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TCT-68 Clinical Outcomes According to Fractional Flow Reserve or Instantaneous Wave-Free Ratio in Deferred Lesions
JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY, VOL. 70, NO. 18, SUPPL B, 2017
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significant trends of decrease in 3-vessel FFR (p <0.001 for trend) and increase in SYNTAX score (p <0.001 for trend). Group 1 and Group 2 showed a similar risk of 2-year MACE (2.6% vs. 2.0%; HR, 1.24; 95% CI 0.45-3.42; p¼0.67). However, Group 3 showed a significantly higher risk than Group 1 (7.3%; HR, 3.81; 95% CI 1.23-11.8; p¼0.02). A multivariable regression model showed that the risk of Group 3 was comparable to that of Group 4 (HR, 1.07; 95% CI, 0.44-2.62; p ¼ 0.87).
CONCLUSION Compared to the deferred lesions of SCAD patients, deferred non-culprit lesion of ACS on the basis of FFR showed a higher rate of clinical events regardless of FFR range. CATEGORIES IMAGING: FFR and Physiologic Lesion Assessment TCT-67 Clinical Relevance of Functionally Insignificant Moderate Coronary Artery Stenosis Assessed by 3-vessel Fractional Flow Reserve Measurement Jonghanne Park,1 Joo Myung Lee,2 Bon-Kwon Koo,3 Eun-Seok Shin,4 Chang-Wook Nam,5 Joon-Hyung Doh,6 Doyeon Hwang,3 Xinyang Hu,7 Jianan Wang,8 Fei Ye,9 Shaoliang Chen,10 Junqing Yang,11 Jiyan Chen,12 Nobuhiro Tanaka,13 Hiroyoshi Yokoi,14 Hitoshi Matsuo,15 Hiroaki Takashima,16 Yasutsugu Shiono,17 Takashi Akasaka18 1 Ministry of Health and Welfare, Seoul, Korea, Republic of; 2Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea, Republic of; 3Seoul National University Hospital, Seoul, Korea, Republic of; 4Ulsan University Hospital, Ulsan, Korea, Republic of; 5Keimyung University Dongsan Medical Center, Daegu, Korea, Republic of; 6Inje University Ilsan Paik Hospital, Seoul, Korea, Republic of; 7The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China; 8 The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China; 9Nanjing First Hospital, Nanjing, China; 10Nanjing First Hospital, Nanjing Medical University, Nanjing, Jiangsu, China; 11Guangdong General Hospital, Guagnzhou, Guangdong, China; 12Guangdong General Hospital, Guangzhou, Guangdong, China; 13Tokyo Medical University, Tokyo, Japan; 14 Kokura Memorial Hospital, Kitakyushu, Japan; 15Gifu Heart Center, Gifu, Japan; 16Aichi Medical University, Nagakute, Japan; 17Imperial College London, London, United Kingdom; 18Wakayama Medical University, Wakayama, Japan BACKGROUND The risk of functionally insignificant lesions in multiple coronary vessels is largely unknown. We investigated the prognostic implication of severity and extent of coronary artery disease (CAD) using fractional flow reserve (FFR) measured in all 3 major epicardial arteries. METHODS 1,136 patients underwent 3-vessel FFR measurement. The vessel was defined to have moderate CAD when the FFR was within the range of the lowest quartile (FFR, 0.81-0.87) among 2,891 vessels with high FFR (>0.8). The patients were classified into ‘No apparent CAD’ (FFR>0.87 in all 3 vessels, Group 1), ‘Moderate CAD affecting 1vessel’ (Group 2), ‘Moderate CAD affecting multi-vessels’ (Group 3), and ‘Functionally significant CAD’ (FFR0.80 in any vessel, Group 4). The primary endpoint was 2-year major adverse cardiac events (MACE), a composite of cardiac death, myocardial infarction and ischemia-driven revascularization. RESULTS 43% of the total patients had moderate CAD (Group 2: 403/ 1136, 35.5%; Group 3: 84/1136, 7.4%). From Group 1 to 4, there were
