Method:

Randomized into BT shunt vs. RV-PA
-275 vs 274 infants
-15 American ctrs
-Outcome: death or cardiac txp
-2nd outcome: unintended interventions/RV size and fxn @14 mths

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Results:
-Transplantation free survival at 12 months was higher in RVPA
-Unintended interventions (P:0.003) and complications (0.002) were higher in RVPA
-At 14 months RV size and fxn were similar
-Rate of nonfatal serious adverse events @ 12 months were similar

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Conclusions:
-Children undergoing the Norwood procedure, transplantation-free survival at 12 months was better with the RVPA
-After 12 months there was no significant difference between the two groups

Other important points

-Norwood procedure has highest mortality among common congenital procedures 7 to 19% & highest cost
-BTS flows continuously during both systole and diastole
-Because coronary bloodflow occurs primarily during diastole a “coronary steal” may occur

-Theoretical advantage of the RVPA: elimination of diastolic runoff and reduction of coronary steal
-Disadvantages: RV dysfunction, arrhythmias, aneurysm related to ventriculotomy, additional volume load due to regurgitation from non-valved shunt, impaired growth of the PA and need for earlier stage II procedure

-Majority of death or transplantations occur during the period from 30 days after the Norwood procedure to the time of Glenn
-Interesting: centers with higher-volume negated the advantage of the RVPA with respect to transplantation-free survival. This finding may reflect better institutional experience w/ BTS

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Take home message:

RVPA lead to better survival the first year but had more unintended interventions. Not advantageous after the first year. If experience is better, ie more volume, then there is no advantage with RVPA.