Predictive Value of Resting Fractional Flow Reserve and Atherogenic Index of Plasma for Evaluation of Physiologically Significant Coronary Artery Lesions

This study aimed to assess the relationship between the atherogenic index of plasma (AIP) and resting distal-to-aortic pressure ratio (Pd/Pa) in patients with intermediate coronary artery stenosis. This retrospective study included 802 chronic coronary syndrome patients with intermediate coronary artery stenosis who underwent fractional flow reserve (FFR) measurement. The resting Pd/Pa showed a significant negative correlation with AIP (rho= -.205, p < .001). When final FFR was divided into three tertiles (≤80, 81-89, ≥90), resting Pd/Pa was significantly lower, and AIP was markedly higher in the lower final FFR tertiles (both AIP and resting Pd/Pa differed significantly across the all three tertiles, p < .001). Furthermore, functionally significant stenosis independent predictors in multivariate analyses were AIP and resting Pd/Pa (p = .010 and p < .001, respectively). We observed for the first time an increase in AIP levels in the presence of functionally significant stenoses that may help better planning and identification of those patients with the functionally substantial atherosclerotic burden.

Quantitative flow ratio as a new tool for angiography-based physiological evaluation of coronary artery disease: a review

The functional evaluation of coronary stenoses has obtained important clinical results in recent years, resulting in strong guideline recommendations. Nonetheless, the use of coronary wire-based functional evaluation has not yet become part of the routine in catheterization laboratories for several reasons, including the need to advance a wire into the coronary vessel to interrogate the stenosis. Angiography-derived indexes have been introduced to expand the current use of physiology to estimate the functional meaning of a stenosis on the basis of angiographic data only. The most studied and validated angiography-derived index is certainly the quantitative flow ratio. This article will summarize the basics of the quantitative flow ratio, the related validation studies and its current and future applications.

Contrast FFR plus intracoronary injection of nitro-glycerine accurately predicts FFR for coronary stenosis functional assessment

BACKGROUND

Fractional flow reserve (FFR) is the "gold standard" for assessing the physiological significance of coronary disease. In the last decade, several alternative adenosine-free indexes have been proposed in order to facilitate the dissemination of the functional evaluation of coronary stenosis. Our aim was to investigate whether radiographic contrast plus intracoronary nitroglycerin (cFFR-NTG) can predict functional assessment of coronary stenosis offering superior diagnostic agreement with FFR compared to non-hyperemic indexes and contrast mediated FFR (cFFR).

METHODS

Three hundred twenty-nine lesions evaluated with pressure wire in 266 patients were prospectively included in this multicenter study.

RESULTS

The ROC curves for cFFR-NTG using an FFR≤0.80 showed a higher accuracy in predicting FFR (AUC=0.97) than resting Pd/Pa (AUC=0.90, P<0.01) and cFFR (AUC=0.93.5, P<0.01). A significant (P<0.01) strong correlation was found between FFR and the four analyzed indexes: Pd/Pa (r=0.78); iFR/RFR (r=0.73); cFFR(r=0.89) and cFFR-NTG (r=0.93). cFFR-NTG showed the closest agreement at Bland-Altman analysis. The cFFR-NTG cut off value >0.84 showed the highest negative predictive value (88%), specificity (91%), sensitivity (94%) and accuracy (92%) of the studied indexes.

CONCLUSIONS

Submaximal hyperemic adenosine-free indexes are an efficient alternative to adenosine for the physiological assessment of epicardial coronary disease. The most accurate index in predicting the functional significance of coronary stenosis using FFR as reference was cFFR-NTG.

Meta-Analysis of Diagnostic Performance of Contrast-Fractional Flow Reserve versus Quantitative Flow Ratio for Functional Assessment of Coronary Stenoses

Background. Use of the fractional flow reserve (FFR) technique is recommended to evaluate coronary stenosis severity and guide revascularization. However, its high cost, time to administer, and the side effects of adenosine reduce its clinical utility. Two novel adenosine-free indices, contrast-FFR (cFFR) and quantitative flow ratio (QFR), can simplify the functional evaluation of coronary stenosis. This study aimed to analyze the diagnostic performance of cFFR and QFR using FFR as a reference index. Methods. We conducted a systematic review and meta-analysis of observational studies in which cFFR or QFR was compared to FFR. A bivariate model was applied to pool diagnostic parameters. Cochran’s Q test and the I2 index were used to assess heterogeneity and identify the potential source of heterogeneity by metaregression and sensitivity analysis. Results. Overall, 2220 and 3000 coronary lesions from 20 studies were evaluated by cFFR and QFR, respectively. The pooled sensitivity and specificity were 0.87 (95% CI: 0.81, 0.91) and 0.92 (95% CI: 0.88, 0.94) for cFFR and 0.87 (95% CI: 0.82, 0.91) and 0.91 (95% CI: 0.87, 0.93) for QFR, respectively. No statistical significance of sensitivity and specificity for cFFR and QFR were observed in the bivariate analysis (P=0.8406 and 0.4397, resp.). The area under summary receiver-operating curve of cFFR and QFR was 0.95 (95% CI: 0.93, 0.97) for cFFR and 0.95 (95% CI: 0.93, 0.97). Conclusion. Both cFFR and QFR have good diagnostic performance in detecting functional severity of coronary arteries and showed similar diagnostic parameters.