Ambiguous coronary angiography: clinical utility of intravascular ultrasound.

We report the use of intravascular ultrasound (IVUS) in situations where angiography was ambiguous or uncertain in assessing the significance of coronary stenoses. The indications for performing intravascular ultrasound were 1) angiographic findings did not correlate with the clinical presentation (n = 5) and 2) the lesion was not seen well by angiography because of overlapping vessels at the site of suspected stenosis (n = 3). We studied eight lesions in seven patients. Six nonobstructive stenoses on angiography were shown by IVUS to be significant. In two patients, stenoses were thought to be significant on angiography, but, due to overlapping of the vessels, there was doubt regarding the severity of the narrowing. In these two patients, IVUS clearly showed that the lesions were nonobstructive. As seen from the above results, angiography underestimated 6/8 stenoses and overestimated in 2/8 stenoses when compared to IVUS. We conclude that IVUS can be used to clarify ambiguous angiographic findings which can have a major impact on the clinical decision making.