NPPB and hydronephrosis: In addition, the changes in TGF-β levels were correlated with the changes in SRIVR, which is a sensitive marker of ventricular diastolic function (a surrogate of ventricular time constant [τ]).[7] 4) After double J catheter placement, patients with hydronephrosis had decreased NT-proBNP levels in the blood and increased NT-proBNP levels in the urine.