Propensity matched-pairs analysis was used to match patients undergoing off-pump coronary artery bypass grafting (n = 245) with patients undergoing coronary artery bypass grafting with cardiopulmonary bypass. RESULTS: Univariate analysis revealed decreased hospital mortality (16/245, 6.5% vs 28/245, 11.4%; P =.058) and stroke prevalence (4/245, 1.6% vs 14/245, 5.7%; P =.03) in off-pump coronary artery bypass grafting compared with coronary artery bypass grafting with cardiopulmonary bypass. Freedom from any postoperative complication was higher in off-pump coronary artery bypass grafting compared with coronary artery bypass grafting with cardiopulmonary bypass (226/245, 92.2% vs 196/245, 80.0%; P <.001). Multivariable analysis of preoperative risk factors showed that increased hospital mortality was associated with coronary artery bypass grafting with cardiopulmonary bypass (odds ratio = 2.7; P =.01), fewer grafts (P =.05), acute myocardial infarction (odds ratio = 11.5; P <.001), chronic obstructive pulmonary disease (odds ratio = 2.4; P =.03), previous cardiac surgery (odds ratio = 10.2, P =.05), and peripheral vascular disease (odds ratio = 2.1; P =.05). Cardiopulmonary bypass was the only independent risk factor for stroke (odds ratio = 3.6, P =.03). At 36 months' follow-up, comparable survival was observed in the off-pump coronary artery bypass grafting and coronary artery bypass grafting with cardiopulmonary bypass groups (74% vs 72%). Multivariable analysis revealed that renal disease (P <.001), advanced age (P <.001), previous myocardial infarction (P =.03), and lower number of grafts (P =.02) were independent risks for late mortality. CONCLUSIONS: Patients with severe atherosclerotic aortic disease who undergo off-pump coronary artery bypass grafting have a significantly lower prevalence of hospital mortality, perioperative stroke, and overall complications than matched patients who underwent coronary artery bypass grafting with cardiopulmonary bypass. Routine intraoperative transesophageal echocardiography identifies severe atheromatous aortic disease and directs the choice of surgical technique.     

On-pump versus off-pump coronary artery bypass grafting: impact on postoperative renal failure requiring renal replacement therapy

BACKGROUND: Despite refinements in perioperative patient management postoperative renal failure requiring hemofiltration or dialysis is still a common complication after coronary artery bypass grafting associated with impaired patient outcome. METHODS: Prospective data on 9,631 patients receiving myocardial revascularization with (coronary artery bypass grafting [n = 8,870]) or without cardiopulmonary bypass (off-pump coronary artery bypass grafting [n = 761]) between April 1996 and August 2001 were evaluated by univariate and multivariate logistic regression analysis. RESULTS: Overall prevalence of postoperative continuous renal replacement therapy was 4.1% (coronary artery bypass grafting, 4.3%; off-pump coronary artery bypass grafting, 1.8%; p = 0.001). Thirty of 40 selected preoperative and intraoperative patient and treatment related variables had a high association with the requirement for postoperative renal replacement therapy; fifteen of these variables were independent predictors in the whole study population. Off-pump coronary artery bypass surgery was identified as having a significantly lower predictive value for postoperative continuous renal placement therapy. In the subgroup of patients undergoing off-pump coronary artery bypass grafting surgery, a second multivariate logistic regression model revealed preoperative cardiogenic shock, urgent operation, intraoperative low cardiac output, and high transfusion requirement as independent predictors for postoperative renal replacement therapy. CONCLUSIONS: Patients with preoperative nondialysis dependent renal insufficiency are at a high risk for further decline in renal function requiring postoperative continuous renal replacement therapy. Off-pump coronary artery bypass surgery is associated with a lower prevalence of postoperative renal replacement therapy after coronary artery bypass grafting.     

Clinical trial of the neuroprotectant clomethiazole in coronary artery bypass graft surgery: a randomized controlled trial

BACKGROUND: The neuroprotective property of clomethiazole has been demonstrated in several animal models of global and focal brain ischemia. In this study the authors investigated the effect of clomethiazole on cerebral outcome in patients undergoing coronary artery bypass surgery. METHODS: Two hundred forty-five patients scheduled for coronary artery bypass surgery were recruited at two centers and prospectively randomized to clomethiazole edisilate (0.8%), 225 ml (1.8 mg) loading dose followed by a maintenance dose of 100 ml/h (0.8 mg/h) during surgery, or 0.9% NaCl (placebo) in a double-blind trial. Coronary artery grafting was completed during moderate hypothermic (28-32 degrees C) cardiopulmonary bypass. Plasma clomethiazole was measured at several intervals during and up to 24 h after the end of infusion. A battery of eight neuropsychological tests was administered preoperatively and repeated 4-7 weeks after surgery. Analysis of the change in neuropsychological test scores from baseline was used to determine the effect of treatment. RESULTS: Neuropsychological assessments were completed in 219 patients (110 clomethiazole; 109 placebo). The mean plasma concentration of clomethiazole during surgery was 66.2 microm. There was no difference between the clomethiazole and placebo group in the postoperative change in neuropsychological test scores. CONCLUSION: Clomethiazole did not improve cerebral outcome following coronary artery bypass surgery.     

