Effects of the imidazoline-receptor agonist moxonidine on hemodynamics, coronary flow, metabolic markers of ischemia and the neurohumoral system in patients with "microvascular angina"

Moxonidine is a new centrally active imidazoline-receptor agonist being effectively applied in the treatment of arterial hypertension due to its sympathicolytic potency. This is the first investigation regarding the effects of moxonidine on coronary and systemic hemodynamics, metabolic markers of ischemia and neurohumoral parameters in patients with essential hypertension (WHO I-II). We studied moxonidine (single dose of 0.4 mg p.o.) in 22 patients with left ventricular (LV) hypertrophy, ST segment depressions during exercise, pectanginal complaints and negative coronarograms. Assessments included arterial blood pressure, cardiac output, pulmonary artery pressure mean (PAPm), pulmonary capillary wedge pressure (PCWP) and coronary sinus flow (CSF) by intravascular Doppler technique. The moxonidine-induced parameter changes 2 hours later were as follows: a decrease in systolic/diastolic pressure by 28/10 mmHg, and in heart rate by 5 bpm, associated with a decline of PAPm by 17% and of PCWP by 26%. LV work was reduced by 26%, MVO2 by 18% and CSF by 16%. Average peak velocity in CS fell by 18% and coronary flow reserve (with adenosine) increased by 12%. CS-O-2 saturation rose by 4%, accompanied by an increase in lactate extraction by 17%, a. decrease in norepinephrine spillover by 30% and in arterial endotheline by 20%. In conclusion, moxonidine produces clinically relevant sympathicolysis with beneficial effects on hemodynamics, coronary circulation and neurohumoral parameters.