Visual Assist is not officially supported in environments whose access is provided by Microsoft Remote Desktop Services (RDS) or Windows Terminal Services, but you may have some success with the instructions in this article.
The challenge with remote services is that Microsoft Visual Studio places extensions such as Visual Assist in AppData\local, and that directory is typically erased after every remote session. In addition to the extension itself, Visual Assist stores its database of symbols in AppData\local, so the entire database must be rebuilt each time a session begins.
To avoid having the extension erased, use the VSIXInstaller to install a .vsix version of Visual Assist on a per-machine basis using the /admin option. (You must run VSIXInstaller from the command line.) With the /admin option, Microsoft should trust the security of the extension and install it in the installation directory for the IDE, not in AppData\local. Learn more in a blog post from Microsoft, VSIX Best Practices.
If you have success installing the .vsix, all updates to Visual Assist must be installed by the administrator. Updates to Visual Assist cannot be installed by users.
Although the extension can be installed per machine, settings within the Visual Assist options dialog are stored in the registry per user. Since the default location of the Visual Assist database is AppData\local, you must follow the separate instructions to change the location of the Visual Assist database for every user of a machine.