With an increase in pulmonary blood flow, as with an atrial septal defect, both the central and peripheral arteries are symmetrically enlarged. With an increase in pulmonary vascular resistance and pulmonary hypertension, the central pulmonary arteries may become strikingly enlarged, while the peripheral pulmonary arteries do not distend, producing a striking disproportion in the size of the two vessels. An estimation of the pulmonary blood flow by fluoroscopy is of particular importance in the presence of congenital heart disease. ICD10 Training.makes you spend more time with patients and increase the quality of the care.