A California grandfather was left brain-damaged after his surgeon reportedly walked out of the operating room in the middle of surgery to attend a luncheon, leaving an important procedure to an unqualified assistant.

Dr. Pervaiz Chaudhry, a cardiologist at Valley Cardiac Surgery in Fresno, Calif., allegedly left a gaping hole in Silvino Perez's chest following open heart surgery and relied on an unlicensed assistant to close the excision so that he could go to a lunch meeting on April 2, 2012.

According to the State Department of Health, Perez's heart stopped as oxygen left his body and the 72-year-old was placed on life support. The California grandfather, who loves gardening and his grandkids, remains in a vegetative state since the surgical mishap two years ago.

"I just want people to know what kind of doctor he is," Cristobal Arteaga, Perez's stepson said in an interview with a local news outlet. "You go in there and you trust this individual with your life ... The fact that he would do this to an individual - one individual - is too much."

The patient's wife, Maria A. Arteaga Alvarez, and his stepson filed a lawsuit on Dec. 23, telling the court they learned of the alleged operating room slip-up from an anonymous caller on Oct. 26.

Cristobal Arteaga claims that his father was left with severe brain damage after Dr. Pervaiz Chaudhry, his cardiovascular surgeon, left in the middle of his open heart surgery to have lunch.

California officials were also tipped off April 11, 2012 by an anonymous caller. Investigators looked into the case and confirmed that the physician violated hospital policies that prohibit the primary surgeon to exit an operating room "before the patient is returned to stable condition."

After he was alerted of the mishap, Chaudhry allegedly rushed back to the operating room to manually massage the 72-year-old's heart but was too late to undo the damage.

"This assertion, apparently made anonymously to the patient's family, is unequivocally false, and it will be proven to be so," said Valley Cardiac Surgery COO, Bruce Eliason, who claimed that the medical has not been served the lawsuit.