Clinical Significance of Fractional Flow Reserve for Evaluation of Functional Lesion Severity in Stent Restenosis and Native Coronary Arteries

Abstract Background International guidelines mandate the use of fractional flow reserve (FFR) and/or non-hyperaemic pressure ratios to assess the physiological significance of moderate coronary artery lesions to guide revascularisation decisions. However, they remain underused such that visual estimation of lesion severity continues to be the predominant decision-making tool. It would be pragmatic to have an improved understanding of the relationship between lesion morphology and haemodynamics. Aims To compute virtual FFR (vFFR) in idealised coronary artery geometries with a variety of stenosis and vessel characteristics Methods Coronary artery geometries were modelled, based upon physiologically realistic branched arteries. Common stenosis characteristics were studied, including % narrowing, length, eccentricity, shape, number, position relative to branch, and distal (myocardial) resistance. Computational fluid dynamics (CFD) modelling was used to calculate vFFRs using the VIRTUheartTM system. Results Percentage lesion severity had the greatest effect upon FFR. Any ≥80% diameter stenosis in two views (i.e. concentric) was physiologically significant (FFR ≤ 0.80), irrespective of length, shape or vessel diameter. Almost all eccentric stenoses and all 50% concentric stenoses were physiologically non-significant, whilst 70% uniform concentric stenoses about 10mm long straddled the ischaemic threshold (FFR 0.80). A low microvascular resistance (MVR) reduced FFR on average by 0.05, and a high MVR increased it by 0.03. Conclusions Using computational modelling, we have produced an analysis of virtual FFR that relates stenosis characteristics to haemodynamic significance. The strongest predictor of a positive virtual FFR was a concentric, ≥80% diameter stenosis. The importance of MVR was quantified. Other lesion characteristics have a limited impact.

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Comparison of fractional flow reserve, instantaneous wave-free ratio and a novel technique for assessing coronary arteries with serial lesions

EuroIntervention ◽

10.4244/eij-d-19-00635 ◽

2020 ◽

Vol 16 (7) ◽

pp. 577-583

Author(s):

Bhavik N. Modi ◽

Haseeb Rahman ◽

Matthew Ryan ◽

Howard Ellis ◽

Antonis Pavlidis ◽

...

Keyword(s):

Coronary Arteries ◽

Fractional Flow Reserve ◽

Fractional Flow ◽

Novel Technique ◽

Flow Reserve

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Abstract 12632: Impact of Systolic Pressure Response on Measurement of Fractional Flow Reserve

Circulation ◽

10.1161/circ.132.suppl_3.12632 ◽

2015 ◽

Vol 132 (suppl_3) ◽

Author(s):

Tomoyuki Ikeda ◽

Masafumi Ueno ◽

Shinichiro Ikuta ◽

Kosuke Fujita ◽

Masakazu Yasuda ◽

...

Keyword(s):

Coronary Arteries ◽

Fractional Flow Reserve ◽

Cardiac Cycle ◽

Systolic Pressure ◽

Pressure Response ◽

The Other ◽

Fractional Flow ◽

Diastolic Phase ◽

Flow Reserve ◽

Significant Difference

Background: Fractional flow reserve (FFR) is calculated as the ratio between distal coronary pressure(Pd)and aortic pressure(Pa)during whole cardiac cycle at stable hyperemia. In clinical practice, we experience various Pd wave pattern during hyperemia, such as decreasing equally in systolic and diastolic phase, or mainly decreasing in diastolic phase. Purpose: The aim of the study was to evaluate the impact of systolic and diastolic pressure response during hyperemia in patients with coronary stenosis and an FFR of less than 0.8. Methods: A total of 35 patients (40 stenosis)had FFR of less than 0.8 were enrolled. FFR measurements were performed using a standard technique. Based on Pa and Pd wave forms, the decreasing area in systolic and diastolic were calculated by integrating Pa-Pd pressure gradient during hyperemia using the RadiView2.2 software. %Sys value was defined as the percentage of delta systolic area during the whole cardiac cycle (Figure). The results of %Sys values were divided into tertiles to evaluate the most significant factors for systolic pressure response. Results: Vessel distribution was as follows: LAD (60%), CX (20%) and RCA (20%). There was a significant difference of vessel distribution in coronary arteries in the upper tertile compared with the other two tertiles of %Sys values (p=0.028). However, the other factors such as FFR value, lesion length and severity, history of diabetes mellitus and previous myocardial infraction were not affected by the %Sys values. In addition, there was a significant difference of %Sys values among three major coronary arteries (LAD 49.4±18.5%, CX 81.5±38.7%, RCA 67.5±20.2%, p=0.006). %Sys values were significantly higher in non-LAD lesions compared with LAD lesions (74.5±30.7% vs 49.4±18.5%, p=0.003). Conclusions: There was a significant difference of decreasing pattern of Pd wave during hyperemia among the three coronary arteries. These findings suggest that iFR might not be accurate in non-LAD lesion.

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