Acute effects of nicardipine and esmolol on the cardiac cycle, intracardiac hemodynamic and endothelial shear stress in patients with unstable angina pectoris and moderate coronary stenosis: results from single center, randomized study.

Objective: This study aimed to compare the acute effects of nicardipine and esmolol on hemodynamic and endothelial shear stress (ESS) in patients with unstable angina (UA) and moderate coronary stenosis (MCS).

Background: Nicardipine and esmolol exhibit cardioprotection via different mechanisms. However, their acute effects on hemodynamic and ESS are still unknown.

Methods: One-hundred sixteen patients with UA and MSC were randomly divided into nicardipine (n = 59) and esmolol (n = 57) groups. Drugs were injected as a bolus followed by continuous infusion to achieve the steady states defined as the mean blood pressure (MBP) reduced by ≥ 10% or a heart-rate change by ≥ 15 bpm, lasting for at least 10 min. The aortic pressure (AP), EKG, blood velocity, right atrial pressure, distal coronary pressure (DCP), systolic time (ST), isovolumetric diastolic time (IVDT), speed filling time (SFT), and ESS were simultaneously calculated at baseline and steady states.

Results: Both drugs significantly reduced blood pressure and rate-pressure load. Infusion of nicardipine was associated with negative remodeling of the distal segment (P= 0.005). Esmolol, rather than nicardipine, increased minimal lumen diameter (P= 0.040), prolonged SFT (0.34 ± 0.03 s vs. 0.41 ± 0.03 s, P < 0.001), reduced DCP (P < 0.001) and increased blood velocity (33.65 ± 1.07 cm/s vs. 43.36 ± 1.25 cm/s, P < 0.001) at SFT stages, with increased blood-flow (P < 0.001). Both drugs increased downstream ESS. Esmolol significantly reversed abnormally increased ESS (P < 0.001) and increased upstream ESS compared with nicardipine (P < 0.001).

Conclusion: Beyond a similar reduction of AP, patients with UA and MCS could benefit more from the reduction of heart rate induced by esmolol (ChiCTR-TRC-10000964).