CONCLUSION Global physiologic assessment by 3-vessel FFR can enable the identification of multi-vessel moderate CAD. The prognostic implication of multi-vessel moderate CAD was comparable to that of functionally significant CAD. (3V FFR-FRIENDS study, NCT01621438). CATEGORIES IMAGING: FFR and Physiologic Lesion Assessment TCT-68 Clinical Outcomes According to Fractional Flow Reserve or Instantaneous Wave-Free Ratio in Deferred Lesions Joo Myung Lee,1 Eun-Seok Shin,2 Chang-Wook Nam,3 Joon-Hyung Doh,4 Doyeon Hwang,5 Jonghanne Park,6 Ahn Chul,7 Bon-Kwon Koo5 1 Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea, Republic of; 2Ulsan University Hospital, Ulsan, Korea, Republic of; 3Keimyung University Dongsan Medical Center, Daegu, Korea, Republic of; 4Inje University Ilsan Paik Hospital, Seoul, Korea, Republic of; 5Seoul National University Hospital, Seoul, Korea, Republic of; 6Ministry of Health and Welfare, Seoul, Korea, Republic of; 7FDA-CDRH, Silver Spring, Maryland, United States BACKGROUND Invasive physiologic index such as fractional flow reserve (FFR) or instantaneous wave-free ratio (iFR) are used in clinical practice to select ischemia-causing stenosis and to guide the treatment strategy for patients with coronary artery disease. We investigated 2-year clinical outcomes according to FFR and iFR values in deferred lesions. METHODS From 3V FFR-FRIENDS study, 821 deferred lesions (374 patients) with available both FFR and iFR were included in this study. The primary outcome was major adverse cardiac events (MACE, a composite of cardiac death, myocardial infarction and ischemia-driven revascularization) at 2 years. The rates of MACE were compared according to FFR using cut-off value 0.80 and iFR using cut-off value 0.90. The rate of MACE was also compared among classifications according to FFR and iFR into concordant normal (Group 1: FFR>0.80 and iFR0.90), high FFR and low iFR (Group 2: FFR>0.80 and iFR<0.90), low FFR and high iFR (Group 3: FFR0.80 and iFR0.90) and concordant abnormal (Group 4: FFR0.80 and iFR<0.90). RESULTS Deferred lesions with low FFR (0.80) or low iFR (<0.90) showed significantly higher rates of 2-year MACE, compared with high FFR (>0.80) or high iFR (0.90), respectively (7.2% in low FFR vs. 2.4% in high FFR, p<0.001; 8.1% in low iFR vs. 2.4% in high iFR, p<0.001). Both FFR and iFR showed significant association with occurrence of MACE as continuous values (HR of FFR 0.570, 95% CI 0.337-0.963, p<0.001; HR of iFR 0.350, 95% CI 0.217-0.567, p<0.001).
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JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY, VOL. 70, NO. 18, SUPPL B, 2017
When comparing the discriminant ability between FFR and iFR, the c-index was comparable between FFR and iFR (C-index: 0.677 vs. 0.685, p¼0.857). Among 4 groups classified according to FFR and iFR levels, only group 4 with concordant abnormal results showed significantly higher risk of MACE, compared with group 1 (HR 7.708, 95% CI 2.621-22.667, p<0.001).
one or more lesions with >90 % not feasible for FFR measurement (n¼57), missing FFR (n¼24) and missing QFR (n¼12). Median FFR was 0.85 (IQR 0.77-0.89) and median QFR was 0.83 (IQR 0.76-0.89), p¼0.22. Perfusion defect was detected in 16 patients (13%). FFR and QFR values were 0.80 in 46 (37%) and 51 (40%) patients, respectively. The overall diagnostic accuracy was not different with 60 % and 59% (p¼ 0.72) for FFR and QFR. The diagnostic performance for FFR and QFR was not different with AUC 0.57 vs. 0.56 (p¼0.93), sensitivity 38 vs. 44 (p¼0.20) and specificity 63 vs. 61 (p¼0.36). CONCLUSION The diagnostic performance of QFR and FFR was similar but modest with MPS and CMR as reference. Performance levels comparable to FFR are highly encouraging for this pressure wire-free, functional lesion evaluation. CATEGORIES CORONARY: Angiography and QCA TCT-70 Influence of microcirculatory resistance on the assessment of coronary stenosis severity with Quantitative Flow Ratio (QFR): Results of an international multicentre study
CONCLUSION Both FFR and iFR showed significant association with future risk of MACE in deferred lesions. Among the 4 groups classified according to FFR and iFR values, the risk of MACE was significantly higher only in lesions with concordant abnormal results of both indices. CATEGORIES IMAGING: FFR and Physiologic Lesion Assessment
