FFR with CT angiography

Brief Review

Fractional flow reserve (FFR) is usually estimated invasively using a Doppler flow wire introduced into the coronary artery and measuring the pressure drop across the coronary stenosis during maximal hyperemia induced by adenosine. FFR has been shown to be of great significance while assessing the severity of borderline coronary stenosis in deciding the need for coronary angioplasty. Fractional flow reserve estimated by computerized tomographic angiography (FFRCT) is a novel technique of getting similar information non invasively. FFRCT has been shown to be superior to conventional CT coronary angiography and it has been shown to have a high negative predictive value of 91.6% [1]. FFRCT estimation is also called non invasive fractional flow reserve derived from coronary CT angiography [2].

The PLATFORM study assessed the quality of life and economic outcomes of using FFRCT [3]. The study involved 584 patients with atypical angina and 49% pretest probability of coronary artery disease. They documented that FFRCT based strategy was associated with less resource utilization and cost at 90 days than invasive evaluation. This was even after setting the cost weight of FFRCT to 7 times that of CT coronary angiography. FFRCT was also associated with better quality of life than conventional non invasive testing.

A recent meta-analysis showed that CT coronary angiography had a pooled sensitivity of 0.92 and specificity of 0.43. FFRCT increased this specificity to 0.72 so that positive predictive value improved from 0.56 to 0.70. There was no improvement in sensitivity [4].

Excellent correlation between FFR and FFRCT while assessing serial coronary stenoses have also been documented, with correlation coefficient of 0.92, in a study involving 18 vessels with serial coronary lesions and stable angina pectoris [5].

References

  1. Xu R, Li C, Qian J, Ge J. Computed Tomography-Derived Fractional Flow Reserve in the Detection of Lesion-Specific Ischemia: An Integrated Analysis of 3 Pivotal Trials. Medicine (Baltimore). 2015 Nov;94(46):e1963.
  2. Min JK, Taylor CA, Achenbach S, Koo BK, Leipsic J, Nørgaard BL, Pijls NJ, De Bruyne B. Noninvasive Fractional Flow Reserve Derived From Coronary CT Angiography: Clinical Data and Scientific Principles. JACC Cardiovasc Imaging. 2015 Oct;8(10):1209-22.
  3. Hlatky MA, De Bruyne B, Pontone G, Patel MR, Norgaard BL, Byrne RA, Curzen N, Purcell I, Gutberlet M, Rioufol G, Hink U, Schuchlenz HW, Feuchtner G, Gilard M, Andreini D, Jensen JM, Hadamitzky M, Wilk A, Wang F, Rogers C, Douglas PS; PLATFORM Investigators. Quality of Life and Economic Outcomes of Assessing Fractional Flow Reserve With Computed Tomography Angiography: The PLATFORM Study. J Am Coll Cardiol. 2015;66(21):2315-2323.
  4. Gonzalez JA, Lipinski MJ, Flors L, Shaw PW, Kramer CM, Salerno M. Meta-Analysis of Diagnostic Performance of Coronary Computed Tomography Angiography, Computed Tomography Perfusion, and Computed Tomography-Fractional Flow Reserve in Functional Myocardial Ischemia Assessment Versus Invasive Fractional Flow Reserve. Am J Cardiol. 2015 Nov 1;116(9):1469-78.
  5. Tanaka K, Bezerra HG, Gaur S, Attizzani GF, Bøtker HE, Costa MA, Rogers C, Nørgaard BL. Comparison Between Non-invasive (Coronary Computed Tomography Angiography Derived) and Invasive-Fractional Flow Reserve in Patients with Serial Stenoses Within One Coronary Artery: A NXT Trial substudy. Ann Biomed Eng. 2015 Sep 2. [Epub ahead of print]