Outpatient Vasodilator Assessment Using Iloprost in Pulmonary Hypertension

Iloprost was the first inhaled prostacyclin analogue to be FDA-approved for the treatment of
pulmonary arterial hypertension. Iloprost aerosol has been shown to significantly improve
pulmonary hemodynamics in patients with idiopathic pulmonary hypertension (PH), with an
effect greater than nitric oxide and sildenafil. It has also been shown to be more effective
than nitric oxide at reducing pulmonary arterial pressure (PAP) than prostacyclin infusion
when used in the cardiac catheterization laboratory. Because of its administration through
inhalational means, iloprost has the advantage of selective action on the pulmonary
vasculature with avoidance of the systemic side effects that plague many of the other
treatments for PH. The investigators intend to compare the efficacy of inhaled iloprost in
reducing pulmonary artery pressure to the gold standard of nitric oxide in patients with
pulmonary hypertension.

Without an established noninvasive algorithm to identify beneficial hemodynamic response to
vasodilators, patients with pulmonary hypertension (PH) are routinely subjected to expensive
and invasive testing. Echocardiography is routinely used to facilitate a diagnosis of PH and
a few echocardiographically-derived estimates have even been shown to correlate with
vasodilator responsiveness and survival. Dynamic, real time changes in echocardiographic
parameters have not been previously evaluated as a predictor of vasodilator responsiveness or
of clinical outcome. The investigators will examine whether echocardiographic changes in
response to inhaled iloprost can predict invasively derived vasodilator responsiveness and
help assess prognosis in patients with pulmonary hypertension, possibly even obviating the
need for invasive testing.

Inclusion Criteria:

- Adult patients no younger than 18 years of age

- Recently diagnosed pulmonary hypertension (defined by RV systolic pressure of ≥ 40
mmHg as measured by echocardiography), going for invasive hemodynamic assessment for
pulmonary hypertension

- Normal left ventricular function defined as a left ventricular ejection fraction
(LVEF) greater than or equal to 50%

Exclusion Criteria:

- Heart failure (LVEF < 50%, diastolic dysfunction > stage 1, history or symptoms of
left heart failure) - Group II pulmonary hypertension

- 2+ or higher MR or AI

- Inadequate echocardiographic windows

- Pregnancy

- Systolic blood pressure ≤ 90 mmHg