Microvascular Response to the Roos Test Has Excellent Feasibility and Good Reliability in Patients With Suspected Thoracic Outlet Syndrome

Background: Exercise oximetry allows operator-independent recordings of microvascular blood flow impairments during exercise and can be used during upper arm provocative maneuvers.Objective: To study the test-retest reliability of upper-limb oximetry during the Roos test in patients with suspected thoracic outlet syndrome (TOS).Materials and Methods: Forty-two patients (28 men, 14 women; mean age: 40.8 years) were examined via transcutaneous oxygen pressure (TcpO2) recordings during two consecutive Roos tests in the standing position. The minimal decrease from rest of oxygen pressure (DROPmin) value was recorded after each maneuver was performed on both arms. The area under the receiver operating characteristic (ROC) curve defined the DROPmin diagnostic performance in the presence of symptoms during the tests. The Mann–Whitney U-test was used to compare the DROPmin in the symptomatic vs. asymptomatic arms. The test-retest reliability was analyzed with Bland-Altman representations. The results are presented as means ± standard deviations (SD) or medians [25–75 percentiles].Results: The symptoms by history were different from the symptoms expressed during the Roos maneuvers in one-third of the patients. The DROPmin measurements were −19 [−36; −7] mmHg and −8 [−16; −5] mmHg in the symptomatic (n = 108) and asymptomatic (n = 60) arms, respectively. When TOS observed on ultrasound imaging was the endpoint, the area under the ROC curve (AUC) was 0.725 ± 0.058, with an optimal cutoff point of −15 mmHg. This value provided 67% sensitivity and 78% specificity for the presence TOS via ultrasound. When symptoms occurring during the test represented the endpoint, the AUC was 0.698 ± 0.04, with a cutoff point of −10 mmHg. This provided 62% sensitivity and 66% specificity for the presence of pain in the ipsilateral arm during the test. The test-retest reliability of DROPmin proved to be good but not perfect, partly because of unreliability of the provocation maneuvers.Conclusion: To the best of our knowledge, this study is the first to investigate microvascular responses during the Roos maneuver in patients with suspected TOS. The presence of symptoms was significantly associated with ischemia. TcpO2 facilitated the recording of both macrovascular and microvascular responses to the Roos test. The Roos maneuver should probably be performed at least twice in patients with suspected TOS

Physiopathology of exercise ischemia

L’ischémie d’exercice caractérisée par l’incapacité du système circulatoire de faire face à l’augmentation des besoins en substrats énergétiques et en oxygène nécessaire à dégrader ces substrats. La claudication à la marche est une cause majeure de limitation fonctionnelle.Il existe de nombres techniques d'évaluation de la macrocirculation et de la microcirculation permettant d'évaluer la réponse endothéliale dépendante(iontophorèse, test au garrot, modification de température locale) avec un enregistrement laser Doppler ou Speckle.Si les techniques ultrasonores permettent d’explorer la présence de lésions, elles rendent mal compte de la collatéralité. Ces techniques peu applicables à l’exercice et nécessitent d’être améliorées pour être applicables à l’effort. L’ischémie artérielle, entraîne une souffrance cellulaire avec métabolisme anaérobie, réversible à l’arrêt de l’exercice. En cas de développement de circulation collatérale suffisante, l’ischémie est alors incomplète, la souffrance des tissus est modérée et réversible rapidement. La recherche de pathologie artérielle au reposa été largement étudiée, nous nous intéressons dans nos études à la pathologie artérielle à l’effort, mais aussi aux phénomènes physiopathologiques susceptibles d’interférer avec la fonctionnalité musculaire (hypoxémie induite par l’exercice). La mesure de la pression partielle transcutanée en oxygène (TcpO2) à l’exercice permet d’estimer en cours de l’exercice l’importance de l’ischémie, segment de membre par segment de membre,de façon bilatérale et continue. Par cette nouvelle technique nous tentons d’explorer la physiopathologie de l’ischémie vasculaire à l’exercice.Exercise ischemia is characterized by the inability of the circulatory system to fulfil the increased need forenergy substrates and the oxygen needed for substrates’ metabolism. Claudication is a major cause of functional limitation. There are several methods for assessing macrocirculation (mainly ultrasound imaging) and microcirculation (iontophoresis, tourniquet test, local temperature modification with Laser or Speckle recording. If ultrasound techniques can explore the occurrence of lesions is not optimal to evaluate the hemodynamic consequences because pressure measurements do not necessarily correlate with flow impairment. Laser techniques are not appropriate during exercise tests and need to be improved to be applicable. During exercise the severity of arterial ischemia depends on collateral circulation. Further ischemia is reversible at the end of exercise. Although research of restingarterial ischemia has been extensively studied few isknown in arterial ischemia during exercise, but al soin other physiopathological dysfunctions that may interfere with muscle function (exercise-inducedhypoxemia). The measurement of the transcutaneous oxygen partial pressure (TcpO2) during exercise estimates during exercise the importance of ischemia, limb segment by limbsegment, bilaterally and continuously. With this new technique we try to investigate the Physiopathology of vascular ischemia during exercise

Validation of risk assessment models predicting venous thromboembolism in acutely ill medical inpatients: a cohort study.

