title: Left Ventricular Myocardial and Hemodynamic Response to Exercise in Young Patients after Endovascular Stenting for Aortic Coarctation.
abstract: BACKGROUND
  Endovascular stenting has emerged as a treatment option for children with coarctation of the aortic (CoA), but the impact on left ventricular (LV) function has been poorly documented. The aim of this study was to characterize the LV myocardial and hemodynamic response to exercise in young patients who underwent endovascular stenting for CoA during childhood using semisupine bicycle exercise stress echocardiography.
  
  
  METHODS
  This was a single-center prospective cross-sectional study including 30 patients with CoA and 30 age- and gender-matched control subjects who underwent semisupine bicycle exercise stress echocardiography. Color Doppler tissue imaging peak systolic (s') and early diastolic (e') velocities in the LV lateral wall and basal septum, LV myocardial acceleration during isovolumic acceleration were measured at rest and with incremental heart rate (HR). The relationship with increasing HR was evaluated for each parameter by plotting the values at each stage of exercise versus HR.
  
  
  RESULTS
  At rest, HR was similar between the two groups. LV ejection fraction and fractional shortening were within the normal range in the CoA group. LV lateral wall and basal septal s' and e' velocities did not differ between the two groups, but isovolumic acceleration values were significantly lower in the CoA group. At peak exercise, HR was similar between the groups, but all Doppler tissue imaging parameters were lower in patients than in control subjects. When assessing the increase of each parameter versus HR, the increase in slope was significantly lower in patients than in control subjects for LV lateral wall Doppler tissue imaging s' and e' velocities, and septal e' velocity, but not for septal s'. The relationship of isovolumic acceleration with HR was significantly reduced in the CoA group.
  
  
  CONCLUSIONS
  The results of this study demonstrate reduced systolic and diastolic myocardial reserve in patients with CoA compared with control subjects. An abnormal myocardial contractile response to exercise was also found, as shown by an abnormal LV force-frequency relationship in patients with stented CoA. The prognostic clinical implications require further study.
authors.affiliation: Department of Pediatrics, Division of Cardiology, The Labatt Family Heart Centre, The Hospital for Sick Children, University of Toronto School of Medicine, Toronto, Ontario, Canada.
authors.forename: Ching Kit
authors.initials: CK
authors.lastname: Chen
authors.affiliation: Department of Pediatrics, Division of Cardiology, The Labatt Family Heart Centre, The Hospital for Sick Children, University of Toronto School of Medicine, Toronto, Ontario, Canada.
authors.forename: Barbara
authors.initials: B
authors.lastname: Cifra
authors.affiliation: Department of Pediatrics, Division of Cardiology, The Labatt Family Heart Centre, The Hospital for Sick Children, University of Toronto School of Medicine, Toronto, Ontario, Canada.
authors.forename: Gareth J
authors.initials: GJ
authors.lastname: Morgan
authors.affiliation: Department of Pediatrics, Division of Cardiology, The Labatt Family Heart Centre, The Hospital for Sick Children, University of Toronto School of Medicine, Toronto, Ontario, Canada.
authors.forename: Taisto
authors.initials: T
authors.lastname: Sarkola
authors.affiliation: Department of Pediatrics, Division of Cardiology, The Labatt Family Heart Centre, The Hospital for Sick Children, University of Toronto School of Medicine, Toronto, Ontario, Canada.
authors.forename: Cameron
authors.initials: C
authors.lastname: Slorach
authors.affiliation: Department of Pediatrics, Division of Cardiology, The Labatt Family Heart Centre, The Hospital for Sick Children, University of Toronto School of Medicine, Toronto, Ontario, Canada.
authors.forename: Hui
authors.initials: H
authors.lastname: Wei
authors.affiliation: Department of Pediatrics, Division of Cardiology, The Labatt Family Heart Centre, The Hospital for Sick Children, University of Toronto School of Medicine, Toronto, Ontario, Canada.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Bradley
authors.affiliation: Department of Pediatrics, Division of Cardiology, The Labatt Family Heart Centre, The Hospital for Sick Children, University of Toronto School of Medicine, Toronto, Ontario, Canada.
authors.forename: Cedric
authors.initials: C
authors.lastname: Manlhiot
authors.affiliation: Department of Pediatrics, Division of Cardiology, The Labatt Family Heart Centre, The Hospital for Sick Children, University of Toronto School of Medicine, Toronto, Ontario, Canada.
authors.forename: Brian W
authors.initials: BW
authors.lastname: McCrindle
authors.affiliation: Department of Pediatrics, Division of Cardiology, The Labatt Family Heart Centre, The Hospital for Sick Children, University of Toronto School of Medicine, Toronto, Ontario, Canada.
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Redington
authors.affiliation: Department of Pediatrics, Division of Cardiology, The Labatt Family Heart Centre, The Hospital for Sick Children, University of Toronto School of Medicine, Toronto, Ontario, Canada.
authors.forename: Lee N
authors.initials: LN
authors.lastname: Benson
authors.affiliation: Department of Pediatrics, Division of Cardiology, The Labatt Family Heart Centre, The Hospital for Sick Children, University of Toronto School of Medicine, Toronto, Ontario, Canada. Electronic address: luc.mertens@sickkids.ca.
authors.forename: Luc
authors.initials: L
authors.lastname: Mertens
mesh_terms: D001017:Aortic Coarctation / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery*; D002648:Child; D055119:Elastic Modulus; D057510:Endovascular Procedures / Q000295:instrumentation*; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015607:Stents; D013318:Stroke Volume; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000517:prevention & control*; D055815:Young Adult
keywords: Coarctation of the aorta; Echocardiography; Endovascular stent; Exercise; Force-frequency relationship; Isovolumic acceleration