The use of isoflurane in patients with coronary artery disease remains controversial because of the possibility of "coronary steal". In this study, the effects of isoflurane and halothane on global and regional myocardial blood flow and metabolism were compared, and the relationship between steal-induced myocardial ischemia and the administered volatile anesthetic was investigated in 40 patients with steal-prone coronary anatomy undergoing elective coronary artery bypass operations. The patients were randomly assigned to receive either isoflurane or halothane (0.5 MAC inspired concentration) immediately after induction with fentanyl (50 micrograms/kg). Hemodynamic measurements and blood samples were obtained at preinduction, postintubation, preincision, poststernotomy, at 60 min after beginning isoflurane or halothane, and precannulation (a total of 238 study events). Throughout the study, heart rate was kept constant by atrial pacing at approximately postintubation values while arterial pressure was maintained within 10% of postintubation values with fluid administration or phenylephrine infusion. Overall, systemic hemodynamic changes observed during the study were similar in the two groups. Myocardial ischemic episodes were defined as a new electrocardiographic ST-segment shift of greater than or equal to 0.1 mV, new echocardiographic regional wall motion abnormalities (RWMA) and/or myocardial lactate production (MLP). A total of 18 new ischemic episodes were detected in 15 patients (7 episodes during isoflurane in 7 patients and 11 during halothane in 8 patients). Ten (56%) episodes were related to acute hemodynamic abnormalities, whereas 8 (44%) were random and unrelated to changes. Seven episodes were detected by echocardiography (38%), 6 by MLP (33%) and 1 by ECG (6%) only, whereas concomitant echocardiographic abnormalities and MLP were observed during 2 episodes (11%), echocardiographic and ECG during 1 (6%), and ECG and MLP during 1 other (6%). Ratios of regional to global coronary venous flow, coronary vascular resistance, myocardial oxygen content, and lactate extraction, along with hemodynamic data obtained during these episodes, do not support coronary steal for the development of myocardial ischemia. We conclude that in patients with steal-prone coronary anatomy anesthetized with fentanyl, neither isoflurane nor halothane administered at concentrations used in the current study is likely to cause myocardial ischemia by the coronary steal mechanism.
As the mainstay of therapy for end-stage liver disease (ESLD), orthotopic liver transplantation (OLT) has complex effects on multiple organ systems. We present a representative case of acute heart failure with apical ballooning syndrome following OLT and review its mechanisms. Recognition of this and other potential cardiovascular and hemodynamic complications of OLT are essential to periprocedural anesthesia management. Once an acute phase of the condition is stabilized, conservative treatment and resolution of physical or emotional stressors usually allow for rapid resolution of symptoms, typically recovering systolic ventricular function within one to three weeks.
The cause of cerebral and peripheral embolism remains undetermined in a significant number of patients. An atherosclerotic thoracic aorta has thus far been considered to be an uncommon one.To define the potential role of the ascending thoracic aorta as an embolic source, intraoperative ultrasonic aortic imaging was performed in 1200 of 1334 consecutive patients aged 50 years and older who were undergoing cardiac surgery. Patients were divided into two groups according to the results of the ultrasound study in terms of presence or absence of atherosclerotic disease. The prevalence of previous neurological events in the two groups was characterized and compared.Ascending aortic atherosclerosis was present in 231 (19.3%) of the patients studied. Patients in this category were older (P < .0001). A higher percentage of them were smokers (P < .0001) compared with patients with less severe disease. Coronary artery disease was more extensive (P = .012), and a higher percentage of these patients had a history of peripheral vascular disease (P < .0001). Univariate analysis of the subjects with (n = 158) and without (n = 1042) previous neurological events indicated that age, body mass index, atrial fibrillation, hypertension, and atherosclerosis of the ascending aorta were associated significantly with previous occurrence of a cerebrovascular accident. For the group as a whole, multiple logistic regression analysis demonstrated that hypertension (odds ratio, 1.81; P = .002), atherosclerosis of the ascending aorta (odds ratio, 1.65; P = .013), and atrial fibrillation (odds ratio, 1.54; P = .060) were significantly and independently associated with the occurrence of previous neurological events.Atherosclerosis of the ascending aorta is an independent risk factor for cerebrovascular events. An atherosclerotic ascending aorta may represent a potential source of emboli or may be a marker of generalized atherosclerosis.
Neurologic injury is the most devastating complication of cardiac surgery, and leads to excessive morbidity, mortality, and increased health care costs. Ascending aorta atherosclerosis is one of the most important risk factors for perioperative stroke, particularly in the el derly. As the number of elderly patients undergoing cardiac surgical procedures continues to increase, it is likely that the frequency of postoperative neurologic complications will increase as well. Strategies aimed toward the identification of high-risk patients include screening for carotid artery disease and ascending aorta atherosclerosis. Epiaortic ultrasound provides high- resolution images of the ascending aorta that allow for evaluation for the presence of atherosclerosis. Minor modifications in the operative technique based on the epiaortic ultrasound findings are easy to perform and require minimal training and relatively inexpensive equipment. Nonrandomized studies that use epiaortic ultrasound have reported perioperative stroke rates that are lower than those in which this approach is not used, suggesting that identification of high-risk patients and minor modifications in the operative technique may lower perioperative stroke rates without increasing operative risk. Prospective, randomized trials are needed to evaluate whether more aggressive changes in surgi cal techniques and/or the use of neuroprotective agents in high-risk patients may prevent neurologic complica tions associated with cardiac surgery.
EditorialHow transoesophageal echocardiography can assist cardiac surgery in adults After its development and clinical application in the early 1 980s transoesophageal echocardiography was rapidly recognised as providing a unique perspective from which
