title: Beneficial effects of intracoronary nicorandil on microvascular dysfunction after primary percutaneous coronary intervention: demonstration of its superiority to nitroglycerin in a cross-over study.
abstract: OBJECTIVE
  In patients undergoing primary percutaneous coronary intervention (PCI) for the treatment of ST-segment elevation myocardial infarction (STEMI), coronary microvascular dysfunction is associated with poor prognosis. Coronary microvascular resistance is predominantly regulated by ATP-sensitive potassium (KATP) channels. The aim of this study was to clarify whether nicorandil, a hybrid KATP channel opener and nitric oxide donor, may be a good candidate for improving microvascular dysfunction even when administered after primary PCI.
  
  
  METHODS
  We compared the beneficial effects of nicorandil and nitroglycerin on microvascular function in 60 consecutive patients with STEMI. After primary PCI, all patients received single intracoronary administrations of nitroglycerin (250 μg) and nicorandil (2 mg) in a randomized order; 30 received nicorandil first, while the other 30 received nitroglycerin first. Microvascular dysfunction was evaluated with the index of microcirculatory resistance (IMR), defined as the distal coronary pressure multiplied by the hyperemic mean transit time.
  
  
  RESULTS
  As a first administration, nicorandil decreased IMR significantly more than did nitroglycerin (median [interquartile ranges]: 10.8[5.2-20.7] U vs. 2.1[1.0-6.0] U, p=0.0002).As a second administration, nicorandil further decreased IMR, while nitroglycerin did not (median [interquartile ranges]: 6.0[1.3-12.7] U vs. -1.4[-2.6 to 1.3] U, p<0.0001). The IMR after the second administration was significantly associated with myocardial blush grade, angiographic TIMI frame count after the procedure, and peak creatine kinase level.
  
  
  CONCLUSIONS
  Intracoronary nicorandil reduced microvascular dysfunction after primary PCI more effectively than did nitroglycerin in patients with STEMI, probably via its KATP channel-opening effect.
authors.affiliation: Senri Critical Care Medical Center, Osaka Saiseikai Senri Hospital, 1-1-6, Tsukumodai, Suita, Osaka 565-0862, Japan. norinoriito@hotmail.co.jp
authors.forename: Noritoshi
authors.initials: N
authors.lastname: Ito
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Nanto
authors.forename: Yasuji
authors.initials: Y
authors.lastname: Doi
authors.forename: Yuma
authors.initials: Y
authors.lastname: Kurozumi
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Natsukawa
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Shibata
authors.forename: Masaya
authors.initials: M
authors.lastname: Morita
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kawata
authors.forename: Ayumu
authors.initials: A
authors.lastname: Tsuruoka
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Sawano
authors.forename: Ken-ichiro
authors.initials: K
authors.lastname: Okada
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Sakata
authors.forename: Tatsuro
authors.initials: T
authors.lastname: Kai
authors.forename: Toru
authors.initials: T
authors.lastname: Hayashi
mesh_terms: D000368:Aged; D018592:Cross-Over Studies; D004333:Drug Administration Routes; D005260:Female; D006801:Humans; D008297:Male; D055806:Microvessels / Q000187:drug effects / Q000503:physiopathology; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology / Q000628:therapy*; D020108:Nicorandil / Q000008:administration & dosage*; D020030:Nitric Oxide Donors / Q000008:administration & dosage*; D005996:Nitroglycerin / Q000008:administration & dosage*; D062645:Percutaneous Coronary Intervention; D014655:Vascular Resistance / Q000187:drug effects
chemical_list: D020030:Nitric Oxide Donors; D020108:Nicorandil; D005996:Nitroglycerin