Development of an Automated Drug Delivery System for an Ultra-Short-acting β-Blocker, Landiolol, to Stably Reduce Myocardial Oxygen Consumption without Inducing Circulatory Collapse in a Canine Heart Failure Model

Abstract Background: Beta-blockers are well known to reduce myocardial oxygen consumption (MVO₂) and improve the prognosis of heart failure (HF) patients. Although the use of β-blockers in the acute phase of HF can be expected to be beneficial, the negative chronotropic and inotropic effects limit their use due to the risk of circulatory collapse (cardiogenic shock, and/or pulmonary congestion). A safe method to administer β-blockers in the acute phase of HF is in great need. In this study, we developed an automated drug delivery system that controls the infusion of landiolol, an ultra-short-acting β-blocker, while preventing circulatory collapse. Method: We designed a system that simultaneously regulates cardiac function and volume status to control haemodynamics. The system monitors arterial pressure (AP), left atrial pressure (PLA), right atrial pressure, and cardiac output. Using negative feedback of haemodynamics, the system controls mean AP and mean PLA by administering landiolol, dextran, and furosemide. We applied the system for 60 min to 5 mongrel dogs with rapid pacing-induced HF, and assessed haemodynamics, MVO₂ and lactate.Results: In all dogs, the system successfully adjusted delivery of the drugs resulting in accurate control of mean AP and mean PLA. From 15 to 60 min after the system was activated, median of absolute performance error (index of precision of control) was small for mean AP (median [interquartile range], 2.5 [2.1 – 3.7] %) and mean PLA (4.1 [1.8 – 6.2] %). Although the system decreased mean AP compared to baseline, mean and systolic AP were maintained not lower than 70 and 100 mmHg, respectively, and lactate did not increase. Furthermore, the system significantly decreased PLA and MVO₂ (3.6 [3.3 – 4.0] to 2.7 [2.5 – 3.3] ml·min⁻¹·100 g left ventricular weight⁻¹) compared to baseline. Consequently, the automated drug delivery system successfully reduced MVO₂ without inducing circulatory collapse.Conclusion: We developed an automated landiolol delivery system that achieved safe administration of landiolol in a canine model of acute HF. The system controlled AP and PLA accurately and stably, and reduced MVO₂. With further development for clinical application, the automated drug delivery system may be the key tool to improve management of patients with HF.