Computed Tomography Derived Fractional Flow Reserve for Coronary Hemodynamic Ischemia Noninvasive Assessment

Computed Tomography Derived Fractional Flow Reserve for Coronary Hemodynamic Ischemia Noninvasive Assessment (CT-FFR-CHINA)

Computed Tomography Derived Fractional Flow Reserve (CT-FFR) is a noninvasive method for evaluating the hemodynamic significance of coronary artery lesions by using coronary CT Angiography (CCTA) as opposed to invasive FFR examination under invasive coronary angiography. The purpose of the CT-FFR-CHINA study is to verify that the diagnostic performance of hemodynamically significant lesions by CT-FFR is superior than routine anatomic evaluation of diameter stenosis using CCTA alone using invasive FFR as the reference standard, exclusively in Chinese population.

Numerous studies have demonstrated high diagnostic accuracy of CCTA to detect and exclude coronary artery disease (CAD). One main limitation of CCTA, however, is a tendency to overestimate the severity of coronary artery stenosis against invasive coronary angiography (ICA). On the other hand, FFR, invasively measured under ICA, is recognized as the current gold standard in determination of coronary artery lesions due to improved long-term clinical outcomes when revascularization is guided by FFR instead of ICA. Moreover, prior studies indicated unreliable relationships between detection of obstructive anatomic coronary artery stenoses defined by CCTA and hemodynamically significant lesions by invasive fractional flow reserve (FFR).

Recent advances in artificial intelligence and computational modeling techniques now permit construction of a 3-dimensional model of coronary arteries visible from CCTA images and computation of FFR anywhere in the entire 3D model noninvasively. Several prior prospective, multicenter studies have reported promising results for the diagnostic performance of CT-FFR using invasive FFR as the reference standard. However, the diagnostic performance of CT-FFR in Chinese population is not clear. Therefore, we hereby designed the CT-FFR-CHINA study to determine the hemodynamically significant lesions, exclusively in Chinese subjects. It is a prospective and multi-center trial with a total of 326 subjects enrolled at 4 Chinese centers.

Inclusion Criteria:

• General Criteria:

  • Stable and unstable angina pectoris or secondary evaluation of stenosis after acute MI
  • Age > 18 years
  • Able to provide signed informed consent

CCTA inclusion criteria:

• At least one stenosis with diameter stenosis of 30%-90% by visual estimate
• Reference vessel size > 2 mm in stenotic segment by visual estimate

Exclusion Criteria:

• General Criteria:

  • Ineligible for diagnostic intervention or FFR examination
  • Myocardial infarction within 72 hours
  • Severe heart failure (NYHA≥III)
  • S-creatinine>150µmol/L or GFR<45 ml/kg/1.73m2
  • Allergy to contrast agent or adenosine
  • Factors that might substantially impact the CCTA image quality, e.g, frequent atrial premature beat or atrial fibrillation

Angiographic exclusion criteria:

• The interrogated stenosis is caused by myocardial bridge
• Ostial lesions less than 3 mm to the aorta
• Poor angiographic image quality precluding contour detection
• Severe overlap of stenotic segments
• Severe tortuosity of target vessel