The subset of patients with acute heart failure able to secrete relaxin-2 at pregnancy concentrations could have a longer survival: a pilot study

Objective: To investigate how many patients with acute heart failure (AHF) hypersecrete relaxin-2 concentrations similar to those of pregnant women and determine their long-term outcome.Methods: In consecutive AHF patients relaxin-2 was quantified by ELISA sandwich method. Patients were divided into pregnancy-like group (PLG, relaxin-2 >= 500pg/mL) and control group (CG, relaxin-2 <500pg/mL). The primary outcome was all-cause death during follow-up. Secondary endpoints were prolonged hospitalisation (>10days), combined endpoint (death, rehospitalisation, ED revisit) 30days after discharge, and 30-day, one-year and three-year death rates.Results: We included 814 patients [81 (SD=9) years; 53.0% women] followed during 1.9 (SD 2.8) years; 517 (63.5%) died. Twenty patients (2.5%) formed the PLG (median relaxin-2=1459pg/mL; IQR=1722) and 794 the CG (median=26; IQR=44). There was no interaction with variables included on adjustment (age, sex, ischaemic cardiomyopathy, NT-proBNP, glycaemia, and sodium). PLG patients did not have better short-term secondary endpoints, but did show a significantly lower three-year mortality [ORadjusted=0.17 (0.05-0.5), p=0.003].Conclusions: The small proportion of AHF patients achieving relaxin-2 concentrations similar to those observed in pregnancy may survive longer.