The researchers noted hospitalized patients diagnosed with acute heart failure had regular decreases in systolic blood pressure (SBP) and hypotensive events. They explored if serelaxin had any link with the drops in SBP. The researchers performed retrospective analyses of 4 prospective trials at the patient level to examine serelaxin in acute heart failure. The primary criteria to include patients were: 1) SBP between 125 and 180 mm Hg 2) Elevated N-terminal pro-B-type natriuretic peptide (NT-proBNP). The researchers specified the drops in SBP as SBP less than 100 mm Hg. Or a drop from the baseline of 40 mm Hg from baseline if SBP stayed more than 100 mm Hg. The researchers found that the results were 180-day mortality and short-term composite outcome. 

Out of 11,226 patients, 2,559 (23%) demonstrated a drop in SBP. A drop in SBP vs. no drop in SBP with a worse outcome. It included a cumulative incidence of 180-day mortality (11% versus 9%, hazard ratio [HR]. 1.21 [95% CI, 1.05–1.39]; P=0.009), and the short-term outcome (11% versus 9%, HR, 1.29 [95% CI, 1.13–1.49]; P<0.001). SBP less than 100 mm Hg was correlated to the worst outcome compared with a 40 mm Hg drop. The short-term outcome was 11% compared to 10%. And, hazard ratio 1.32 (95% CI, 1.13–1.55; P=0.0005) and 1.22 (95% CI, 0.97–1.56; P=0.09), respectively. The P-value for interaction was 0.05. In the placebo group (HR, 1.46 [95% CI, 1.19–1.79]; P=0.0003), the drops in SBP was linked with worse short-term outcome. However, it was not the case in the serelaxin group (HR, 1.18 [95% CI, 0.97–1.42]; P=0.10). The P-value for interaction was 0.003.

The researchers concluded that hospitalized patients with acute heart failure who experienced the drops in SBP, and patients with normal to high SBP at admission were linked with worse short-term and long-term outcomes, mainly for patients with SBP less than 100 mm Hg. Yet, the drops in SBP appeared less detrimental in patients who received intravenous vasodilator serelaxin.