Q. Visualize Patient Ductus Arteriosus?

Best view to visualize a patient ductus arteriosus is high parasternal or ductal view. A patient ductus arteriosus in this view is seen as a 3rd channel beside RPA and LPA producing a dinner fork appearance. Descending aorta can also be imagined in this view when it curves down to meet ductus in its anterior aspect and left subclavian artery; Opening of PDA in pulmonary artery is clearly seen and can be measured. A PDA size beyond 4-5 mm can be send for surgical ligation. A smaller sized PDA can be closed by interventional procedure like coiling or device closure. In a patient with PDA one should further interrogate for VSD, bicuspid aortic valve and coarctation of aorta. Some times PDA can be sole source of pulmonary blood flow (like in pulmonary atresia) or systemic blood flow (aortic &-esia/HLHS). CW Doppler velocity of PDA can be used to assess PA pressure. PDA flow signals are continuous, maximal in late systole and are above the baseline. Like the VSD, end diastolic LV dimension is an important echocarddographic indicator of the level of shunt.