The acute treatment of severe Pulmonary Arterial Hypertension (PAH) poses a therapeutic challenge. Immediate access to agents such as prostacyclin and endothelin receptor blockers (ERBs) is limited. Sildenafil has been shown to have a direct vasodilator effect in the pulmonary circulation. The goal of this study is to describe the treatment response to Sildenafil for unstable, WHO Class IV PAH patients.
We performed a retrospective, cohort review of 14 consecutive patients with WHO Class IV PAH admitted to the hospital in severe right heart failure (RHF) and treated with Sildenafil. Treatment also included digoxin, diuretics and inhaled nitric oxide. Sildenafil was initiated at 50 mg TID and increased to 100 mg TID after 24 hours. Outpatient follow-up data and outcome measurements included periodic 6-minute walks (6MW), supplemental oxygen requirements, WHO classification status, need for additional PAH therapy, hospitalizations and death.
All patients were discharged on Sildenafil without concomitant prostacyclin or ERBs. After ≥ 4 weeks of therapy with Sildenafil, the mean increase in 6MW (compared to pre-discharge 6MW) was 122.4 meters (95%CI:50.5-194.3, p=0.004). The mean reduction in oxygen supplementation by nasal cannula was 2.1L (95%CI:3.53-0.75, p=0.005). The degree of improvement in 6MW distance, oxygen requirements, and WHO classification status was statistically associated with the time of treatment on Sildenafil. At 6 months, the average 6MW distance was 351M (n=5). Four patients had additional therapy added ≥ 5 months. One patient died and 3 patients required re-hospitalization prior to 1 year for progressive PAH and RHF. At 1 year, 13 patients remained on Sildenafil and were WHO Class II-III, without signs of RHF. No significant side effects were noted.
Sildenafil 100 mg TID can be used in the acute setting to stabilize patients with WHO Class IV PAH. Long-term therapy with Sildenafil was associated with good clinical outcomes, including improvement in WHO classification and 6MW distance.
This study proposes a treatment strategy for decompensated PAH that circumvents problems of delayed access to prostacyclins and ERBs therapy.
Lalaine Corate, None.