Department of Cardiovascular Medicine, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan; Division of Metabolic and Cardiovascular Research, Center for Metabolic Regulation of Healthy Aging, Kumamoto University Faculty of Life Sciences, Kumamoto, Japan.
Department of Cardiovascular Medicine, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan; Division of Metabolic and Cardiovascular Research, Center for Metabolic Regulation of Healthy Aging, Kumamoto University Faculty of Life Sciences, Kumamoto, Japan.
J Cardiol. 2020 Jul;76(1):73-79. doi: 10.1016/j.jjcc.2020.01.009. Epub 2020 Feb 20.
Although pressure equalization of the sensor-tipped guidewire and systemic pressure is mandatory in measuring fractional flow reserve (FFR), pressure in the distal artery (Pd) with wire advancement can be influenced by hydrostatic pressure related to the height difference between the catheter tip and the distal pressure sensor. We therefore analyzed the impact of hydrostatic pressure on FFR in vivo by modification of the height difference.
To reveal the anatomical height difference in human coronary arteries, measurement was performed during computed tomography angiography (CTA) of five consecutive patients. Utilizing the healthy coronary arteries of female swine, height difference diversity was reproduced by body rotation and vertical inclination. FFR measurements were performed during maximum hyperemia with adenosine. The height difference was calculated fluoroscopically with a contrast medium-filled balloon for reference.
In human coronary CTA, height averages from the ostium in the left anterior descending artery (34.6 mm) were significantly higher than in the left circumflex (-15.5 mm, p = 0.008) and right coronary arteries (-2.3 mm, p = 0.008). In our swine model, reproduced height variation ranged from -7.2 cm to +6.5 cm. Mean FFR was significantly lower in positive sensor height and higher in negative sensor height compared to the reference height. Linear regression analyses revealed significant correlations between height difference and FFR, observed among all coronary arteries, as well as between the height difference and Pd-aortic pressure mismatch. Subtracting 0.622 mmHg/cm height difference from Pd could correct the expected hydrostatic pressure influence.
Hydrostatic pressure variation resulting from sensor height influenced FFR values might affect interpretation during FFR assessment.
在测量分比流量储备（FFR）时，必须使传感器尖端导丝和系统压力均衡，但随着导丝推进，远端动脉（Pd）的压力可能会受到与导管尖端和远端压力传感器之间高度差相关的静水压力的影响。因此，我们通过改变高度差来分析静水压力对体内 FFR 的影响。
在连续五名患者的计算机断层血管造影（CTA）期间进行测量，以揭示人体冠状动脉的解剖学高度差。利用雌性猪的健康冠状动脉，通过身体旋转和垂直倾斜来再现高度差的多样性。在腺苷引起的最大充血期间进行 FFR 测量。通过填充对比剂的气球进行荧光透视计算以作为参考来测量高度差。
在人体冠状动脉 CTA 中，左前降支（LAD）开口处的高度平均值（34.6mm）明显高于左回旋支（-15.5mm，p=0.008）和右冠状动脉（-2.3mm，p=0.008）。在我们的猪模型中，重现的高度变化范围从-7.2cm 到+6.5cm。与参考高度相比，正传感器高度时的平均 FFR 显著较低，负传感器高度时的平均 FFR 显著较高。线性回归分析显示，在所有冠状动脉以及在高度差和 Pd-主动脉压力不匹配之间都存在高度差与 FFR 之间的显著相关性。从 Pd 中减去 0.622mmHg/cm 的高度差可以校正预期的静水压力影响。
由于传感器高度引起的静水压力变化可能会影响 FFR 评估期间的解释。
