More than 50% of preterm babies with PH respond to Revatio: Study
Response rate similar among those with very low, higher birth weights
Treatment with intravenous Revatio (sildenafil) can improve oxygen delivery and heart health in some premature babies with pulmonary hypertension, although more than four in 10 patients don’t respond to it.
“Our study adds new insights on preterm and [very low birth weight]-infants with sildenafil treatment for primary early PH in the first days of life,” the researchers wrote in “Intravenous sildenafil for treatment of early pulmonary hypertension in preterm infants,” which was published in Scientific Reports.
Revatio is approved for pulmonary arterial hypertension (PAH) and reduces blood pressure by prompting blood vessels to widen and relax. It’s available in both oral and intravenous (into the bloodstream) formulations, and is sold by Pfizer, which was not involved in the study.
Pulmonary hypertension (PH) can be a complication in premature newborns. Some studies have explored using Revatio to help manage the disease in premature babies, but data for this indication is still lacking, especially for babies born before 34 weeks of pregnancy and those who are born very small with early PH.
Researchers in Germany reviewed data on 58 infants born prematurely who were treated with Revatio, just under half of whom had a very low birth weight. All were given the intravenous formulation continuously at a dose of 1.6 mg/kg/day. Half were also given an initial infusion at the discretion of the treating clinician.
Effect of Revatio on premature babies
The severity of PH decreased significantly following Revatio in the overall group among the babies with available heart imaging data, results showed. Measures of strain on the right side of the heart, namely right ventricle dysfunction (RVD) and the right to left ventricle ratio (RV/LV), also tended to improve.
The patients were divided into responders and nonresponders, based on whether Revatio led to notable improvement on a combination of measures of the ability to take in and transport oxygen. Based on this measure, just over half (57%) the patients responded to the treatment and the response rate was similar among those with very low birth weights or higher birth weights.
Those who didn’t respond to Revatio more often had lung hypoplasia (abnormally small, underdeveloped lungs) and higher rates of kidney and urinary tract problems. The mortality rate was significantly lower among responders (21%) than nonresponders (72%).
“Continuous intravenous sildenafil treatment is associated with a significant improvement of the oxygenation impairment in preterm infants … Additionally, continuous intravenous sildenafil treatment is associated with an improvement of PH, RVD and RV/LV ratio in the echocardiographic assessment in this population,” the researchers said. “Nevertheless, a substantial proportion (43%) of preterm infants do not respond to sildenafil, especially infants with prenatal diagnosed lung hypoplasia. These infants are at high risk for in-hospital mortality.”
The researchers said the results should be interpreted with caution because their study was a retrospective review that lacked a comparison or placebo group.
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