title: Impact of aortic root size on left ventricular afterload and stroke volume.
abstract: OBJECTIVE
  The left ventricle (LV) ejects blood into the proximal aorta. Age and hypertension are associated with stiffening and dilation of the aortic root, typically viewed as indicative of adverse remodeling. Based on analytical considerations, we hypothesized that a larger aortic root should be associated with lower global afterload (effective arterial elastance, EA) and larger stroke volume (SV). Moreover, as antihypertensive drugs differ in their effect on central blood pressure, we examined the role of antihypertensive drugs for the relation between aortic root size and afterload.
  
  
  METHODS
  We studied a large group of patients (n = 1250; 61 ± 12 years; 78 % males; 64 % hypertensives) from a single-center registry with known or suspected coronary artery disease. Aortic root size was measured by echocardiography as the diameter of the tubular portion of the ascending aorta. LV outflow tract Doppler was used to record SV.
  
  
  RESULTS
  In the population as a whole, after adjusting for key covariates in separate regression models, aortic root size was an independent determinant of both SV and EA. This association was found to be heterogeneous and stronger in patients taking a calcium channel blocker (CCB; 10.6 % of entire population; aortic root size accounted for 8 % of the explained variance of EA).
  
  
  CONCLUSIONS
  Larger aortic root size is an independent determinant of EA and SV. This association was heterogeneous and stronger in patients on CCB therapy.
authors.affiliation: National Heart Centre Singapore, 5 Hospital Drive, Singapore, 169609, Singapore. anders.sahlen@ki.se.|Karolinska Institutet, Department of Cardiology, Karolinska University Hospital, 141 86, Stockholm, Sweden. anders.sahlen@ki.se.
authors.forename: Anders
authors.initials: A
authors.lastname: Sahlén
authors.affiliation: National Heart Centre Singapore, 5 Hospital Drive, Singapore, 169609, Singapore.
authors.forename: Nadira
authors.initials: N
authors.lastname: Hamid
authors.affiliation: National Heart Centre Singapore, 5 Hospital Drive, Singapore, 169609, Singapore.
authors.forename: Mohammed Rizwan
authors.initials: MR
authors.lastname: Amanullah
authors.affiliation: National Heart Centre Singapore, 5 Hospital Drive, Singapore, 169609, Singapore.
authors.forename: Jiang Ming
authors.initials: JM
authors.lastname: Fam
authors.affiliation: National Heart Centre Singapore, 5 Hospital Drive, Singapore, 169609, Singapore.
authors.forename: Khung Keong
authors.initials: KK
authors.lastname: Yeo
authors.affiliation: National Heart Centre Singapore, 5 Hospital Drive, Singapore, 169609, Singapore.
authors.forename: Yee How
authors.initials: YH
authors.lastname: Lau
authors.affiliation: National Heart Centre Singapore, 5 Hospital Drive, Singapore, 169609, Singapore.
authors.forename: Carolyn S P
authors.initials: CS
authors.lastname: Lam
authors.affiliation: National Heart Centre Singapore, 5 Hospital Drive, Singapore, 169609, Singapore.
authors.forename: Zee Pin
authors.initials: ZP
authors.lastname: Ding
mesh_terms: D001011:Aorta / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000502:physiology*; D062186:Arterial Pressure / Q000502:physiology*; D003198:Computer Simulation; D004452:Echocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D009929:Organ Size / Q000502:physiology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013318:Stroke Volume / Q000502:physiology*; D016277:Ventricular Function, Left / Q000502:physiology*; D017725:Ventricular Pressure / Q000502:physiology*
keywords: Afterload; Aorta; Calcium antagonist; Stroke volume