High performance computing in heterogeneous environments is a dynamically developing area. A number of highly efficient heterogeneous parallel algorithms have been designed over last decade. At the same time, scientific software based on the algorithms is very much under par. The paper analyses main issues encountered by scientific programmers during implementation of heterogeneous parallel algorithms in a portable form. It explains how programming systems can address the issues in order to maximally facilitate implementation of parallel algorithms for heterogeneous platforms and outlines two existing programming systems for high performance heterogeneous computing, mpC and HeteroMPI.