To treat or not to treat pulmonary arteries: epinephrine provocation to unmask right ventricular load

Background: Pulmonary artery stenosis (PAS) is common in congenital heart disease (CHD). The indication for treatment of PAS is primarily based on invasively measured pressure gradients. Anesthetics used during cardiac catheterization cause systemic and pulmonary hypotension. We hypothesize that this leads to underestimation of right ventricular (RV) pressure load and under treatment of PAS. The aim of this study is to describe the use of epinephrine to unmask RV pressure load in patients with PAS. Methods: All cardiac catheterizations in which epinephrine was administered to evaluate RV load were included. There was an indication for treatment in case of a right to left ventricular (RV:LV) pressure ratio >0.6. The indication for treatment before and after epinephrine was evaluated to determine its role in clinical decision making. Results: A total of 74 procedures were included. In all procedures the invasively measured LV pressure was below the awake blood pressure. At baseline, 33 patients had a RV:LV ratio >0.6. In 41 patients the baseline RV:LV ratio was <0.6. After epinephrine bolus, the LV pressure was raised up to the awake blood pressure. In 19 of the 41 patients without baseline indication, this resulted in a RV:LV ratio >0.6 thereby revealing the indication for treatment. No epinephrine related complications were registered. Conclusion: The hypotensive properties of anesthetics during cardiac catheterization may lead to underestimation of RV pressure load. Invasive pressure measurements should be performed under conditions similar to awake conditions. Epinephrine provocation prevented under treatment in 25% of our patients.