Vadim Babokin1, Nikolai Trofimov2. 1. Division of Cardiovascular Surgery, Central Clinical Hospital of the Russian Academy of Sciences, Litovskij bulvar, 1A, 117593 Moscow, Russia. Electronic address: babokin@bk.ru. 2. Republic Cardiac Dispensary of the Ministry of Health of the Chuvash Republic, Cheboksary, Russia.