Thanks for your response, I tried the following but still no luck.
$treeView_hnd = ControlGetHandle($title, "", $window)
$findItem = _GUICtrlTreeView_FindItem($treeView_hnd, "Scapa Test Trace - FullTest 20170605-11403", $bInStr = True)
_GUICtrlTreeView_ClickItem($treeView_hnd, $findItem)
Update, I failed to realize that the variable didn't need to be in the actual code. The following code worked.
$treeView_hnd = ControlGetHandle($title, "", $window)
$findItem = _GUICtrlTreeView_FindItem($treeView_hnd, "Scapa Test Trace - FullTest", True)
_GUICtrlTreeView_ClickItem($treeView_hnd, $findItem)