Is it possible to reference environment variables from a php_value statement in .htaccess?

Question

I am trying to access an environment variable in a php_value statement within an .htaccess file.

Here's a couple example usages:

php_value include_path ".:/usr/lib/php:[b]%{My_Environment_Variable}[/b]"

or

php_value auto_prepend_file %{env:MY_BASE_PATH}/lib/classes/SomeClass.php

I am okay with setting the environment variable within the .htaccess if that works and it happens to be the only way to do it. Otherwise, it would be great to be able to reference an environment variable that was set outside of the .htaccess.