The Effect of Amlodipine and Lisinopril on Retinal Autoregulation in Type 1 Diabetes
The purpose of this study is to compare the effect of two antihypertensive drugs on retinal vessel diameter in young type 1 diabetics. The retinal vessel analyzer (RVA) was used to investigate how the drugs affected vessel diameter, when the subjects were exposed to an increase in blood pressure, induced by isometric muscle contraction and when they were stimulated by flickering light.
Type 1 Diabetes
|Study Design:||Allocation: Randomized
Endpoint Classification: Pharmacodynamics Study
Intervention Model: Crossover Assignment
Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor)
|Official Title:||Lack of Effect of Antihypertensive Treatment With Amlodipine and Lisinopril on Retinal Autoregulation in Patients With Type 1 Diabetes and Mild Diabetic Retinopathy. A Prospective Randomized Clinical Trial.|
- Vessel diameter changes in arbitrary units as measured with the Retinal Vessel Analyzer [ Time Frame: 120,240,360,480,600,720 and at 840secs ] [ Designated as safety issue: No ]
- Blood pressure (mmHG) [ Time Frame: 120,240,360,600,720,840 secs ] [ Designated as safety issue: No ]
- 24 hour ambulatory blood pressure (mmHg) [ Time Frame: 24 hours ] [ Designated as safety issue: No ]
|Study Start Date:||July 2006|
|Study Completion Date:||February 2009|
|Primary Completion Date:||February 2009 (Final data collection date for primary outcome measure)|
Crossover design. Arm is same all the way
1 (5mg) tablet daily, given 14 days totally before measure of outcome.Drug: Lisinopril
Lisinopril 10 mg given daily for 14 days and then outcome was measured.
Diabetes is a leading cause of blindness in the western part of the world. Diabetic patients develop diabetic retinopathy which can progress to blindness. Diabetic retinopathy is associated with an increase of blood flow in the retinal vessels, ischaemia in the periphery and macular oedema. It has been shown in previous trials, that the pressure and metabolic autoregulation is disturbed in patients with diabetes, and it is believed to contribute to the development of diabetic retinopathy.
In healthy subjects the retinal arterioles will contract during an increase in blood pressure, but trials have shown that this response is impaired in diabetics. When the retina is exposed to flickering lights, the metabolism increase and the arterioles in healthy subjects dilates. In diabetics this dilation is impaired. In this trial we want to investigate if an ACE-inhibitor (lisinopril) or calcium channel blocker (amlodipine) influence this response in subjects exposed to increased blood pressure vs increased retinal metabolism.
|Aarhus university hospital|
|Aarhus, Denmark, 8000|
|Principal Investigator:||Toke Bek, MD, PhD||Aarhus university hospital, Dep. of ophthalmology|
|Principal Investigator:||Per L Poulsen, MD, PhD||Aarhus University hospital, Dep. of endocrinology (M)|