Researchers from the Chinese University (CUHK) have called on patients who had heart bypass surgery to keep their cholesterol levels in check, saying it could significantly reduce the risks of cardiac deaths.

The research team said it tracked 309 patients who underwent such surgery at the Prince of Wales Hospital for more than 12 years, and found that the higher their "bad" cholesterol level, the more likely they will die of cardiovascular diseases.

Randolph Wong, a CUHK professor who led the research, said it's crucial for these patients to control their lipid levels.

"They're already considered as those having a critical level of cholesterol. They are a group of patients that fall into what we call a metabolic syndrome, and this group of patients actually are of high risk of developing cardiovascular events. And that's why maintaining a good cholesterol level should be beneficial to their overall survival," he said.

The expert added that while medication is key to controlling cholesterol, leading a healthy lifestyle is equally important.

"Dietary intake is one consideration. Avoid fatty foods, especially those with trans fat or unsaturated fats, and also [engage in an] appropriate amount of exercise."