Reflux through Normal Aortic Valves

Contrast injection in the ascending aorta above the aortic valve was performed in dogs to ascertain the presence and degree of reflux through the normal aortic valve and the modifying effect of varying certain parameters of the injection. Reflux through the aortic valve was observed in 35% of 190 injections. When present, it usually represented a trace or 1+ but in about 20% of cases 2+ reflux was noted. Incidence of regurgitation increased with higher injection rates. Similarly, higher intrabronchial pressures were associated with increased incidence of reflux as were larger volumes of contrast agent. Neither the type of catheter nor the position of the catheter, unless it was placed through the valve itself, affected the incidence of reflux. Reflux usually was observed initially at the termination of ventricular systole, but also occurred through early, mid and late diastole. There was some variation in the incidence of reflux from animal to animal under identical conditions. When thoracic aortography is accompanied by reflux into the left ventricle, it is important to make an effort to distinguish normal reflux from regurgitation through a diseased valve. Careful appraisal of the clinical and aortographic data is helpful in making this distinction.