PHYSIOLOGIC LESION ASSESSMENT: NEW INDICES
Abstract nos: 69 - 72 TCT-69 Comparison of Quantitative Flow Ratio and Fractional Flow Reserve to Identify Myocardial Ischemia: Validation With Myocardial Perfusion Scintigraphy and Cardiovascular Magnetic Resonance Jelmer Westra,1 Simon Winther,2 Shengxian Tu,3 Louise Nissen,2 Lars Gormsen,4 Steffen Petersen,5 June Ejlersen,2 Christin Isaksen,6 Morten Bottcher,2 Evald Christiansen,1 Niels Holm7 1 Aarhus University Hospital, Aarhus, Denmark; 2Hospital Unit West, Herning, Denmark; 3Shanghai Jiao Tong University, Shanghai, Shanghai, China; 4Aarhus University Hospital, Skejby, Aarhus, Denmark; 5William Harvey Research Institute, London, United Kingdom; 6Regional Hospital of Silkeborg, Silkeborg, Denmark; 7Aarhus University Hospital, Aarhus N, Denmark BACKGROUND Quantitative flow ratio (QFR) is a novel method for physiological lesion assessment that has documented useful diagnostic performance with FFR as reference standard. However, the two modalities have not yet been compared head to head with a third modality for myocardial ischemia detection as reference. METHODS This study is a post-hoc analysis of the Dan-NICAD study (NCT02264717). Patients with suspected coronary artery disease by coronary computed tomography angiography were randomized 1:1 to myocardial perfusion assessment by scintigraphy (MPS) and magnetic resonance imaging (CMR). All randomized patients were reffered to invasive coronary angiography with FFR and QFR measurement on all lesions with 30-90 % diameter stenosis. QFR and FFR 0.80 were used as diagnostic cut-off. Perfusion defect on either CMR or MPS was used as reference standard. RESULTS Invasive coronary angiography and MPS or MRI was performed in 291 patients. Paired data with FFR, QFR and MPS (n¼62) or CMR (n¼66) was available for 128 patients after excluding patients with no lesions visualized on invasive coronary angiography (n¼72),
Hernan Mejia-Renteria,1 Francesco Lauri,1 Joo Myung Lee,2 Nina van der Hoeven,3 Guus de Waard,3 Alfonso de Hoyos,4 Fernando Macaya,5 Nicola Ryan,6 Nieves Gonzalo,7 Pilar Jimenez-Quevedo,1 Luis Nombela Franco,7 Ivan Nuñez-Gil,7 Pablo Salinas,7 Maria Del Trigo,8 Maria Perez-Vizcayno,7 Antonio Fernandez-Ortiz,7 Carlos Macaya,9 Bon-Kwon Koo,10 Niels van Royen,11 Javier Escaned7 1 Hospital Universitario Clinico San Carlos, Madrid, Spain; 2Samsung Medical Center, Seoul, Korea, Republic of; 3VU University Medical Centre, Amsterdam, Netherlands; 4Hospital Clínico San Carlos and Universidad Complutense de Madrid, Madrid, Spain; 5Hospital Universitario San Carlos, Madrid, Spain; 6HCSC, Madrid, Spain; 7 Hospital Clínico San Carlos, Madrid, Spain; 8Hospital Clinico San Carlos, Madrid, Spain; 9Hospital Clinico de San Carlos, Madrid, Spain; 10 Seoul National University Hospital, Seoul, Korea, Republic of; 11 Radboud University, Nijmegen, Netherlands BACKGROUND QFR, an angiographic index of stenosis severity based on computational fluid dynamics, estimates fractional flow reserve (FFR) without coronary instrumentation. Although QFR incorporates TIMI frame count as a surrogate of flow, it is unknown whether QFR is influenced by microvascular dysfunction. We investigated the impact of microcirculatory resistance on the diagnostic performance of QFR. METHODS We evaluated 300 vessels (248 patients) from 4 centers in Spain, South Korea and the Netherlands. In all cases FFR and the index of microcirculatory resistance (IMR) were measured. QFR was performed at a central corelab by analysts blinded to FFR and IMR results. Vessels were stratified into low IMR (Group 1) and high IMR (Group 2) using the 75th percentile of IMR (23 U). RESULTS Microcirculatory dysfunction occurred in 28% cases. Figure and Table show the statistical analysis results. The diagnostic accuracy of QFR (AUC) and stenosis classification agreement with FFR were significantly lower in cases with high IMR.
