Читать книгу Interventional Cardiology - Группа авторов - Страница 184

The current iteration of FFR measurement does not distinguish between the impact of collateral flow and as such, FFR does not provide stenosis specific information, rather a measurement of total ischemia in a given myocardial bed. To calculate stenosis specific information, (FFRcor) requires coronary wedge pressure (Pw) to be measured by performing balloon occlusion of a stenosis; the measured distal pressure during balloon occlusion estimates the flow contribution from collateral vessels. The final equation is: (Pd–Pw/Pa–Pw). Clearly this is not desirable for most moderate stenoses where balloon occlusion of a moderate stenosis essentially risks converting a potential deferral of PCI, into bailout stenting after endothelial injury or dissection. This is a limitation, and it means that FFR values reflect not only pressure loss generated by the stenosis, but the capacity of the myocardial microcirculation to dilate; vasodilatation in other territories may contribute to additional pressure loss, over and above caused by the stenosis.