Prospective evaluation of the left main coronary artery using digital two-dimensional echocardiography.

Recent clinical studies emphasize the importance of identification of patients with left main coronary artery obstruction. Although two-dimensional echocardiography can detect left main coronary artery disease, the technique requires frame by frame analysis, as no single frame provides all the necessary information. To determine if newly available computer-based digital processing techniques could overcome some of these technical difficulties, 119 consecutive patients were prospectively evaluated with two-dimensional echocardiography before coronary angiography. A continuous loop recording of the left main coronary artery was recorded as it passed through the ultrasonic beam in the short-axis view. Starting at a point when the vessel was first visualized, the ensuing eight consecutive fields, each 17 ms apart, were captured in digital format, thus providing a series of parallel, sequential, longitudinal slices of the left main coronary artery as it traversed the imaging plane. This was successfully accomplished in 100 (84%) of the 119 consecutive patients. By angiography, 16 patients (16%) had greater than 50% narrowing of the left main coronary artery. Digital echocardiography correctly identified 15 of these 16 patients (94% sensitivity) and accurately localized the lesion in 12 (80%) of 15. Of 84 patients without significant left main coronary artery obstruction, digital echocardiography correctly identified 78 (93% specificity). It was concluded that computer-based digital processing techniques can be applied to two-dimensional echocardiography to allow reliable visualization of the left main coronary artery. The technique provides more information than a single still frame and allows accurate noninvasive detection and possible localization of left main coronary artery lesions.