Intracoronary-administered urapidil does not influence myocardial contractility, metabolic activity, or coronary sinus blood flow in humans

Objective: To compare the acute effect of intracoronary administration of urapidil and saline on myocardial contractility and metabolic activity. Design: Prospective, controlled, open-label study. Setting: University teaching hospital. Participants and Interventions: Eight patients with stable coronary artery disease (CAD) undergoing elective percutaneous transluminal coronary angioplasty (PTCA) received normal saline followed by urapidil, 4 mg, injected directly into the left main coronary artery Measurements and Main Results: Because local intracoronary administration is a non-steady-state condition, an in vitro model was used before the clinical experiments to establish the kinetic effects of acute administration of urapidil. The clinical experiments were performed in eight patients with CAD after PTCA. Measurements included a complete hemodynamic profile, coronary sinus blood flow (continuous thermodilution), left ventricular (LV) peak (+) dP/dt, LV peak(-) dP/dt, LV dP/dt/P(D)40, and LV end-diastolic pressures. Arterial and coronary venous blood samples were also obtained for the calculation of myocardial oxygen consumption. Baseline measurements I were first obtained, followed by intracoronary injection of 2 mt of saline. Additional measurements were obtained 1, 5, and 10 minutes after administration of saline. After a resting period (15 minutes), baseline measurements II, and intracoronary injection of urapidil, 4 mg (dissolved in 2 mi saline), additional measurements were obtained 1. 5, and 10 minutes later. Heart rate decreased 2.7 +/- 3.5 beats/min after injection of saline, whereas heart rate increased 2.0 +/- 1.8 beats/min after inrtracoronary urapidil, resulting in a significant difference in treatment effect (p = 0.003). There were no additional differences in treatment effect for any of the other measured or calculated parameters reflecting systemic hemodynamics, LV contractility, coronary dynamics, and myocardial metabolic activity. Conclusion: The results suggest that intracoronary bolus administration of preservative-free urapidil, 4 mg, is not associated with any detectable effect on myocardial contractility or coronary smooth muscle in awake nonsurgical patients with CAD, after PTCA. Copyright (C) 1999 by W.B. Saunders Company.