[Visual assessment or quantitative measurement of coronary stenoses: significance for "prima vista"-PTCA]

In 300 patients with 339 coronary lesions the percent diameter stenosis (%-DS) was assessed both by visual estimation and by digital quantitative coronary angiography (DQCA) by use of an on-line computer work-station. The decision for coronary angioplasty in the same setting ("prima vista"-PTCA) was based on history, evidence of ischemia and visual estimation of %-DS. DQCA measurements of the 339 stenoses revealed a normal distribution of lesion severity with a mean of 58.4 +/- 11.3%. In contrast to DQCA visual estimation led to a bimodal distribution with a nadir at approximately 55% between two peaks at approximately 45% and approximately 75% and a mean of 70.5 +/- 19.6%. Visual estimation underestimated lesions in the range of 30-55% and overestimated the %-DS between 55-99%. Visual estimation revealed a %-DS > or = 60% in 251 stenoses (74.0%) of the 339 lesions, an estimate that led to subsequent "prima vista"-PTCA. Conversely, DQCA revealed only 184 stenoses (54.3%) with a %-DS > or = 60%; thus, 86 stenoses (25.3%) did not meet the morphologic indication criteria for PTCA. The bimodal distribution of stenosis severity according to visual analysis with an overestimation of borderline stenosis severity reflects at tendency for "self-referral" of patients for PTCA. DQCA serves as an objective tool in the decision-making process for PTCA and may reduce "cosmetic" interventions or justify to defer PTCA. Especially in the selection process for "prima vista"-PTCA DQCA-quantification of stenosis severity is recommended.