A conception for the use of mechanical support for the treatment of advanced cardiac or pulmonary failure in the Czech Republic: A joint statement of the Czech Society of Cardiology, Czech Society of Intensive Care Medicine ČLS JEP, Czech Society of Cardiovascular Surgery ČLS JEP, Czech Society of Anesthesiology, Resuscitation and Intensive care Medicine ČLS JEP, Czech Transplantation Society, Czech Society for Extracorporeal Circulation and Society for Organ Transplantations ČLS JEP