title: A randomized, double blind pilot study to assess the effects of losartan vs. atenolol on the biophysical properties of the aorta in patients with Marfan and Loeys-Dietz syndromes.
abstract: BACKGROUND
  Patients with Marfan (MFS) and Loeys-Dietz (LDS) syndromes have been shown to have abnormal aortic biophysical properties. The purpose of this study was to compare the effects of 12-months of therapy with atenolol or losartan on vascular function in young patients with MFS and LDS.
  
  
  METHODS
  Seventeen patients with MFS or LDS were recruited and randomized to treatment with atenolol, 25-50mg, or losartan, 25mg daily. Prior to treatment and following therapy, echocardiography for left ventricular size, function and aortic root size was performed. Pulse wave velocity (PWV), input (Zi, ZiF) and characteristic (Zc, ZcF) impedances, arterial stiffness (Ep and β-index), total arterial compliance (TAC), mean (Wm) and total (Wt) hydraulic power, efficiency, power cost per unit of forward flow (Wt/CI) and brachial artery flow-mediated dilation (FMD) were measured.
  
  
  RESULTS
  The atenolol group consisted of 9 females (17.6years) and the losartan group 7 males and 1 female (17.0years). Their height, weight, BSA, BMI, systolic and diastolic blood pressures were similar. Baseline to 12-month changes for atenolol and losartan were PWV (20% vs -14%), Zi (-2% vs -27%), Zc (-20% vs -27%), Ep (1%, vs -13%), β-index (10% vs 14%), FMD (11% vs 20%), TAC (3% vs 42%), Wm (-24% vs 15%), Wt (-24% vs 17%), and Wt/CI (3% vs 21%). There was a trend for losartan to decrease PWV and stiffness indexes while atenolol decreased power and power/unit flow.
  
  
  CONCLUSIONS
  This pilot study suggests that atenolol and losartan may have different mechanisms of action on vascular function. A larger clinical trial is needed to confirm these effects.Clinical trials registration NCT00593710 (ClinicalTrials.gov).
authors.affiliation: Children's Heart Centre, British Columbia Children's Hospital, The University of British Columbia, Vancouver, Canada. Electronic address: gsandor@cw.bc.ca.
authors.forename: George G S
authors.initials: GG
authors.lastname: Sandor
authors.affiliation: Children's Heart Centre, British Columbia Children's Hospital, The University of British Columbia, Vancouver, Canada.
authors.forename: Mohammed H
authors.initials: MH
authors.lastname: Alghamdi
authors.affiliation: Children's Heart Centre, British Columbia Children's Hospital, The University of British Columbia, Vancouver, Canada.
authors.forename: Leslie A
authors.initials: LA
authors.lastname: Raffin
authors.affiliation: Children's Heart Centre, British Columbia Children's Hospital, The University of British Columbia, Vancouver, Canada.
authors.forename: Mary T
authors.initials: MT
authors.lastname: Potts
authors.affiliation: Children's Heart Centre, British Columbia Children's Hospital, The University of British Columbia, Vancouver, Canada.
authors.forename: Lindsey D
authors.initials: LD
authors.lastname: Williams
authors.affiliation: Children's Heart Centre, British Columbia Children's Hospital, The University of British Columbia, Vancouver, Canada.
authors.forename: James E
authors.initials: JE
authors.lastname: Potts
authors.affiliation: Division of Cardiology, Department of Medicine, St. Paul's Hospital, The University of British Columbia, Vancouver, Canada.
authors.forename: Marla
authors.initials: M
authors.lastname: Kiess
authors.affiliation: Department of Pharmacology and Therapeutics, The University of British Columbia, Vancouver, Canada.
authors.forename: Casey
authors.initials: C
authors.lastname: van Breemen
mesh_terms: D000293:Adolescent; D058671:Adrenergic beta-1 Receptor Antagonists / Q000627:therapeutic use*; D047228:Angiotensin II Type 1 Receptor Blockers / Q000627:therapeutic use*; D001011:Aorta / Q000187:drug effects* / Q000503:physiopathology*; D001262:Atenolol / Q000627:therapeutic use*; D004311:Double-Blind Method; D004452:Echocardiography; D004730:Endothelium, Vascular / Q000187:drug effects / Q000503:physiopathology; D005260:Female; D006801:Humans; D055947:Loeys-Dietz Syndrome / Q000188:drug therapy* / Q000503:physiopathology*; D019808:Losartan / Q000627:therapeutic use*; D008297:Male; D008382:Marfan Syndrome / Q000188:drug therapy* / Q000503:physiopathology*; D010865:Pilot Projects; D063177:Pulse Wave Analysis; D016896:Treatment Outcome
chemical_list: D058671:Adrenergic beta-1 Receptor Antagonists; D047228:Angiotensin II Type 1 Receptor Blockers; D001262:Atenolol; D019808:Losartan
keywords: Atenolol; Clinical trial; Loeys–Dietz syndrome; Losartan; Marfan syndrome; Vascular function