Four-time Indianapolis 500 winner and current Verizon IndyCar Series team owner AJ Foyt is recovering in hospital after undergoing triple bypass surgery on Monday. His condition is described as stable.

Foyt, who turns 80 in January, was admitted to the Baylor St. Luke's Medical Center on Friday with intermittent chest pains. Initial tests proved inconclusive, but a cardiac catheterisation procedure performed Monday revealed blockages in arteries where Foyt had previously received several stents, from past procedures as recent as March 2010.

Foyt has had a number of stays in various Houston hospitals in recent years. Last year he underwent back surgery and had his left hip and right knee replaced in separate surgeries. The previous year he battled back from a life-threatening staph infection after surgery to remove bone spurs in his artificial left knee, which had been replaced in 2006.

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Many of Foyt's surgeries were originally the result of an IndyCar accident at Road America in 1990 when Foyt was 55 years old. Foyt suffered a broken left knee, broken left heel and dislocated right foot when his car went off at the first turn in spectacular fashion halfway through a 200-mile race as he duelled with Dominic Dobson.

Foyt had been badly injured several times before that, including a crash in the inaugural Michigan 500 in 1981 in which he broke his right arm. A stock car crash at Charlotte, N.C. in 1989 saw him receive a serious concussion. Prior to his retirement, Foyt had held the record for the most IndyCar wins with 67 victories, the last of which came in 1981 at the Pocono 500. During his racing career he also had seven wins in the NASCAR Cup Series including the Daytona 500, and victories in the 24 Hours of Daytona and the 24 Hours of Le Mans.

This week's surgery was undertaken by renowned cardiothoracic surgeons OH "Bud" Frazier, the Director of Cardiovascular Surgery Research at Texas Heart Institute (THI) and Chief of Transplant Service at St. Luke's Medical Center, together with William Cohn, the Director of Minimally Invasive Surgical Technology at THI.

Both men trained under artificial heart pioneer Dr Michael DeBakey. Dr Frazier also worked with Dr Denton Cooley, a former partner of DeBakey's and founder of the Texas Heart Institute.

Team spokesman Anne Fornoro said that Foyt is expected to remain in hospital for the rest of the week until at least next Monday.

Foyt and his son Larry recently announced the expansion of their IndyCar team AJ Foyt Racing to a two-car line-up, signing British racer Jack Hawksworth to race in the new #41 entry alongside former F1 driver Takuma Sato who is staying with the team for a third season in the race seat of the #14 car. ABC Supply is to act as primary sponsor on both cars for the 2015 season.

Last month, Foyt purchased a building in Speedway, Indiana which will be used by the expanded race team as a Midwest base during the summer.