The sympathetic nervous system plays a key role in the regulation of cardiovascular and ventilatory responses during exercise. The regulation of the heart and peripheral circulation by the autonomic nervous system is accomplished by control centers that receive input from mechanical and chemical receptors through the body. Therefore, the changes in sympathetic and parasympathetic activity allow for rapid responses. <p><p>Exercise is associated with increases of ventilation, heart rate and blood pressure. Ventilation increases adaptedly to increased oxygen uptake (VO2) and carbon dioxide output (VCO2) and eventually to limit metabolic acidosis occurring above the ventilatory threshold. Cardiac output increases to meet the contracting muscles’ requirement for flow. The increase in cardiac output occurs through increases in both heart rate and stroke volume and is regulated by feed-forward mechanisms: central command and exercise pressor reflex. <p><p>Skeletal muscle contraction elicits a reflex increase in sympathetic outflow which causes vasoconstriction contributing to the exercise induced rise in blood pressure. This reflex is triggered by stimulation of metabo- and chemoreceptors. Although the precise stimulus is not known, adrenergic receptor signaling is involved in the cardiovascular and respiratory alterations in response to exercise. <p><p>This thesis has been devoted to a better understanding of the functional aspects of sympathetic nervous system activation during dynamic and resistive exercise, with use of β blocker and β2 stimulant interventions The hypotheses were: 1) that β blocker interventions would decrease aerobic exercise capacity by a limitation of maximal cardiac output, but more so the ventilatory responses to exercise because of a decreased chemosensitivity, thereby decreasing dyspnea, and 2) β2 stimulant interventions would slightly increase aerobic exercise capacity by an increase in maximal cardiac output, but also the ventilatory responses because of an increased chemosensitivity, with possible decrease of the ventilatory reserve at exercise and increased dyspnea. Both interventions could affect maximal muscle strength through central effects.<p><p>Ventilatory responses to hyperoxic hypercapnia (central chemoreflex) and to isocapnic hypoxia (peripheral chemoreflex) were confronted to measurements of ventilatory equivalents for oxygen (O2) and carbon dioxide (CO2) during standard cardiopulmonary exercise test (CPET). Resting 5 measurements of muscle sympathetic nervous activity (MSNA) were obtained in different conditions with and without pharmacological interventions. Muscle metaboreflex and muscle stength measurements were also considered. Drugs with β blocker or β2 stimulant properties were administered in range of doses used in clinical practice for the teatment of cardiovascular or rerspiratory conditions. The results show that β blockade with bisoprolol slightly reduced maximal exercise capacity as assessed by a maximal oxygen uptake (VO2max) or maximal workload (Wmax), with a decreased maximal heart rate, without significant effect on ventilation (VE) or MSNA responses to hypercapnia, hyperoxia or to isometric muscle contraction or ischemia. Both VE/VO2 and VE/VCO2 slopes were decreased during CPET, which was attributable to β blockade-related hemodynamic changes. On the other hand, stimulation of β2 receptors with salbutamol did not affect exercise capacity as assessed by VO2max or Wmax in spite of increased peripheral chemosensitivity with increased VE/VCO2 slopes and early lactic acidosis. MSNA burst frequency, muscle metaboreflex and maximal isokinetic muscle strength were not affected by salbutamol. <p><p>Thus, aerobic exercise capacity in healthy subjects is sensitive to sympathetic nervous system modulation by β blocker or β2 stimulant interventions with drugs at doses prescribed in clinical practice. B blocker intervention has a slight limitation of aerobic exercise capacity and a hemodynamic decrease in ventilation, while β2 stimulant intervention has no change in exercise capacity with associated increased ventilatory responses because of increased chemosensitivity, partly related to early lactic acidosis. None of the studied phamacologic interventions affected MSNA or muscle strength measurements. <p><p>We hope that these results might be useful for the understanding of the effects of revalidation to exercise of patients treated with β blocker or β2 stimulant drugs, document the limited ergogenic properties and also side effects of the intake of these substances in healthy exercising subjects.<p> / Doctorat en Sciences de la motricité / info:eu-repo/semantics/nonPublished

