INTRAOPERATIVE TRANSESOPHAGEAL ECHOCARDIOGRAPHY FOR DETECTION OF MYOCARDIAL-ISCHEMIA

Properative myocardial ischemia seems to be a predictor of poor outcom e when detected by electrocardiography, pulmonary capillary wedge/pres sure measurement and echocardiography. It could be demonstrated, that regional wall motion abnormalities appear earlier and are more sensiti ve signs of myocardial ischemia than the ECG. Using intraoperative epi cardial and transesophageal echocardiography, high quality 2-d echocar diographic images of the heart can be recorded. For monitoring of left ventricular function and wall motion the transesophageal approach is most often used. By the transesophageal approach the left ventricle ca n be scanned in the long axis and by the transgastric approach in cros s sections. They correspond to the apical four-chamber and left parast ernal cross sectional imaging of the heart. Using the transgastric app roach in the papillary short axis view all segments representing the t hree coronary arteries can be imaged. Recording in this position have been found to be highly reproducible. Only localized ischemia of the a pex of the ventricle may be missed. Methologically the rotation and tr anslocation of the heart remain a problem using the cross section imag es of the heart. But the left ventricular papillary muscles and the se ptal-right ventricular boarders can be used as land marks. Wall motion is scored in five grades. In addition to the semiquantitative analysi s also a quantitative calculation using computers is possible. Using t he midd papillary short axis view in nearly 120 intraoperative transes ophageal echocardiograms since 1989 analysis of the systolic wall thic kening was possible in 73% of the patients. According to the literatur e review 87% of the patients undergoing coronary bypass surgery or non -cardiac surgery have signs of preoperative ischemia. In 33% of the pa tients wall motion abnormalities were detected but only 21% of them sh owed ECG changes. In 6 patients with ECG changes 50% had wall motion a bnormalities. In 14% of the patients the ischemia was detected in the pre-bypass period, in the post-bypass period in 60%. The sensitivity o f pre-bypass wall motion abnormalities was 47% and the specificity 63% for predicting cardiac complications. The post-bypass analysis was se nsitivity was 95% the specificity in 64%. Only in 56% of the patients wall motion abnormalities were accompanied by hemodynamic changes. Acu te increased in heart rate was found in only 35% of the patients with regional wall motion abnormalities and blood pressure drop in 25%. Als o in relation to the literature review, the authors concluded, that th e transesophageal echocardiographic wall motion analysis remains the m ost sensitive method for intraoperative detection of myocardial ischem ia. Intraoperative transesophageal echocardiography seems to be a pred ictor of poor outcome in patients with coronary bypass surgery.