基于心脏磁共振特征追踪技术的高血压患者早期左房功能障碍的定量研究

Cardiovascular magnetic resonance feature tracking in the quantitative assessment of early left atrial dysfunction in hypertensive patients

目的采用心脏磁共振特征追踪技术定量评估高血压患者早期左房功能障碍。材料与方法连续性收集2012年1月至2013年12月在我院确诊为高血压并接受心脏磁共振检查的患者30例。所有患者均除外左房扩大、左室射血分数<50%及其他心血管疾病,并纳入同时期30名年龄及性别匹配的正常人作为对照组。采用心脏磁共振特征追踪技术,同时在心脏两腔心及四腔心电影序列上进行左房纵向应变分析,分别获得左房存储期、导管期及泵血期的射血分数、应变力及应变率,比较两组的临床及心脏磁共振参数。结果两组的平均年龄均为(45.93±10.38)岁,男性占66.6%(20/30)。高血压组的体表面积、体重指数及静息状态下收缩压和舒张压均显著高于对照组。同时,高血压患者左室射血分数[(64.08±7.99)%vs(59.89±4.59)%,P=0.018]及左室心肌质量[(61.14±10.59)g/m^2 vs(37.93±10.45)g/m^2,P<0.001]亦显著增大。左房最大容积、收缩期前容积及最小容积指数两组间均无显著差异。高血压组左房存储期及导管期的射血分数及应变力较对照组均明显减小,而左房泵血期各参数两组间差异均无统计学意义。结论心脏磁共振特征追踪技术有潜力在左房增大之前定量检测高血压患者的左房功能障碍,主要表现为左房存储期及导管期功能下降而泵血期功能保留。

Objective:To evaluate the early left atrial(LA)dysfunction in hypertensive patients by using cardiovascular magnetic resonance feature tracking(CMR-FT).Materials and Methods:Thirty patients diagnosed with hypertension in our hospital from January 2012 to December 2013 were consecutively recruited and all patients underwent CMR examinations.Patients with LA enlargement,left ventricular ejection fraction(LVEF)<50%and other cardiovascular diseases were excluded.Thirty age-and sex-matched healthy subjects were included as controls.LA strain analysis was performed both on the two-and four-chamber cine images.LA reservoir,conduit and contractile functional parameters including ejection fraction(EF),strain and strain rate were collected respectively.All the clinical and CMR parameters were compared between the two groups.Results:The mean age was 45.93±10.38 yrs,66.6%(20/30)were males.In hypertensive patients,body surface area,body mass index and resting systolic/diastolic blood pressure were all significantly higher than those of the controls.Similar results were observed in terms of LVEF[(64.08±7.99)%vs(59.89±4.59)%,P=0.018]and LV mass[(61.14±10.59)g/m^2 vs(37.93±10.45)g/m^2,P<0.001].Regarding the LA parameters,there were no significant differences in terms of the LA maximum volume,pre-atrial contractile LA volume and minimum volume index between the two groups.In hypertensive patients,the LA EF and strain in both reservoir and conduit phases were significantly impaired,while no statistical differences were observed in LA contractile parameters.Conclusions:CMR-FT technique could be used to detect LA dysfunction before LA enlargement in hypertensive patients.In those patients,the LA reservoir and conduit function were impaired while the contractile function was preserved.