[Coronary ultrasonography. More exact than coronary angiography? Description of two case histories]

Coronary angiography as the "golden standard" in diagnostic imaging, guiding and assessing the results of interventional therapy has well known limitations inherent to the two dimensional imaging of three dimensional structures. Intravascular ultrasonography provides cross-sectional images of coronary artery, allowing an accurate calculation of cross-sectional luminal area and assessment of the degree of eccentricity of plaque and its structure including fissures, dissections and intracoronary thrombi. Case 1: Coronary angiography was performed in a 60 y. male patient with unstable angina revealing only a 40% stenosis in proximal LAD. The inconsistency of clinical presentation with angiography findings led to perform an intravascular ultrasound (IVUS) examination of LAD. The angiographic 40% stenosis was found to be over 80% on IVUS. Subsequent PTCA procedure led to a good IVUS and clinical result with no obvious changes in angiography. Case 2: PTCA of 80% Cx stenosis was performed with good immediate angiographic result, without dissection nor residual stenosis. However, IVUS immediately after PTCA assessed a dissection of the plaque with a flap protruding into the lumen. The patient was sent back to coronary angiography several hours later with clinical and ecg symptoms of acute myocardial ischemia. An important, occlusive dissection was found at the PTCA site. Angioplasty was performed again restoring a wide lumen at intervention site. IVUS was able to clarify the ambiguous angiographic findings with an important impact on interventional therapy. The immediate results of invasive procedures were readily and safely assessed by intravascular ultrasound.