Hirano Shojiro, Yabe Takayuki, Okubo Ryo, Amano Hideo, Ikeda Takanori
Department of Internal Medicine, Division of Cardiovascular Medicine, Toho University, Tokyo, Japan.
Department of Cardiovascular Medicine, Faculty of Medicine, Toho University Graduate School of Medicine, Tokyo, Japan.
Catheter Cardiovasc Interv. 2025 Oct;106(4):2439-2447. doi: 10.1002/ccd.70085. Epub 2025 Aug 6.
The thermodilution technique, employing bolus injections to measure coronary flow reserve (CFR) and the index of microcirculatory resistance (IMR), is widely used to assess coronary microvascular function. However, the potential influence of catheter size and operator differences on these measurements has not been systematically evaluated.
This study aimed to evaluate the feasibility and consistency of thermodilution-based CMD assessment with respect to different catheter sizes and operators.
A total of 320 coronary arteries were assessed using a 0.014-inch pressure-temperature sensor-tipped guidewire. The data set included both angiographically normal vessels and those with varying degrees of stenosis.
Four cases using 4 Fr catheters and data from three of seven operators (due to insufficient case numbers) were excluded. No statistically significant differences in CFR or IMR values were observed among the four operators. Similarly, no significant differences were found between experienced and less-experienced operators (CFR: 1.90 vs. 1.80, p = 0.178; IMR: 19.00 vs. 20.50, p = 0.968). In contrast, CFR values varied significantly by catheter size (5 Fr: 2.20; 6 Fr: 1.80; 7 Fr: 1.50; 8 Fr: 1.70; p < 0.001), whereas IMR remained unaffected. When catheter sizes were dichotomized (small: 5-6 Fr; large: 7-8 Fr), CFR was significantly higher in the small-size group (1.95 vs. 1.65, p = 0.003), while IMR showed no significant difference (20.00 vs. 20.00, p = 0.239).
While the selection of larger catheter sizes may affect CFR with thermodilution, common sizes and operator techniques show consistent results in practice.
热稀释技术通过团注法测量冠状动脉血流储备（CFR）和微循环阻力指数（IMR），被广泛用于评估冠状动脉微血管功能。然而，导管尺寸和操作者差异对这些测量的潜在影响尚未得到系统评估。
本研究旨在评估基于热稀释的冠状动脉微血管功能障碍（CMD）评估在不同导管尺寸和操作者方面的可行性和一致性。
使用0.014英寸压力温度传感器导丝对总共320条冠状动脉进行评估。数据集包括血管造影正常的血管和不同程度狭窄的血管。
排除了4例使用4Fr导管的病例以及7名操作者中3人的数据（因为病例数不足）。4名操作者之间在CFR或IMR值上未观察到统计学显著差异。同样，经验丰富和经验较少的操作者之间也未发现显著差异（CFR：1.90对1.80，p = 0.178；IMR：19.00对20.50，p = 0.968）。相比之下，CFR值因导管尺寸而异（5Fr：2.20；6Fr：1.80；7Fr：1.50；8Fr：1.70；p < 0.001），而IMR不受影响。当将导管尺寸分为两类（小：5 - 6Fr；大：7 - 8Fr）时，小尺寸组的CFR显著更高（1.95对1.65，p = 0.003），而IMR无显著差异（20.00对20.00，p = 0.239）。
虽然选择较大尺寸的导管可能会影响热稀释法测量的CFR，但在实际操作中，常用尺寸和操作者技术显示出一致的结果。
