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Hypertension Related Damage to the Microcirculation in South Asian: Emergence, Predictive Power and Reversibility

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ClinicalTrials.gov Identifier: NCT00331370
Recruitment Status : Unknown
Verified May 2006 by Aga Khan University.
Recruitment status was:  Not yet recruiting
First Posted : May 31, 2006
Last Update Posted : May 31, 2006
Sponsor:
Collaborator:
Imperial College London
Information provided by:
Aga Khan University

Brief Summary:
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.

Condition or disease Intervention/treatment Phase
Hypertension Diabetes Cardiovascular Disease Retinopathy Behavioral: GP training and Health Education Not Applicable

Detailed Description:

Background

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

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Study Type : Interventional  (Clinical Trial)
Enrollment : 2880 participants
Allocation: Randomized
Intervention Model: Factorial Assignment
Masking: Single
Primary Purpose: Prevention
Official Title: Hypertension Related Damage to the Microcirculation in South Asian: Emergence,Predictive Power and Reversibility
Study Start Date : May 2006
Study Completion Date : June 2009

Resource links provided by the National Library of Medicine





Primary Outcome Measures :
  1. 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.


Information from the National Library of Medicine

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Ages Eligible for Study:   9 Years and older   (Child, Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

All subjects aged 9 years or over residing in randomly selected communities

Exclusion Criteria:

Pregnancy

Those who have severe co-morbid conditions

Patients with known history of glaucoma will be excluded from our study because instillation of mydriatic drops was thought to be hazardous for them.


Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00331370


Contacts
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Contact: Tazeen H Jafar, Md,MPH 0092-4930051 ext 4818 tazeen.jafar@aku.edu
Contact: Muhamamd Saleem Khan, MSc Epi&Bio 0092-4930051 ext 4936 muhammad.saleem@aku.edu

Locations
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Pakistan
Aga Khan University
Karachi, Sindh, Pakistan, 74800
Contact: Tazeen H Jafar, MD, MPH    0092-21-4930051 ext 4818    tazeen.jafar@aku.edu   
Contact: Muhammad Saleem Khan, MSc Epi&Bio    0092-21-4930051 ext 4936    muhammad.saleem@aku.edu   
Sponsors and Collaborators
Aga Khan University
Imperial College London
Investigators
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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
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ClinicalTrials.gov Identifier: NCT00331370    
Other Study ID Numbers: DHCPP00493
First Posted: May 31, 2006    Key Record Dates
Last Update Posted: May 31, 2006
Last Verified: May 2006
Additional relevant MeSH terms:
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Hypertension
Cardiovascular Diseases
Vascular Diseases