A joint Korean and Chinese research team proved that fractional flow reserve (FFR) or intravascular ultrasonography (IVUS) are useful in guiding percutaneous coronary intervention (PCI) surgery in patients with moderate stenosis. FFR measures coronary pressure, and IVUS is an intravascular imaging test.

According to the Ajou University Hospital, for patients with 40-70 percent internal stenosis in coronary angiography, it is very difficult to determine whether patients with moderate stenosis have myocardial ischemia by using coronary angiography only.

If a coronary artery is severely blocked, surgeons have clear ideas what to do. But in cases of severe stenosis, surgeons debate about which method to use other than coronary angiography, as some patients do not have myocardial ischemia even if there is significant stenosis, the hospital said.

Patients do not require a coronary intervention such as a stent to treat the symptoms in such cases.

So, the joint research team, led by Professors Tahk Seung-jea and Yoon Myeong-ho at Ajou University Hospital, Wang Jian An at China's Zhejiang University School of Medicine Second Affiliated Hospital, and Koo Bon-kwon and Kang Jee-hoon at Seoul National University Hospital, randomly assigned 1,682 patients who were being evaluated for PCI for the treatment of intermediate stenosis at 18 hospitals in Korea and China in a 1:1 ratio to undergo either an FFR-guided or IVUS-guided procedure.

The team followed up and compared the clinical course during, immediately after, and up to two years after the procedures.

As a result, the team confirmed that for patients with intermediate stenosis, who were being evaluated for PCI, FFR guidance was non-inferior to IVUS guidance with respect to the composite primary outcome of death, myocardial infarction, or revascularization at 24 months.

The researchers stressed that although there have been small-scale retrospective studies on the same topic, the research is the first large-scale, prospective, randomized, comparative study that can provide definitive results and end the long-standing controversy about which procedure to use.

"We finally conducted a large-scale research with the cooperation of Korean and Chinese researchers and received recognition in a prestigious international medical journal," Professor Tahk said. "There is a need to analyze more diverse perspectives through a sub-study, and we hope that the clinical results for long-term observation will continue to be published."

The research results were published in the September edition of the New England Journal of Medicine, with the title "Fractional Flow Reserve or Intravascular Ultrasound to Guide PCI."