DK2985_C000 1..28 - AlSharqia Echo Club

270 Transesophageal Echocardiography(A)(B)AoFigure 12.14Short-axis view of a 4.1 mm thick plaque (grade 3) in the aorta (Ao) before cardiopulmonary bypass.administration of postoperative antithrombotic therapy todecrease the risk of stroke is unclear.B. Sensitivity and Specificity ofIntraoperative Techniques forAssessment of Aortic Atheromatosis:TEE, Epiaortic Scan, Clinical PalpationSeveral authors (12,13) have demonstrated the lowerreliability of both palpation and TEE examination for assessingatheromatosis in the mid- and distal ascending Ao.Transesophageal echocardiography detection of significantatheromatosis in the descending Ao has been felt toindicate a high likelihood of coexisting involvement ofthe ascending Ao. However, in one study (14), the positivepredictive value for ascending aortic atheroma or the presenceof atheroma in the descending Ao was only 39%.However, of the 32 patients with only mild or no atheromain the descending Ao, only one had moderate to severeatheromatous disease in the ascending Ao (negative predictivevalue 94%).The presence of atherosclerosis in the aortic arch can bepredicted in ,50% of patients preoperatively by age, chestX-ray (CXR), and aortogram. Transesophageal echocardiographydetects atheromatous disease in 55% of patientswith a normal CXR (8). Furthermore, 50–80% of significantatherosclerotic lesions present in the ascending Ao aremissed by intraoperative palpation when compared withTEE (8,9,15–17). Katz et al. (5), in a prospective studyinvolving 130 patients, found on TEE that 19 of 23patients (83%) initially considered to have no or mildatheroma by manual palpation had in fact severe disease.While calcific plaque can be reasonably well detected,atheroma it is more difficult to detect by palpation (18).Direct manual palpation of the Ao was shown to have asensitivity of only 46% for detecting aortic atherosclerosiswhen compared with intraoperative EAS in 89 cardiacsurgical patients (19). In 11.2% of patients, the operativeapproach was modified to avoid the plaques detected byEAS. This diagnostic tool appears to be the most sensitivemethod to assess the ascending Ao intraoperatively. As thepresence of significant atherosclerosis in the descendingAo on TEE would predict a 40% probability of concomitantinvolvement of the ascending Ao, the authorssuggested the use of more sensitive EAS in such patients.C. Related Echocardiographic Findings withAortic AtherosclerosisFurther indication of the presence of atherosclerosis in theAo may be inferred from the presence of cardiac valvularcalcification. A significant association between the presenceof aortic valvular and mitral annular calcificationand the presence and severity of ascending aortic atheromahas been demonstrated (20). Thus, aortic valve calcificationmay serve as a marker for atherosclerosis of the Ao(20). When preoperative TEE discloses AoV or mitralannulus calcification, plaque in the ascending or descendingAo, some authors have recommended proceedingdirectly to EAS of the ascending Ao prior to cannulationand instrumentation (20,21).Other indications for EAS include age (.60 years old),calcified aortic knob on CXR or palpable calcifications inthe ascending Ao, severe peripheral vascular disease(PVD) and previous history of transient ischemic attack(TIA) or cerebrovascular accident (CVA).VI.AORTIC DILATATION AND ANEURYSMSAn aortic aneurysm is defined as a localized dilatation orenlargement of the Ao. As the Ao dilates, its wall tensilestrength becomes progressively weakened and may leadto dissection and/or rupture (2,22). Aneurysms canresult from a variety of congenital and acquired pathologiesand involve any segment of the Ao. Aortic aneurysmsare considered significant when their diameterexceeds two standard deviations above the normal