THE EFFECTIVENESS OF COMBINATION THERAPY WITH BOSENTAN AND SILDENAFIL IN PATIENTS WITH THE CLINICAL WORSENING OF IDIOPATHIC PULMONARY HYPERTENSION ON THE BACKGROUND OF SPECIFIC MON... oleh V. M. Paramonov, T. V. Martynyuk, Yu. G. Matchin, V. P. Masenco, S. N. Nakonechnikov, I. Ye. Chazova