Alex Zanardi is in intensive care after undergoing surgery for a head injury sustained when he was hit by a truck during a handbike race.

The two-time CART series winner, and Paralympic gold medallist, is in a “very serious” condition according to the Santa Maria alle Scotte hospital in Siena, Italy, where he was operated on.

Zanardi had been competing in the Obiettivo Tricolore handbike relay race when the accident occurred on Friday at around 17:05 local time.

According to Italian team coach Mario Valentini, the 53-year-old had veered into the wrong lane of the road which he was riding on before the truck hit him.

“It happened on a straight downhill, just before the road makes a slight bend,” Valentini was quoted as saying by Italian newspaper La Repubblica.

“Alex slightly crossed in to the other lane. The truck tried to steer but was not able to avoid the impact.”

The hospital issued a statement at 19:45 local time, which read, “Alex Zanardi, car driver, paracyclist and TV presenter, was hospitalised in very serious conditions at the polyclinic Santa Maria alle Scotte.

“He was involved in a road accident in the province of Siena. Zanardi was transported with the Pegaso helicopter and landed at the hospital in Siena at 6.00 pm.

“He was immediately taken care of by the emergency room professionals, assessed in the shock room and his conditions are very serious due to the severe head injury and is currently undergoing a delicate neurosurgery.”

A subsequent update advised that surgery ended just before 22:00.

“The patient was then transferred to intensive care, with a reserved prognosis,” it added.

“His health condition is very serious.”

Zanardi won the CART title in 1997 and 1998, and raced in Formula 1 on either side of his first stint in North American open-wheel racing.

It was back in CART in 2001 that he crashed heavily at the Lausitzring, resulting in amputation of both of his legs.

The Italian has claimed Gold four times in para-cycling at the Paralympic Games, across London 2012 and Rio 2016.

Zanardi also continues to compete in motorsport, in modified vehicles, including sharing a GT Le Mans class BMW M8 with Chaz Mostert, as well as John Edwards and Jesse Krohn, at last year’s 24 Hours of Daytona.