title: Differential effects of antihypertensive treatment on the retinal microcirculation: an anglo-scandinavian cardiac outcomes trial substudy.
abstract: Changes in the retinal microcirculation are associated with hypertension and predict cardiovascular mortality. There are few data describing the impact of antihypertensive therapy on retinal vascular changes. This substudy of the Anglo-Scandinavian Cardiac Outcomes Trial compared the effects of an amlodipine-based regimen (373 patients) with an atenolol-based regimen (347 patients) on retinal microvascular measurements made from fundus photographs. The retinal photographs were taken at a stage in the trial when treatments were stable and blood pressure was well controlled. Amlodipine-based treatment was associated with a smaller arteriolar length:diameter ratio than atenolol-based treatment (13.32 [10.75 to 16.04] versus 14.12 [11.27 to 17.81], median [interquartile range]; P<0.01). The association remained significant after adjustment for age, sex, cholesterol, systolic and diastolic blood pressures, body mass index, smoking, and statin treatment. This effect appeared to be largely attributable to shorter retinal arteriolar segment lengths in the amlodipine-treated group and is best explained by the vasodilator effects of amlodipine causing the visible emergence of branching side vessels. Photographic assessment of the retinal vascular network may be a useful approach to evaluating microvascular structural responses in clinical trials of antihypertensive therapy.
authors.affiliation: International Centre for Circulatory Health, 59-61 North Wharf Rd, Paddington, London W2 1NY, United Kingdom. s.thom@imperial.ac.uk.
authors.forename: Simon
authors.initials: S
authors.lastname: Thom
authors.forename: Christoph
authors.initials: C
authors.lastname: Stettler
authors.forename: Alice
authors.initials: A
authors.lastname: Stanton
authors.forename: Nicholas
authors.initials: N
authors.lastname: Witt
authors.forename: Robyn
authors.initials: R
authors.lastname: Tapp
authors.forename: Nish
authors.initials: N
authors.lastname: Chaturvedi
authors.forename: Sabin
authors.initials: S
authors.lastname: Allemann
authors.forename: Jamil
authors.initials: J
authors.lastname: Mayet
authors.forename: Peter
authors.initials: P
authors.lastname: Sever
authors.forename: Neil
authors.initials: N
authors.lastname: Poulter
authors.forename: Eoin
authors.initials: E
authors.lastname: O'Brien
authors.forename: Alun
authors.initials: A
authors.lastname: Hughes
mesh_terms: D000368:Aged; D017311:Amlodipine / Q000008:administration & dosage*; D000959:Antihypertensive Agents / Q000008:administration & dosage*; D001262:Atenolol / Q000008:administration & dosage*; D002318:Cardiovascular Diseases / Q000517:prevention & control; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy*; D016014:Linear Models; D008297:Male; D008833:Microcirculation / Q000187:drug effects* / Q000502:physiology; D008875:Middle Aged; D015999:Multivariate Analysis; D011336:Probability; D011446:Prospective Studies; D012164:Retinal Diseases / Q000188:drug therapy / Q000209:etiology; D012171:Retinal Vessels / Q000187:drug effects*; D018570:Risk Assessment; D012537:Scandinavian and Nordic Countries; D012720:Severity of Illness Index; D016896:Treatment Outcome; D006113:United Kingdom
chemical_list: D000959:Antihypertensive Agents; D017311:Amlodipine; D001262:Atenolol