Review | 合法醫療器材資訊網

由MMichail著作·2020—DFR,diastolichyperaemia-freeratio;iFR,instantaneouswave-freeratio;Pd/Pa,ratioofmeandistalcoronaryarterypressuretomeanaortic ...

FFR is an invasively determined index, derived as a method for assessing the functional impact of coronary stenosis. It is defined as the maximal blood flow to the myocardium in the presence of a stenosis in the supplying coronary artery, divided by the theoretical normal maximal flow in the same distribution.9 This can be calculated by measuring the ratio of the mean distal coronary artery pressure (Pd; distal to the stenosis) to the mean aortic pressure (Pa) during maximal microvascular vasodilatation. Maximal vasodilatation using hyperaemic agents minimises and maintains constant microcirculatory resistance. During these conditions, pressure is proportional to coronary flow—thus allowing the measurement of pressure gradient across a lesion without being confounded by pressure changes in the distal microcirculatory bed. FFR was brought i...