经颅多普勒-二氧化碳试验评价老年高血压病患者的脑血管反应性

目的探讨乙酰唑胺(ACZ)负荷试验、过度换气及屏气试验[经颅多普勒-二氧化碳(TCD-CO2)试验]对脑动脉调节能力的影响。方法选择老年高血压病患者33例为观察对象,应用3种TCD-CO2试验方法,测定经长效血管紧张素转换酶抑制剂及利尿药降压治疗前、后患者的脑血流动力学参数。结果①3种试验方法测定的MCA平均峰值流速(Vm)变化值、变化率及搏动指数(PI)变化率在降压治疗前、后,差异均有统计学意义(P<0.05);②治疗前、后,过度换气试验与ACZ试验的Vm变化值、变化率间均呈显著负相关性(r=-0.693及-0.595,P<0.01;r=-0.346及-0.371,P<0.05);前者的PI变化率亦与后者呈显著负相关(r=-0.344及-0.351,P<0.05);③治疗前、后,屏气试验与ACZ试验的Vm变化值、变化率及PI变化率均呈显著正相关(r=0.709及0.665;r=0.560及0.539;r=0.483及0.550,P均<0.01),其屏气指数与ACZ试验的Vm上升率亦呈正相关(r=0.470及0.402,P<0.05);④屏气试验与ACZ试验的各项血流动力学参数相关系数高于过度换气试验。结论3种TCD-CO2试验均可评价老年高血压患者治疗前、后脑血管反应性;与过度换气试验相比,屏气试验对脑血管反应性的评价更接近于ACZ试验。

Assessment of cerebrovascular reactivity with transcranial Doppler CO2 test in the elderly hypertensives

Objective To evaluate the effect of acetazolamide(ACZ) stress test,hyperventilation and breath-holding test [transcranial Doppler carbon dioxide(TCD-CO2) test] on regulatory ability of cerebral arteries.Methods Thirty-three elderly hypertensives were selected as observation subjects,their cerebral hemodynamic parameters were measured by using the above three TCD-CO2 tests before and after the antihypertensive treatment with long-acting angiotensin converting enzyme inhibitor and diuretic.Results There were significant differences between the change value,change rate of the peak mean flow velocity(Vm) and the change rate of pulsatility index(PI) in middle cerebral artery(MCA) in the three TCD-CO2 test methods before and after antihypertensive treatment(P<0.05).The Vm change value between the change rate of the hyperventilation test were all significantly negatively correlated with those of the ACZ test before and after the treatment(r=-0.693 and-0.595,P<0.01;r=-0.346 and-0.371,P<0.05);the PI change rate of the former was also negatively correlated with the latter(r=-0.344 and-0.351,P<0.05).The Vm change value,the change rate and the PI change rate of the breath-holding test were all significantly positively correlated with the ACZ test before and after the treatment(r=0.709 and 0.665;r=0.560 and 0.539;r=0.483 and 0.550,all P<0.01),and the breath-holding index(BHI) was positively correlated with the Vm increasing rate of the ACZ test(r=0.470 and 0.402,P<0.05).All the correlation coefficients of hemodynamic parameters in both breath-holding and ACZ tests were higher than those in the hyperventilation test.Conclusion All the three TCD-CO2 tests can be used to assess cerebral vasoreactivity before and after the treatment in the elderly hypertensives.The assessment of the breath-holding test on cerebral vasoreactivity is much more close to the ACZ test as compared with the hyperventilation.