LoadRunner - using a %d in lr_eval_string function

I need to create a string with multiple values of 'x'. For instance I tried saving a string while referencing another variable as such...

lr_save_string("xyz", lr_eval_string("{x_%d}", intVar)); I've also have tried,

lr_save_string(lr_eval_string("{x_%d}", intVar), "xyz");

Is there any option/way to use %d and a int variable which always changes in the lr_eval_string function? or, how could this be performed?

Cheers