EDIT: There was an earlier trial, https://clinicaltrials.gov/ct2/show/NCT01002157 (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4663571/), exploring MK-7 supplementation for CAC which should have been completed and the results published. The lack of published results doesn't bode well for efficacy.
EDIT: Here's a similar study for CAVD/AVC also still lacking results: https://clinicaltrials.gov/ct2/show/NCT02917525