La décompensation cardiaque se manifeste par une symptomatologie de dyspnée et de fatigue, et par une diminution de l’aptitude aérobie. La décompensation cardiaque peut être globale ou gauche (DCG), ou droite comme dans le cas de l’hypertension artérielle pulmonaire (HTAP). Les mesures fonctionnelles de repos (fonction ventriculaire gauche ou pression artérielle pulmonaire moyenne) sont peu corrélées à l’aptitude aérobie, qui est cependant un élément important de la mise au point et du suivi clinique des patients atteints de DCG ou d’HTAP. <p>\ / Doctorat en Sciences de la motricité / info:eu-repo/semantics/nonPublished

Introduction : Le Test de Marche de 6 Minutes (6MWT) est le test le plus utilisé chez les patients atteints de cancer, évaluant la capacité fonctionnelle, tout en demeurant simple, sécuritaire et standardisé. Toutefois, aucune équation actuelle ne peut prédire la consommation maximale d’oxygène ("V" ̇O2 max) chez les survivants de cancer. Ainsi, l’objectif principal est de valider une équation spécifique pour prédire le "V" ̇O2 max à partir du 6MWT, alors que le second est de valider une équation spécifique pour prédire la distance de marche (6MWD) à partir du 6MWT. Méthodes : Au total, 250 survivants d’au moins cinq ans de la leucémie lymphoblastique aigüe (LLA) (n=80 femmes (48%); n=88 hommes (52%)) avec un âge moyen de 22 ans (22.2 ± 6.3) ont été recrutés. Parmi ceux-ci, 168 survivants ont réalisé un 6MWT ainsi qu’un test d’effort maximal sur ergocycle pour évaluer respectivement leur capacité fonctionnelle et leur fonction cardiorespiratoire. Une évaluation de leur pratique d’activités physiques a été réalisée par questionnaire. Les survivants ont ensuite été randomisés en deux groupes : le premier (n=118 (70%)) pour créer les équations et le deuxième groupe (n=50 (30%)) pour valider les équations créées. Des régressions linéaires multiples ont été réalisées pour prédire chacune des équations ("V" ̇O2 max et 6MWD) à partir du 6MWT. Les variables incluses dans les équations comprenaient l’âge, le poids, la taille, la fréquence cardiaque à la fin du test (FCfin), la distance de marche effectuée (6MWD), le niveau de la pratique d’activités physiques (MVLPA), la perception d’effort (EPE) ainsi que la durée des traitements (DT). La méthode de Bland et Altman a été utilisée pour valider chacune des équations en déterminant les différences moyennes et en comparant nos équations avec des équations de références. Résultats : Équation spécifique "V" ̇O2 max (différence moyenne = 2.51mL.kg-1.min-1) = (-0,236 * âge(années)) - (0,094 * poids(kg)) - (0,120 * FCfin(bpm)) + (0,067 * 6MWD(mètres)) + (0,065 * MVLPA(min/jour)) - (0,204 * DT(années)) + 25,145 ; R2=0.61. Équation spécifique 6MWD (différence moyenne = 10.86 mètres) = (3,948 * taille(cm)) - (1,223 * poids(kg)) + (1,913 * FCfin(bpm)) - (6,863 * EPE(/10)) + (0,556 * MVLPA(min/jour)) - 242,241 ; R2=0.36. Conclusion : Il s’agit de la première étude qui prédit le "V" ̇O2 max et la 6MWD en utilisant des variables cliniques et spécifiques des survivants de LLA. Nos résultats permettent d’évaluer la capacité cardiorespiratoire des survivants de LLA et facilitera leur suivi. / Introduction: In cancer patients, the 6-Minute Walking Test (6MWT) is the most widely used test because it can assess the functional capacity in patients, while remaining simple, safe and standardized. However, it is reported that the actual equations cannot accurately predict a valid "V" ̇O2 peak value or a 6-minute walk distance (6MWD) in cancer survivors. Thus, the first aim is to validate a specific equation using the 6MWT to predict "V" ̇O2peak, while the second is to validate a specific equation to predict walk distance during 6MWT. Methods: A total of 250 childhood acute lymphoblastic leukemia (ALL) survivors were enrolled in this study, among which 168 participants aged 22 years on average (22.2 ± 6.3) (n=80 females (48%); n=88 males (52%)) underwent a cardiopulmonary exercise test (CPET) and a 6MWT to assess their functional capacity and their cardiorespiratory fitness. Additionally, participants completed a physical activity questionnaire. Participants were randomly divided in two groups to create (n=118 (70%)) and to validate (n=50 (30%)) the equations. Multiple linear regression analyses were used to determine a new prediction equation for "V" ̇O2 peak and 6MWD from 6MWT. The validity in between the measured and predicted "V" ̇O2 peak and between the measured and predicted 6MWD was assessed using the Bland and Altman method. Results: Specific "V" ̇O2 peak equation (mean of bias=2.51mL.kg-1.min-1) = (-0.236*age(years)) - (0.094*weight(kg)) - (0.120*HR end(bpm)) + (0.067*6MWD(meters)) + (0.065*MVLPA(min/day)) - (0.204*DT(years)) + 25.145. Specific 6MWD equation (mean of bias=10.86meters) = (3.948*height(cm)) - (1.223*weight(kg)) + (1.913*HR end(bpm)) - (6.863*RPE) + (0.556*MVLPA(min/day)) - 242.241 Conclusion: This is the first study that predicted "V" ̇O2 peak and 6MWD using clinical and specific variables related to the disease from a 6MWT in childhood ALL survivors. It refines an already available tool that will strengthen an objective evaluation of the patient.

