If a patient has persistent ascites requiring diuretics after TIPS, at what point do you consider re-evaluation of TIPS?  

Some may still require some diuretics, particularly if lower extremity edema is an issue post-TIPS. Otherwise, if paracentesis is needed ~6 weeks after TIPS and the patient is free of HE, then consider IR dilating the TIPS further. When TIPS is for ascites, IR should really start with a small calibe...

Certainly, there are cases where even a TIPS well placed with an appropriate drop in pressure gradient to around 6-8 mmHg may not work, in particular when they have seriously impaired renal function. But in most cases, I check at least once with an ultrasound with Doppler to assess velocities and TI...