What approaches do you take to avoid further eGFR decline in patients undergoing unilateral nephrectomy for renal cell carcinoma?

The most important/effective intervention by far is good blood pressure control. Secondarily, if there is proteinuria, one should consider ACE/ARB, SGLT-2, etc. What is the optimal blood pressure can be uncertain, but I would advocate for a systolic pressure of less than 130 mmHg.