You may be interested in this negative result, thatwhich shows the space of realizations of an abstract $4$-polytope may be arbitrarily wild:
![Universality4Polytopes][1]
Quote from the [*Handbook of Discrete and Computational Geometry*](http://www.crcpress.com/product/isbn/9781584883012), 2nd Edition, p.370.
As the link Hugh Thomas provided indicates, Richter-Gebert also proved that determining whether an abstract polytope is realizable is NP-hard for fixed dimensions $d \ge 4$.