title: Shock Index as a Predictor of Myocardial Injury in ST-segment Elevation Myocardial Infarction.
abstract: BACKGROUND
  Little is known about the association between shock index and myocardial injury in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI).
  
  
  METHODS
  We analyzed cardiac magnetic resonance imaging from 306 consecutive patients treated with primary PCI for STEMI. The patients were divided into the following 2 groups: initial shock index >0.7 (n = 88) and ≤0.7 (n = 218). Shock index was calculated as the ratio of heart rate to systolic blood pressure based on the first recorded vital signs upon arrival. The primary end point was myocardial infarct size.
  
  
  RESULTS
  The shock index >0.7 group, exhibited a lower baseline left ventricular ejection fraction (P = 0.01), higher N-terminal prohormone of brain natriuretic peptide level (P = 0.01), higher Killip class (P < 0.01) and higher prevalence of diabetes (P = 0.02) than the shock index ≤0.7 group. There were no significant differences in the angiographic or procedural characteristics between the 2 groups. In cardiac magnetic resonance imaging analysis, the shock index >0.7 group had a larger infarct size than did the shock index ≤0.7 group (22.9 ± 11.2% versus 19.2 ± 11.5%, P < 0.01). According to multivariate analysis, shock index >0.7 was associated with large myocardial infarctions (odds ratio = 3.02; 95% CI: 1.62-5.65; P < 0.01).
  
  
  CONCLUSIONS
  Initial shock index is a potentially reliable predictor of myocardial injury in patients with STEMI undergoing primary PCI.
authors.affiliation: Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Jin Kyung
authors.initials: JK
authors.lastname: Hwang
authors.affiliation: Department of Internal Medicine, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Republic of Korea.
authors.forename: Woo Jin
authors.initials: WJ
authors.lastname: Jang
authors.affiliation: Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea. Electronic address: youngbin.song@gmail.com.
authors.forename: Young Bin
authors.initials: YB
authors.lastname: Song
authors.affiliation: Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.
authors.forename: Joao A C
authors.initials: JA
authors.lastname: Lima
authors.affiliation: Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Eliseo
authors.initials: E
authors.lastname: Guallar
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 Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Soonuk
authors.initials: S
authors.lastname: Choi
authors.affiliation: Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Eun Kyoung
authors.initials: EK
authors.lastname: Kim
authors.affiliation: Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Joo-Yong
authors.initials: JY
authors.lastname: Hahn
authors.affiliation: Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Seung-Hyuk
authors.initials: SH
authors.lastname: Choi
authors.affiliation: Department of Medicine, 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: Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Hyeon-Cheol
authors.initials: HC
authors.lastname: Gwon
mesh_terms: D000368:Aged; D057791:Cardiac Imaging Techniques; D017023:Coronary Angiography; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology*; D000072657:ST Elevation Myocardial Infarction / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy; D012720:Severity of Illness Index
keywords: Magnetic resonance imaging; Myocardial injury; ST-segment elevation myocardial infarction; Shock index