Mahendiran Thabo, Keulards Daniëlle, Pijls Nico H J, Viscusi Michele, Gallinoro Emanuele, Bertolone Dario, Damman Peter, van Royen Niels, Sonck Jeroen, Collet Carlos, Wilgenhof Adriaan, Knaapen Paul, De Bruyne Bernard
Cardiovascular Center Aalst, OLV Clinic, Aalst, Belgium.
Department of Cardiology, Lausanne University Hospital, Lausanne, Switzerland.
Catheter Cardiovasc Interv. 2025 Jul;106(1):128-135. doi: 10.1002/ccd.31515. Epub 2025 Apr 7.
Continuous thermodilution quantifies absolute microvascular resistance (R, Wood units), a key metric of microvascular function. R is minimal during hyperemia (R) with increased R suggestive of microvascular dysfunction. Bolus thermodilution measures the index of microcirculatory resistance (IMR), a dimensionless surrogate of R.
We compared R measured by continuous thermodilution (invasive R) with the gold standard [O]HO positron emission tomography (PET R), and assessed the correlation between invasive R and IMR.
First, the accuracy of invasive R was assessed in a cohort of 24 patients in which both invasive R and PET R were measured in the left anterior descending (LAD) and circumflex (LCX) arteries, corresponding to 46 measurements of R in total (LAD = 24, LCX = 22). Next, agreement between invasive R and IMR was evaluated in the LAD in a cohort of 250 patients with angina and non-obstructive coronary arteries.
Invasive R exhibited a strong correlation with PET R (r = 0.86 [95% CI 0.76-0.92], p < 0.001), with good absolute agreement (ICC 0.82 [95% CI 0.70-0.90], p < 0.001). Passing-Bablok regression analysis found no significant systematic (intercept A: 54.53 [95% CI -18.95 to 120.96]) or proportional (slope B: 0.90 [95% CI 0.71-1.15]) bias between invasive R and PET R. However, invasive R exhibited no significant correlation with IMR (r = 0.11 [95% CI -0.01 to 0.23], p = 0.08).
Invasive R derived from continuous thermodilution exhibited excellent agreement with noninvasive R measured by [O]HO PET, the current non-invasive standard of reference. In contrast, IMR exhibited no significant correlation with invasive R in patients with angina and non-obstructive coronary arteries.
连续热稀释法可量化绝对微血管阻力（R，伍德单位），这是微血管功能的一项关键指标。在充血期间R最小（R），R升高提示微血管功能障碍。团注热稀释法测量微循环阻力指数（IMR），它是R的无量纲替代指标。
我们将连续热稀释法测量的R（有创R）与金标准[O]HO正电子发射断层扫描（PET R）进行比较，并评估有创R与IMR之间的相关性。
首先，在24例患者队列中评估有创R的准确性，在左前降支（LAD）和回旋支（LCX）动脉中同时测量有创R和PET R，总共进行了46次R测量（LAD = 24，LCX = 22）。接下来，在250例心绞痛且冠状动脉无阻塞的患者队列中评估LAD中有创R与IMR之间的一致性。
有创R与PET R表现出强相关性（r = 0.86 [95% CI 0.76 - 0.92]，p < 0.001），绝对一致性良好（ICC 0.82 [95% CI 0.70 - 0.90]，p < 0.001）。Passing - Bablok回归分析发现有创R与PET R之间无显著的系统偏差（截距A：54.53 [95% CI -18.95至120.96]）或比例偏差（斜率B：0.90 [95% CI 0.71 - 1.15]）。然而，有创R与IMR无显著相关性（r = 0.11 [95% CI -0.01至0.23]，p = 0.08）。
连续热稀释法得出的有创R与[O]HO PET测量的无创R（当前无创参考标准）表现出极佳的一致性。相比之下，在心绞痛且冠状动脉无阻塞的患者中，IMR与有创R无显著相关性。
