ISSN 2996-8215
International Journal of Cardiology | Vol. 10, No. 3, March 2019 | pp. 17–24
DOI: 10.46882/2019/IJC/000120
Original Research Article
Diagnostic Utility of Non-Invasive FFR-CT for Ischemia Detection in Patients with High Coronary Calcium Scores
Arjun Patel¹, Rohan Mehta¹, Vikram Singh²
¹Department of Cardiology, Post Graduate Institute of Medical Education and Research, Chandigarh, India
²Division of Cardiovascular Radiology, All India Institute of Medical Sciences, New Delhi, India
Abstract:
Computed tomography coronary angiography (CTCA) exhibits limited diagnostic specificity in patients with heavy coronary calcification due to blooming artifacts that obscure luminal narrowings. Fractional flow reserve computed from CTCA datasets (FFR-CT) integrates computational fluid dynamics to evaluate lesion-specific ischemia non-invasively. This study evaluated the diagnostic accuracy of FFR-CT for identifying lesion-specific ischemia specifically in patients with high coronary artery calcium (CAC) scores. We prospectively enrolled 110 symptomatic patients with intermediate coronary stenoses and an Agatston CAC score greater than 400 who were scheduled for invasive coronary angiography and fractional flow reserve (FFR). FFR-CT was computed off-line using specialized processing software. Ischemia was defined as an invasive FFR less than or equal to 0.80. On a vessel-based analysis (134 vessels total), invasive FFR confirmed lesion-specific ischemia in 42 vessels (31.3%). FFR-CT demonstrated a diagnostic sensitivity, specificity, positive predictive value, and negative predictive value of 85.7% (95% CI: 71.5%–94.6%), 81.5% (95% CI: 72.1%–88.9%), 67.9% (95% CI: 53.7%–80.1%), and 92.6% (95% CI: 84.6%–97.2%), respectively. The area under the receiver operating characteristic curve for FFR-CT was significantly superior to standard anatomical CTCA luminal assessment alone (0.87 vs. 0.64, p < 0.01). FFR-CT maintains high diagnostic accuracy and strong negative predictive value for identifying hemodynamically significant coronary stenoses even in the presence of severe calcification.
Keywords: Computed tomography coronary angiography, Fractional flow reserve, Coronary calcification, Computational fluid dynamics, Myocardial ischemia, Diagnostic accuracy
Received: December 05, 2013; Revised: January 18, 2014; Accepted: February 11, 2014; Published: March 20, 2019