Summer pruning

planted an Apricot about 6years ago. Spread it out on a sunny wall and it produces plenty of fruit. Unfortunately I have only cut the new stem and leaf back to 4 leaves every late summer. It is now growing out from the wall by a good 12 to 15 inches. Will I kill it if I cut all the small branches back to the main branch.. Will it sprout again and form new fruiting spurs or die back. Advice please as it is next to a narrow path. 

Thanks