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significant trends of decrease in 3-vessel FFR (p <0.001 for trend) and increase in SYNTAX score (p <0.001 for trend). Group 1 and Group 2 showed a similar risk of 2-year MACE (2.6% vs. 2.0%; HR, 1.24; 95% CI 0.45-3.42; p¼0.67). However, Group 3 showed a significantly higher risk than Group 1 (7.3%; HR, 3.81; 95% CI 1.23-11.8; p¼0.02). A multivariable regression model showed that the risk of Group 3 was comparable to that of Group 4 (HR, 1.07; 95% CI, 0.44-2.62; p ¼ 0.87).
CONCLUSION Compared to the deferred lesions of SCAD patients, deferred non-culprit lesion of ACS on the basis of FFR showed a higher rate of clinical events regardless of FFR range. CATEGORIES IMAGING: FFR and Physiologic Lesion Assessment TCT-67 Clinical Relevance of Functionally Insignificant Moderate Coronary Artery Stenosis Assessed by 3-vessel Fractional Flow Reserve Measurement Jonghanne Park,1 Joo Myung Lee,2 Bon-Kwon Koo,3 Eun-Seok Shin,4 Chang-Wook Nam,5 Joon-Hyung Doh,6 Doyeon Hwang,3 Xinyang Hu,7 Jianan Wang,8 Fei Ye,9 Shaoliang Chen,10 Junqing Yang,11 Jiyan Chen,12 Nobuhiro Tanaka,13 Hiroyoshi Yokoi,14 Hitoshi Matsuo,15 Hiroaki Takashima,16 Yasutsugu Shiono,17 Takashi Akasaka18 1 Ministry of Health and Welfare, Seoul, Korea, Republic of; 2Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea, Republic of; 3Seoul National University Hospital, Seoul, Korea, Republic of; 4Ulsan University Hospital, Ulsan, Korea, Republic of; 5Keimyung University Dongsan Medical Center, Daegu, Korea, Republic of; 6Inje University Ilsan Paik Hospital, Seoul, Korea, Republic of; 7The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China; 8 The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China; 9Nanjing First Hospital, Nanjing, China; 10Nanjing First Hospital, Nanjing Medical University, Nanjing, Jiangsu, China; 11Guangdong General Hospital, Guagnzhou, Guangdong, China; 12Guangdong General Hospital, Guangzhou, Guangdong, China; 13Tokyo Medical University, Tokyo, Japan; 14 Kokura Memorial Hospital, Kitakyushu, Japan; 15Gifu Heart Center, Gifu, Japan; 16Aichi Medical University, Nagakute, Japan; 17Imperial College London, London, United Kingdom; 18Wakayama Medical University, Wakayama, Japan BACKGROUND The risk of functionally insignificant lesions in multiple coronary vessels is largely unknown. We investigated the prognostic implication of severity and extent of coronary artery disease (CAD) using fractional flow reserve (FFR) measured in all 3 major epicardial arteries. METHODS 1,136 patients underwent 3-vessel FFR measurement. The vessel was defined to have moderate CAD when the FFR was within the range of the lowest quartile (FFR, 0.81-0.87) among 2,891 vessels with high FFR (>0.8). The patients were classified into ‘No apparent CAD’ (FFR>0.87 in all 3 vessels, Group 1), ‘Moderate CAD affecting 1vessel’ (Group 2), ‘Moderate CAD affecting multi-vessels’ (Group 3), and ‘Functionally significant CAD’ (FFR0.80 in any vessel, Group 4). The primary endpoint was 2-year major adverse cardiac events (MACE), a composite of cardiac death, myocardial infarction and ischemia-driven revascularization. RESULTS 43% of the total patients had moderate CAD (Group 2: 403/ 1136, 35.5%; Group 3: 84/1136, 7.4%). From Group 1 to 4, there were
