title: Coronary Microvascular Dysfunction as a Mechanism of Angina in Severe AS: Prospective Adenosine-Stress CMR Study.
abstract: BACKGROUND
  Although a common symptom in patients with severe aortic stenosis (AS) without obstructive coronary artery disease (CAD), little is known about the pathogenesis of exertional angina.
  
  
  OBJECTIVE
  This study sought to prove that microvascular dysfunction is responsible for chest pain in patients with severe AS and normal epicardial coronary arteries using adenosine-stress cardiac magnetic resonance (CMR) imaging.
  
  
  METHODS
  Between June 2012 and April 2015, 117 patients with severe AS without obstructive CAD and 20 normal controls were enrolled prospectively. After exclusions, study patients were divided into 2 groups according to presence of exertional chest pain: an angina group (n = 43) and an asymptomatic group (n = 41), and the semiquantitative myocardial perfusion reserve index (MPRI) was calculated.
  
  
  RESULTS
  MPRI values were significantly lower in severe AS patients than in normal controls (0.90 ± 0.31 vs. 1.25 ± 0.21; p < 0.001), and were much lower in the angina group than the asymptomatic group (0.74 ± 0.25 vs. 1.08 ± 0.28; p < 0.001). In logistic regression analysis, the only independent predictor for angina was MPRI (odds ratio: 0.003; p < 0.001). Univariate associations with MPRI were identified for diastolic blood pressure, E/e' ratio, left ventricular volume and ejection fraction, cardiac index, presence of late gadolinium enhancement, and left ventricular mass index (LVMI). In multivariate analysis, LVMI was the strongest contributing factor to MPRI (standardization coefficient: -0.428; p < 0.001).
  
  
  CONCLUSIONS
  Our results suggest that, in patients with severe AS without obstructive CAD, angina is related to impaired coronary microvascular function along with LV hypertrophy detectable by semiquantitative MPRI using adenosine-stress CMR.
  
  
  BACKGROUND
  NCT02575768.
authors.affiliation: Division of Cardiology, Department of Medicine, Cardiovascular Imaging Center, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Jong-Hwa
authors.initials: JH
authors.lastname: Ahn
authors.affiliation: Department of Radiology, Cardiovascular Imaging Center, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Sung Mok
authors.initials: SM
authors.lastname: Kim
authors.affiliation: Division of Cardiology, Department of Medicine, Cardiovascular Imaging Center, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea. Electronic address: tyche.park@gmail.com.
authors.forename: Sung-Ji
authors.initials: SJ
authors.lastname: Park
authors.affiliation: Department of Thoracic Surgery, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Dong Seop
authors.initials: DS
authors.lastname: Jeong
authors.affiliation: Biostatistics and Clinical Epidemiology Center, Research Institute for Future Medicine, Samsung Medical Center, Seoul, Republic of Korea.
authors.forename: Min-Ah
authors.initials: MA
authors.lastname: Woo
authors.affiliation: Biostatistics and Clinical Epidemiology Center, Research Institute for Future Medicine, Samsung Medical Center, Seoul, Republic of Korea.
authors.forename: Sin-Ho
authors.initials: SH
authors.lastname: Jung
authors.affiliation: Division of Cardiology, Department of Medicine, Cardiovascular Imaging Center, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Sang-Chol
authors.initials: SC
authors.lastname: Lee
authors.affiliation: Division of Cardiology, Department of Medicine, Cardiovascular Imaging Center, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Seung Woo
authors.initials: SW
authors.lastname: Park
authors.affiliation: Department of Radiology, Cardiovascular Imaging Center, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Yeon Hyeon
authors.initials: YH
authors.lastname: Choe
authors.affiliation: Department of Thoracic Surgery, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Pyo Won
authors.initials: PW
authors.lastname: Park
authors.affiliation: Division of Cardiology, Department of Medicine, Cardiovascular Imaging Center, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea; Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota.
authors.forename: Jae K
authors.initials: JK
authors.lastname: Oh
mesh_terms: D000241:Adenosine / Q000008:administration & dosage*; D000368:Aged; D001024:Aortic Valve Stenosis / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D017023:Coronary Angiography; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D015150:Echocardiography, Doppler; D025401:Echocardiography, Stress / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007269:Injections, Intra-Arterial; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D017566:Microvascular Angina / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D011446:Prospective Studies; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*; D014665:Vasodilator Agents / Q000008:administration & dosage
chemical_list: D014665:Vasodilator Agents; D000241:Adenosine
keywords: cardiac magnetic resonance; exertional angina; left ventricular mass index; myocardial perfusion reserve