What is the angiography error when defining myocardial ischemia during percutaneous coronary interventions?

Abstract

Background: The angiography has been used as a reference standard to define coronary artery disease (CAD), although its limitations are well-known. The significance of the myocardial fractional flow reserve (FFR) in the assessment of CAD is well established.

Objective: The aim of this study was to evaluate the accuracy of angiography when defining ischemic lesions and its correlation with FFR.

Methods: Two hundred and fifty consecutive patients (471 arteries) were included in this study. All stenoses >or= 50% at the angiography visual estimate (AVE) were assessed by FFR measurements. When FFR was < 0.75, stenting was performed; when FFR was >or= 0.75, no interventional treatment was carried out. Offline quantitative coronary angiography (QCA) was performed in all stenoses, which were divided in intermediate (< 70% - 327) and severe (125). The correlation coefficients between the diameter of the stenosis (%DS) and FFR and the accuracy of VA of the angiography when assessing ischemia were determined.

Results: FFR could be obtained in 452 lesions (96%). Mean %DS and FFR were 56 +/- 8% and 0.74 and 76 +/- 6% and 0.48 for moderate and severe stenoses, respectively. Concordance between QCA and FFR was poor, especially in intermediate stenoses (Spearman's rho = - 0.33, p<0.0001). Visual assessment resulted in an accuracy of 57% and 96% in intermediate and severe lesions, respectively.

Conclusion: Neither the visual assessment of an angiogram nor QCA can accurately predict the significance of most intermediate coronary stenoses, which emphasizes the importance of associating it to a functional evaluation of the coronary circulation, resulting in an adequate treatment of these stenoses.