Increased Urine Aquaporin-2 Relative to Plasma Arginine Vasopressin Is a Novel Marker of Response to Tolvaptan in Patients With Decompensated Heart Failure

Background:Preserved function of the renal collecting duct may be essential for response to the vasopressin V2receptor antagonist, tolvaptan (TLV), but the predictors of response to TLV are unknown.Methods and Results:Sixty consecutive patients with stage D decompensated heart failure (HF) who had received TLV on a de novo basis were retrospectively enrolled (TLV(+) group). Among them, 41 patients were responders defined according to urine volume (UV) increase after TLV initiation. In the UV-defined responders, plasma arginine vasopressin (P-AVP) had a close correlation with urine aquaporin-2 (U-AQP2; 5.42±3.54 ng/ml; r=0.843, P