title: Thermodilution-derived coronary blood flow pattern immediately after coronary intervention as a predictor of microcirculatory damage and midterm clinical outcomes in patients with ST-segment-elevation myocardial infarction.
abstract: BACKGROUND
  Despite a sufficient coronary blood flow after primary percutaneous coronary intervention for patients with ST-segment-elevation myocardial infarction; some patients have a poor outcome because of microcirculatory damage. This study evaluates whether the thermodilution-derived coronary blood flow parameters immediately after primary percutaneous coronary intervention predict early microvascular damage and midterm outcomes in patients with ST-segment-elevation myocardial infarction.
  
  
  RESULTS
  Using a pressure sensor/thermistor-tipped guidewire, we measured the index of microcirculatory resistance at maximum hyperemia, and coronary blood flow pattern was assessed from the thermodilution curves after successful primary percutaneous coronary intervention in 88 patients with ST-segment-elevation myocardial infarction. Coronary blood flow pattern was classified into 3 groups according to the shape of thermodilution curve: a narrow unimodal (n=41), a wide unimodal (n=32), or bimodal (n=15). All patients had contrast-enhanced cardiac magnetic resonance scans within 2 weeks. The index of microcirculatory resistance values were significantly higher both in a wide unimodal and in a bimodal groups than in a narrow unimodal group (65±41 and 76±38 versus 20±9U; P<0.001). Bimodal group had higher prevalence of microvascular obstruction on contrast-enhanced cardiac magnetic resonance when compared with the other groups (100%, 78%, and 30%; P<0.001). Patients in bimodal group had a higher risk of death and heart failure rehospitalization at 6 months (73%, 6.3%, 7.3%; P<0.001). Multivariate analysis revealed that bimodal shape of the thermodilution curve was the only independent predictor of cardiac death at 6 months after ST-segment-elevation myocardial infarction (P<0.01).
  
  
  CONCLUSIONS
  A bimodal shape of the thermodilution curve, which may indicate myocardial edema and consequent extrinsic compression of the capillary network, is associated with microcirculatory damage and poor midterm clinical outcomes rather than index of microcirculatory resistance value itself.
authors.affiliation: From the Cardiovascular Division (M.F., K.F., D.K., H.S., K.M., H.T., T. Imanaka, T. Iwasaku, T.N., M.S., H.A., T.M.), Division of Coronary Heart Disease (M.M., M.O.), and Department of Radiology (K.K.), Hyogo College of Medicine, Nishinomiya, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Fukunaga
authors.forename: Kenichi
authors.initials: K
authors.lastname: Fujii
authors.forename: Daizo
authors.initials: D
authors.lastname: Kawasaki
authors.forename: Hisashi
authors.initials: H
authors.lastname: Sawada
authors.forename: Koujiro
authors.initials: K
authors.lastname: Miki
authors.forename: Hiroto
authors.initials: H
authors.lastname: Tamaru
authors.forename: Takahiro
authors.initials: T
authors.lastname: Imanaka
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Iwasaku
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Nakata
authors.forename: Masahiko
authors.initials: M
authors.lastname: Shibuya
authors.forename: Hirokuni
authors.initials: H
authors.lastname: Akahori
authors.forename: Motomaru
authors.initials: M
authors.lastname: Masutani
authors.forename: Kaoru
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Mitsumasa
authors.initials: M
authors.lastname: Ohyanagi
authors.forename: Tohru
authors.initials: T
authors.lastname: Masuyama
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003331:Coronary Vessels / Q000473:pathology / Q000503:physiopathology*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D008875:Middle Aged; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000503:physiopathology / Q000628:therapy*; D009206:Myocardium / Q000473:pathology; D062645:Percutaneous Coronary Intervention / Q000009:adverse effects*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012039:Regional Blood Flow / Q000502:physiology*; D012189:Retrospective Studies; D013815:Thermodilution / Q000379:methods; D016896:Treatment Outcome; D014655:Vascular Resistance / Q000502:physiology*
keywords: catheterization; microcirculation; myocardial infarction; renal blood flow