Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States.
Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States.
Am J Physiol Heart Circ Physiol. 2024 Jul 1;327(1):H261-H267. doi: 10.1152/ajpheart.00292.2024. Epub 2024 May 24.
Reduced peripheral microvascular reactivity is associated with an increased risk for major adverse cardiac events (MACEs). Tools for noninvasive assessment of peripheral microvascular function are limited, and existing technology is poorly validated in both healthy populations and patients with cardiovascular disease (CVD). Here, we used a handheld incident dark-field imaging tool (CytoCam) to test the hypothesis that, compared with healthy individuals (no risk factors for CVD), subjects formally diagnosed with coronary artery disease (CAD) or those with ≥2 risk factors for CAD (at risk) would exhibit impaired peripheral microvascular reactivity. A total of 17 participants (11 healthy, 6 at risk) were included in this pilot study. CytoCam was used to measure sublingual microvascular total vessel density (TVD), perfused vessel density (PVD), and microvascular flow index (MFI) in response to the topical application of acetylcholine (ACh) and sublingual administration of nitroglycerin (NTG). Baseline MFI and PVD were significantly reduced in the at-risk cohort compared with healthy individuals. Surprisingly, following the application of acetylcholine and nitroglycerin, both groups showed a significant improvement in all three microvascular perfusion parameters. These results suggest that, despite baseline reductions in both microvascular density and perfusion, human in vivo peripheral microvascular reactivity to both endothelial-dependent and -independent vasoactive agents remains intact in individuals with CAD or multiple risk factors for disease. To our knowledge, this is the first study to comprehensively characterize in vivo sublingual microvascular structure and function (endothelium-dependent and -independent) in healthy patients and those with CVD. Importantly, we used an easy-to-use handheld device that can be easily translated to clinical settings. Our results indicate that baseline microvascular impairments in structure and function can be detected using the CytoCam technology, although reactivity to acetylcholine may be maintained even during disease in the peripheral microcirculation.
外周微血管反应性降低与主要不良心脏事件（MACEs）风险增加相关。用于评估外周微血管功能的非侵入性工具有限，现有的技术在健康人群和心血管疾病（CVD）患者中的验证效果都很差。在这里，我们使用手持式入射暗场成像工具（CytoCam）来检验以下假设：与健康个体（无 CVD 风险因素）相比，经正式诊断患有冠状动脉疾病（CAD）或具有≥2 个 CAD 风险因素的个体（有风险）将表现出外周微血管反应性受损。这项初步研究共纳入 17 名参与者（11 名健康个体，6 名有风险个体）。CytoCam 用于测量舌下微血管总血管密度（TVD）、灌注血管密度（PVD）和微血管血流指数（MFI），以响应乙酰胆碱（ACh）的局部应用和舌下硝酸甘油（NTG）的给药。与健康个体相比，有风险个体的基线 MFI 和 PVD 显著降低。令人惊讶的是，在应用乙酰胆碱和硝酸甘油后，两组的所有三种微血管灌注参数都有显著改善。这些结果表明，尽管微血管密度和灌注的基线降低，CAD 或多种疾病风险因素个体的体内外周微血管对内皮依赖性和非依赖性血管活性物质的反应性仍然完整。据我们所知，这是第一项全面描述健康患者和 CVD 患者体内舌下微血管结构和功能（内皮依赖性和非依赖性）的研究。重要的是，我们使用了一种易于使用的手持式设备，该设备可以很容易地转化为临床环境。我们的研究结果表明，CytoCam 技术可以检测到基线微血管结构和功能的损伤，尽管在周围微循环的疾病期间，对乙酰胆碱的反应性可能仍然保持。
