Currently PeopleVine can only leverage HTML templates into the platform, so as long as you can convert your Wordpress theme to HTML, you can leverage it.
Alternatively your designer can strip out the head data, header and footer and apply it to a page layout in PeopleVine. As well they can leverage the generated HTML to create a page template for editing by a business user.
We do have a future plan to support importing a Wordpress theme. If you need assistance, reach out to a PeopleVine partner and they can help.