1) McGoon ratio:
(Diameter of RPA/DAo + Diameter of LPA/DAo)
Adequate for VSD closure 1.2
Inadequate <0.8 for VSD closure
2) Nakata Index:
(CSA of RPA + CSA of LPA)/BSA
Normal value > 200 mm2/m2
> 150 mm2/m2 is adequate.
(Not usable preoperatively when MAPCAs are the major source of PBF & one-stage unifocalization + full repair is planned).
(> 200 for single ventricle repair, > 100 for 2-ventricle repair...check correctness of this statement first)
3) Total Neo-Pulmonary Artery Index (TNPAI) = APC index + Nakata Index
APC index is the sum of CSA of all usable APCs/BSA
>250 - suitable for one-stage repair including VSD closure (These pts. have low RV/LV pressure ratio postoperatively).
Critique of all these indices: These indices consider only the size of proximal vessel and not consider the condition of distal parts of the vessels (which may be stenosed, etc).
MAPCAs in PA-VSD
Surgical Outcome (Journal Club blog)
Surgical Treatment algorithm