You must put the filter logic in the expressions of the table in order for the table to be filtered when you input a variable (variables aren't connected to the data structure, so inputting a variable does not affect which records are included in your selection).
Replace your expression for field, "A" in the table with the following, which will return NULL when A < the value of the variable set by your slider.
if(A > vValueOfSlider, A)
You will also want to make the other fields in that table check if A > vValueOfSlider as well. For example, the column for field, "B" should be changed to: