NPPB and hydrops fetalis: The ASTRAAS-HF (NCT04836182) is a phase 2 trial that will evaluate the effect an antisense inhibitor of angiotensinogen production (IONIS-AGT-LRX) on plasma angiotensinogen (AGT) concentration and N-terminal prohormone of B-type natriuretic peptide (NT-proBNP) levels in chronic heart failure participants with reduced ejection fraction (HFrEF, FE < 40%).