Quantitative analysis of venous outflow with photo-plethysmography in patients with suspected thoracic outlet syndrome

Abstract

BackgroundVenous compression is the second most frequent form of thoracic outlet syndrome (TOS). Although venous photo-plethysmography (PPG) has been largely used to estimate the consequences of chronic thromboses (Paget Schroetter syndrome), systematic direct quantitative recording of hemodynamic consequences of positional venous outflow impairment in patients with suspected TOS has never been reported.ObjectiveWe hypothesized that moving the arms forward (prayer: “Pra” position) while keeping the hands elevated after a surrender/candlestick position (Ca) would allow quantification of 100% upper limb venous emptying (PPGmax) and quantitative evaluation of the emptying observed at the end of the preceding abduction period (End-Ca-PPG), expressed in %PPGmax.Materials and methodsWe measured V-PPG in 424 patients referred for suspected TOS (age 40.9 years old, 68.3% females) and retrieved the results of ultrasound investigation at the venous level. We used receiver operating characteristics curves (ROC) to determine the optimal V-PPG values to be used to predict the presence of a venous compression on ultrasound imaging. Results are reported as a median (25/75 centiles). Statistical significance was based on a two-tailed p < 0.05.ResultsAn End-Ca-PPG value of 87% PPGmax at the end of the “Ca” period is the optimal point to detect an ultrasound-confirmed positional venous compression (area under ROC: 0.589 ± 0.024; p < 0.001). This threshold results in 60.9% sensitivity, 47.6% specificity, 27.3% positive predictive value, 79.0% negative predictive value, and 50.8% overall accuracy.ConclusionV-PPG is not aimed at detecting the presence of a venous compression due to collateral veins potentially normalizing outflow despite subclavicular vein compression during abduction, but we believe that it could be used to strengthen the responsibility of venous compression in upper limb symptoms in TOS-suspected patients, with the possibility of non-invasive, bilateral, recordable measurements of forearm volume that become quantitative with the Ca-Pra maneuver.Clinical trial registration[ClinicalTrials.gov], identifier [NCT04376177].

Estimation of the prevalence of isolated inter-scalene compression from simultaneous arterial and venous photoplethysmography in patients referred for suspected thoracic outlet syndrome

“…For V-PPG analysis, the value observed at the end of the surrender position (Vs) and at the end of the Prayer position (Vp) were recorded as shown in figure 1. Incomplete venous emptying (Vs+ or Vp+) was defined as a V-PPG value lower than 87% max consistent with previous report (Hersant et al 2022b). Nevertheless, since this initial publication, this threshold in our experience seems to be too 'inclusive' because minor changes in elbow level may result in values lower than 87% max.…”

“…Surrender-Prayer procedure was performed as previously reported with two consecutive phases (Hersant et al 2021a(Hersant et al , 2021b(Hersant et al , 2022b. From the resting position with the arms along the torso, the patients were requested to rapidly elevate their upper limb to the 'surrender' (Su) position (shoulder and elbow at the same level and forearm vertical) as for an EAST test.…”

“…First, the choice of the restrictive or inclusive definition changes the number of observations found in each type of possible discrepancies (Gergoudis and Barnes 1980, Geven et al 2006, Hersant et al 2022b. Future studies are required to improve the definition of the cutoff points to be used for both A-PPG and V-PPG.…”

“…Ultrasound has been reported of imperfect accuracy in TOS, even in case of venous thrombosis (Antignani et al 1990, Gillard et al 2001, Orlando et al 2016. Simultaneous and bilateral detection of arterial inflow and venous outflow impairment during the provocative procedures can be done with arterial fingertip photoplethysmography (A-PPG) (Gergoudis and Barnes 1980, Likes et al 2014b, Adam et al 2018, Farina et al 2021, Hersant et al 2022a, and forearm venous photoplethysmography (V-PPG), provided that the 'surrender' position of the EAST is immediately followed by a 'Prayer' position (90 • antepulsion) to normalize V-PPG results (Hersant et al 2021a(Hersant et al , 2021b(Hersant et al , 2022b.…”