Abstract
Objective: Hemodynamic investigations in thoracic outlet syndrome (TOS) remain difficult, even in trained hands. Results are generally reported as either presence or absence of venous compression. In fact, in patients with suspected TOS but without chronic venous occlusion, the forearm volume changes may result from various combinations of forearm position from heart level, arterial inflow, and/or venous outflow positional impairment.Design: Cross sectional, retrospective, single center study, accessible on Clinicaltrial.gov under reference NCT04376177.Material: We used venous photo-plethysmography (V-PPG) in 151 patients with suspected TOS. The subjects elevated their arms to the “candlestick” (Ca) position for 30 s and then kept their arm elevated in front of the body for an additional 15 s (“prayer” position; Pra). This CA–Pra procedure was repeated three times by each patient with recording of both arms.Method: We classified V-PPG recordings using an automatic clustering method.Result: The blinded clustering classification of 893 V-PPG recordings (13 missing files) resulted in four out of seven clusters, allowing the classification of more than 99% of the available recordings. Each cluster included 65.73, 6.16, 17.13, and 10.8% of the recordings, respectively.Conclusion: Venous hemodynamic profiles in TOS are not only either normal or abnormal. With V-PPG, four clusters were observed to be consistent with, and assumed to result from, the four possible associations of presence/absence of arterial inflow/venous outflow positional impairment: (1) normal response (maximal emptying in Ca and Pra), (2) isolated inflow impairment (emptying in Ca and filling in Pra due to post-ischemic vasodilation), (3) isolated venous outflow impairment (emptying then filling in Ca due to arterial inflow and emptying in Pra), and (4) simultaneous inflow/outflow impairment (emptying in Ca but no filling due to concomitant inflow impairment and further emptying in Pra).
Highlights
Movements of the upper limb may be responsible for the compression of the neural plexus and/or vascular structures at different levels
Since the observations of Antignani et al (1990) the hemodynamic consequences of the positional maneuvers in patients with suspected Thoracic outlet syndrome (TOS) have received little attention (Illig et al, 2013; Chen et al, 2014). One reason for this is that PPG is a semiquantitative technique, leading to question the fact that during the candlestick maneuvers the volume decrease observed with PPG corresponded to completely emptied forearm veins during
This is the first study classifying usual venous photo-plethysmography (V-PPG) changes observed during a specific candlestick position (Ca)–Pra procedure derived from the candlestick maneuver in patients with suspected TOS
Summary
Movements of the upper limb may be responsible for the compression of the neural plexus and/or vascular structures at different levels (costoclavicular, pectoris minor, humeral head, etc.). Since the observations of Antignani et al (1990) the hemodynamic consequences of the positional maneuvers in patients with suspected TOS have received little attention (Illig et al, 2013; Chen et al, 2014). One reason for this is that PPG is a semiquantitative technique, leading to question the fact that during the candlestick maneuvers the volume decrease observed with PPG corresponded to completely emptied forearm veins during
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