Background: Even though specific agents for the treatment of patients with pulmonary hypertension (PH) are available, in PH patients, physical capacity and quality of life (QoL) are often restricted and survival is reduced. Objectives: This study prospectively investigated the long-term effects of respiratory and exercise training in patients with severe chronic PH regarding safety, time to clinical worsening and survival. Methods: Fifty-eight consecutive patients with severe PH on stable disease-targeted medication received exercise and respiratory training in hospital for 3 weeks and continued at home. They were prospectively followed for 24 ± 12 months. Primary endpoints were time to clinical worsening and survival. Adverse events and changes in the 6-min walking test, QoL, WHO functional class and gas exchange were secondary endpoints and were evaluated at baseline and at weeks 3 and 15. Results: All patients tolerated the exercise training well without severe adverse events. In week 15, 6-min walking test results were significantly improved compared to baseline (by 84 ± 49 m, p < 0.001), as well as QoL scores, WHO functional class (from 2.9 ± 0.5 to 2.6 ± 0.6, p < 0.01), peak oxygen consumption (from 12.5 ± 3.0 to 14.6 ± 3.9 ml/min/kg, p < 0.001), heart rate at rest (from 75 ± 12 to 61 ± 18 beats/min, p < 0.001) and maximal workload (from 65 ± 21 to 80 ± 25 W, p < 0.001). Survival at 1 and 2 years was 100 and 95%, respectively. Fifteen events occurred during the follow-up. Conclusion: This study indicates that exercise and respiratory training as add-on to medical treatment may improve exercise capacity and QoL, and that they have a good long-term safety in the described setting. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Doctorat en Sciences biomédicales et pharmaceutiques / info:eu-repo/semantics/nonPublished

Indiana University-Purdue University Indianapolis (IUPUI) / 17-β estradiol (E2) exerts protective effects in hypoxia-induced pulmonary hypertension (HPH) via endothelial cell estrogen receptor (ER)-dependent mechanisms. However, the effects of hypoxia on ER expression in the pulmonary-right ventricle (RV) axis remain unknown. Based on previous data suggesting a role of ER-β in mediating E2 protection, we hypothesized that hypoxia selectively up-regulates ER-β in the lung and pulmonary endothelial cells. In our Male Sprague-Dawley rat model, chronic hypoxia exposure (10% FiO2) resulted in a robust HPH phenotype associated with significant increases in ER- β but not ER-α protein in the lung via western blotting. More importantly, this hypoxia-induced ER-β increase was not replicated in the RV, left ventricle (LV) or in the liver. Hence, hypoxia-induced ER-β up-regulation appears to be lung-specific. Ex vivo, hypoxia exposure time-dependently up-regulated ER-β but not ER-α in cultured primary rat pulmonary artery endothelial cells (RPAECs) exposed to hypoxia (1% O2) for 4, 24 or 72h. Furthermore, the hypoxia induced ER-β protein abundance, while not accompanied by increases in its own transcript, was associated with ER-β nuclear translocation, suggesting increase in activity as well as post-transcriptional up-regulation of ER-β. Indeed, the requirement for ER-β activation was indicated in hypoxic ER-βKO mice where administration of E2 failed to inhibit hypoxia-induced pro-proliferative ERK1/2 signaling. Interestingly, HIF-1α accumulation was noted in lung tissue of hypoxic ER-βKO mice; consistent with previously reported negative feedback of ER-β on HIF-1α protein and transcriptional activation. In RAPECs, HIF-1 stabilization and overexpression did not replicate the effects of ER- β up-regulation seen in gas hypoxia; suggestive that HIF-1α is not sufficient for ER-β up- regulation. Similarly, HIF-1 inhibition with chetomin did not result in ER-β down-regulation. HIF-1α knockdown in RPAECs in hypoxic conditions is currently being investigated. Hypoxia increases ER- β, but not ER-α in the lung and lung vascular cells. Interpreted in context of beneficial effects of E2 on hypoxic PA and RV remodeling, our data suggest a protective role for ER-β in HPH. The mechanisms by which hypoxia increases ER-β appears to be post-transcriptional and HIF-1α independent. Elucidating hypoxia-related ER-β signaling pathways in PAECs may reveal novel therapeutic targets in HPH.

