Intra-operative contrast echocardiography in coronary artery disease.

Abstract

Intra-operative echocardiography is becoming a reference standard for the evaluation of the results of cardiac surgery. Myocardial contrast echocardiography has been recently introduced to study regional myocardial blood flow and cardioplegia distribution in patients undergoing coronary artery surgery. It can be used in three different stages: before cardiopulmonary bypass, to identify the most hypoperfused myocardial segments; during cardioplegic arrest, to check the adequacy of myocardial protection; postoperatively, to assess graft patency. The priority in revascularization can be assigned according to the regional perfusion pattern, which depends not only on coronary artery narrowing, but also on the extent of collateral circulation. The distribution of cardioplegia to the myocardium can be monitored in real time with clear identification of poorly protected myocardial segments. The injection in the graft after weaning from cardiopulmonary bypass allows assessment of graft patency and measurement of the 'area at risk' for graft occlusion. In conclusion, the information obtained in the operating theatre by myocardial contrast echocardiography is original and promises to have a significant impact on surgical strategy. Implementation of the ultrasonic equipment to obtain quantitative on-line data on myocardial blood flow is desirable.