Value of transthoracic echocardiography for the detection of left main coronary artery obstruction in patients undergoing coronary angiography

ABSTRACT

To determine the clinical feasibility and reliability of transthoracic echocardiography for the detection of significant Left Main Coronary Artery [LMCA] obstructions in patients undergoing coronary angiography. Sixty patients [thirty with normal LMCA; group A and thirty with angiographically proven LMCA disease; group B] were studied to evaluate the feasibility of use 2-D echocardiography to detect the LMCA disease. Visualization of the LMCA was attempted in all patients using a parasternal short-axis view at the level of the aortic root with the transducer in the third or fourth left intercostal space, with 30°Clockwise rotation, or apically from a five-chamber view with cranial angulation of the transducer. Evidence of LMCA stenosis was defined qualitatively as an area of apparent luminal narrowing, usually as a result of high-intensity echoes, with visualization of a larger lumen beyond that area. The LMCA was successfully imaged by 2-D echo in 51 [85%] of the sixty patients studied; 26[86.66%] patients in group A and 25 [83.33%] patients in group B. Echocardiographic criteria of LMCA stenosis were noted in 24 patients 22 from group B [true positive] and two from group A [false positive]. The LMCA appeared normal on echocardiographic examination in 27 patients; 24 from group A [true negative] and 3 from group B [false negative]. The sensitivity of echocardiography for detection of significant lesion of the LMCA was 88%, specificity was 92.31% and accuracy was 90.2%. These findings are encouraging and indicate that echocardiography can be a practical mean of detecting or excluding obstruction of the LMCA and it may be a useful adjunct to coronary arteriography because it can alert the arteriographer to the potential presence of a LMCA disease