INVITED COMMENTARY

Abstract

Despite recommendations [1Eagle KA, Guyton RA, Davidoff R, et al. ACC/AHA guidelines for coronary artery bypass graft surgery. J Am Coll Cardiol 1999;34:1262–347.Google Scholar], routine epiaortic ultrasound examination of the ascending and transverse aorta has not been widely accepted. Many still rely on palpation to evaluate the aorta at surgery, although this is less sensitive than transesophageal or epiaortic ultrasonic evaluation, particularly for soft atheromas or mobile debris. Similarly, transesophageal echocardiogram is not as sensitive for examination of the proximal aorta and misses the cross-clamp area because of the tracheal shadow. The study from Dr Schachner and colleagues from Innsbruck is particularly relevant to the surgeon who does not use epiaortic ultrasound routinely, because it demonstrates an association between the degree of descending aorta involvement and the proximal aorta. Because most surgical groups use transesophageal echocardiogram more often than epiaortic ultrasound, absence of descending aortic involvement may be a good indicator for performing epiaortic cannulation. In the absence of other risks factors, such as age and cerebral and peripheral vascular disease, the study by Schachner and colleagues looked only at the ascending aorta and not the arch. Our group has been using epiaortic ultrasonic evaluation for 10 years in more than 8,000 patients, and we found the strongest association to a diseased aorta to be the presence of a brachial pressure gradient (arch vessel disease) or carotid occlusion. Epiaortic ultrasound is a simple, quick technique easily instituted in the cardiac operating room and should be a main part of a global stroke prevention strategy. Our current practice includes preoperative brachial pressures before catheterization, and carotid duplex and ankle-brachial index measurements on all patients. At surgery, transesophageal and epiaortic ultrasound are performed in most cases as well. Routine ligation of the left atrial appendage is performed at surgery in the hope of reducing the risk of embolization from possible postoperative atrial fibrillation. One obstacle to a wider adoption of the technique is the lack of an established strategy to manage the so-called bad aorta. Our strategy is fairly straightforward, according to the location (arch or ascending aorta) of disease and includes cannula change to axillary cannulation with or without circulatory arrest, beating heart surgery (cold or warm), or off-bypass operation. For the most part, the beating heart procedure involves a side-biting clamp and epiaortic ultrasound that should assure the surgeon that the targeted area is free of significant atherosclerotic disease. Although proximal anastomotic devices are clampless, they involve manipulation of the anterior aortic wall. Therefore they should be preceded by ultrasonic evaluation. In a young patient, resection of the atherosclerotic area may be an option in view of the significant risk of stroke during follow-up. Our specialty will survive only if we continue to strive to eliminate complications of cardiac surgery, particularly neurologic events. In all fairness to perfusionists, some of the bad publicity regarding extracorporeal circulation may come from our denial of the mechanical risks of blind cannulation, embolization, or jet or blast effects. We have the technology, and we should all use it for the benefit of our patients and our profession.