By 3 years , RVPAS subjects had a higher incidence of catheter interventions ( P < 0.001 ) with an increasing HR over time ( P = 0.005 ) : < 5 months , 1.14 ( 95 % confidence interval , 0.81-1 .60 ) ; from 5 months to 1 year , 1.94 ( 95 % confidence interval , 1.02-3 .69 ) ; and > 1 year , 2.48 ( 95 % confidence interval , 1.28-4 .80 ) .