title: Reduced Myocardial Flow in Heart Failure Patients With Preserved Ejection Fraction.
abstract: There remains limited insight into the pathophysiology and therapeutic advances directed at improving prognosis for patients with heart failure with preserved ejection fraction (HFpEF). Recent studies have suggested a role for coronary microvascular dysfunction in HFpEF. Rb-82 cardiac positron emission tomography imaging is a noninvasive, quantitative approach to measuring myocardial flow reserve (MFR), a surrogate marker for coronary vascular health. The aim of this study was to determine whether abnormalities exist in MFR in patients with HFpEF without epicardial coronary artery disease.
  
  
  
  A total of 376 patients with ejection fraction ≥50%, no known history of obstructive coronary artery disease, and a confirmed diagnosis of heart failure (n=78) were compared with patients with no evidence of heart failure (n=298), further stratified into those with (n=186) and without (n=112) hypertension. Global and regional left ventricular MFR was calculated as stress/rest myocardial blood flow using Rb-82 positron emission tomography. Patients with HFpEF were more likely to be older, female, and have comorbid hypertension, diabetes mellitus, dyslipidemia, atrial fibrillation, anemia, and renal dysfunction. HFpEF was associated with a significant reduction in global MFR (2.16±0.69 in HFpEF versus 2.54±0.80 in hypertensive controls; P<0.02 and 2.89±0.70 in normotensive controls; P<0.001). A diagnosis of HFpEF was associated with 2.62 times greater unadjusted odds of having low global MFR (defined as <2.0) and remained a significant predictor of reduced global MFR after adjusting for comorbidities.
  
  
  
  HFpEF, in the absence of known history for obstructive epicardial coronary artery disease, is associated with reduced MFR independent of other risk factors.
authors.affiliation: From the Division of Cardiology, University of Ottawa Heart Institute, Ontario, Canada.
authors.forename: Kajenny
authors.initials: K
authors.lastname: Srivaratharajah
authors.affiliation: From the Division of Cardiology, University of Ottawa Heart Institute, Ontario, Canada.
authors.forename: Thais
authors.initials: T
authors.lastname: Coutinho
authors.affiliation: From the Division of Cardiology, University of Ottawa Heart Institute, Ontario, Canada.
authors.forename: Robert
authors.initials: R
authors.lastname: deKemp
authors.affiliation: From the Division of Cardiology, University of Ottawa Heart Institute, Ontario, Canada.
authors.forename: Peter
authors.initials: P
authors.lastname: Liu
authors.affiliation: From the Division of Cardiology, University of Ottawa Heart Institute, Ontario, Canada.
authors.forename: Haissam
authors.initials: H
authors.lastname: Haddad
authors.affiliation: From the Division of Cardiology, University of Ottawa Heart Institute, Ontario, Canada.
authors.forename: Ellamae
authors.initials: E
authors.lastname: Stadnick
authors.affiliation: From the Division of Cardiology, University of Ottawa Heart Institute, Ontario, Canada.
authors.forename: Ross A
authors.initials: RA
authors.lastname: Davies
authors.affiliation: From the Division of Cardiology, University of Ottawa Heart Institute, Ontario, Canada.
authors.forename: Sharon
authors.initials: S
authors.lastname: Chih
authors.affiliation: From the Division of Cardiology, University of Ottawa Heart Institute, Ontario, Canada.
authors.forename: Girish
authors.initials: G
authors.lastname: Dwivedi
authors.affiliation: From the Division of Cardiology, University of Ottawa Heart Institute, Ontario, Canada.
authors.forename: Ann
authors.initials: A
authors.lastname: Guo
authors.affiliation: From the Division of Cardiology, University of Ottawa Heart Institute, Ontario, Canada.
authors.forename: George A
authors.initials: GA
authors.lastname: Wells
authors.affiliation: From the Division of Cardiology, University of Ottawa Heart Institute, Ontario, Canada.
authors.forename: Jordan
authors.initials: J
authors.lastname: Bernick
authors.affiliation: From the Division of Cardiology, University of Ottawa Heart Institute, Ontario, Canada.
authors.forename: Robert
authors.initials: R
authors.lastname: Beanlands
authors.affiliation: From the Division of Cardiology, University of Ottawa Heart Institute, Ontario, Canada. lmielniczuk@ottawaheart.ca.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Mielniczuk
mesh_terms: D000367:Age Factors; D000368:Aged; D016009:Chi-Square Distribution; D015897:Comorbidity; D003326:Coronary Circulation; D003430:Cross-Sectional Studies; D016208:Databases, Factual; D015150:Echocardiography, Doppler; D005260:Female; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D016014:Linear Models; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D015999:Multivariate Analysis; D055414:Myocardial Perfusion Imaging / Q000379:methods; D016017:Odds Ratio; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D019275:Radiopharmaceuticals / Q000008:administration & dosage; D012189:Retrospective Studies; D012307:Risk Factors; D012413:Rubidium / Q000008:administration & dosage; D012737:Sex Factors; D013318:Stroke Volume; D016277:Ventricular Function, Left
chemical_list: D019275:Radiopharmaceuticals; D012413:Rubidium
keywords: comorbidity; coronary circulation; echocardiography; heart failure; positron emission tomography