title: Inter-arm Blood Pressure Difference and its Relationship with Retinal Microvascular Calibres in Young Individuals: The African-PREDICT Study.
abstract: BACKGROUND
  Bilateral systolic blood pressure (SBP) differences > 10mmHg is a common finding in clinical practice. Such BP differences in older individuals are associated with peripheral vascular disease, linked to microvascular dysfunction. Investigating retinal vessel calibres could provide insight into systemic microvascular function and may predict cardiovascular outcomes. Therefore we investigated the link between inter-arm systolic blood pressure differences (IASBPD) and the retinal microvasculature to determine the usefulness of IASBPD as an early marker of microvascular changes.
  
  
  METHODS
  In this cross-sectional study, we used data from 403 apparently healthy participants (20-30 years) (42% men; 49% black) taking part in the African-PREDICT study. Participants underwent retinal vessel imaging, anthropometric measurements and blood sampling. Brachial BP was measured sequentially in both arms to determine the mean IASBPD.
  
  
  RESULTS
  Participants were stratified into two groups with an IASBPD < 10mmHg (n=329) and ≥ 10mmHg (n=47), the only difference in characteristics being a higher right arm SBP in the latter group (p=0.005). We found no association between IASBPD and retinal vessel calibres in any group. Less than 2% of the variance in IASBPD was explained by potential risk factors, with only SBP associating independently with IASBPD (β=115; p=0.039).
  
  
  CONCLUSIONS
  In a young population an increased IASBPD is not related to retinal vessel diameters suggesting that it does not reflect early microvascular alterations.
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa.
authors.forename: Michél
authors.initials: M
authors.lastname: Strauss
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa.
authors.forename: Wayne
authors.initials: W
authors.lastname: Smith
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa; MRC Research Unit: Hypertension and Cardiovascular Disease, North-West University, Potchefstroom, South Africa. Electronic address: Alta.Schutte@nwu.ac.za.
authors.forename: Aletta E
authors.initials: AE
authors.lastname: Schutte
mesh_terms: D000328:Adult; D001132:Arm / Q000503:physiopathology*; D001794:Blood Pressure; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D016491:Peripheral Vascular Diseases / Q000175:diagnosis / Q000503:physiopathology*; D012171:Retinal Vessels / Q000503:physiopathology*; D013019:South Africa
keywords: Inflammation; Inter-arm systolic blood pressure difference; Microvascular alterations; Peripheral vascular disease; Retinal vessel calibres; Young