Hypertension Related Damage to the Microcirculation in South Asian: Emergence, Predictive Power and Reversibility
Recruitment status was Not yet recruiting
Damage to very small blood vessels is a consequence, but can also precede high blood pressure. Such damage, measured by disturbances in the vessels in the retina (back of the eye) is a strong predictor of heart disease and stroke. South Asian people have one of the highest rates of hypertension in the world (30% in adults). In Pakistan, this is usually severe, undetected and untreated. The Wellcome Trust has already funded a study of blood pressure control in adults and children in this population. We propose a substudy, taking photographs of the retina and making measurements of the vessels, to determine whether such blood pressure related changes occur at an early age in young children with a family history of high blood pressure compared to those without, whether such changes predict an increase in blood pressure over time, and whether, in adults, such changes can be reversed by blood pressure treatment. The hypothesis of our study is: young offspring of South Asian people with hypertension have a disturbed microcirculation, as assessed by abnormalities of retinal vessels, compared to offspring of normotensive parents. Our 2nd hypothesis is: Abnormal retinal vascular geometry will improve proportionately to achieved reductions in BP.
Behavioral: GP training and Health Education
|Study Design:||Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Factorial Assignment
Masking: Single Blind
Primary Purpose: Prevention
|Official Title:||Hypertension Related Damage to the Microcirculation in South Asian: Emergence,Predictive Power and Reversibility|
- Primary outcome would be abnormal retinal geometry defined as the composite outcome of a) abnormal arteriolar length: diameter, b) narrowed branching angles, or c) disturbed junction exponents.
|Study Start Date:||May 2006|
|Estimated Study Completion Date:||June 2009|
The role of the microcirculation is increasingly being recognized in the etiopathogenesis of cardiovascular disease. Delays in this recognition are in part due to the difficulty of studying the microcirculation non-invasively, in large numbers of individuals. Retinal vessels provide an easily accessible “window” to the microcirculation. Abnormalities of the retinal vasculature have been shown to be associated with cardiovascular risk factors and all cause mortality. Non-invasive assessment of the retinal circulation presents a valuable opportunity to study the structure and function of the microvasculature
Aims of the project
To compare geometry of retinal microvasculature of 1) hypertensive vs normotensive adults, 2) children aged 10 to 14 years of hypertensive parent (test group) versus normotensive parent (control group), and, 3) to assess the impact of blood pressure lowering on these changes over 2 years.
Primary outcome would be abnormal retinal geometry defined as the composite outcome of a) abnormal arteriolar length: diameter ratios (a measure of relative arteriolar narrowing), b) narrowed branching angles (an indicator of arteriolar rarefaction), or c) disturbed junction exponents (a marker of endothelial dysfunction.
Significance of the study
If successful, this work could be extended to address future questions, including the predictive value of these abnormalities for development of diabetes and hypertension as well as CVD; to explore further the role of microvascular disturbances in disease etiology, and to assess the impact of drug therapy on these abnormalities and their relationship to outcomes in the South Asian population
|Contact: Tazeen H Jafar, Md,MPH||0092-4930051 ext email@example.com|
|Contact: Muhamamd Saleem Khan, MSc Epi&Bio||0092-4930051 ext firstname.lastname@example.org|
|Aga Khan University||Not yet recruiting|
|Karachi, Sindh, Pakistan, 74800|
|Contact: Tazeen H Jafar, MD, MPH 0092-21-4930051 ext 4818 email@example.com|
|Contact: Muhammad Saleem Khan, MSc Epi&Bio 0092-21-4930051 ext 4936 firstname.lastname@example.org|
|Principal Investigator:||Tazeen H Jafar, MD, MPH||Aga Khan University|
|Study Chair:||Nish Chaturvedi, MD, MFPHM||Imperial College London|
|Study Chair:||Alun Hughes, MD, Phd||Imperial College London|
|Study Chair:||Juanita Hatcher, Phd, MSc||Aga Khan University|
|Study Chair:||Simon Thom, MD, FRCP||Imperial College London|
|Study Chair:||Khabir Ahmad, MD, MSc||Aga Khan University|
|Study Chair:||Muhammad Saleem Khan, MSc Epi&Bio||Aga Khan University|