Jan. 15, 2014 -- Cristobal "Cris" Arteaga had come to terms with the fact that his stepfather, Silvino Perez, had been in a vegetative state for more than a year following complications from open-heart surgery, when he said an anonymous phone call suddenly shattered his peace.

The man on the other end of the line, Arteaga said, told him that his stepfather's cardiologist, Dr. Parvaiz Chaudhry, at Fresno Community Regional Medical Center in California, had walked out before completing Perez's surgery to attend a luncheon, leaving Perez's chest cavity open on the table.

The caller told Arteaga that the physician's assistant was left to close Perez's chest even though he wasn't qualified to do so, Arteaga said. When complications arose and Perez's heart stopped, Chaudhry drove back from the luncheon, 20 or 30 minutes away, to save the patient, Arteaga said the caller told him. But the brain damage had already been done.

Artaega said the caller told him that this was why Perez was left in a vegetative state.

"It was awful to hear that," Arteaga said. "I just want people to know what kind of doctor he is. 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 man on the other end of the line told Arteaga to look at the previous day's newspaper, The Fresno Bee, for an article about a state health department report detailing how a cardiologist at Fresno Community Regional Medical Center left a patient open on the operating table the previous April. Though neither the story nor the report named the patient or the patient's doctor, the caller said it was about Arteaga's stepfather and Chaudhry. Arteaga said the caller told him he was sure of it, because he was in the operating room that day.

The document on the California Department of Public Health's website revealed that the investigation began because the department had received an anonymous call placed to the health department a week after Perez's surgery.

Arteaga's lawyer, Jeffrey Mitchell, said the dates and medical details listed on the report were too similar to Perez's case for this to be a coincidence.

Neither the California Department of Public Health nor the hospital would confirm whether the report was about Chaudhry and Perez to ABCNews.com, but Arteaga's lawyer, Jeffrey Mitchell, said the dates and medical details listed on the report matched Perez's case and therefore couldn't be a coincidence.

Before his surgery, Perez was an active 72-year-old, Arteaga said. He could climb 30 feet up his trees to prune them himself, and if he didn't answer his front door, Arteaga knew he could find his stepfather tinkering away at a project in the backyard.

Perez didn't go to the doctor much, said his stepson, but on March 30, 2012, Arteaga got a call from a health facility that his stepfather was having chest pains and needed to be taken to the emergency room, Arteaga said. A few days later, they both learned that Perez had a heart defect, a calcified heart valve and an aortic aneurism. He was scheduled for surgery at Fresno Community Regional Medical Center on April 2, 2012, but was in good spirits, Arteaga said.

The day of the surgery, Arteaga said he and his mother were led to a private waiting room and told that they would receive updates on the surgery via the waiting-room phone. Arteaga said it rang when Perez's surgery started, and two hours into the surgery, Chaudhry came into the room to proclaim the surgery a success. He then walked out.

Unknown to Arteaga and his mother in the waiting room, this was likely when the doctor left the hospital before closing the patient's chest, according to Jeffrey Mitchell, the family's attorney.

Arteaga and his mother were still in the hospital waiting room on April 2 when the phone rang again to tell them that Perez was facing complications, Arteaga said.

"It was somewhat of a whirlwind," Arteaga said. "At one point in time, they told us to round up the whole family, because they didn't think he was going to pull through.

"I didn't know that the doctor walked out, and that was the reason my dad was in the state that he's in," he said.

After the physician's assistant, who was not named in the report, closed the patient, another person, also not named, noticed that Perez continued to bleed from his chest, according to the health department's report. By phone, Chaudhry ordered staff to administer blood products, the report said.

Then, the patient's heart began to quiver, and he went into cardiac arrest, according to the report. The physician's assistant rushed to the operating room to reopen the patient's chest and manually massage the heart, but that didn't work. The physician's assistant and another general surgeon tried to restart a bypass, but they couldn't insert the hollow tubes into the patient's heart, according to the report.

About 45 minutes after the patient "coded," the cardiologist returned to the hospital and successfully inserted the tubes to restart the full heart bypass machine, according to the report. The patient continued to bleed heavily and was placed on a machine that oxygenates the blood, called an ECMO, several hours later. The patient was transferred to the cardiovascular intensive care unit that evening, according to the report.

When Arteaga visited his father, his chest remained open in case something else went wrong, he said. He was also experiencing complications with his kidneys and bile production, he said.

"It looked like somebody put a clear piece of tape over his chest," Arteaga said. "He was like that, I want to say, for a couple of days."

Although Perez's body gradually healed, his brain did not, Arteaga said.

"He never regained consciousness," Arteaga said. "He never spoke, never really moved."

Perez has been in an acute care facility since he was released from the hospital.

According to the health department's investigative report, prompted by an anonymous call on April 11, 2012, the unnamed cardiologist was given a 14-day medical staff suspension. His surgeries also were monitored for two months by the hospital's patient safety department.

On Dec. 23, Arteaga and his mother filed a lawsuit against Fresno Community Regional Medical Center, Chaudhry and Valley Cardiac Surgery Medical Group, of which Chaudhry is a part. They are asking for unspecified damages.

In an interview with the California Department of Public Health as part of its investigation, the unnamed doctor said he let the physician's assistant do the closure to give her extra practice, even though it was above her hospital privileges, according to the report.

Chaudhry and the Valley Cardiac Surgery Medical Group have not yet been served with the lawsuit, but they've seen news reports containing the accusations against them, the medical group's chief operating officer, Bruce Eliason, said in a statement last Friday.

"The assertion is being made that Dr. Chaudhry left the operating room prior to the patient's chest being closed and before the patient was in a stable condition," Eliason said in the statement. "This assertion, apparently made anonymously to the patient's family, is unequivocally false, and it will be proven so."

"Dr. Chaudhry's patient underwent a complex cardiac surgery, and he suffered one of the known complications," Eliason said. "The patient and his family have obviously suffered greatly as a result. Dr. Chaudhry and Valley Cardiac Surgery Medical Group recognize this and have only the deepest sympathies for the continuing issues he has suffered."

Fresno Community Regional Medical Center spokeswoman Mary Lisa Russell said the hospital was surprised to hear that the family said it was left in the dark regarding surgery details.

"The medical record documents multiple times that surgeons talked with family immediately following stages in the surgery," Russell said in an emailed statement to ABCNews.com.

She said the hospital has added improved safeguards since then.

"The very unfortunate patient outcome, which occurred in April 2012, immediately prompted some tighter operating-room procedures at Community Regional Medical Center," Russell said. "Those procedures have long since been approved by the state. We are surprised now, however, to hear of a civil lawsuit by family members, more than 20 months later."