PATHOLOGICAL ANATOMY OF CORRECTED TRANSPOSITION OF THE GREAT-ARTERIES- MEDICAL AND SURGICAL IMPLICATIONS

Background Because the double-switch operation (atrial switch plus art erial switch) has recently become Feasible in selected patients with c ongenitally physiologically corrected transposition of the great arter ies, a detailed understanding of the pathologic anatomy is now mandato ry for cardiologists, radiologists, and surgeons. Methods A detailed s tudy of the pathologic anatomy, the clinical implications, and the sur gical implications was undertaken on 33 postmortem cases with two vent ricles. A companion study was also performed of 44 postmortem cases wi th functionally only one ventricle. Hence this was an investigation of 77 postmortem cases. Results Three main anatomic types of corrected t ransposition of the great arteries (TGA) with two ventricles were Foun d: (1) TGA with solitus atria (S), L-loop ventricles (L), and L-TGA (L ), that is, TGA {S,L,L} in 31 cases (94%); (2) TGA with solitus atria (S), L-loop ventricles (L), and D-TGA (D), that is, TGA {S,L,D} in 1 c ase (3%); and (3) TGA with inverted atria (I), D-loop ventricles (D), and D-TGA (D), that is, TGA {I,D,D} in 1 case (3%). Associated malform ations resulted in 13 anatomic subtypes. In classical corrected TGA IS ,I,LJ with two ventricles, anomalies of the left-sided systemic tricus pid valve were present in 97%, with malformations of the left-sided sy stemic right ventricle in 91%. Conclusions The findings in corrected T GA with two ventricles and in cases with single ventricle support the view that anatomic repair such as the double-switch procedure, or left -sided right ventricle bypass such as the modified Norwood procedure f ollowed by the modified Fontan procedure, is indicated in selected pat ients.