[Cardioselective beta-adrenoblockers in patients with stable angina pectoris. Comparison of efficacy and safety].

AIM: To compare efficacy and safety of cardioselectivc beta-blockers (BB) in patients with stable angina. MATERIAL AND METHODS: An open comparative randomized trial with participation of 40 patients suffering from stable angina (NYHA FC II-III) was made. All the patients were divided into two groups. Patients of group 1 received betaxolol, those of group 2--other selective BB: metoprolol (n = 13), bisoprolol N = 6, nebivolol (n = 1). The BB dose was doubled each 2 weeks up to achievement of the maximal tolerable dose. The trial continued for 2 months during which the patients were also given aspirin, statins, ACE inhibitors, mononitrates, amlodipin and thiazide diuretics. The efficacy of the treatment was assessed by the data of the treadmill test by Brus protocol, echocardiography according to ASE recommendations, high resolution ultrasound examination of endothelium-related relaxation of the brachial artery. Lipid transport parameters were estimated with enzyme techniques. RESULTS: A mean dose of betaxolol, metoprolol and bisoprolol was 14 +/- 4.5 mg/day, 127 +/- 24 mg/ day, 10 +/- 4 mg/day. A noticeable lowering of heart rate (HR) and blood pressure (BP) was observed in both groups, but HR in group 1 decreased more (57.35 +/- 5.19 and 62.4 +/- 8.84 b/m, respectively, p = 0.033) and systolic pressure showed a trend to greater reduction. Exercise tolerance in both groups was compatible. The lowest threshold HR was achieved in betaxolol group (a fall from 133.8 +/- 23.5) to 105.0 +/- 14, 23 b/min (p+0.027). Endotheium-related relaxation of the brachial artery was improved in betaxolol group: the diameter of the artery increased from 6.38 +/- 4.32 to 9.22 +/- 4.37% (p = 0.057), the peak blood flow velocity--from 14.81 +/- 3.91 to 23.87 +/- 3.7% (p = 0.031). In group 2 a positive trend in these parameters was not observed. BB had no negative effect on left ventricular contractility, parameters of transmitral blood flow, bronchial conduction, metabolism. CONCLUSION: Compared to other BB, betaxolol had a stronger effect on hemodynamic parameters (HR and BP) at rest and exercise, improved endothelial vascular function in patients with stable angina.