This double-blind , multicentre study randomized 71 AHF patients with pulmonary capillary wedge pressure ( PCWP ) 18 mmHg , systolic blood pressure ( BP ) 115 mmHg , and estimated glomerular filtration rate 30 mL/min/1 .73 m ( 2 ) to serelaxin ( n = 34 ) or placebo ( n = 37 ) within 48 h of hospitalization .