More than half of heart stent surgeries performed on the Chinese mainland are unnecessary, burdening patients and straining relations between doctors and patients, said a top heart doctor.

Hu Dayi, a well-known cardiologist, made the remarks on Sunday at the 23rd Great Wall International Congress of Cardiology, an event for which he is acting as president.

"We've wasted lots of resources and haven't solved patients' problems," he warned. "Some people even turn out to be worse off with these unnecessary stent implants."

To help prevent the devices from being used in instances when they are not needed, Hu urged health authorities to take a variety of steps concerning insurance policy payments, clinical guidelines, regulations, monitoring and the assessment of surgical outcomes.

China has no formal registry system that tracks the number of heart stent surgeries that occur annually in the country. Official estimates have put the number at about 340,000 in recent years, making the country only second to the United States by that measure.

A mere decade ago, only 20,000 heart stent surgeries had been performed annually in China, the China Youth Daily reported, citing an industry source.

A stent is a tiny tube placed into an artery, blood vessel or other duct to hold it open. Stenting is clinically practiced to treat acute heart attacks or serious angina.

Hu said only 10 percent of heart stent operations in China are performed in response to heart attacks.

"That's contrary to the situation in developed countries that have sound regulations and clinical management," he said.

That is not to say that stent overuse, let alone abuse, has not occurred abroad.

A 2010 clinical study conducted in the US and Britain found that among patients who underwent a stent operation to treat a condition other than a heart attack, about half would have been all right without the costly procedure. It said about 12 percent of the patients should have forgone the operation completely, noting that their condition actually became worse after they received a stent.

"The problem in China is far worse than that," Hu warned.

A single stent can be enough to save the lives of heart attack patients. But people suffering from stable angina, a condition arising from poor blood flow in the blood vessels of the heart, usually need three to five of the devices, he said.

"An intentional overuse of stents has become common on the mainland, a practice that must be changed immediately," he said.

Performing stent surgery can be highly profitable and patients have been known to pay as much as 27,000 yuan ($4,500) for a domestically produced stent that carries a factory price of 3,000 yuan.

The Ministry of Health has taken various steps to prevent the devices from being overused. The ministry now requires collective assessments for surgeries that use more than three stents.

Hu said these haven't been strictly adopted by hospitals.

William A. Zoghbi, president of the American College of Cardiology, suggested that China establish a registry system for heart stent operations.

"With that we can know exactly how it is being used in a particular city or hospital and ensure medicine is being practiced properly," he said.

Huo Yong, president-elect of the Chinese Society of Cardiology, said many heart attack patients in rural areas do not have the opportunity to undergo a stent procedure, either because they live far away from the places where those procedures are performed or because of economic reasons.

According to his estimates, 600,000 heart attack cases occur in China annually but only 20,000 of them lead to the use of heart stents.

Contact the writer at shanjuan@chinadaily.com.cn