Such pumps have been implanted in more than 90 patients in various European countries during the past 3 years. Experience shows that most of the patients selected for implantation have FC II-IV under combination therapy (2-3 specific PH-medications). The previous medication was either regarded as insufficient in respect to cardiopulmonary stabilization or the side effects of the therapy were intolerable. The latter applied particularly to patients with subcutaneous delivery of treprostinil in fairly large doses.