Coronary compression testing by balloon interrogation during pulmonary valve implantation: room for doubt?

OBJECTIVE: To evaluate the reliability of balloon coronary compression testing during percutaneous pulmonary valve implantation. BACKGROUND: Despite the widespread use of the 'balloon coronary test' as the preferable method to rule out the risk of coronary compression, this adverse event has been described after pulmonary valve implantation where coronary balloon test suggested no risk or low risk, calling into question the accuracy of the test. METHODS: We performed a retrospective chart review of 84 patients who underwent pulmonary valve implantation between January 2018 and December 2019 and selected 36 patients whose archived imaging was suitable to perform quantitative analysis of the 'balloon coronary test'. We focused on the spatial disparity between the right ventricular outflow tract position defined by the inflated testing balloon and the eventual implanted valve position, to classify the test as inaccurate or accurate. RESULTS: In total, 36.1% of cases were classified as having an inaccurate coronary balloon test. Among the baseline characteristics, right ventricular outflow tract substrate was identified as a significant predictor of test accuracy. Related to this characteristic, the type of testing balloon used and the size of the eventually implanted valve were found to be associated with test accuracy. CONCLUSIONS: Based on our findings, balloon coronary testing is not an accurate method of predicting final valve position with respect to fixed structures in the thorax. This may translate to a high false positive rate for the likelihood of coronary compression in pulmonary valve implantation.