title: Invasive evaluation of patients with angina in the absence of obstructive coronary artery disease.
abstract: BACKGROUND
  More than 20% of patients presenting to the cardiac catheterization laboratory with angina have no angiographic evidence of coronary artery disease. Despite a "normal" angiogram, these patients often have persistent symptoms, recurrent hospitalizations, a poor functional status, and adverse cardiovascular outcomes, without a clear diagnosis.
  
  
  RESULTS
  In 139 patients with angina in the absence of obstructive coronary artery disease (no diameter stenosis >50%), endothelial function was assessed; the index of microcirculatory resistance, coronary flow reserve, and fractional flow reserve were measured; and intravascular ultrasound was performed. There were no complications. The average age was 54.0±11.4 years, and 107 (77%) were women. All patients had at least some evidence of atherosclerosis based on an intravascular ultrasound examination of the left anterior descending artery. Endothelial dysfunction (a decrease in luminal diameter of >20% after intracoronary acetylcholine) was present in 61 patients (44%). Microvascular impairment (an index of microcirculatory resistance ≥25) was present in 29 patients (21%). Seven patients (5%) had a fractional flow reserve ≤0.80. A myocardial bridge was present in 70 patients (58%). Overall, only 32 patients (23%) had no coronary explanation for their angina, with normal endothelial function, normal coronary physiological assessment, and no myocardial bridging.
  
  
  CONCLUSIONS
  The majority of patients with angina in the absence of obstructive coronary artery disease have occult coronary abnormalities. A comprehensive invasive assessment of these patients at the time of coronary angiography can be performed safely and provides important diagnostic information that may affect treatment and outcomes.
authors.affiliation: From Division of Cardiovascular Medicine, Stanford University Medical Center, Stanford, CA (B.-K.L., H.-S.L., W.F.F., A.S.Y., R.Y., S.T., D.P.L., A.C.Y., J.A.T.); Division of Cardiology, Kangwon National University School of Medicine, Chuncheon, Republic of Korea (B.-K.L.); and Department of Cardiology, Ajou University School of Medicine, Suwon, Republic of Korea (H.-S.L.).
authors.forename: Bong-Ki
authors.initials: BK
authors.lastname: Lee
authors.affiliation: From Division of Cardiovascular Medicine, Stanford University Medical Center, Stanford, CA (B.-K.L., H.-S.L., W.F.F., A.S.Y., R.Y., S.T., D.P.L., A.C.Y., J.A.T.); Division of Cardiology, Kangwon National University School of Medicine, Chuncheon, Republic of Korea (B.-K.L.); and Department of Cardiology, Ajou University School of Medicine, Suwon, Republic of Korea (H.-S.L.).
authors.forename: Hong-Seok
authors.initials: HS
authors.lastname: Lim
authors.affiliation: From Division of Cardiovascular Medicine, Stanford University Medical Center, Stanford, CA (B.-K.L., H.-S.L., W.F.F., A.S.Y., R.Y., S.T., D.P.L., A.C.Y., J.A.T.); Division of Cardiology, Kangwon National University School of Medicine, Chuncheon, Republic of Korea (B.-K.L.); and Department of Cardiology, Ajou University School of Medicine, Suwon, Republic of Korea (H.-S.L.). wfearon@stanford.edu.
authors.forename: William F
authors.initials: WF
authors.lastname: Fearon
authors.affiliation: From Division of Cardiovascular Medicine, Stanford University Medical Center, Stanford, CA (B.-K.L., H.-S.L., W.F.F., A.S.Y., R.Y., S.T., D.P.L., A.C.Y., J.A.T.); Division of Cardiology, Kangwon National University School of Medicine, Chuncheon, Republic of Korea (B.-K.L.); and Department of Cardiology, Ajou University School of Medicine, Suwon, Republic of Korea (H.-S.L.).
authors.forename: Andy S
authors.initials: AS
authors.lastname: Yong
authors.affiliation: From Division of Cardiovascular Medicine, Stanford University Medical Center, Stanford, CA (B.-K.L., H.-S.L., W.F.F., A.S.Y., R.Y., S.T., D.P.L., A.C.Y., J.A.T.); Division of Cardiology, Kangwon National University School of Medicine, Chuncheon, Republic of Korea (B.-K.L.); and Department of Cardiology, Ajou University School of Medicine, Suwon, Republic of Korea (H.-S.L.).
authors.forename: Ryotaro
authors.initials: R
authors.lastname: Yamada
authors.affiliation: From Division of Cardiovascular Medicine, Stanford University Medical Center, Stanford, CA (B.-K.L., H.-S.L., W.F.F., A.S.Y., R.Y., S.T., D.P.L., A.C.Y., J.A.T.); Division of Cardiology, Kangwon National University School of Medicine, Chuncheon, Republic of Korea (B.-K.L.); and Department of Cardiology, Ajou University School of Medicine, Suwon, Republic of Korea (H.-S.L.).
authors.forename: Shigemitsu
authors.initials: S
authors.lastname: Tanaka
authors.affiliation: From Division of Cardiovascular Medicine, Stanford University Medical Center, Stanford, CA (B.-K.L., H.-S.L., W.F.F., A.S.Y., R.Y., S.T., D.P.L., A.C.Y., J.A.T.); Division of Cardiology, Kangwon National University School of Medicine, Chuncheon, Republic of Korea (B.-K.L.); and Department of Cardiology, Ajou University School of Medicine, Suwon, Republic of Korea (H.-S.L.).
authors.forename: David P
authors.initials: DP
authors.lastname: Lee
authors.affiliation: From Division of Cardiovascular Medicine, Stanford University Medical Center, Stanford, CA (B.-K.L., H.-S.L., W.F.F., A.S.Y., R.Y., S.T., D.P.L., A.C.Y., J.A.T.); Division of Cardiology, Kangwon National University School of Medicine, Chuncheon, Republic of Korea (B.-K.L.); and Department of Cardiology, Ajou University School of Medicine, Suwon, Republic of Korea (H.-S.L.).
authors.forename: Alan C
authors.initials: AC
authors.lastname: Yeung
authors.affiliation: From Division of Cardiovascular Medicine, Stanford University Medical Center, Stanford, CA (B.-K.L., H.-S.L., W.F.F., A.S.Y., R.Y., S.T., D.P.L., A.C.Y., J.A.T.); Division of Cardiology, Kangwon National University School of Medicine, Chuncheon, Republic of Korea (B.-K.L.); and Department of Cardiology, Ajou University School of Medicine, Suwon, Republic of Korea (H.-S.L.).
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Tremmel
mesh_terms: D000328:Adult; D000368:Aged; D000787:Angina Pectoris / Q000000981:diagnostic imaging*; D001783:Blood Flow Velocity / Q000502:physiology; D017023:Coronary Angiography / Q000379:methods / Q000592:standards*; D003324:Coronary Artery Disease; D003326:Coronary Circulation / Q000502:physiology*; D005260:Female; D053805:Fractional Flow Reserve, Myocardial / Q000502:physiology*; D006801:Humans; D008297:Male; D008833:Microcirculation / Q000502:physiology; D008875:Middle Aged; D018084:Ultrasonography, Interventional / Q000379:methods / Q000592:standards*
keywords: chest pain; endothelium; fractional flow reserve, myocardial; myocardial bridging