Division of Cardiovascular Medicine, Stanford University Medical Center, Stanford, CA 94305, USA.
Circ Cardiovasc Interv. 2013 Apr;6(2):161-5. doi: 10.1161/CIRCINTERVENTIONS.112.000104. Epub 2013 Apr 2.
Several studies have shown that fractional flow reserve (FFR) measurement can aid in the assessment of left main coronary stenosis. However, the impact of downstream epicardial stenosis on left main FFR assessment with the pressure wire in the nonstenosed downstream vessel remains unknown.
Variable stenoses were created in the left main coronary arteries and downstream epicardial vessels in 6 anaesthetized male sheep using balloon catheters. A total of 220 pairs of FFR assessments of the left main stenosis were obtained, before and after creation of a stenosis in a downstream epicardial vessel, by having a pressure-sensor wire in the other nonstenosed downstream vessel. The apparent left main FFR in the presence of downstream stenosis (FFR(app)) was significantly higher compared with the true FFR in the absence of downstream stenosis (FFR(true); 0.80±0.05 versus 0.76±0.05; estimate of the mean difference, 0.035; P<0.001). The difference between FFR(true) and FFR(app) correlated with composite FFR of the left main plus stenosed artery (r=-0.31; P<0.001) indicating that this difference was greater with increasing epicardial stenosis severity. Among measurements with FFR(app) >0.80, 9% were associated with an FFR(true) of <0.75. In all instances, the epicardial lesion was in the proximal portion of the stenosed vessel, and the epicardial FFR (combined FFR of the left main and downstream stenosed vessel) was ≤0.50.
A clinically relevant effect on the FFR assessment of left main disease with the pressure wire in a nonstenosed downstream vessel occurs only when the stenosis in the other vessel is proximal and very severe.
多项研究表明，分流量储备（FFR）测量有助于评估左主干冠状动脉狭窄。然而，压力导丝在非狭窄下游血管中测量左主干 FFR 时，下游心外膜狭窄对其的影响尚不清楚。
通过球囊导管在 6 只麻醉雄性绵羊的左主干冠状动脉和下游心外膜血管中创建可变狭窄。在另一支非狭窄下游血管中放置压力传感器导丝，总共获得 220 对左主干狭窄的 FFR 评估，分别在创建下游心外膜狭窄前后进行。存在下游狭窄时左主干 FFR（FFR(app)）明显高于无下游狭窄时的真实 FFR（FFR(true)）（0.80±0.05 比 0.76±0.05；平均差值估计值为 0.035；P<0.001）。FFR(true)和 FFR(app)之间的差异与左主干加狭窄动脉的复合 FFR 相关（r=-0.31；P<0.001），表明随着心外膜狭窄严重程度的增加，这种差异越大。在 FFR(app)>0.80 的测量中，有 9%与 FFR(true)<0.75 相关。在所有情况下，心外膜病变均位于狭窄血管的近端部分，心外膜 FFR（左主干和下游狭窄血管的联合 FFR）≤0.50。
当另一支血管的狭窄位于近端且非常严重时，压力导丝在非狭窄下游血管中测量左主干疾病的 FFR 评估会产生临床相关影响。
