[Hemodynamic study: indications for right- and left-sided catheterization in the diagnosis and follow-up of pulmonary hypertension].

Pulmonary artery hypertension (PAH) is a category of pulmonary hypertension consisting of mean pulmonary artery pressure greater than 25 mmHg at rest, with normal pulmonary capillary occlusion pressure (less than 15 mmHg) and pulmonary vascular resistance greater than 3 Wood units. The diagnosis of PAH is made through the exclusion of other disorders, including pulmonary, thromboembolic, left ventricular and valvular heart disease. All patients with PAH suspected on the basis of non-invasive tests should undergo right-sided catheterization before treatment is started, with measurement of pulmonary artery pressure, pulmonary capillary wedge pressure, and pulmonary vascular resistance. Pulmonary vasoreactivity and cardiac output should also be measured. To test pulmonary vasoreactivity, inhaled nitric oxide and intravenous adenosine or epoprosterenol are used. A reduction of 10 mmHg in mean pulmonary arterial pressure or achieving a mean pulmonary artery pressure of less than 40 mmHg, with no change or an increase in cardiac output, is considered a positive response. These criteria are met by only 10% of patients with PAH undergoing this test. Patients with a positive response will probably also show a sustained response to calcium channel blockers. This test should not be used in patients with PAH secondary to left cardiac disease, pulmonary disease or pulmonary embolism.