Coronary cross-sectional area stenosis severity determined using coronary CT highly correlated with coronary functional flow reserve: a pilot study

TL;DR

This study shows that measuring coronary cross-sectional area stenosis with CT scans is highly accurate in predicting blood flow issues in heart arteries.

Contribution

The study demonstrates that CT-based cross-sectional area stenosis is a reliable predictor of functional flow reserve in coronary arteries.

Findings

Percentage cross-sectional area stenosis had high sensitivity and specificity in distinguishing FFR-positive and FFR-negative cases.

Lesions with less than 45% area stenosis were not FFR-positive.

CT angiography stenosis measurements are clinically useful for predicting FFR.

Abstract

Fractional flow reserve (FFR) is the gold standard for assessing the physiological significance of coronary stenosis. We examined the potential correlation between digitally measured coronary cross-sectional area stenosis using coronary computed tomography (CT) angiography and FFR. We analyzed data of 32 consecutive patients with stenoses who underwent invasive FFR determination. The cross-sectional area was assessed using 128-slice coronary detector-based spectral CT angiography. Power analysis revealed that the sample size enabled the detection of an area under the receiver operating characteristic (ROC) curve (AUC) of 0.90. FFR ≤ 0.8 and > 0.8 were defined as FFR-positive and FFR-negative, respectively. Intra- and interobserver differences were negligible. Percentage cross-sectional area stenosis was calculated as 100 × (A−B)/A, where A is the cross-sectional area at non-stenotic pre-stenotic segment and B is the cross-sectional area of the most severe stenotic lesion. AUC indicated that percentage cross-sectional area stenosis effectively discriminated between FFR-positive and FFR-negative cases, yielding a sensitivity of 0.882 and specificity of 0.933 at a cutoff of 50% area reduction, with an AUC of 0.976. Lesions with less than 45% cross-sectional area stenosis on coronary CT angiography were not FFR-positive. When ROC analysis was conducted for lesion characteristics, AUC did not significantly improve. In conclusion, the percent coronary cross-sectional area stenosis measured using coronary CT angiography distinguished between FFR-positive and FFR-negative lesions with high accuracy. The severity of coronary cross-sectional area stenosis determined using CT angiography is clinically useful for predicting FFR.

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