Fractional flow reserve derived from coronary computed tomography (CT) angiography and cardiac magnetic resonance stress perfusion imaging may provide comparable diagnostic accuracy for predicting coronary revascularization in patients with stable chest pain and obstructive coronary artery disease (CAD), according to a study published in the Journal of the American College of Cardiology, Cardiovascular Imaging.

This head-to-head comparison study was a prespecified substudy of the Dan-NICAD trial (Danish Study of Non-Invasive Diagnostic Testing in Coronary Artery Disease; NCT02264717), which was conducted to assess diagnostic performances of single-photon emission CT and cardiac magnetic resonance imaging in patients with obstructive CAD. Coronary CT angiography is the current standard of care for patients with new-onset chest pain in Denmark. Coronary CT angiography was completed at 2 centers in Denmark using a 320-slice volume CT scanner, with cardiologists reporting all lesions. For revascularization, standard techniques were used to complete coronary angiography. The decision to conduct revascularization was based on fractional flow reserve for stenoses from 30% to 90%. Cardiac magnetic resonance scans were performed after an injection of contrast agent, and a standard 16-segment model was used to evaluate images.

Of the 110 patients who met enrollment criteria for this substudy, the mean age was 61 years old, 60% were men, the mean body mass index was 27 kg/m2, and 100% were white. Of the 44 patients diagnosed with obstructive CAD, 6 were not revascularized. In the remaining 38 patients, a total of 55 vessels were revascularized, with 91% of these vessels having a coronary CT angiography fractional flow reserve value ≤0.80. When comparing these modalities head-to-head, 72% of patients were diagnosed with obstructive CAD using the fractional flow reserve derived from coronary CT angiography modality, and 25% of patients were diagnosed with obstructive CAD using cardiac magnetic resonance modality (P <.001). There was concordance of both modalities for 53% of the patients (47% of the patients diagnosed with obstructive CAD and 53% of the patients showing normal test results).

The diagnostic performance for revascularization had 97% sensitivity for the fractional flow reserve derived from coronary CT angiography modality and 47% sensitivity for the cardiac magnetic resonance modality (P <.001). The diagnostic performance for revascularization had 42% specificity for the fractional flow reserve derived from coronary CT angiography modality and 88% specificity for the cardiac magnetic resonance modality (P <.001). When the lesion-specific coronary CT angiography fractional flow reserve value was used rather than distal-tip value, the specificity for diagnostic performance increased to 68%. The diagnostic performance for revascularization was found to have 61% accuracy for the fractional flow reserve derived from coronary CT angiography modality and 74% accuracy for the cardiac magnetic resonance modality (P >.05).


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Study limitations include the relatively small sample size, the limited number of patients able to complete all planned tests, and the sole use of patients for whom CT angiography testing was appropriate.

Testing by fractional flow reserve derived from coronary CT angiography and cardiac magnetic resonance “yielded similar overall accuracy for prediction of coronary revascularization. However, a significant difference in diagnostic sensitivity in favour of [fractional flow reserve derived from coronary CT angiography] was demonstrated, while the specificity of [cardiac magnetic resonance] was highest,” concluded the study authors.

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

Reference

Rønnow Sand NP, Nissen L, Winther S, et al. Prediction of coronary revascularization in stable angina: comparison of FFRCT with CMR stress perfusion imaging [published online August 14, 2019]. JACC Cardiovasc Imaging. doi: 10.1016/j.jcmg.2019.06.028