Atsushi Yamamoto1, Michinobu Nagao2, Kiyoe Ando3, Risako Nakao3, Akiko Sakai3, Eri Watanabe3, Mitsuru Momose4, Kayoko Sato3, Kenji Fukushima5, Shuji Sakai4, Nobuhisa Hagiwara3. 1. Department of Cardiology, Tokyo Women's Medical University, Tokyo, Japan; Department of Diagnostic Imaging and Nuclear Medicine, Tokyo Women's Medical University, 8-1, Kawadacho, Shinjuku-ku, 162-8666 Tokyo, Japan. 2. Department of Diagnostic Imaging and Nuclear Medicine, Tokyo Women's Medical University, 8-1, Kawadacho, Shinjuku-ku, 162-8666 Tokyo, Japan. Electronic address: nagao.michinobu@twmu.ac.jp. 3. Department of Cardiology, Tokyo Women's Medical University, Tokyo, Japan. 4. Department of Diagnostic Imaging and Nuclear Medicine, Tokyo Women's Medical University, 8-1, Kawadacho, Shinjuku-ku, 162-8666 Tokyo, Japan. 5. Department of Radiology, Saitama Medical University International Medical Center, Saitama, Japan.
Abstract
RATIONALE AND OBJECTIVES: Physiological measurements from coronary angiography show that coronary stenosis with necrotic core plaque reduces coronary flow reserve (CFR). Myocardial flow reserve (MFR) estimated by 13N-ammonia PET (NH3-PET) is a different index from CFR. Low attenuation plaque (LAP) on coronary CTA (CCTA) contains necrotic core, but the link between LAP and MFR has not been elucidated. We aimed to investigate the influence of LAP on MFR in coronary artery disease (CAD). MATERIALS AND METHODS: The study included 105 consecutive patients who underwent NH3-PET and CCTA within 3 months. Nonevaluable coronary arteries due to severe calcification and stent implants were excluded. Finally, 290 major vessels were retrospectively analyzed. Coronary arteries were divided into mild (1%-49%), moderate (50%-69% stenosis), and severe (≥70% stenosis) groups. Coronary plaques were classified either LAP (including soft tissue CT value <30 HU) or completely classified plaques. MFR for the major vessels were calculated and MFR <2.0 was considered a significant decrease. Comparison of MFR between territories with and without LAP, and the effect of plaque characteristics on MFR was analyzed. RESULTS: MFR was significantly lower for territories with LAP than with calcified plaques or no plaque (2.1 ± 0.7, 2.4 ± 0.7, and 2.3 ± 0.7; p < 0.05). There was no difference between calcified plaque and no plaque territories (p = 0.79). Multivariate logistic analysis for plaque characteristics and stenosis severity revealed that LAP and severe stenosis were independent predictors for territories with MFR <2.0 with odds ratios of 3.1 (95% confidence interval, 1.2-8.1) and 3.0 (95% confidence interval, 1.7-5.3). CONCLUSION: LAP reduced MFR compared with calcified plaque or no plaque in CAD. LAP is an independent predictor of the territory with MFR <2.0.
RATIONALE AND OBJECTIVES: Physiological measurements from coronary angiography show that coronary stenosis with necrotic core plaque reduces coronary flow reserve (CFR). Myocardial flow reserve (MFR) estimated by 13N-ammonia PET (NH3-PET) is a different index from CFR. Low attenuation plaque (LAP) on coronary CTA (CCTA) contains necrotic core, but the link between LAP and MFR has not been elucidated. We aimed to investigate the influence of LAP on MFR in coronary artery disease (CAD). MATERIALS AND METHODS: The study included 105 consecutive patients who underwent NH3-PET and CCTA within 3 months. Nonevaluable coronary arteries due to severe calcification and stent implants were excluded. Finally, 290 major vessels were retrospectively analyzed. Coronary arteries were divided into mild (1%-49%), moderate (50%-69% stenosis), and severe (≥70% stenosis) groups. Coronary plaques were classified either LAP (including soft tissue CT value <30 HU) or completely classified plaques. MFR for the major vessels were calculated and MFR <2.0 was considered a significant decrease. Comparison of MFR between territories with and without LAP, and the effect of plaque characteristics on MFR was analyzed. RESULTS: MFR was significantly lower for territories with LAP than with calcified plaques or no plaque (2.1 ± 0.7, 2.4 ± 0.7, and 2.3 ± 0.7; p < 0.05). There was no difference between calcified plaque and no plaque territories (p = 0.79). Multivariate logistic analysis for plaque characteristics and stenosis severity revealed that LAP and severe stenosis were independent predictors for territories with MFR <2.0 with odds ratios of 3.1 (95% confidence interval, 1.2-8.1) and 3.0 (95% confidence interval, 1.7-5.3). CONCLUSION: LAP reduced MFR compared with calcified plaque or no plaque in CAD. LAP is an independent predictor of the territory with MFR <2.0.