Objectives: We sought to evaluate the early postoperative hemodynamics and clinical aspects in patients with moderate to severe pulmonary artery pressure (PAP) who underwent mitral valve replacement (MVR) due to isolated mitral valve stenosis. Study design: Fifty patients (33 women, 17 men; mean age 45.8±11.2) were divided into two groups according to mean PAP levels (PAP <50 mmHg as Group I and PAP >50 mmHg as Group II). PAP and pulmonary capillary wedge pressure (PCWP) values were recorded using Swan-Ganz catheter just before the surgery in the operation theatre. These measurements were repeated after weaning from cardiopulmonary bypass, at 1, 12 and 24 hours. Intubation period in the intensive care unit, need for inotropic agents in the pre-and postoperative course, and mortality and morbidity data were also evaluated. Transthoracic echocardiography was used to measure PAP at the postoperative 24th hour and at the 2nd month after the surgery. Results: Mean PAP decreased significantly in both groups compared with basal levels. The regression was higher in Group II than Group I. Decrease in PCWP was more significant in Group II. PAP had decreased similarly in both groups according to the postoperative 24th hour echocardiographic evaluation; however, at the postoperative second month follow-up, the decrease in PAP was more significant in Group II. Conclusion: Pulmonary arterial and left atrial pressures significantly decreased in the early periods when the stenosis was alleviated in the isolated mitral stenosis cases with moderate or high PAP levels. This study demonstrates the increased morbidity in patients with higher PAP levels undergoing surgery. It seems that moderate PAP levels do not have a negative influence on postoperative outcomes. © 2012 Türk Kardiyoloji Derneǧi.