平板运动负荷超声心动图结合心肌声学造影对运动中高血压反应患者心肌微循环的评估

Evaluation of myocardial microcirculation in patients with hypertensive responses after exercise by treadmill exercise stress echocardiography and myocardial contrast echocardiography

目的 采用平板运动负荷超声心动图结合心肌声学造影技术评估运动中高血压反应(HRE)对心肌功能的影响.方法 选取2017年1月至2018年12月于四川省人民医院进行平板运动负荷超声心动图,同时运动过程中出现高血压反应的患者32例(HRE组)及同期进行平板运动负荷超声心动图且结果正常者28例(对照组),运用平板运动负荷超声心动图结合心肌声学造影技术分别于基线状态及运动后即刻采集常规超声心动图及心肌灌注图像,比较不同状态下2组的运动耐量、血压、左心房和左心室大小、心室壁相对厚度、不同阶段左心室收缩功能和舒张功能及心肌灌注参数.结果 基线状态下,HRE组E/e′高于对照组,差异有统计学意义(t=3.018,P<0.05).HRE组运动耐量参数低于对照组,差异有统计学意义(t=4.786,P<0.01);HRE组中10例出现ST段水平或下斜型压低≥0.1 mV,对照组中无一例出现ST段改变,2组比较差异有统计学意义(χ2=24.97,P<0.01);对照组中仅1例于运动期间出现偶发房性早搏,而HRE组中5例于运动期间出现房性或室性早搏,2组比较差异有统计学意义(χ2=21.45,P<0.05);HRE组峰值期收缩压高于对照组,2组比较差异有统计学意义(t=2.131,P<0.05);HRE组中6例出现广泛性心室壁运动幅度降低,对照组均未出现节段性心室壁运动异常,2组比较差异有统计学意义(χ2=18.58,P<0.05);HRE组运动后e′、运动后E/e′高于对照组,2组比较差异均有统计学意义(t=2.472、3.018,P均<0.05).基线状态下,HRE组与对照组的心内膜下心肌及心外膜下心肌的心肌血流速度、造影峰值强度和心肌血流量(MBF)比较,差异均无统计学意义(P均>0.05).运动后即刻观察,HRE组心内膜下心肌广泛出现造影剂稀疏改变,其心肌血流速度、造影峰值强度、MBF均低于对照组,差异均有统计学意义(t=3.692、2.582、4.673,P均<0.05);心外膜下心肌灌注参数造影峰值强度2组间差异无统计学意义(P>0.05),但HRE组的心肌血流速度、MBF值低于对照组,2组比较差异均有统计学意义(t=3.147、2.375,P均<0.05).将HRE组中出现广泛性心室壁运动幅度降低的6例与其余26例的灌注参数进行对比发现,运动幅度降低组与未降低组之间比较,运动后即刻运动幅度降低组心内膜下心肌的心肌血流速度、造影峰值强度、MBF均低于未降低组,差异均有统计学意义(t=3.487、2.453、4.298,P均<0.05).结论 HRE患者左心室舒张功能明显降低,心肌灌注特别是心内膜下心肌微循环明显受损.平板运动负荷超声心动图作为一项简单、无创评估心脏功能的方法,结合心肌声学造影技术可在常规超声心动图正常情况下早期发现HRE患者心肌微循环功能异常,对HRE人群心脏功能异常的早期诊断及远期随访有重要的临床应用价值.

Objective To evaluate the effect of hypertensive responses(HRE) on myocardial function by treadmill exercise stress echocardiography(ESE) and myocardial contrast echocardiography(MCE). Methods Thirty-two patients with HRE were enrolled as an HRE group and 28 adults with negative stress echocardiography results were included as a control group from January 2017 to December 2018 at Sichuan Provincial People′s Hospital. Treadmill ESE combined with MCE were used to acquire the 2 D and myocardial perfusion images at baseline and after exercises. The exercise capacity, blood pressure(BP), left atria(LA) and left ventricle(LV) volume, relative wall thickness(RWT), LV systolic function, LV diastolic function, and myocardial perfusion parameters during different stages were compared between the two groups. Results At baseline, the E/e’ in the HRE group was significantly higher than that in the control group(t=3.018, P < 0.05). The exercise tolerance parameter(METs) in the HRE group was significantly lower than that in the control group(t=4.786, P < 0.01). In the HRE group, ST-segment depression ≥ 0.1 mV with level/down-slope type appeared in 10 cases, and none of the control group showed ST-segment changes(χ2=24.97, P < 0.01). One subject had atrial premature heartbeat in the control group, while there were five cases of atrial/ventricular premature heartbeat in the HRE groups;there was a statistically significant difference between the two groups(χ2=21.45, P < 0.05). The peak SBP in the HRE group was significantly higher than that in the control group(t=2.131, P < 0.05). Wall motion abnormalities were observed in six cases in the HRE group, while there was no wall motion abnormalities in the control group(χ2=18.58, P < 0.05). e′ and E/e′ after exercise were significantly higher in cases than in controls(t=2.472 and 3.018, respectively, P < 0.05). At baseline, there was no significant difference in myocardial blood flow velocity(k), peak intensity(A), or myocardial blood flow(MBF) between the two groups(P > 0.05). Immediately after exercise, the k, A, and MBF of the subendocardial myocardium in the HRE group were significantly lower than those of the control group(t=3.692, 2.582, and 4.673, respectively, P < 0.05). There was no significant difference in the subepicardial myocardium perfusion parameter A between the two groups(P > 0.05). The k and MBF values in the subepicardial myocardium in the HRE group were significantly lower those of the control group(t=3.147 and 2.375, respectively, P < 0.05). We also compared the perfusion parameters between the six subjects with low wall motion and the other 26 subjects with normal wall motion in the HRE group. We found that k, A, and MBF of the subendocardial myocardium after exercise were significantly lower in the low wall motion group(t=3.487, 2.453, and 4.298, respectively, P < 0.05). Conclusion LV diastolic function is significantly reduced in patients with HRE, and myocardial perfusion, especially subendocardial myocardial microcirculation, is significantly impaired. Treadmill ESE is a simple, non-invasive method for assessing cardiac function, and it can be used to early detect myocardial microcirculation dysfunction in HRE patients with normal rest conventional echocardiography images if combined with MCE. These two combined techniques might have important value in early diagnosis and long-term follow-up of cardiac dysfunction in HRE patients.