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Published on: June 28, 2019
Coronary stenosis: Morphologic index characterized by using CT angiography correlates with fractional flow reserve
Minghua Li1, Jiayin Zhang, Jingwei Pan
1From the Departments of Radiology (M.L., J.Z.) and Cardiology (J.P., Z.L.), Shanghai No. 6 People's Hospital, School of Medicine, Shanghai Jiaotong University, No. 600, Yishan Rd, Shanghai, China 200233.
Insights
The lesion length to minimal lumen diameter (fourth power) ratio from coronary CT angiography effectively differentiates significant coronary artery stenosis. This ratio is an independent predictor of hemodynamic significance, correlating with fractional flow reserve measurements.
Area of Science:
- Cardiovascular imaging
- Interventional cardiology
- Radiology
Background:
- Fractional flow reserve (FFR) is the gold standard for assessing the hemodynamic significance of coronary artery stenosis.
- Coronary computed tomographic (CT) angiography is a non-invasive imaging modality used for evaluating coronary artery disease.
- Differentiating between hemodynamically significant and nonsignificant coronary lesions non-invasively remains a clinical challenge.
Purpose of the Study:
- To evaluate the diagnostic performance of the lesion length (LL) to the fourth power of minimal lumen diameter (MLD(4)) ratio derived from coronary CT angiography.
- To assess the correlation of the LL/MLD(4) ratio with fractional flow reserve (FFR) for differentiating hemodynamically significant lesions.
Main Methods:
- A retrospective analysis of 61 patients who underwent both coronary CT angiography and FFR measurement.
- Calculation of the LL/MLD(4) ratio and other lesion parameters, including minimal luminal area (MLA) and plaque burden.
- Statistical analysis to identify predictors of hemodynamically significant lesions (FFR < 0.8).
Main Results:
- The LL/MLD(4) ratio was significantly higher in lesions with FFR < 0.8 (9.7 ± 7.5) compared to those with FFR ≥ 0.8 (3.1 ± 3.6).
- The LL/MLD(4) ratio was the sole independent predictor of hemodynamically significant stenosis (odds ratio = 1.44, P = .043).
- A cutoff value of 3.86 for the LL/MLD(4) ratio demonstrated 82.9% sensitivity and 82% specificity for diagnosing significant lesions.
Conclusions:
- The LL/MLD(4) ratio derived from coronary CT angiography is a valuable non-invasive marker for assessing the hemodynamic significance of coronary stenoses.
- This ratio shows an inverse correlation with FFR measurements, aiding in the differentiation of functionally significant lesions.
- The LL/MLD(4) ratio offers a promising tool for improving the non-invasive assessment of coronary artery disease severity.
Purpose:
To study the diagnostic performance of the ratio of lesion length (LL) to the fourth power of minimal lumen diameter (MLD) (MLD(4)) at coronary computed tomographic (CT) angiography for differentiating between hemodynamically significant and nonsignificant lesions, with correlation with fractional flow reserve (FFR).
Materials And Methods:
This retrospective study had institutional review board approval, and the need to obtain informed consent was waived. Sixty-one patients (mean age, 65.3 years ± 8.8 [standard deviation]; range, 43-82 years; 43 men and 18 women; P = .019 for age) who underwent both coronary CT angiography and FFR measurement at conventional coronary angiography within 2 weeks were retrospectively included in this study. LL/MLD(4) ratio, along with other parameters, including minimal luminal area (MLA), stenosis diameter, stenosis area, plaque burden, remodeling index, and Agatston score of lesions, were recorded. Lesions with FFRs of less than 0.8 were considered to be functionally significant. Univariate and multivariate statistical tests were performed to identify variables associated with hemodynamically significant lesions.
Results:
Sixty-one patients with 85 lesions were ultimately included for analysis. LL, stenosis diameter, stenosis area, and plaque burden were longer or larger in the group with FFRs of less than 0.8 (P < .001 for all), while smaller MLA and MLD were also noted (P < .001). Mean LL/MLD(4) ratio was significantly larger in the group with FFRs of less than 0.8 than in the group with FFRs of 0.8 or greater (9.7 ± 7.5 vs 3.1 ± 3.6, P < .001). Rest myocardial perfusion defect was recorded in five lesions with FFRs of less than 0.8 (P = .006). LL/MLD(4) ratio proved at multivariate analysis to be the only independent predictor of hemodynamically significant stenosis (odds ratio = 1.44; P = .043). When 3.86 was used as the cutoff value for LL/MLD(4) ratio, the sensitivity and specificity for diagnosing hemodynamically significant lesions were 82.9% (29 of 35) and 82% (41 of 50), respectively.
Conclusion:
The LL/MLD(4) ratio, as characterized by using coronary CT angiography, correlates inversely with FFR measurements and is associated with the hemodynamic status of coronary stenoses. Online supplemental material is available for this article.
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