Background-Cinaciguat (BAY 58 -2667) is the first of a new class of soluble guanylate cyclase activators in clinical development for acute decompensated heart failure. We aimed to assess the hemodynamic effects, safety, and tolerability of intravenous cinaciguat in patients with acute decompensated heart failure (pulmonary capillary wedge pressure Ն18 mm Hg). Methods and Results-After initial dose finding (part A; nϭ27), cinaciguat was evaluated in the nonrandomized, uncontrolled proof-of-concept part of the study (part B; nϭ33) using a starting dose of 100 g/h, which could be titrated depending on hemodynamic response. Patients were categorized as responders if their pulmonary capillary wedge pressure decreased by Ն4 mm Hg compared with baseline. Final doses of cinaciguat after 6 hours of infusion in part B were 50 g/h (nϭ2), 200 g/h (nϭ12), and 400 g/h (nϭ16). Compared with baseline, a 6-hour infusion of cinaciguat led to significant reductions in pulmonary capillary wedge pressure (Ϫ7.9 mm Hg), mean right atrial pressure (Ϫ2.9 mm Hg), mean pulmonary artery pressure (Ϫ6.5 mm Hg), pulmonary vascular resistance (Ϫ43.4 dynes · s · cm Ϫ5 ), and systemic vascular resistance (Ϫ597 dynes · s · cm Ϫ5 ), while increasing heart rate by 4.4 bpm and cardiac output by 1.68 L/min. The responder rate was 53% after 2 hours, 83% after 4 hours, and 90% after 6 hours. Cinaciguat was well tolerated, with 13 of 60 patients reporting 14 drug-related treatment-emergent adverse events of mild to moderate intensity, most commonly hypotension. Conclusions-Cinaciguat has potent preload-and afterload-reducing effects, increasing cardiac output. Further investigation of cinaciguat for acute decompensated heart failure is warranted
