Successful Treatment of Saddle Pulmonary Thromboembolism in 23-Week Preterm Infant.

Saddle pulmonary thromboembolism (PTE) is defined as a thromboembolism straddling the bifurcation of the main pulmonary artery trunk and it is rarely seen in extremely low birth weight infants (ELBWI). Saddle PTE is a critical disease that requires urgent treatment. However, the treatment guidelines for ELBWI are not established. We present the case of a 1-day-old preterm infant (gestational age 23 weeks) who showed sudden desaturation and pulmonary hypertension due to saddle PTE. A thrombus was observed in the bifurcation of the pulmonary artery. The blood flow to the pulmonary artery on the left side was interrupted, and the right side showed severe stenosis. Since the patient was an ELBWI in the acute phase, we decided to use recombinant tissue plasminogen activator (rt-PA) and administered a maintenance dose (0.08 mg/kg/hour), instead of the loading dose. After using rt-PA, the thrombus dissolved in 8 hours without adverse events. This case suggests that starting with a maintenance dose of rt-PA may be an effective treatment option for saddle PTE in ELBWI in the acute phase under the high risk of bleeding.