Abstract：
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.NEW & NOTEWORTHY 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.
摘要：
外周微血管反应性降低与主要不良心脏事件（MACE）的风险增加有关。用于外周微血管功能的非侵入性评估的工具是有限的，并且现有技术在健康人群和心血管疾病（CVD）患者中的验证不佳。这里,我们利用手持式入射暗场成像工具（CytoCam）来检验与健康个体（无CVD危险因素）相比的假设，正式诊断为冠状动脉疾病(CAD)或具有≥2个CAD危险因素(内皮功能障碍;ED)的受试者会表现出外周微血管反应性受损.共有17名参与者（11名健康，6ED)被纳入本试点研究。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）响应于局部应用乙酰胆碱（Ach）和舌下施用硝酸甘油（NTG）。与健康个体相比，ED队列中的基线MFI和PVD显着降低。令人惊讶的是,应用乙酰胆碱和硝酸甘油后，两组3个微血管灌注参数均有显著改善.这些结果表明，尽管基线微血管密度和灌注降低，在患有CAD或多种疾病危险因素的个体中,人体内对内皮依赖性和非依赖性血管活性剂的外周微血管反应性保持完整.
