Courtesy of Dr. Pablo Baglioni.
The visual interpretation of coronary angiographies is still used to decide for or against revascularization of ambiguous coronary lesions. Multiple factors other than stenosis degree, have been associated with the functional significance of lesions. The aim of this study was to analyze the ability of interventionists to visually assess the functional significance of coronary lesions, and the clinical and angiographic factors associated with misinterpretation.
This is a concordance analyzis between expert prediction of functional significance and the diagnostic value of fractional flow reserve (FFR) obtained via intracoronary pressure wire in 665 intermediate lesions (stenosis diameter 40–70%) in 587 patients. Researchers determined the factors independently associated to prediction errors.
FFR was done using increasing intracoronary adenosine doses of 300 to 1,200 µg. The angiographic estimate of functional significance degree lesions was done by 2 experienced interventional cardiologists blinded to the FFR study results, taking into account not only stenosis degree, but also FFR parameters such as severe calcification, bifurcation, angulation, ostial location, perfused myocardial territory, and location of the lesion in the stent.
Over estimation was defined as a predicted FFR ≤0.80, and a resulting higher value. Under estimation was defined as a predicted FFR > 0.80 and a resulting lower value.
Results
Intra observer agreement was 83%, with Kappa index 0.54±0.039 (p<0.0005).
There was 30.1% disagreement (overestimation 11.3%; underestimation 18.8%) between predicted and measured FFR values.
Stent localization in an artery other than anterior descending or in a bifurcation, was associated to overestimation.
Male sex, severe calcification, and a greater myocardial territory distal to the lesion were significantly associated with the functional significance of the underestimated lesion.
Conclusion
Even integrating important characteristics into FFR values, visual estimate of functional importance of intermediate coronary stenosis was associated to high disagreement when compared to direct measurement. Specific angiographic and clinical characteristics are associated with an increased tendency to overestimate or underestimate the significance of lesions.
Editorial Comment
Once more, angiographic estimate of intermediate lesion severity presents great inter-observer variability and low correlation with FFR values, even considering clinical and angiographic variables.
All this information has fortunately influenced the way we assess the importance of coronary stenosis, incorporating factors such as lesion localization, myocardial territory perfusion calcification degree, bifurcation, and length, among others. Even so, the gap remains open.
Courtesy of Dr. Pablo Baglioni. Buenos Aires British Hospital, Argentina.
Original Title: Factores asociados al error en la estimación visual de la importancia funcional de lesiones coronarias.
Reference: Ramón López-Palop et al. Rev Esp Cardiol. 2016;69:657-63 – Vol. 69 Núm.07.
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