Sutton was riding the Philip Hobbs-trained 9/4 favourite in the Halloween Handicap Chase when the pair fell at the third fence in the extended two-mile-one-furlong contest.
The yellow 'stop race' flag was deployed, with the race declared void by the stewards.
The jockey was reported to be conscious when transferred to the ambulance, but the injuries Kepy Blanc sustained in the fall proved fatal.
"Ben Sutton was transferred to Wrexham Hospital with one of our doctors where he will receive further assessment," said clerk of the course Andrew Tulloch.
"He was conscious when he was picked up and transferred to the ambulance.
"Sadly, the horse was euthanised."