Validating Practicality: Impact of Right Atrial Pressure on Fractional Flow Reserve.
Validating Practicality: Impact of Right Atrial Pressure on Fractional Flow Reserve.
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DOI：
10.1016/j.jcin.2015.12.014
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发表时间：
2016-03
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影响因子：
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通讯作者：
M. Kern
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作者：
M. Kern
在介入心脏病学使用的所有诊断试验中，没有一项具有血流储备分数(FFR)的影响。通过适当地减少我们经常错误地依赖血管造影术，FFR在正确测量和应用时，可以产生更好的经皮冠状动脉介入治疗(PCI)结果(1，2)。根据冠状动脉血流储备的基本原理，Pijls、Kirkeeide、De Bruyne和Gould发展的FFR导数的数学是复杂的，当人们建立一种新的方法来计算心肌和侧支血流量时，可以理解的是，当人们建立一种新的方法时，只使用在固定的最小心肌阻力的关键时期(即，在最大充血期间)测量的压力来计算心肌和侧支血流量(表1)(3，4)。FFR公式允许相对于正常值确定心肌(FFRmyo)、冠状动脉(FFRcor)和侧支循环血流的百分比。FFRcor很少被测量，因为它需要在冠状动脉血管成形术中使用冠状动脉球囊闭塞楔压(PW)。FFRmyo与FFRcor的不同之处在于包括了一个术语，静脉，或者更准确地说，右房压(Pra)来解释侧支循环对心肌灌注的贡献。然而，为了实用，无论是从数学上还是日常临床使用，Pra都被省略了，因为它被认为相对于平均主动脉压(Pa.)可以忽略不计(右房[RA]压5-10 mm Hg对主动脉压80-100 mm Hg)。因此，FFRmyo在名称和公式上都简化为FFR：Pd/pa。然而，FFR的精确度及其对决策的影响一直受到质疑，部分原因是这种简化(5，6)，担心排除Pra项可能会产生低于缺血阈值的值，具有不同的治疗决定和最终不同的患者结果，这肯定是不可忽视的事情。尽管笔记本电脑数学表明，RA压力对FFRmyo计算几乎没有影响，除非RA压力为&>15 mm Hg(7)，但这一事实的临床证据一直缺乏。针对这一问题，Toth和他的著名冠状动脉生理学同事(8)在本期《JACC：心血管干预》中测量了RA压力对1,235名患者1,675条狭窄的简化FFR和完整公式FFRmyo之间的差异的影响。当将结果分组为三分位数(平均为4、7和12毫米汞柱)时，在统计学上显著，但在临床上微不足道，FFR和FFR myo之间的差值增加(分别为0.01vs.0.01vs.0.02；p<；0.001)。重要的是，在1,146个FFR>；0.80的病变中，没有一个FFR<；0.75；在110个(9%)狭窄中，FFRmyo下降到#0.80，FFR和FFRmyo之间的平均差值为0.02。至
Among all diagnostic tests used in interventional cardiology, none has had the impact of fractional flow reserve (FFR). By appropriately reducing our often misplaced reliance on angiography, FFR, when measured and applied correctly, produces better percutaneous coronary intervention (PCI) outcomes (1, 2). On the basis of the fundamental principles of coronary blood flow reserve, the mathematics of the FFR derivations developed by Pijls, Kirkeeide, De Bruyne, and Gould are complex, understandably so when one is establishing a new method of calculating myocardial and collateral blood flow using only pressure, measured during the critical period of fixed minimal myocardial resistance (ie, during maximal hyperemia)(Table 1)(3, 4). The FFR formulas permit the determination of the percentage of myocardial (FFRmyo), coronary (FFRcor), and collateral blood flow relative to the normal values. FFRcor is rarely measured because it requires the use of a coronary balloon occlusion wedge pressure (Pw) during coronary angioplasty. FFRmyo differs from FFRcor by including a term, the venous, or more precisely, the right atrial pressure (Pra) to account for the collateral flow contribution to myocardial perfusion. However, for practicality, both mathematically and for daily clinical use, the Pra is omitted because it is assumed to be negligible relative to mean aortic pressure (Pa)(right atrial [RA] pressure 5 to 10 mm Hg vs. aortic pressure 80 to 100 mm Hg). Thus, the FFRmyo was simplified in both name and formula to FFR º Pd/Pa. However, the precision of FFR and its influence on decision making has been questioned, in part because of this simplification (5, 6), fearing that the exclusion of the Pra term may yield a value below the ischemic threshold with a different treatment decision and ultimately different patient outcome, certainly something that is not negligible.Although laptop mathematics demonstrated that the RA pressure has little impact on the FFRmyo computation unless the RA pressure is> 15 mm Hg (7), the clinical proof of this fact had been lacking. Addressing this issue, Toth and his renowned coronary physiology colleagues (8) in this issue of JACC: Cardiovascular Interventions, measured the impact of RA pressure on the difference between the simplified FFR and full formula FFRmyo in 1,675 stenoses from 1,235 patients. When grouping results into tertiles of Pra (mean 4, 7, and 12 mm Hg), statistically significant, but clinically trivial, increases in the difference between FFR and FFRmyo was seen (0.01 vs. 0.01 vs. 0.02, respectively; p< 0.001). Importantly, of 1,146 lesions with FFR> 0.80, none had FFRmyo< 0.75; in 110 (9%) stenoses, the FFRmyo fell to# 0.80 with a mean difference between FFR and FFRmyo of 0.02. To