Fractional flow reserve, ratio of the instantaneous pressure in the wave free period and the coronary computed tomographic angiography

Abstract The physiological indices can help to calculate the haemodynamic impact of coronary lesions. The most currently most used physiological indices those that better evaluate the functional severity of these lesions, are the fractional flow reserve and relationship of the instantaneous pressure in the wave free period. The simplified formula of the fractional flow reserve is the ratio between the mean pressure distal to the lesion and the mean aortic pressure
under hyperaemic stimulation with adenosine. A cut-off value of 0.8 is accepted in order to define that a coronary lesion is significant from a haemodynamic point of view. For its part, the wave free period is defined as a ratio between the distal mean intracoronary pressure and the mean aortic pressure, during a diastolic period that starts after 25% of the diastole and ends 5 milliseconds before this finishes (wave free period). This helps to determine this ratio
without the need to administer hyperaemic agents. The coronary angiography using computed tomography, has been shown to be a non-invasive alternative for the evaluation of the coronary anatomy, and to the present one, the addition of function tests to this study, as are the fractional flow reserve and computed tomography angiograph, provide information on the coronary anatomy, and in a complementary manner, of the physiological impact of the coronary lesions. © 2019 Sociedad Colombiana de Cardiolog´ıa y Cirug´ıa Cardiovascular. Published by Elsevier Espana, ˜ S.L.U. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).