Comparison of coronary bypass surgery with and without cardiopulmonary bypass in patients with multivessel disease

BACKGROUND: Coronary artery bypass grafting can now be performed with or without cardiopulmonary bypass. Our objective was to determine whether off-pump coronary artery bypass grafting is associated with better early outcomes compared with conventional coronary artery bypass grafting. METHODS: In 4 centers with off-pump coronary surgery experience, a retrospective analysis of all coronary artery bypass grafting in a 3-year period was performed. Groups were compared to determine selection criteria, mortality, and morbidity, then computer-matched by propensity score to control for selection bias. Multivariate logistic regression identified risk factors predictive of mortality. Specific subgroups most likely to benefit were identified. RESULTS: In all, 17,401 isolated coronary artery bypass grafts were performed, 7283 (41.9%) off-pump coronary artery bypass grafts and 10,118 (58.1%) conventional coronary artery bypass with cardiopulmonary bypass. Factors determining selection of patients for off-pump coronary artery bypass grafting included female gender (55.5% vs 44.5%), preexisting renal failure (57.0% vs 43.0%), and reoperations (52.6% vs 47.4%). Operative mortality was 2.8%; off-pump coronary artery bypass grafting versus conventional coronary artery bypass with cardiopulmonary bypass (1.9% vs 3.5%, P <.001) had the same predicted risk. Of the patients with multivessel disease, 11,548 were matched by propensity scoring. Mortality was significantly less in the off-pump coronary artery bypass grafting group (2.8% vs 3.7%, P <.001). By multivariate logistic regression analysis of the matched sample, predictors for mortality were female gender (odds ratio 1.83, confidence interval 1.37-2.44), preexisting renal failure (odds ratio 2.85, confidence interval 2.64-4.95), history of stroke (odds ratio 1.74, confidence interval 1.08-2.80), previous coronary artery bypass grafting surgery (odds ratio 4.22, confidence interval 2.92-6.09), use of cardiopulmonary bypass (odds ratio 2.08, confidence interval 1.52-2.83), and recent myocardial infarction (odds ratio 2.31, confidence interval 1.68-3.22). Cardiopulmonary bypass was predictive of mortality in reoperations, female patients, and patients aged >or= 75 years. Off-pump coronary artery bypass grafting was associated with less morbidity, including reductions in blood transfusion (32.6% vs 40.6%, P <.001), stroke (1.4% vs 2.1%, P =.002), renal failure (2.6% vs 5.2%, P <.001), pulmonary complications (4.1% vs 9.5%, P <.001), reoperation (1.7% vs 3.2%, P <.001), atrial fibrillation (21.1% vs 24.99%, P <.001), and gastrointestinal complications (3.6% vs 4.8%, P =.02). CONCLUSION: In 4 centers with beating-heart operation experience, there is an overall early benefit in off-pump surgery, especially in patients traditionally considered at high risk for coronary artery bypass grafting.     

Minimal invasive direct coronary artery bypass in moyamoya disease

A 56-year-old woman with moyamoya disease presented with angina pectoris. Coronary artery stenosis of atherosclerosis origin was resistant to repeated transluminal angioplasty. Coronary artery bypass grafting was performed by minimal invasive direct coronary artery bypass (MIDCAB), avoiding cardiopulmonary bypass and intraoperative hypotension. Since coronary artery bypass grafting on cardiopulmonary bypass for patients with moyamoya disease has a potential risk of brain ischemia, MIDCAB may avoid perioperative cerebral ischemic complication.     

Short-term and long-term cognitive function and cerebral perfusion in off-pump and on-pump coronary artery bypass patients.

OBJECTIVE: The aim of this study was to evaluate cognitive function, as measured by serial neuropsychological testing, and cerebral perfusion, as measured by brain SPECT scanning in patients with coronary artery diseases (CAD) following off-pump and on-pump coronary artery bypass graft surgery. Besides, the relationship between cerebral blood flow, cognitive functions, surgery parameters, and cardiac function in these patients were estimated. Also, brain-protective effects of instenon were studied. METHODS: Brain SPECT and comprehensive neuropsychological testing were performed 1 day before, 10-14 days and 6 months after coronary artery bypass graft surgery (CABG). The study involved 65 patients (62 males and 3 females, mean age 55+/-2) who underwent CABG with cardiopulmonary bypass (CPB) (43 pts) and off-pump coronary revascularization (OPCAB) using the Octopus stabilization system (22 pts). In 21 cases employing CPB, for prevention of the impairments of cerebral perfusion and cognitive deficit instenon was administered. RESULTS: CABG with the use of extracorporeal circulation is complicated by short-term and long-term neurocognitive dysfunction (in 96 and 55% cases, correspondingly). Also, in the early period after CABG, in 68% patients, decrease in regional cerebral blood flow (rCBF) was found, and after 6 months brain perfusion was lower than the baseline in 55% cases. Relationship between postoperative rCBF changes and the dynamics of cognitive function was found in early period and after 6 months following CABG. CONCLUSION: The coronary revascularization on beating heart or preventive administration of instenon in CPB patients helps significantly to diminish the risk of cerebrovascular complication.