Pulmonary hypertension increases the perioperative risk in patients undergoing cardiac surgery for valvular heart diseases, especially in patients with a long life mitral valve disease. The present study wants to test the hypothesis that intravenous administration of sildenafil reduces pulmonary vascular resistances and afterload of the right ventricle.

Pulmonary hypertension represents an increased risk for perioperative patients undergoing cardiac surgery for valvular heart disease especially in patients with a long life mitral valve disease complicated by sever pulmonary hypertension, with high risk of developing post operative right ventricular failure during separation from cardiopulmonary by pass. A recent study showed that a single oral administration of sildenafil at the beginning of the cardiac intervention in patients undergoing valvular heart surgery complicated by pulmonary hypertension reduces pulmonary vascular resistances without inducing significant effects on systemic vascular resistances. The present study wants to test the hypothesis that intravenous administration of sildenafil reduces pulmonary vascular resistances and afterload of the right ventricle avoiding right ventricular failure. This should support weaning from cardiopulmonary by pass in patients undergoing cardiac surgery for valvular heart diseases associated to pulmonary hypertension.

Inclusion Criteria:

• all patients undergoing valvular heart surgery associated to post capillary pulmonary hypertension with a mean pulmonary arterial pressure (mPAP)>30mmHg or pulmonary vascular resistance (PVR)>3Wu.

Exclusion Criteria:

• patients younger than 18 years old
• ischemic cardiomyopathy
• Ejection Fraction (EF)<30%
• severe Chronic obstructive pulmonary disease (COPD) with oxygen and bronchodilators therapy
• chronic pulmonary disease, chronic renal failure on dialysis
• hepatic failure
• patients with orotracheal intubation and already admitted to the ICU before the intervention