BACKGROUND As hospital-acquired venous thromboembolism (VTE) represents a frequent cause of preventable deaths in medical inpatients, identifying at risk patients requiring thromboprophylaxis is critical. We aimed to externally assess the Caprini, IMPROVE and Padua VTE risk scores and to compare their performance to advanced age as a stand-alone predictor. METHODS We performed a retrospective analysis of patients prospectively enrolled in the PREVENU trial. Patients aged 40-years and older, hospitalised for at least 2-days on a medical ward were consecutively enrolled and followed for three months. Critical ill patients were not recruited. Patients diagnosed with VTE within 48-hours from admission, or receiving full dose anticoagulant treatment or who underwent surgery were excluded. All suspected VTE and deaths occurring during the three-month follow-up were adjudicated by an independent committee. The three scores were retrospectively assessed. Body mass index, needed for the Padua and Caprini scores were missing in 44% of patients. RESULTS Among 14,910 eligible patients, 14,660 were evaluable, of which 1.8% experienced symptomatic VTE or sudden unexplained death during the three-month follow-up. The area under the receiver operating characteristic curves (AUC) were 0.60 (95%CI 0.57-0.63), 0.63 (95%CI 0.60-0.66) and 0.64 (95%CI 0.61-0.67) for Caprini, IMPROVE and Padua scores, respectively. None of these scores performed significantly better than advanced age as a single predictor (AUC 0.61, 95%CI 0.58-0.64). CONCLUSION In our study, Caprini, IMPROVE and Padua VTE risk scores have poor discriminative ability to identify not-critically ill medical inpatients at risk of VTE, and do not perform better than a risk evaluation based on patient's age alone

Calf and non-calf hemodynamic recovery in patients with arterial claudication: Implication for exercise training

International audienceBackgroundPrevious studies in patients with arterial claudication have focused on calf hemodynamic recovery. We hypothesized that the duration of hemodynamic recovery with TcpO2 at calf and non-calf levels would be shorter than 10 min. We analyzed the factors that influence the recovery time.MethodsWe monitored limb changes minus chest changes from rest (DROP) of transcutaneous oximetry on buttocks, thighs and calves, during and following a treadmill test (3.2 km/h; 10% grade). We calculated the time required to reach 50% (50%RT) and 10% (90%RT) of minimal DROP value (DROPm) from walking cessation. Regression analyses were used to determine the factors associated to 50%RT and 90%RT.ResultsOf the 132 patients studied, 18.2% reported isolated non-calf pain by history. Of the 792 recovery time values, only 3 (0.4%) and 23 (2.9%) were in excess of 10 min for 50%RT and for 90%RT, respectively. A weak correlation was found between each of the 792 DROPm and 50%RT (r = −0.270, p < 0.001) as well as for 90%RT (r = −0.311 p < 0.001). Lowest DROPm and BMI (but not age, sex, the use of beta-blockers, the duration of the walking period) were associated to both 50%RT and 90%RT.ConclusionAlthough recovery duration correlates significantly with the severity of ischemia of the same location, a wide discrepancy exists and the longest recovery time does not always correlate to the localization of the most severe ischemia. Non-calf ischemia should be measured when one aims at objectifying the biological effects of exercise or the effects of treatments on recovery from exercise

Gait alterations in patient with intermittent claudication: Effect of unilateral vs bilateral ischemia

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Investigation of arterial claudication with transcutaneous oxygen pressure at exercise: Interests and limits

International audienceTranscutaneous oxygen pressure (TcpO2) measurement has been used for years at rest in patients with lower extremity artery disease. It was proposed for exercise testing (Ex-TcpO2) in the 80ies to evaluate regional blood flow impairment (RBFI) at the proximal and distal levels simultaneously and on both sides, in case of claudication. It was suggested that the use of a chest electrode was mandatory to show that decreases in TcpO2 at the limb level result from limb RBFI and not from a systemic pO2 decrease of cardiopulmonary origin (exercise-induced hypoxemia). Unfortunately, a major pitfall of Ex-TcpO2 was the low absolute reliability of the regional perfusion index (RPI: ratio of limb to chest values) and the technique was almost abandoned until 2003, when the DROP index (Decrease from rest of oxygen pressure: limb changes minus chest changes from rest) was proposed. The DROP mathematical formula makes Tcpo2 results independent from the absolute pO2 starting values, improving reliability of Ex-TcpO2 as compared to the RPI. Since then, Ex-TcpO2 has been of renewed interest. The present paper addresses the physiology of Ex-TcpO2, interpretation of its results, and common misunderstandings about its use