Pulmonary hypertension (PH) signifies elevated blood pressure in the pulmonary circulation either due to clearly defined causes (cardiac, pulmonary-parenchymatous, systemic) or of idiopathic origin (primary PH, PPH). While conservative treatment is beneficial only for a small number of patients, lung transplantation represents a curative measure. The optimal form of transplantation [i.e. single lung (SLTX), bilateral lung (BLTX) or combined heart-lung transplantation (HLTX)] is still under discussion. This study is a retrospective analysis of 16 patients with different forms of PH who underwent BLTX from 1992 to 1996 in Vienna. Four patients had Eisenmenger's disease due to atrial septum defect, 3 had chronic thromboembolic PH and 9 had PPH. BLTX with cardiopulmonary bypass was the standard procedure in all patients. Acute retransplantation had to be performed in 3 patients. Mean pulmonary arterial pressure was reduced from 63 +/- 11 mmHg preoperatively to 23 +/- 5 mmHg on the second day postoperatively (p < 0.0001), while the cardiac index concomitantly improved from 2.1 +/- 0.5 to 3.9 +/- 1.2 l/min/m2 (p < 0.05). Echocardiography proved normalisation of right ventricular wall thickness and end-diastolic diameter within 12 months, while tricuspid insufficiency, present in all patients before transplantation, resolved completely. Perioperatively 4 patients (25%) died due to septic complications (n = 3) or therapy refractory rejection (n = 1). Follow-up of the remaining patients ranged from 6 to 51 months (mean 33 +/- 17). One patient died at 8 months due to fungal sepsis. Eleven patients (68%) are currently alive. Only 2 of them show functional signs of chronic allograft rejection (bronchiolitis obliterans syndrome). All patients are at present in NYHA functional class I or II. In conclusion, BLTX results in complete recovery of right ventricular function and morphology and offers good functional long-term results. Because SLTX correlates with a high incidence of reperfusion edema, and HLTX is seriously limited by the scarcity of donor organs, BLTX should be the method of choice for treating end stage PH.