Rosen Boaz D, Lima João A C, Nasir Khurram, Edvardsen Thor, Folsom Aaron R, Lai Shenghan, Bluemke David A, Jerosch-Herold Michael
Cardiology Division, Department of Medicine, Johns Hopkins University, Baltimore, MD, USA.
Circulation. 2006 Jul 25;114(4):289-97. doi: 10.1161/CIRCULATIONAHA.105.588525. Epub 2006 Jul 17.
Myocardial ischemia is an important determinant of regional left ventricular systolic function. Myocardial blood flow reserve may be impaired by cardiovascular disease before alterations of myocardial perfusion at rest become manifest. Nevertheless, the relation between flow reserve and regional myocardial function has not been studied in individuals without a history of clinical heart disease.
Seventy-four participants (66+/-9 years, mean+/-SD) of the Multi-Ethnic Study of Atherosclerosis (MESA) underwent myocardial magnetic resonance tagging and contrast-enhanced perfusion studies. Regional myocardial function was evaluated as peak systolic circumferential strain (Ecc) in the three main coronary territories (left anterior descending [LAD], left circumflex, and right coronary artery [RCA]). Myocardial blood flow at rest and during adenosine-induced hyperemia was quantified by contrast-enhanced magnetic resonance imaging, to study the relation between regional flow and function after multivariable adjustment for age, gender, body mass index, left ventricular mass, and traditional risk factors. Lower regional myocardial blood flow during hyperemia was associated with reduced regional left ventricular function expressed as lower Ecc in the RCA (P<0.01) and left circumflex regions (P<0.05) measured in the subendocardium, mid-wall, and subepicardium. In contrast, no significant association was seen in the LAD territory (P=0.16). In addition, segmental function in LAD and RCA regions was reduced when individuals in the lowest 10th percentile for regional myocardial flow reserve were compared with the other participants. Absolute decreases in mid-wall Ecc LAD and RCA and global Ecc were 3.0%, 3.4%, and 2.8%, respectively (P<0.05 for all regions).
Lower myocardial flow reserve is related to reduced regional function in asymptomatic individuals.
心肌缺血是左心室局部收缩功能的重要决定因素。在静息心肌灌注改变显现之前，心血管疾病可能已损害心肌血流储备。然而，尚未在无临床心脏病史的个体中研究血流储备与局部心肌功能之间的关系。
动脉粥样硬化多民族研究（MESA）的74名参与者（66±9岁，均值±标准差）接受了心肌磁共振标记和对比增强灌注研究。局部心肌功能评估为三个主要冠状动脉区域（左前降支[LAD]、左旋支和右冠状动脉[RCA]）的收缩期峰值圆周应变（Ecc）。通过对比增强磁共振成像对静息和腺苷诱导的充血期间的心肌血流进行定量，以研究在对年龄、性别、体重指数、左心室质量和传统危险因素进行多变量调整后局部血流与功能之间的关系。充血期间较低的局部心肌血流与较低的Ecc所表示的局部左心室功能降低相关，Ecc在RCA的心内膜下、中层和心外膜下区域测量时（P<0.01）以及左旋支区域（P<0.05）。相比之下，在LAD区域未观察到显著相关性（P=0.16）。此外，将局部心肌血流储备处于最低十分位数的个体与其他参与者进行比较时，LAD和RCA区域的节段性功能降低。LAD和RCA中层Ecc的绝对降低以及整体Ecc分别为3.0%、3.4%和2.8%（所有区域P<0.05）。
较低的心肌血流储备与无症状个体的局部功能降低有关。
