Department of Mechanical Engineering, University of Cincinnati, Cincinnati, Ohio 45221-0072, USA.
Am J Physiol Heart Circ Physiol. 2011 Jan;300(1):H382-7. doi: 10.1152/ajpheart.00412.2010. Epub 2010 Oct 8.
A limitation in the use of invasive coronary diagnostic indexes is that fluctuations in hemodynamic factors such as heart rate (HR), blood pressure, and contractility may alter resting or hyperemic flow measurements and may introduce uncertainties in the interpretation of these indexes. In this study, we focused on the effect of fluctuations in HR and area stenosis (AS) on diagnostic indexes. We hypothesized that the pressure drop coefficient (CDP(e), ratio of transstenotic pressure drop and distal dynamic pressure), lesion flow coefficient (LFC, square root of ratio of limiting value CDP and CDP at site of stenosis) derived from fluid dynamics principles, and fractional flow reserve (FFR, ratio of average distal and proximal pressures) are independent of HR and can significantly differentiate between the severity of stenosis. Cardiac catheterization was performed on 11 Yorkshire pigs. Simultaneous measurements of distal coronary arterial pressure and flow were performed using a dual sensor-tipped guidewire for HR < 120 and HR > 120 beats/min, in the presence of epicardial coronary lesions of <50% AS and >50% AS. The mean values of FFR, CDP(e), and LFC were significantly different (P < 0.05) for lesions of <50% AS and >50% AS (0.88 ± 0.04, 0.76 ± 0.04; 62 ± 30, 151 ± 35, and 0.10 ± 0.02 and 0.16 ± 0.01, respectively). The mean values of FFR and CDP(e) were not significantly different (P > 0.05) for variable HR conditions of HR < 120 and HR > 120 beats/min (FFR, 0.81 ± 0.04 and 0.82 ± 0.04; and CDP(e), 95 ± 33 and 118 ± 36). The mean values of LFC do somewhat vary with HR (0.14 ± 0.01 and 0.12 ± 0.02). In conclusion, fluctuations in HR have no significant influence on the measured values of CDP(e) and FFR but have a marginal influence on the measured values of LFC. However, all three parameters can significantly differentiate between stenosis severities. These results suggest that the diagnostic parameters can be potentially used in a better assessment of coronary stenosis severity under a clinical setting.
在使用有创性冠状动脉诊断指标时存在一个局限性，即心率 (HR)、血压和收缩性等血流动力学因素的波动可能会改变静息或充血时的血流测量值，并对这些指标的解释引入不确定性。在这项研究中，我们专注于 HR 波动和面积狭窄 (AS) 对诊断指标的影响。我们假设从流体动力学原理得出的压力下降系数 (CDP(e)，跨狭窄压力下降与远端动力压力的比值)、病变流量系数 (LFC，限制值 CDP 与狭窄部位 CDP 的平方根) 和血流储备分数 (FFR，远端和近端平均压力的比值) 不受 HR 影响，并且可以显著区分狭窄的严重程度。对 11 头约克夏猪进行了心脏导管插入术。当存在 <50%AS 和 >50%AS 的心外膜冠状动脉病变时，使用双传感器尖端导丝进行 HR < 120 和 HR > 120 次/分时，同时进行远端冠状动脉压力和流量的同步测量。<50%AS 和 >50%AS 病变的 FFR、CDP(e) 和 LFC 的平均值差异有统计学意义 (P < 0.05) (0.88 ± 0.04，0.76 ± 0.04；62 ± 30，151 ± 35，和 0.10 ± 0.02 和 0.16 ± 0.01)。当 HR < 120 和 HR > 120 次/分时，FFR 和 CDP(e) 的平均值在不同 HR 条件下差异无统计学意义 (P > 0.05) (FFR，0.81 ± 0.04 和 0.82 ± 0.04；CDP(e)，95 ± 33 和 118 ± 36)。LFC 的平均值随 HR 略有变化 (0.14 ± 0.01 和 0.12 ± 0.02)。结论：HR 的波动对 CDP(e) 和 FFR 的测量值没有显著影响，但对 LFC 的测量值有轻微影响。然而，这三个参数都可以显著区分狭窄的严重程度。这些结果表明，在临床环境下，诊断参数可用于更好地评估冠状动脉狭窄的严重程度。