CONCLUSION Global physiologic assessment by 3-vessel FFR can enable the identification of multi-vessel moderate CAD. The prognostic implication of multi-vessel moderate CAD was comparable to that of functionally significant CAD. (3V FFR-FRIENDS study, NCT01621438). CATEGORIES IMAGING: FFR and Physiologic Lesion Assessment TCT-68 Clinical Outcomes According to Fractional Flow Reserve or Instantaneous Wave-Free Ratio in Deferred Lesions Joo Myung Lee,1 Eun-Seok Shin,2 Chang-Wook Nam,3 Joon-Hyung Doh,4 Doyeon Hwang,5 Jonghanne Park,6 Ahn Chul,7 Bon-Kwon Koo5 1 Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea, Republic of; 2Ulsan University Hospital, Ulsan, Korea, Republic of; 3Keimyung University Dongsan Medical Center, Daegu, Korea, Republic of; 4Inje University Ilsan Paik Hospital, Seoul, Korea, Republic of; 5Seoul National University Hospital, Seoul, Korea, Republic of; 6Ministry of Health and Welfare, Seoul, Korea, Republic of; 7FDA-CDRH, Silver Spring, Maryland, United States BACKGROUND Invasive physiologic index such as fractional flow reserve (FFR) or instantaneous wave-free ratio (iFR) are used in clinical practice to select ischemia-causing stenosis and to guide the treatment strategy for patients with coronary artery disease. We investigated 2-year clinical outcomes according to FFR and iFR values in deferred lesions. METHODS From 3V FFR-FRIENDS study, 821 deferred lesions (374 patients) with available both FFR and iFR were included in this study. The primary outcome was major adverse cardiac events (MACE, a composite of cardiac death, myocardial infarction and ischemia-driven revascularization) at 2 years. The rates of MACE were compared according to FFR using cut-off value 0.80 and iFR using cut-off value 0.90. The rate of MACE was also compared among classifications according to FFR and iFR into concordant normal (Group 1: FFR>0.80 and iFR0.90), high FFR and low iFR (Group 2: FFR>0.80 and iFR<0.90), low FFR and high iFR (Group 3: FFR0.80 and iFR0.90) and concordant abnormal (Group 4: FFR0.80 and iFR<0.90). RESULTS Deferred lesions with low FFR (0.80) or low iFR (<0.90) showed significantly higher rates of 2-year MACE, compared with high FFR (>0.80) or high iFR (0.90), respectively (7.2% in low FFR vs. 2.4% in high FFR, p<0.001; 8.1% in low iFR vs. 2.4% in high iFR, p<0.001). Both FFR and iFR showed significant association with occurrence of MACE as continuous values (HR of FFR 0.570, 95% CI 0.337-0.963, p<0.001; HR of iFR 0.350, 95% CI 0.217-0.567, p<0.001).
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JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY, VOL. 70, NO. 18, SUPPL B, 2017
When comparing the discriminant ability between FFR and iFR, the c-index was comparable between FFR and iFR (C-index: 0.677 vs. 0.685, p¼0.857). Among 4 groups classified according to FFR and iFR levels, only group 4 with concordant abnormal results showed significantly higher risk of MACE, compared with group 1 (HR 7.708, 95% CI 2.621-22.667, p<0.001).
one or more lesions with >90 % not feasible for FFR measurement (n¼57), missing FFR (n¼24) and missing QFR (n¼12). Median FFR was 0.85 (IQR 0.77-0.89) and median QFR was 0.83 (IQR 0.76-0.89), p¼0.22. Perfusion defect was detected in 16 patients (13%). FFR and QFR values were 0.80 in 46 (37%) and 51 (40%) patients, respectively. The overall diagnostic accuracy was not different with 60 % and 59% (p¼ 0.72) for FFR and QFR. The diagnostic performance for FFR and QFR was not different with AUC 0.57 vs. 0.56 (p¼0.93), sensitivity 38 vs. 44 (p¼0.20) and specificity 63 vs. 61 (p¼0.36). CONCLUSION The diagnostic performance of QFR and FFR was similar but modest with MPS and CMR as reference. Performance levels comparable to FFR are highly encouraging for this pressure wire-free, functional lesion evaluation. CATEGORIES CORONARY: Angiography and QCA TCT-70 Influence of microcirculatory resistance on the assessment of coronary stenosis severity with Quantitative Flow Ratio (QFR): Results of an international multicentre study
CONCLUSION Both FFR and iFR showed significant association with future risk of MACE in deferred lesions. Among the 4 groups classified according to FFR and iFR values, the risk of MACE was significantly higher only in lesions with concordant abnormal results of both indices. CATEGORIES IMAGING: FFR and Physiologic Lesion Assessment
PHYSIOLOGIC LESION ASSESSMENT: NEW INDICES
