目的:对异常经颅多普勒脑血管反应性(CVR)研究的阈值知之甚少,尤其是脑血管病患者。使用真实世界的脑动脉狭窄队列,我们试图描述二氧化碳反应性(CO2R)和血管舒缩范围(VMR)的临床显著阈值.
方法:在正常呼吸室内空气的条件下进行CVR研究,呼吸8%的二氧化碳空气混合物,和过度换气。计算单侧狭窄患者未受影响侧的CO2R和VMR的平均值和标准偏差(SD);选择低于平均值2个SD的偏差作为异常阈值。评估单侧和双侧狭窄患者两侧的受试者工作特征(ROC)曲线的敏感性(Sn)和特异性(Sp)。
结果:共对62例狭窄患者进行了133项连续的CVR研究,平均年龄为55±16岁。合并症包括高血压(60%),糖尿病(15%),中风(40%),吸烟(35%)。在单侧狭窄患者中,未患侧的平均±SDCO2R为1.86±0.53%,将异常CO2R定义为<0.80%。患侧的平均值±SDCO2R为1.27±0.90%。CO2R阈值预测异常乙酰唑胺单光子发射计算机断层扫描(SPECT)(Sn=.73,Sp=.79),CT/MRI灌注异常(Sn=.42,Sp=.77),MRI梗死(Sn=.45,Sp=.76),和压力依赖性检查(Sn=.50,Sp=.76)。对于未受影响的一方,平均±SDVMR为39.5±15.8%,将异常VMR定义为<7.9%。对于受影响的一方,平均±SDVMR为26.5±17.8%。VMR阈值预测异常乙酰唑胺SPECT(Sn=.46,Sp=.94),MRI梗死(Sn=.27,Sp=.94),和压力依赖性检查(Sn=.31,Sp=.90)。
结论:在具有多种血管危险因素的患者中,临床显著异常CO2R的合理阈值为<0.80%,VMR为<7.9%.无创CVR可能有助于狭窄患者的诊断和风险分层。
OBJECTIVE: Thresholds for abnormal transcranial Doppler cerebrovascular reactivity (CVR) studies are poorly understood, especially for patients with cerebrovascular disease. Using a real-world cohort with cerebral arterial stenosis, we sought to describe a clinically significant threshold for carbon dioxide reactivity (CO2R) and vasomotor range (VMR).
METHODS: CVR studies were performed during conditions of breathing room air normally, breathing 8% carbon dioxide air mixture, and hyperventilation. The mean and standard deviation (SD) of CO2R and VMR were calculated for the unaffected side in patients with unilateral stenosis; a deviation of 2 SDs below the mean was chosen as the threshold for abnormal. Receiver operating characteristic (ROC) curves for both sides for patients with unilateral and bilateral stenosis were evaluated for sensitivity (Sn) and specificity (Sp).
RESULTS: A total of 133 consecutive CVR studies were performed on 62 patients with stenosis with mean±SD age 55±16 years. Comorbidities included hypertension (60%), diabetes (15%), stroke (40%), and smoking (35%). In patients with unilateral stenosis, mean±SD CO2R for the unaffected side was 1.86±0.53%, defining abnormal CO2R as <0.80%. Mean±SD CO2R for the affected side was 1.27±0.90%. The CO2R threshold predicted abnormal acetazolamide single-photon emission computed tomography (SPECT) (Sn = .73, Sp = .79), CT/MRI perfusion abnormality (Sn = .42, Sp = .77), infarction on MRI (Sn = .45, Sp = .76), and pressure-dependent exam (Sn = .50, Sp = .76). For the unaffected side, mean±SD VMR was 39.5±15.8%, defining abnormal VMR as <7.9%. For the affected side, mean±SD VMR was 26.5±17.8%. The VMR threshold predicted abnormal acetazolamide SPECT (Sn = .46, Sp = .94), infarction on MRI (Sn = .27, Sp = .94), and pressure-dependent exam (Sn = .31, Sp = .90).
CONCLUSIONS: In patients with multiple vascular risk factors, a reasonable threshold for clinically significant abnormal CO2R is <0.80% and VMR is <7.9%. Noninvasive CVR may aid in diagnosing and risk stratifying patients with stenosis.