Reduced congestion and improved response to a fluid/sodium challenge in chronic heart failure patients after initiation of sacubitril/valsartan: The NATRIUM-HF study.

Aims: The effects of initiating sacubitril/valsartan in patients with stable heart failure with reduced ejection fraction (HFrEF) on response to fluid and sodium expansion are unknown.

Methods And Results: We have explored changes in natriuresis, diuresis, and congestion in response to the administration of intravenous fluid/sodium load in patients with HFrEF before as compared to after the initiation of sacubitril/valsartan. At baseline (before sacubitril/valsartan initiation) and 2 and 3 months after the initiation, patients underwent an evaluation that consisted of three phases of 3 h: the rest phase (0-3 h), the load phase (3-6 h) in which 1 L of intravenous Ringer solution was administered, and the diuretic phase (6-9 h) at the beginning of which furosemide was administered. Overall, 216 patients completed the study. In comparison to baseline values, at 2 and 3 months after sacubitril/valsartan initiation, patients' diuresis and natriuresis in response to Ringer administration significantly increased (mean difference: 38.8 [17.38] ml, p = 0.0040, and 9.6 [2.02] mmol, p < 0.0001, respectively). Symptoms and signs of congestion after the fluid/sodium challenge were significantly decreased at months 2 and 3 compared to baseline. Compared to baseline, there was also an increment of natriuresis after furosemide administration on sacubitril/valsartan (9.8 [5.13] mmol, p = 0.0167). There was a significant decrease in body weight in subsequent visits when compared to baseline values (-0.50 [-12.7, 7.4] kg at 2 months, and -0.75 [-15.9, 7.5] kg at 3 months; both p < 0.0001).

Conclusions: The initiation of sacubitril/valsartan in HFrEF patients was associated with improvements in natriuresis, diuresis, and weight loss and better clinical adaptation to potentially decongestive stressors.