Contrast echocardiography: from left ventricular opacification to myocardial perfusion. Are the promises to be realised?

Virtually every cardiac imaging technique utilises contrast agents into the routine practice of echocardiography has been slow. The commercial and clinical promise of contrast echo has not yet been fulfilled and we are truly standing at the crossroad between success and failure of the technique. In this introductory article to the mini-symposium on contrast echocardiography, I attempt to give a general overview of the current clinical role of echo contrast agents. Three further articles examine in more critical detail where we currently stand with respect to the role of contrast for left ventricular opacification, for perfusion imaging during stress and in patients with acute myocardial infarction. Patent issues, cost, reimbursement, difficult regulatory issues in the USA, and a smaller market than originally envisaged has led a number of contrast agent manufacturers to review their position. Some agents have been withdrawn from development and some put on hold. Instrument manufacturers have been reflecting upon their substantial investment in contrast imaging technology. Fortunately, a number of key issues have occurred which indicates a far more optimistic future for contrast echo. These issues include agreement on reimbursement for the use of contrast in the USA, resolution of some patent disputes, new technology which makes myocardial perfusion imaging realistic, and more of a consensus on what is needed to make contrast echo successful. In many countries there are currently three licensed contrast agents. Although all three have a licence for left ventricular opacification and Doppler enhancement, improvements in imaging technology, particularly second harmonics, have paradoxically reduced the need for contrast in routine studies. Stress echocardiography remains an area when contrast can and should make a significant contribution. Stress echo is an operator dependent …