Diastolic flow reversal in the ascending aorta may indicate severe aortic regurgitation, but could be a false positive if the patient has which condition?

Diastolic flow reversal in the ascending aorta is commonly associated with severe aortic regurgitation, where there is backflow of blood from the aorta into the left ventricle during diastole. However, this phenomenon can be misinterpreted in the presence of certain conditions that affect blood flow dynamics.

In the case of patent ductus arteriosus (PDA), this condition involves an abnormal connection between the aorta and the pulmonary artery that remains open after birth. With PDA, there can be significant left-to-right shunting of blood. During diastole, blood can flow from the aorta into the pulmonary artery, created by the higher pressure in the aorta. Thus, patients with significant PDA may exhibit diastolic flow reversal in the ascending aorta due to the altered hemodynamics rather than true aortic regurgitation.

This means that while diastolic flow reversal is a concerning indicator of severe aortic regurgitation, the presence of a PDA could produce a false positive in this assessment, leading to a misunderstanding of the patient's cardiac status. In essence, it is the shunting from the high-pressure aorta to the lower-pressure pulmonary artery that contributes to the observed flow reversal, distinguishing it from