Following acute pulmonary embolism (PE), a relevant number of patients experience decreased exercise capacity which can be associated with disturbed pulmonary perfusion. Cardiopulmonary exercise testing (CPET) shows several patterns typical for disturbed pulmonary perfusion. Research question: We aimed to examine whether CPET can also provide prognostic information in chronic thromboembolic pulmonary hypertension (CTEPH). Study Design and Methods: We performed a multicenter retrospective chart review in Germany between 2002 and 2020. Patients with CTEPH were included if they had 6 months of follow-up and complete CPET and hemodynamic data. Symptom-limited CPET was performed using a cycle ergometer (ramp or Jones protocol). The association of anthropometric data, comorbidities, symptoms, lung function, and echocardiographic, hemodynamic, and CPET parameters with survival was examined. Mortality prediction models were calculated by Cox regression with backward selection. Results: 345 patients (1532 person-years) were included; 138 underwent surgical treatment (pulmonary endarterectomy or balloon pulmonary angioplasty) and 207 received only non-surgical treatment. During follow-up (median 3.5 years), 78 patients died. The death rate per 1000 person-years was 24.9 and 74.2 in the surgical and non-surgical groups, respectively (p < 0.001). In age- and sex-adjusted Cox regression analyses, CPET parameters including peak oxygen uptake (VO2peak, reflecting cardiopulmonary exercise capacity) were prognostic in the non-surgical group but not in the surgical group. In mortality prediction models, age, sex, VO2peak (% predicted), and carbon monoxide transfer coefficient (% predicted) showed significant prognostic relevance in both the overall cohort and the non-surgical group. In the non-surgical group, Kaplan–Meier analysis showed that patients with VO2peak below 53.4% predicted (threshold identified by receiver operating characteristic analysis) had increased mortality (p = 0.007). Interpretation: The additional measurement of cardiopulmonary exercise capacity by CPET allows a more precise prognostic evaluation in patients with CTEPH. CPET might therefore be helpful for risk-adapted treatment of CTEPH.

Durch die Fortschritte bei der Transplantation wird zunehmend ein längeres Überleben der Patienten ermöglicht. Vor diesem Hintergrund gewinnen während der Zeit der chronischen Erkrankung erworbene Störungen sowie die im Verlauf nach der Transplantation auftretenden Nebenwirkungen an Bedeutung. Bei Beschränkung auf Veränderungen an der Lunge konnte bei Patienten mit chronischem Organversagen (Herz, Leber und Niere) gezeigt werden, dass lungenfunktionell messbare Störungen nachweisbar sind. Diese manifestieren sich vorrangig als Veränderungen der Diffusion, gefolgt von restriktiven und obstruktiven Ventilationsstörungen. Es bisher ungeklärt, inwieweit an deren Ausprägung interstitielle Lungenerkrankungen beteiligt sind. Gegenstand der Arbeit war die Analyse der Art, der Häufigkeit und des Umfanges lungenfunktioneller Störungen sowie die Bestimmung des Anteils computertomografisch nachweisbarer interstitieller Lungenveränderungen (ILD) bei transplantierten Patienten. Dazu wurden 79 Patienten nach Nierentransplantation (NTX), 40 Patienten nach Lebertransplantation (LTX), 40 Patienten nach Herztransplantation (HTX) zwischen 45-83 Monaten nach Transplantation mittels kompletter Lungenfunktionsanalyse und hochauflösender Computertomografie untersucht. Für eine vergleichende Betrachtung wurden 75 Patienten mit einer progressiven systemischen Sklerodermie (als ein Krankheitsbild mit Modellcharakter für ILD) ausgewertet. Die lungenfunktionellen Daten von 642 Patienten, eine spiroergometrische Analyse sowie eine autoptische Untersuchung bei Patienten nach HTX ergänzten die Erhebung. Als Ergebnisse konnten restriktive Ventilationsstörungen bei 2,5 - 10 Prozent in den drei Gruppen transplantierter Patienten nachgewiesen werden. Eine Obstruktion fand sich in vergleichbarer Größenordnung mit Werten zwischen 7,5 - 10 Prozent. Störungen der Diffusion konnten bei Verwendung des Transferfaktors der Lunge (TLCO) bzw. des Transferkoeffizienten (KCO) bei Patienten nach HTX mit 65 bzw. 98 Prozent, nach NTX mit 44 bzw. 68 Prozent und nach LTX mit 32 bzw. 68 Prozent ermittelt werden. Damit waren diese Veränderungen signifikant häufiger bei Patienten nach HTX gegenüber den beiden anderen Gruppen transplantierter Patienten nachweisbar. Computertomografisch nachweisbare ILD wurden nach LTX mit 5 Prozent , nach HTX mit 12 Prozent und nach NTX mit 24 Prozent gefunden. Damit konnte eine signifikant unterschiedliche Häufigkeit bei Patienten nach LTX und NTX festgestellt werden. Bei keiner der untersuchten Gruppen konnte eine signifikante Korrelation zwischen den Befunden der Diffusionsstörungen und dem Nachweis der ILD erfasst werden. Bei der Modellerkrankung waren die radiologischen Befunde häufiger nachweisbar, jedoch qualitativ gleich. Die Daten der 642 Patienten nach HTX zeigten eine konstante Häufigkeit von Diffusionsein-schränkungen, die unabhängig von der Zeit nach Transplantation waren. Die spiroergometrische Analyse nach HTX dokumentierte bei 92 Prozent der Patienten eine eingeschränkte kardiopulmonale Leistungsfähigkeit, wobei daran eine ventilatorische Begrenzung ursächlich nicht beteiligt war. Bei der autoptischen Untersuchung nach HTX fanden sich in 56 Prozent der untersuchten Fälle eine Verbreiterung des Interstitiums der Lunge sowie in 94 Prozent der Fälle Veränderungen an den Blutgefäßen. Die vorliegenden Daten erlauben die Aussage, dass bei transplantierten Patienten Diffusionsstörungen in relevantem Umfang nachweisbar waren. Diese stehen in keinem ursächlichem Zusammenhang mit den geringgradig computertomografisch nachweisbaren interstitiellen Veränderungen. Somit wird mit den Daten die hypothetische Annahme einer vorrangig gefäßbedingten Einschränkung der Diffusion bei den transplantierten Patienten gestützt. / Progress made in transplantation medicine is increasingly leading to longer survival of patients. This means that impairment acquired during the time of chronic illness and side effects during the postoperative course are increasingly significant. Considering pulmonary changes, it was shown that in patients with chronic organ failure (heart, liver, kidneys) impairment of lung function was measurable. This manifests mainly as changes in diffusion, followed by restrictive and obstructive ventilatory impairment. It is to date unclear to what extent interstitial lung disease is involved. This study analyzes the kind, prevalence and extent of lung impairment and the role of interstitial lung disease (ILD) revealed by computed tomography in transplanted patients. For this purpose we examined 79 patients after kidney transplantation (KTX), 40 patients after liver transplantation (LTX) and 40 patients after heart transplantation (HTX) between 45 and 83 months after transplantation by means of comprehensive lung function analysis and high-resolution computed tomography. For purposes of comparison, 75 patients with progressive systemic sclerodermia (chosen because of its exemplary nature for ILD) were evaluated. The study also includes lung function data for 642 patients, an analysis of exercise testing and an autopsy investigation of 73 patients after HTX. The results showed restrictive ventilatory impairment of 2.5-10% in the three groups of transplanted patients. The values for obstruction were similar at between 7.5 and 10%. Taking into account the lung transfer factor (TLCO) and the transfer coefficient (KCO), diffusion impairment was calculated to be 65 and 98% respectively in HTX patients, 44 and 68 % in KTX patients and 32 and 68% in LTX patients. These changes were therefore shown to be significantly more common in patients after HTX than in the other two patient groups. ILD revealed by computed tomography was 5% after LTX, 12% after HTX and 24% after KTX, i.e. a significantly different occurrence was found in patients after LTX and KTX. In none of the groups was a significant correlation between diffusion impairment data and ILD shown. In the sclerodermia group ILD could be shown more often than in the transplanted patients but corresponded in quality. The data of the 642 patients after HTX showed a constant incidence of diffusion impairment independent of the posttransplant time. The analysis of exercise testing established in patients after HTX restricted cardiopulmonary function, of which ventilatory impairment was not the cause. The autopsy investigation of patients after HTX showed widening of the pulmonary interstitium in 56% and changes in the blood vessels in 94% of the cases investigated. The data studied show that diffusion impairment was present to a relevant extent in transplanted patients. This impairment has no causative correlation with the interstitial changes shown by computed tomography to be minimal. Therefore the data support the hypothesis of diffusion impairment in transplanted patients being caused mainly by vascular changes.