Influence of Microcirculatory Dysfunction on Angiography-Based Functional Assessment of Coronary Stenoses

Hernán Mejía-Rentería, Joo Myung Lee, Francesco Lauri, Nina W. van der Hoeven, Guus A. de Waard, Fernando Macaya, María José Pérez-Vizcayno, Nieves Gonzalo, Pilar Jiménez-Quevedo, Luis Nombela-Franco, Pablo Salinas, Iván Núñez-Gil, María del Trigo, Sonoka Goto, Hyun Jong Lee, Catherine Liontou, Antonio Fernández-Ortiz, Carlos Macaya, Niels van Royen, Bon-Kwon KooJavier Escaned

Research output: Contribution to journalArticleAcademicpeer-review


Objectives: The authors sought to evaluate the influence of coronary microcirculatory dysfunction (CMD) on the diagnostic performance of the quantitative flow ratio (QFR). Background: Functional angiographic assessment of coronary stenoses based on fluid dynamics, such as QFR, constitutes an attractive alternative to fractional flow reserve (FFR). However, it is unknown whether CMD affects the reliability of angiography-based functional indices. Methods: FFR and the index of microcirculatory resistance (IMR) were measured in 300 vessels (248 patients) as part of a multicenter international registry. QFR was calculated at a blinded core laboratory. Vessels were classified into 2 groups according to microcirculatory status: low IMR (<23 U), and high IMR (≥23 U, CMD). The impact of CMD on the diagnostic performance of QFR, as well as on incremental value of QFR over quantitative angiography, was assessed using FFR as reference. Results: Percent diameter stenosis (%DS) and FFR were similar in low- and high-IMR groups (%DS 51 ± 12% vs. 53 ± 11%; p = 0.16; FFR 0.80 ± 0.11 vs. 0.81 ± 0.11; p = 0.23, respectively). In the overall cohort, classification agreement (CA) between QFR and FFR and diagnostic efficiency of QFR (area under the receiver-operating characteristics curve [AUC]) were high (CA: 88%; AUC: 0.93 [95% confidence interval (CI): 0.90 to 0.96]). However, when assessed according to microcirculatory status, a significantly lower CA and AUC of QFR were found in the high-IMR group as compared with the low-IMR group (CA: 76% vs. 92%; p < 0.001; AUC: 0.88 [95% CI: 0.79 to 0.94] vs. 0.96 [95% CI: 0.92 to 0.98]; p < 0.05). Compared with angiographic assessment, QFR increased by 0.20 (p < 0.001) and by 0.16 (p < 0.001) the AUC of %DS in low- and high-IMR groups, respectively. Independent predictors of misclassification between QFR and FFR were high IMR and acute coronary syndrome. Conclusions: CMD decreases the diagnostic performance of QFR. However, even in the presence of CMD, QFR remains superior to angiography alone in ascertaining functional stenosis severity.
Original languageEnglish
Pages (from-to)741-753
JournalJACC: Cardiovascular Interventions
Issue number8
Publication statusPublished - 2018

Cite this