New methods in diagnostic and therapy Invasive and non-invasive fractional flow reserve index in validation of hemodynamic severity of intracoronary lesions

Abstract

This review discusses visual and functional evaluation of the hemodynamic significance of the degree of stenosis in coronary angiography, with respect to the indications for revascularization. The concept of the coronary flow reserve is defined, and the theoretical assumptions of the invasive measurement of the fractional flow reserve (FFR) are presented. In the following part, the publication describes the basic steps of numerical stimulations in terms of computational fluid dynamics (CFD) in calculating the fractional flow reserve based on computed tomography (CT) coronary angiography (FFRCT). The numerical FFRCT estimation in correlation with invasive measurements, as well as benefits deriving from FFRCT in the diagnosis of coronary artery disease, is presented in the example of the multicentre prospective DISCOVER-FLOW trial and the DeFACTO project. The CDF method enables to obtain hemodynamic significance of stenosis solely from the coronary anatomy vizualized by CT angiography. The calculation of FFRCT increases the diagnostic reliability of coronary flow reserve estimations. It contributes to the improvement in patients’ qualification for contrast coronarography. If the accuracy of FFRCT is confirmed in clinical practice, and the time required for computational processing is shortened, it may turn out that the algorithms of coronary heart disease diagnosis will be verified and it will be to a greater extent based on the CT results.

Combined analysis of myocardial function, viability, and stress perfusion in patients with chronic total occlusion in relation to collateral flow

“…Moreover, contrary to previous CMR/CT studies and our findings, the SPECT studies did not demonstrate any differences in the prevalence of MI of the segments supplied by the CTO between patients with well-developed and poor collaterals [10,11]. These facts suggest that inherent features of each method may influence the results [25]. Unfortunately, there is only one CMR study that can be used as a comparison to our findings [13].…”

Numerical analysis of the impact of flow rate, heart rate, vessel geometry, and degree of stenosis on coronary hemodynamic indices

“…One of them is the fact that two-dimensional images of the atherosclerotic plaque is different in different planes of the projection. In this case the visual assessment of stenosis in coronary angiography is subject to error and does not express the functional significance of the lesion [ 2 ]. In addition, not only the degree of narrowing but also the shape and location of the atherosclerotic plaque may indicate its hemodynamic significance.…”

“…Therefore, some lesions that are considered hemodynamically insignificant may cause a reduction in coronary flow reserve (CFR). For these reasons, especially in the case of intermediate stenosis, in which the reduction of the arterial light is in the range of 50 to 70% (“borderline stenosis”), the fractional flow reserve (FFR) measurement should be performed [ 2 , 3 ].…”

Cardiovascular imaging Noninvasive assessment of cerebral artery stenoses from anatomic computed tomography angiography

“…They have been demonstrated as a promising tool to identify patients who would likely benefit from revascularization [4–6]. However, TSPG and FFR measurement has significant restrictions in clinical practice due to its invasiveness and high cost.…”

“…Trans-stenotic pressure gradient (TSPG) and fractional flow reserve (FFR) are two well-validated functional indices to assess the ischemic severity of arterial stenoses [ 1 – 3 ]. They have been demonstrated as a promising tool to identify patients who would likely benefit from revascularization [ 4 – 6 ]. However, TSPG and FFR measurement has significant restrictions in clinical practice due to its invasiveness and high cost.…”