title: Ventriculo-vascular interactions in patients with beta thalassaemia major.
abstract: OBJECTIVE
  To determine potential interactions between the heart and arterial system in patients with beta thalassaemia major.
  
  
  METHODS
  Vascular compliance, systemic vascular resistance, and left ventricular (LV) contractility was determined in 34 asymptomatic thalassaemia patients at 2-4 hours after blood transfusion and also in 34 age and sex matched controls using a non-invasive device. The results were compared between groups and inter-relationships between LV contractility and indices of vascular load were explored.
  
  
  METHODS
  Tertiary paediatric cardiac centre.
  
  
  RESULTS
  When compared with controls, patients had greater systemic vascular resistance (1633 (259) v 1377 (276) dynes/s/cm5, p < 0.001) and effective arterial elastance (E(a)) (1.86 (0.25) v 1.65 (0.29) mm Hg/ml, p = 0.001), an index of combined pulsatile and static vascular load. On the other hand, their systolic blood pressure (104 (9) v 112 (13) mm Hg, p = 0.006), pulse pressure (45 (9) v 57 (10) mm Hg, p < 0.001), adjusted systemic vascular compliance (1.21 (0.09) v 1.37 (0.14), p < 0.001), adjusted brachial artery distensibility (21 (0.29) v 7.95 (0.29)%/mm Hg, p < 0.001) and LV+dP/dt (1059 (183) v 1239 (237) mm Hg/s, p = 0.001) were significantly lower. Significant determinants of LV contractility, as reflected by LV+dP/dt, were age (standardised beta = -0.24, p = 0.003), body mass index (standardised beta = -0.34, p = 0.004), systolic blood pressure (standardised beta = 0.90, p < 0.001), and effective E(a) (standardised beta = -0.50, p < 0.001) (model R2 = 0.69). No significant correlation existed between serum ferritin concentration and any of the cardiac or vascular indices.
  
  
  CONCLUSIONS
  An unfavourable ventriculo-vascular interaction, as characterised by impaired cardiac contractility and increased static and pulsatile vascular load, occurs in patients with beta thalassaemia major.
authors.affiliation: Division of Paediatric Cardiology, Grantham Hospital, University of Hong Kong, Aberdeen, Hong Kong, PRC. xfcheung@hkucc.hku.hk
authors.forename: Y F
authors.initials: YF
authors.lastname: Cheung
authors.forename: S Y
authors.initials: SY
authors.lastname: Ha
authors.forename: G C F
authors.initials: GC
authors.lastname: Chan
mesh_terms: D001158:Arteries / Q000503:physiopathology; D001794:Blood Pressure / Q000502:physiology; D003187:Compliance; D005260:Female; D006801:Humans; D008297:Male; D009200:Myocardial Contraction / Q000502:physiology; D013318:Stroke Volume / Q000502:physiology; D014655:Vascular Resistance / Q000502:physiology; D018487:Ventricular Dysfunction, Left / Q000150:complications / Q000503:physiopathology*; D017086:beta-Thalassemia / Q000150:complications / Q000503:physiopathology*