Hemodynamic Effect of Iloprost Inhalation and Oral Sildenafil during Acute Vasoreactivity Test in Pulmonary Arterial Hypertension
Suree Sompradeekul MD*, Siriphan Wattanasiriphakdee MD*
Affiliation : * Division of Respiratory Disease and Tuberculosis, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
Background : The vasoreactivity test is usually performed to identify pulmonary arterial hypertension (PAH) patients who
may benefit from long-term calcium channel blocker (CCB). The first and most commonly used agent is intravenous
epoprostenol. A few other agents such as intravenous adenosine and inhaled nitric oxide are also used. In Thailand,
epoprostenol is not available and the others are costly. Therefore, inhaled iloprost or oral sildenafil may be alternatives to
test vasoreactivity.
Objective : To evaluate the hemodynamic effect and response rate of inhaled iloprost and oral sildenafil during acute
vasoreactivity test in PAH patients.
Material and Method: In this retrospective descriptive study, the authors recruited patients with idiopathic PAH (IPAH) or
PAH associated with connective tissue disease (PAH-CNT) seen at the Medicine department Siriraj Hospital between January
2005 and December 2011 for whom acute vasoreactivity test was indicated. All patients used 20 microgram of inhaled
iloprost via Delphinus® nebulizer for the test. Hemodynamic parameters were recorded before and after iloprost
administration. Eight of those patients subsequently had a repeated test using 100 mg of oral sildenafil.
Results : Fifteen patients had acute vasoreactivity testing. Eleven patients were IPAH and four were PAH-CNT. Using
ESC/ERS guidelines criteria for responsiveness to vasoreactivity test, the response rate was 13% (2 out of 15 patients) using
inhaled iloprost. Hemodynamic change was seen as early as five minutes after the inhalation and the effect lasted up to
35 minutes. The response rate was 25% (2 out of 8 patients) using oral sildenafil. Hemodynamic change was seen as early
as 30 minutes after sildenafil ingestion and lasted up to 480 minutes.
Conclusion : Inhaled iloprost can be used for acute vasoreactivity test in Thailand. The hemodynamic parameters should
be recorded immediately after iloprost inhalation. Oral sildenafil, however, is not a suitable agent for acute vasoreactivity
test due to its extended effect.
Keywords : Acute vasoreactivity test, Pulmonary hypertension, Inhaled iloprost, Sildenafil
