Hmm, thickened or hardened blood vessels are not reversible as far as I know, but this is based on what happens during the course of heart disease development. So I can't say the same will apply in the case of spike proteins. There's also no guarantee if results from such lab studies (cell culture or animals) would translate exactly into human clinical settings.

https://www.mountsinai.org/health-library/diseases-conditions/hardening-of-the-arteries#