EVALUATION OF HYPERCAPNIA-INDUCED CHANGES IN CFV BY TTDE IN HEALTHY SUBJECTS

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子项目和研究者（PI）可能从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。所列机构为中心，不一定是研究者所在机构。这项研究已经完成。 背景：高碳酸血症对人类冠状动脉的影响目前尚不清楚。该初步研究评估了在健康成人中使用经胸多普勒超声心动图（TTDE）检测不同吸入CO2水平下冠状动脉血流速度（CFV）变化的可行性。 研究方法：健康成人在呼吸室内空气、氧气补充至吸入空气的40%、CO2调整至高于其基线部分潮气末CO2（PET CO2）水平+5、+7.5和+10 mm Hg（在FiO 2为40%的背景下）的情况下，接受远端左前降支冠状动脉（LAD）的TTDE。在每个实验状态下测量CFV和其他参数。使用重复测量的单因素方差分析比较每个状态下的平均舒张期CFV峰值。 结果如下：在20名成人（平均[标准差]年龄33 [6]岁，52%女性，90%白色）中，17名受试者在所有实验条件下均可获得TTDE图像。按照室内空气、40%FiO2和+5、+7.5和+10 mmHg PETCO 2条件的顺序，平均峰值（SD）CFV值分别为23.1（9.1）cm/s、23.0（9.0）cm/s、25.5（9.3）cm/s、27.9（11.5）cm/s和31.5（13.0）cm/s。治疗间差异具有显著性差异（p <0.001），进行性高碳酸血症水平之间的p <0.05，经多重比较校正。基线条件之间或各自基线和+5 mmHg PETCO 2状态之间未观察到显著CFV差异。 结论：随着高碳酸血症水平的进行，观察到健康受试者的LAD的CFV增加，并且这些变化可以通过TTDE检测到。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This study is completed. Background: The effect of hypercapnia on the coronary arteries in humans is currently unknown. This pilot study assessed the feasibility of using transthoracic Doppler echocardiography (TTDE) in healthy adults to detect changes in coronary artery blood flow velocity (CFV) with varying levels of inspired CO2. Methods: Healthy adults underwent TTDE of the distal left anterior descending coronary artery (LAD) while breathing room air, oxygen supplemented to 40% of inspired air, and CO2 adjusted to +5, +7.5, and +10 mm Hg above their baseline partial end-tidal CO2 (PET CO2) levels on a background of 40% FiO2. CFV and other parameters were measured at each experimental state. Mean peak diastolic CFV values were compared at each state using one-way analysis of variance of repeated measures. Results: Among twenty adults (mean [standard deviation] age 33 [6] years, 52% female, 90% white), TTDE images could be acquired at all experimental conditions in 17 subjects. In order of room-air, 40%FiO2, and +5, +7.5, and +10 mm Hg PETCO2 conditions, mean peak (SD) CFV values were 23.1 (9.1) cm/s, 23.0 (9.0) cm/s, 25.5 (9.3) cm/s, 27.9 (11.5) cm/s, and 31.5 (13.0) cm/s. Between-treatment differences were significantly different (p0.001), with p0.05 between progressive levels of hypercapnia, adjusted for multiple comparisons. No significant CFV differences were seen between baseline conditions or between respective baseline and +5 mm Hg PETCO2 states. Conclusions: With progressive levels of hypercapnia, CFV of the LAD in healthy subjects was observed to increase, and these changes could be detected by TTDE.