Prolonged Coronary Transit Time and Reversed Flow Causing Functional Ischemia, Chest Pain and Syncope in Patients with Aortic Stenosis and Patent Coronary Arteries: An Angiographic and Machine Learning Analysis

Abstract

Background. Patients afflicted with aortic stenosis (AS) may present chest pain (CP), shortness of breath (SOB), syncope, and no lesion in the coronary arteries. So far, no clear mechanism could convincingly elucidate the pathophysiology of symptoms in such patients. We conducted a study to clarify the mechanism of CP, SOB, and syncope in AS patients without coronary artery stenosis based on coronary flow patterns or abnormalities. Methods. One hundred and thirty two (132) patients visiting the emergency room with CP, SOB, or syncope were screened for AS. Forty four (44) patients with a clinical diagnosis of AS underwent right and left heart catheterization and a novel dynamic coronary angiographic technique. Twenty AS patients without coronary artery disease (CAD) were enrolled. All patients were divided into either: group A for severe AS or group B for mild to moderate AS. The control group consisted of Five patients with normal left ventricular function without CAD or AS (group C). The flow data included the coronary transit time duration, the presence of retrograde flow at the proximal coronary segment, and the persistence of contrast spill-out from the coronary ostium. Results There was prolonged arterial phase and retrograde flow in the proximal coronary segment, including persistent spilling of contrast into the coronary sinus (p<0.01 when compared with groups B and C) in 20 patients with severe AS (group A). In 24 patients in the mild to moderate AS group (group C), there was only a moderately prolonged arterial phase without retrograde flow nor spilling of contrast from the ostium (p=0.99 when compared with control group C). Conclusions In patients with AS, significantly prolonged arterial coronary transit time, reversed coronary flow, and retrograde ejection of contrast into the coronary sinus correlated statistically with the severity of AS. In patients with mild to moderate AS, with only moderate prolongation of the arterial phase without reversed coronary flow nor retrograde ejection of contrast into the coronary sinus.