985-67 Study of Pulmonary Perfusion Using Scintigraphy in Total or Partial By-pass of the Right Ventricle at Rest and with Exertion

The purpose of our study was to determine the distribution of pulmonary flow at rest and with exertion in total or partial by-pass of the right ventricle (TBP and PBP). During 1990–1994, 98 patients (p) were studied within their first post-operative year utilizing pulmonary scintigraphy with 99 m TcMM. The radioactive agent was injected intravenously by superior(arm) and inferior (leg) routes in these patients with congenital cardiopathies consisting of a univentricular atrioventricular (AV) connection or other complex cardiopathies with pulmonary stenosis or previous pulmonary arterial banding unamendable to biventricular correction. Pulmonary perfusion was considered to be homogeneous with a right/left lung ratio of l60/40, right dominant with g80/20, and slightly right dominant with a 60–70/30–40 ratio. 10 p were further studied utilizing 99 m Tc-MAA scintigraphy during maximal exertion (ergometric stress test). Results TBP (33 p): The pulmonary perfusion was homogeneous (52/48) in 20 p with Atriopulmonary anastomosis (APA), right dominant (88/12) in 7 p [5 p with Total Cavo-pulmonary anastomosis (TCP) and 2 p with Kawashima's operation] as determined equally by superior and inferior injection routes (p l 0.001). Perfusion was slightly right dominant (68/32) aw determined via superior injection routes in 6 p with combined surgery: Bidirectional Cavopulmonary anastomosis (CP2-D) and APA (p l 0.001). PBP (65 p): Pulmonary perfusion, as determined by superior injection routes, was right dominant (86/14) in CP2-D (p l 0.001). It was equally right dominant in 59 p with pulsatile flow (87/13), -anteriograde ventricular flow or subclavian-pulmonary anastomosis-, as in 6 p with non-pulsatile flow (88/12) (p:NS). Exercise The pulmonary perfusion was right dominant (92/8) in 9 p (3 CP2-D, 3 TCP. 3 CP2-D and APA) and remained right dominant with exertion (88/12), In 1 p with APA and homogeneous perfusion (52/48) flow persisted to be homogeneous (54/46) with exertion. Conclusions 1] Pulmonary perfusion is homogeneous in APA as determined equally by superior and inferior injection routes; there is a dominantly right disbalance in TCP, Kawashima's operation, and CP2-D pulsatile or non-pulsatile flow; and slightly right dominant in CP2-D and APA combined surgery. Perfusion appears to dominate the lung on whose respective side the Cavo-pulmonary anastomosis (CPA) was placed. 2] After present techniques of CPA to a branch of the pulmonary artery, a disbalance of pulmonary perfusion was observed and found to persist exertion. 3] With respect to pulmonary perfusion, APA appears to be the best option as it provides a mixing chamber to maintain homogeneous perfusion to both lungs.