Déjà Vu is not able to import data from a Trados translation memory in the SDLTM format, but there are 3rd party tools that can be used to convert these translation memories to TMX format, which is fully supported by Déjà Vu. Following are 2 such tools that have been used successfully by many users of Déjà Vu.
SDL Trados Studio has the ability to open translation memories in the SDLTM format and export them to other formats, including TMX. If you have a copy of Trados Studio you can use it to convert your SDLTM to TMX.
Trados Studio Resource Converter
The Trados Studio Resource Converter is a tool that can be used to convert Trados Studio translation memories (.sdltm) to TMX or Trados Studio termbases (.sdltb) to csv or txt. It does not require installation, but it does require that Java 1.7 or newer be installed. You can find a download link and instructions on how to use it here.
WfConverter is a simple that can convert Trados Studio translation memories (.sdltm) to TMX or Trados Studio termbases (.sdltb) to csv. It was originally developed to convert files generated by Wordfast, but now supports many different file types. It does not require installation, though you must download another 3rd party DLL to enable it to read the SDLTM file.
You can download WfConverter from here.
To use WfConverter, unzip all the downloaded files, and put them all in the same folder. Then, double-click on the file WfConverter.exe. The tool is very simple: you just need to select the file you want to convert, and then clicking on Start. The output file will be placed in the same folder where the input file is located.