Abstract nos: 69 - 72 TCT-69 Comparison of Quantitative Flow Ratio and Fractional Flow Reserve to Identify Myocardial Ischemia: Validation With Myocardial Perfusion Scintigraphy and Cardiovascular Magnetic Resonance Jelmer Westra,1 Simon Winther,2 Shengxian Tu,3 Louise Nissen,2 Lars Gormsen,4 Steffen Petersen,5 June Ejlersen,2 Christin Isaksen,6 Morten Bottcher,2 Evald Christiansen,1 Niels Holm7 1 Aarhus University Hospital, Aarhus, Denmark; 2Hospital Unit West, Herning, Denmark; 3Shanghai Jiao Tong University, Shanghai, Shanghai, China; 4Aarhus University Hospital, Skejby, Aarhus, Denmark; 5William Harvey Research Institute, London, United Kingdom; 6Regional Hospital of Silkeborg, Silkeborg, Denmark; 7Aarhus University Hospital, Aarhus N, Denmark BACKGROUND Quantitative flow ratio (QFR) is a novel method for physiological lesion assessment that has documented useful diagnostic performance with FFR as reference standard. However, the two modalities have not yet been compared head to head with a third modality for myocardial ischemia detection as reference. METHODS This study is a post-hoc analysis of the Dan-NICAD study (NCT02264717). Patients with suspected coronary artery disease by coronary computed tomography angiography were randomized 1:1 to myocardial perfusion assessment by scintigraphy (MPS) and magnetic resonance imaging (CMR). All randomized patients were reffered to invasive coronary angiography with FFR and QFR measurement on all lesions with 30-90 % diameter stenosis. QFR and FFR 0.80 were used as diagnostic cut-off. Perfusion defect on either CMR or MPS was used as reference standard. RESULTS Invasive coronary angiography and MPS or MRI was performed in 291 patients. Paired data with FFR, QFR and MPS (n¼62) or CMR (n¼66) was available for 128 patients after excluding patients with no lesions visualized on invasive coronary angiography (n¼72),
Hernan Mejia-Renteria,1 Francesco Lauri,1 Joo Myung Lee,2 Nina van der Hoeven,3 Guus de Waard,3 Alfonso de Hoyos,4 Fernando Macaya,5 Nicola Ryan,6 Nieves Gonzalo,7 Pilar Jimenez-Quevedo,1 Luis Nombela Franco,7 Ivan Nuñez-Gil,7 Pablo Salinas,7 Maria Del Trigo,8 Maria Perez-Vizcayno,7 Antonio Fernandez-Ortiz,7 Carlos Macaya,9 Bon-Kwon Koo,10 Niels van Royen,11 Javier Escaned7 1 Hospital Universitario Clinico San Carlos, Madrid, Spain; 2Samsung Medical Center, Seoul, Korea, Republic of; 3VU University Medical Centre, Amsterdam, Netherlands; 4Hospital Clínico San Carlos and Universidad Complutense de Madrid, Madrid, Spain; 5Hospital Universitario San Carlos, Madrid, Spain; 6HCSC, Madrid, Spain; 7 Hospital Clínico San Carlos, Madrid, Spain; 8Hospital Clinico San Carlos, Madrid, Spain; 9Hospital Clinico de San Carlos, Madrid, Spain; 10 Seoul National University Hospital, Seoul, Korea, Republic of; 11 Radboud University, Nijmegen, Netherlands BACKGROUND QFR, an angiographic index of stenosis severity based on computational fluid dynamics, estimates fractional flow reserve (FFR) without coronary instrumentation. Although QFR incorporates TIMI frame count as a surrogate of flow, it is unknown whether QFR is influenced by microvascular dysfunction. We investigated the impact of microcirculatory resistance on the diagnostic performance of QFR. METHODS We evaluated 300 vessels (248 patients) from 4 centers in Spain, South Korea and the Netherlands. In all cases FFR and the index of microcirculatory resistance (IMR) were measured. QFR was performed at a central corelab by analysts blinded to FFR and IMR results. Vessels were stratified into low IMR (Group 1) and high IMR (Group 2) using the 75th percentile of IMR (23 U). RESULTS Microcirculatory dysfunction occurred in 28% cases. Figure and Table show the statistical analysis results. The diagnostic accuracy of QFR (AUC) and stenosis classification agreement with FFR were significantly lower in cases with high IMR.