Abstract 9411: Urine Aquaporin-2 Level is a Novel Marker for the Better Prognosis After Long-Term Tolvaptan Treatment in Patients With Advanced Heart Failure

Abstract

Introduction: Preserved function of collecting duct is essential for the response to tolvaptan (TLV), and urinary level of aquaporin 2 (U-AQP2) can be a marker for vasopressin-dependent activity of collecting duct. Hypothesis: Higher levels of U-AQP2 in proportion to plasma levels of vasopressin (P-AVP) may be associated with better initial responses to TLV and eventually result in the improved prognosis after long-term treatment of TLV. Methods: Consecutive 60 in-hospital patients with stage D heart failure (HF) who received TLV on a de novo basis were enrolled during 2011-2013. We also selected 60 HF patients by propensity score matching who were hospitalized during the same period but never treated with TLV. Events were defined as death and/or HF re-hospitalization. Results: TLV (3.75-15 mg/day) was continuously administered except death or ventricular assist device implantation occurred. There were 41 patients (group 1) who had increases in UV over the first 24 h after TLV initiation, and all of them had U-AQP2/P-AVP ≥0.5 х103 with higher U-AQP2 levels (5.42 ± 3.54 ng/mL) before TLV treatment. On the other hand, UV rather decreased even after TLV initiation in 19 patients over the first 24 h (group 2). Those in the group 2 universally had U-AQP2/P-AVP <0.5 х103, extremely low U-AQP2 levels (0.76 ± 0.59 ng/mL, p<0.001 vs. group 1), and similar P-AVP with the group 1 at baseline. The 41 and 19 patients without TLV treatment (group 3 and 4) were respectively matched to the group 1 and 2 by propensity scores. Interestingly, every patient in the group 3 had U-AQP2/P-AVP ≥0.5 х103, and vice versa in the group 4. Among the four groups, congestion-related symptoms were only improved in the group 1 after 1 month of enrollment. The patients in the group 1 had significantly better event-free survival over 2-year by TLV treatment compared with the group 3 (76% vs. 43%, p<0.014). In contrast, the patients in the group 2 and 4 had very poor prognoses regardless of TLV treatment (7% vs. 11%, p=0.823). Conclusions: U-AQP2/P-AVP is a novel predictor for the initial response to TLV in HF patients. Patients with higher U-AQP2/P-AVP may enjoy a better prognosis by long-term TLV treatment probably due to efficient resolution of congestion.