Correlation of machine learning computed tomography-based fractional flow reserve with instantaneous wave free ratio to detect hemodynamically significant coronary stenosis

Clin Res Cardiol. 2020 Jun;109(6):735-745. doi: 10.1007/s00392-019-01562-3. Epub 2019 Oct 29.

Abstract

Background: Fractional flow reserve based on coronary CT angiography (CT-FFR) is gaining importance for non-invasive hemodynamic assessment of coronary artery disease (CAD). We evaluated the on-site CT-FFR with a machine learning algorithm (CT-FFRML) for the detection of hemodynamically significant coronary artery stenosis in comparison to the invasive reference standard of instantaneous wave free ratio (iFR®).

Methods: This study evaluated patients with CAD who had a clinically indicated coronary computed tomography angiography (cCTA) and underwent invasive coronary angiography (ICA) with iFR®-measurements. Standard cCTA studies were acquired with third-generation dual-source computed tomography and analyzed with on-site prototype CT-FFRML software.

Results: We enrolled 40 patients (73% males, mean age 67 ± 12 years) who had iFR®-measurement and CT-FFRML calculation. The mean calculation time of CT-FFRML values was 11 ± 2 min. The CT-FFRML algorithm showed, on per-patient and per-lesion level, respectively, a sensitivity of 92% (95% CI 64-99%) and 87% (95% CI 59-98%), a specificity of 96% (95% CI 81-99%) and 95% (95% CI 84-99%), a positive predictive value of 92% (95% CI 64-99%), and 87% (95% CI 59-98%), and a negative predictive value of 96% (95% CI 81-99%) and 95% (95% CI 84-99%). The area under the receiver operating characteristic curve for CT-FFRML on per-lesion level was 0.97 (95% CI 0.91-1.00). Per lesion, the Pearson's correlation between the CT-FFRML and iFR® showed a strong correlation of r = 0.82 (p < 0.0001; 95% CI 0.715-0.920).

Conclusion: On-site CT-FFRML correlated well with the invasive reference standard of iFR® and allowed for the non-invasive detection of hemodynamically significant coronary stenosis.

Keywords: Coronary CT angiography; Coronary artery disease; Fractional flow reserve derived from coronary computed tomography angiography; Instantaneous wave-free ratio; Invasive coronary angiography; Myocardial ischemia.

MeSH terms

  • Aged
  • Algorithms*
  • Computed Tomography Angiography / methods*
  • Coronary Angiography / methods*
  • Coronary Stenosis / diagnosis*
  • Coronary Stenosis / physiopathology
  • Coronary Vessels / diagnostic imaging*
  • Coronary Vessels / physiopathology
  • Female
  • Follow-Up Studies
  • Fractional Flow Reserve, Myocardial / physiology*
  • Hemodynamics / physiology
  • Humans
  • Machine Learning*
  • Male
  • Prognosis
  • Prospective Studies