The purpose of this pilot study is to obtain a preliminary assessment of the effect of VK supplementation on cognitive performance and vascular function in adults with stable Coronary Heart Disease (CHD)
The overall goal of this study is to obtain a preliminary assessment of the effect of a VK1 (phylloquinone) supplementation on cognitive performance (primary outcome) and vascular function (secondary outcome) in adults with stable CHD. Specifically, the investigators will conduct a double-blind, 2-armed, parallel-group intervention study in which 40 men and women aged 60 years and over with stable CHD will be randomly assigned to 0.5 mg phylloquinone per day or matching placebo for a period of 3 months. All participants will have signed a written consent form before taking part in the study
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
QUADRUPLE
Enrollment
40
Montreal Heart Institute
Montreal, Quebec, Canada
Change in general cognitive functioning
Montreal Cognitive Assessment (0-30 score, with a higher score indicating a better cognitive functioning)
Time frame: Baseline and post-intervention at 12 weeks
Change in processing speed
Processing speed is assessed using the Coding subtest from the Wechsler Adult Intelligence Scale (WAIS)IV. The participant is asked to reproduce, as rapidly as possible, a series of symbols associated with digits in a 2-min time period
Time frame: Baseline and post-intervention at 12 weeks
Change in executive functions
Executive function is assessed using 1. Delis-Kaplan Executive Function System (D-KEFS) subtests \[Trail Making Test; Phonological and Semantic Fluency test \[Letters P, T, L (60s maximum); Categories: animals, men's names (60s maximum)\] 2. WAISIV subtests ("Switching" between naming fruit and furniture (60s maximum)\] 3. Neuropeak platform developed by Dr Bherer's laboratory: dual-task (divided attention) and n-back (working memory and updating). These tasks are tablet/computer-based As these tests use different scales, z-scores will be calculated for the different tests and a composite z-score will be generated for the domain
Time frame: Baseline and post-intervention at 12 weeks
Change in episodic memory
Episodic memory is assessed using: 1. Rey auditory verbal learning test (RAVLT). Score 0-75, with a higher score indicating a better memory 2. Digit span, a test that requires participants to repeat series of digits of increasing length As these tests use different scales, z-scores will be calculated for the different tests and a composite z-score will be generated for the domain
Time frame: Baseline and post-intervention at 12 weeks
Change in cerebral autoregulation - middle cerebral arteries
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Variations of cerebral blood flow velocity at the level of the middle cerebral artery will be measured in response to hypercapnic breathing using transcranial Doppler (TCD)
Time frame: Baseline and post-intervention at 12 weeks
Change in cerebral pulsatility - middle cerebral arteries
Pulsatility will be measured as the normalized difference of relative blood flow velocities between systole and diastole, using TCD in the middle cerebral arteries
Time frame: Baseline and post-intervention at 12 weeks
Change in peripheral endothelial function
Brachial artery flow-mediated dilation (FMD) will be quantified noninvasively by measuring blood velocity in the brachial artery and its diameter before and after 5 minutes of forearm hypoxia, using a high-resolution ultrasound device
Time frame: Baseline and post-intervention at 12 weeks
Central arterial stiffness
Central arterial stiffness will be assessed by measuring the carotid-femoral pulse-wave velocity (cfPWV), using a non-invasive surface tonometer
Time frame: Baseline and post-intervention at 12 weeks