title: Microvascular coronary artery spasm presents distinctive clinical features with endothelial dysfunction as nonobstructive coronary artery disease.
abstract: BACKGROUND
  Angina without significant stenosis, or nonobstructive coronary artery disease, attracts clinical attention. Microvascular coronary artery spasm (microvascular CAS) can cause nonobstructive coronary artery disease. We investigated the clinical features of microvascular CAS and the therapeutic efficacy of calcium channel blockers.
  
  
  RESULTS
  Three hundred seventy consecutive, stable patients with suspected angina presenting nonobstructive coronary arteries (<50% diameter) in coronary angiography were investigated with the intracoronary acetylcholine provocation test, with simultaneous measurements of transcardiac lactate production and of changes in the quantitative coronary blood flow. We diagnosed microvascular CAS according to lactate production and a decrease in coronary blood flow without epicardial vasospasm during the acetylcholine provocation test. We prospectively followed up the patients with calcium channel blockers for microvascular coronary artery disease. We identified 50 patients with microvascular CAS who demonstrated significant impairment of the endothelium-dependent vascular response, which was assessed by coronary blood flow during the acetylcholine provocation test. Administration of isosorbide dinitrate normalized the abnormal coronary flow pattern in the patients with microvascular CAS. Multivariate logistic regression analysis indicated that female sex, a lower body mass index, minor-borderline ischemic electrocardiogram findings at rest, limited-baseline diastolic-to-systolic velocity ratio, and attenuated adenosine triphosphate-induced coronary flow reserve were independently correlated with the presence of microvascular CAS. Receiver-operating characteristics curve analysis revealed that the aforementioned 5-variable model showed good correlation with the presence of microvascular CAS (area under the curve: 0.820). No patients with microvascular CAS treated with calcium channel blockers developed cardiovascular events over 47.8±27.5 months.
  
  
  CONCLUSIONS
  Microvascular CAS causes distinctive clinical features and endothelial dysfunction that are important to recognize as nonobstructive coronary artery disease so that optimal care with calcium channel blockers can be provided.
  
  
  BACKGROUND
  URL: www.umin.ac.jp/ctr. Unique identifier: UMIN000003839.
authors: Department of Cardiovascular Medicine, Faculty of Life Sciences, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors: Keisuke
authors: K
authors: Ohba
authors: Seigo
authors: S
authors: Sugiyama
authors: Hitoshi
authors: H
authors: Sumida
authors: Toshimitsu
authors: T
authors: Nozaki
authors: Junichi
authors: J
authors: Matsubara
authors: Yasushi
authors: Y
authors: Matsuzawa
authors: Masaaki
authors: M
authors: Konishi
authors: Eiichi
authors: E
authors: Akiyama
authors: Hirofumi
authors: H
authors: Kurokawa
authors: Hirofumi
authors: H
authors: Maeda
authors: Koichi
authors: K
authors: Sugamura
authors: Yasuhiro
authors: Y
authors: Nagayoshi
authors: Kenji
authors: K
authors: Morihisa
authors: Kenji
authors: K
authors: Sakamoto
authors: Kenichi
authors: K
authors: Tsujita
authors: Eiichiro
authors: E
authors: Yamamoto
authors: Megumi
authors: M
authors: Yamamuro
authors: Sunao
authors: S
authors: Kojima
authors: Koichi
authors: K
authors: Kaikita
authors: Shinji
authors: S
authors: Tayama
authors: Seiji
authors: S
authors: Hokimoto
authors: Kunihiko
authors: K
authors: Matsui
authors: Tomohiro
authors: T
authors: Sakamoto
authors: Hisao
authors: H
authors: Ogawa
mesh_terms: D000109:Acetylcholine; D000368:Aged; D000787:Angina Pectoris / Q000188:drug therapy / Q000503:physiopathology*; D002121:Calcium Channel Blockers / Q000627:therapeutic use*; D006328:Cardiac Catheterization; D017023:Coronary Angiography; D003326:Coronary Circulation; D003329:Coronary Vasospasm / Q000175:diagnosis* / Q000188:drug therapy*; D004562:Electrocardiography; D004730:Endothelium, Vascular / Q000187:drug effects / Q000503:physiopathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D019344:Lactic Acid; D008297:Male; D008875:Middle Aged
chemical_list: D002121:Calcium Channel Blockers; D019344:Lactic Acid; D000109:Acetylcholine
keywords: angina; follow-up studies; microcirculation; vasospasm; women