title: Combination of the Thermodilution-Derived Index of Microcirculatory Resistance and Coronary Flow Reserve Is Highly Predictive of Microvascular Obstruction on Cardiac Magnetic Resonance Imaging After ST-Segment Elevation Myocardial Infarction.
abstract: OBJECTIVE
  The aim of this study was to investigate the predictive accuracy of invasive coronary microvascular indexes for identifying microvascular obstruction (MVO) on cardiac magnetic resonance imaging (CMR) in patients treated with primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI).
  
  
  BACKGROUND
  We hypothesized that a combination of the index of microcirculatory resistance (IMR) and the thermodilution-derived coronary flow reserve (CFRthermo) will enhance the predictive accuracy of detecting MVO compared with either index alone.
  
  
  METHODS
  The IMR and CFRthermo were measured using a single pressure sensor/thermistor-tipped guidewire in 40 STEMI patients immediately after PCI and related to MVO assessed by CMR day 7. The primary endpoint was the predictive accuracy of the IMR for detecting MVO.
  
  
  RESULTS
  Patients with an IMR >36 (upper tertile) had a higher rate of MVO compared with those with an IMR ≤36 (93% vs. 39%; p = 0.001). MVO occurred in all patients with an IMR >36 and a CFRthermo ≤1.7 and in no patients with an IMR ≤36 and a CFRthermo >1.7. The IMR remained an independent predictor of MVO (odds ratio: 1.212, 95% confidence interval [CI]: 1.004 to 1.464; p = 0.045) after adjustment for age, creatine kinase-myocardial band, myocardial blush grade, thrombus burden, and CFRthermo. Both the IMR (area under the curve, 0.868, 95% CI: 0.719 to 0.956; p = 0.001) and the CFRthermo (area under the curve, 0.706, 95% CI: 0.536 to 0.842; p = 0.03) were predictive of MVO. Combined IMR and CFRthermo increased the area under the curve for MVO to 0.941.
  
  
  CONCLUSIONS
  In patients who underwent primary PCI for STEMI, an increased IMR has an independent predictive value for MVO detection, and combined high IMR and low CFRthermo are highly predictive of MVO. These indexes could be used to further risk-stratify patients and guide regional and systemic therapies.
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju Severance Christian Hospital, Wonju, Republic of Korea; Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia.
authors.forename: Sung Gyun
authors.initials: SG
authors.lastname: Ahn
authors.affiliation: Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia.
authors.forename: Olivia Y
authors.initials: OY
authors.lastname: Hung
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju Severance Christian Hospital, Wonju, Republic of Korea.
authors.forename: Jun-Won
authors.initials: JW
authors.lastname: Lee
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju Severance Christian Hospital, Wonju, Republic of Korea.
authors.forename: Ji Hyun
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju Severance Christian Hospital, Wonju, Republic of Korea.
authors.forename: Young Jin
authors.initials: YJ
authors.lastname: Youn
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju Severance Christian Hospital, Wonju, Republic of Korea.
authors.forename: Min-Soo
authors.initials: MS
authors.lastname: Ahn
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju Severance Christian Hospital, Wonju, Republic of Korea.
authors.forename: Jang-Young
authors.initials: JY
authors.lastname: Kim
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju Severance Christian Hospital, Wonju, Republic of Korea.
authors.forename: Byung-Su
authors.initials: BS
authors.lastname: Yoo
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju Severance Christian Hospital, Wonju, Republic of Korea.
authors.forename: Seung-Hwan
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju Severance Christian Hospital, Wonju, Republic of Korea.
authors.forename: Junghan
authors.initials: J
authors.lastname: Yoon
authors.affiliation: Department of Radiology, Yonsei University Wonju College of Medicine, Wonju Severance Christian Hospital, Wonju, Republic of Korea. Electronic address: wckwon@yonsei.ac.kr.
authors.forename: Woocheol
authors.initials: W
authors.lastname: Kwon
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju Severance Christian Hospital, Wonju, Republic of Korea. Electronic address: hsamady@emory.edu.
authors.forename: Habib
authors.initials: H
authors.lastname: Samady
mesh_terms: D000368:Aged; D019540:Area Under Curve; D006328:Cardiac Catheterization; D016009:Chi-Square Distribution; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D006801:Humans; D016015:Logistic Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D016017:Odds Ratio; D062645:Percutaneous Coronary Intervention / Q000009:adverse effects*; D011237:Predictive Value of Tests; D012372:ROC Curve; D015203:Reproducibility of Results; D012307:Risk Factors; D000072657:ST Elevation Myocardial Infarction / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D013815:Thermodilution; D016896:Treatment Outcome; D014655:Vascular Resistance
keywords: blood flow velocity; cardiac magnetic resonance imaging; coronary circulation; myocardial infarction