Chen Huiting, Doornbos Nichole, Williams Kimberly, Criado Enrique
Department of Surgery, Vascular Surgery Section, University of Michigan, Cardiovascular Center, Ann Arbor, MI.
Department of Surgery, Vascular Surgery Section, University of Michigan, Cardiovascular Center, Ann Arbor, MI.
Ann Vasc Surg. 2014 Oct;28(7):1583-8. doi: 10.1016/j.avsg.2014.05.003. Epub 2014 Jun 6.
Hemodynamic changes in vascular flow and waveforms measured across the thoracic outlet (TO) during positional changes may occur in normal individuals. The aim of this study was to establish the prevalence of significant arterial and venous hemodynamic variation in the limbs of normal volunteers during standardized upper extremity positional changes.
Using Doppler ultrasound and photoplethysmography (PPG), we evaluated arterial and venous flow in 100 limbs of 50 normal volunteers in neutral position and in 5 different standardized arm positions, including 90° arm abduction (with head in neutral position, head turned ipsilaterally, and head turned contralaterally), arm extended above the head at 180°, and arm hyperextended at 200°.
There was great variability in the prevalence of abnormal venous and arterial flow changes depending on the arm position. Venous flow anomalies (loss of flow phasicity resulting in continuous, minimally continuous, or absent flow) were demonstrated in 60% of the limbs. The maneuver producing the greatest prevalence of venous flow abnormality was 90° arm abduction with contralateral head turn (34% of limbs), while arm hyperextension produced the least venous flow abnormalities (25% of limbs). In 13% of the limbs arterial flow abnormalities were found by PPG (absent tracings in 10% and dampened waveform in 5%), while 23% of the limbs showed increased arterial velocities (positional to neutral velocity ratio >2.0). The arm position producing the greatest prevalence of arterial flow anomaly was hyperextension (21% of limbs); while the arm positioning at 90° of abduction with the head in neutral position resulted in no arterial flow abnormalities.
The prevalence of upper extremity venous and arterial hemodynamic changes varies substantially in different arm positions. Our data suggest that physiologic anomalies in venous flow across the TO during postural changes are very common, while the absence of finger PPG arterial tracings occur in a very small percentage of the population. Abnormal venous flow across the TO with postural changes should be considered a highly prevalent finding in the normal population, and therefore carries little value in the diagnosis of TO syndrome. On the other hand, absence of arterial waveforms measured at the fingers by PPG testing during positional changes occurs in a small percentage of the normal population, and may represent abnormal compression at the TO in patients with upper extremity symptomatology.
在正常个体中，体位改变时测量胸廓出口（TO）处血管血流和波形的血流动力学变化可能会发生。本研究的目的是确定正常志愿者在标准化上肢体位改变期间四肢动脉和静脉血流动力学显著变化的发生率。
我们使用多普勒超声和光电容积脉搏波描记法（PPG），对50名正常志愿者的100条肢体在中立位以及5种不同的标准化手臂位置进行评估，包括手臂外展90°（头部处于中立位、头部向同侧转动、头部向对侧转动）、手臂伸展至180°高于头部、手臂过度伸展至200°。
根据手臂位置不同，静脉和动脉血流变化异常的发生率差异很大。60%的肢体出现静脉血流异常（血流搏动性丧失导致血流持续、微弱持续或无血流）。导致静脉血流异常发生率最高的动作是头部向对侧转动的手臂外展90°（34%的肢体），而手臂过度伸展导致的静脉血流异常最少（25%的肢体）。通过PPG在13%的肢体中发现动脉血流异常（10%的肢体描记缺失，5%的肢体波形衰减），而23%的肢体显示动脉速度增加（体位与中立位速度比>2.0）。导致动脉血流异常发生率最高的手臂位置是过度伸展（21%的肢体）；而头部处于中立位的手臂外展90°时未出现动脉血流异常。
上肢静脉和动脉血流动力学变化的发生率在不同手臂位置有很大差异。我们的数据表明，体位改变时经TO的静脉血流生理异常非常常见，而手指PPG动脉描记缺失在人群中所占比例非常小。体位改变时经TO的静脉血流异常应被视为正常人群中非常普遍的发现，因此在胸廓出口综合征的诊断中价值不大。另一方面，在体位改变期间通过PPG测试在手指处测量不到动脉波形在一小部分正常人群中出现，可能代表有上肢症状的患者在TO处存在异常压迫。