Introduction: La circulation extracorporelle (CEC) peut entraîner une dysfonction endothéliale pulmonaire et l’hypertension pulmonaire. Le SN50 agit au niveau de la signalisation cellulaire pour prévenir ces réactions à la CEC et pourrait renverser la dysfonction endothéliale pulmonaire post-CEC sans effets néfastes sur l’hémodynamie. Méthodes: Quatre groups de porcs ont reçu un parmi quatre traîtements avant de subir 90 minutes de CEC et 60 minutes de reperfusion: (1) milrinone nébulisé; (2) sildenafil nébulisé; (3) placebo nébulisé; et (4) SN-50 intraveineux. Un monitoring hémodynamique invasif a été utilisé. La réactivité vasculaire des artères pulmonaires de deuxième ordre a été évaluée face à l’acétylcholine et la bradykinine. Résultats: Le sildénafil produit une augmentation significative de la pression de l’artère pulmonaire (PAP) moyenne à 60 minutes de reperfusion par rapport au début de la chirurgie. Les relaxations dépendantes de l’endothélium face à la bradykinine étaient meilleurs dans les groupes milrinone et SN-50 et surtout dans le groupe sildénafil par rapport au groupe placébo. Le SN-50 produisait de moins bonnes relaxations dépendantes de l’endothélium face à l’acétylcholine que les autres traitements incluant placébo. Conclusion: Le sildénafil prévient mieux la dysfonction endothéliale pulmonaire que les autres traitements. Les bénéfices du SN-50 sont possiblement sous-estimés vu que la dose n’a pas pu être ajustée à la durée de CEC. Le sildenafil inhalé mérite une étude plus importante chez l’humain et le SN-50 dans un model de CEC animal. / Background: Cardiopulmonary bypass (CPB) can lead to pulmonary endothelial dysfunction and consequent pulmonary hypertension. The novel agent SN-50 acts at the level of the transduction pathway to prevent these responses and may limit or reverse post-CPB pulmonary endothelial dysfunction and pulmonary hypertension without the untoward effects on hemodynamics seen with other known therapies. Methods: Four groups of Landrace-Yorkshire swine that received one of four treatments before undergoing 90 minutes of normothermic CPB and 60 minutes of reperfusion were compared: (1) Nebulized milrinone; (2) nebulized sildenafil; (3) placebo consisting of nebulized NaCl solution; and (4) intravenous SN-50. Invasive hemodynamic monitoring was used throughout all experiments. Vascular reactivity of second-degree pulmonary arteries was evaluated in response to acetylcholine and bradykinin. Results: Sildenafil produced a significant increase in mean pulmonary artery pressure (PAP) at 60 minutes after CPB compared to baseline. Both the sildenafil and milrinone groups had increased mean PAP/MAP ratio at 60 minutes after CPB compared to baseline, however this ratio was not different between the groups. Endothelial-dependent relaxations to bradykinin were improved in the SN-50 and milrinone groups and especially the sildenafil group as compared to placebo. SN-50 produced worse endothelium-dependent relaxations in response to acetylcholine compared to the other groups including placebo. Conclusion: Sildenafil better prevented pulmonary endothelial dysfunction than all other treatments. The improvements seen with SN-50 may be suboptimal as dose could not be titrated to length of CPB. Inhaled sildenafil and SN-50 both merit further study in human trials and animal models, respectively.

L’hypertension pulmonaire (HP) est une maladie dont l’étiologie est inconnue et qui entraîne ultimement une défaillance du ventricule droit (VD) et le décès. L’HP peut être induite chez le rat par la la monocrotaline (MCT), un alcaloïde pyrrolizidique extrait de la plante Crotalaria Spectabilis, causant des lésions à l’endothélium des artères pulmonaires, menant à un épaississement de ces dernières et à une augmentation de la résistance vasculaire. Ceci à pour conséquence de causer une hypertrophie du VD, de l’inflammation, une dysfonction endothéliale NO-dépendante des artères coronariennes et une augmentation des peptides natriurétiques circulants. Objectif: Nous avons testé l’hypothèse selon laquelle l’étiopathologie de l’HP impliquerait le récepteur à ocytocine (OTR) dû à son implication fonctionnelle avec les cytokines inflammatoires et la libération du peptide natriurétique atrial (ANP) et du NO. Méthodes: Des rats mâles Sprague-Dawley pesant 220-250g reçurent une seule injection sous-cutanée de MCT (60 mg/kg). 6 à 7 semaines (46±1 jours) suivant l’injection, les rats furent sacrifiés et l’expression génique et protéique fut déterminée par PCR en temps réel et par western blot, respectivement, dans le VD et le ventricule gauche (VG) Résultats: Les rats traités au MCT démontrèrent une augmentation significative du VD. Une hypertrophie du VD était évidente puisque le ratio du VD sur le VG ainsi que le poids du septum étaient près de 77% plus élevés chez les rats traités au MCT que chez les rats contrôles. Le traitement au MCT augmenta l’expression génique d’ANP (3.7-fois dans le VG et 8-fois dans le VD) ainisi que le NP du cerveau (2.7-fois dans le VG et 10-fois dans le VD). Les transcrits de trois récepteurs de NP augmentèrent significativement (0.3-2 fois) seulement dans le VD. L’expression protéique de la NO synthase (iNOS) fut également augmentée de façon sélective dans le VD. Par contre, les transcripts de NOS endothéliale et de NOS neuronale étaient plus élevés (0.5-2 fold) dans le VG. L’ARNm et l’expression protéique d’OTR furent diminués de 50% dans le VD, tandis qu’une augmentation de l’expression des cytokines IL-1β and IL-6 fut observée. L’ARNm de Nab1, un marqueur d’hypertrophie pathologique, fut augmentée de deux-fois dans le VD. Conclusion: L’augmentation d’expression génique de NP dans le VD des rats traités au MCT est associée à une augmentation des transcripts du récepteur NP, suggérant une action locale de NP dans le VD durant l’HP. L’expression d’OTR est atténuée dans le VD, possiblement par des cytokines inflammatoires puisque le promoteur du gène de l’OTR contient de multiples éléments de réponse aux interleukines. Diminuer l’expression d’OTR dans le VD durant l’hypertension pulmonaire pourrait influencer de manière positive la fonction cardiaque car l’OTR régule la contractilité et le rythme cardiaque. Mots clés: hypertension pulmonaire, hypertrophie du ventricule droit monocrotaline, récepteur à ocytocine, inflammation, peptides natriurétiques. / Pulmonary hypertension (PH) is a disease of unknown etiology that ultimately causes failure of right ventricle (RV) with a lethal outcome. PH can be induced in the rat with monocrotaline (MCT), a pyrrolizidine alkaloid from the plant Crotolaria spectabilis that damages the pulmonary artery endothelium leading to thickening of the pulmonary arteries and increased vascular resistance. This subsequently results in RV hypertrophy, inflammation, nitric oxide (NO)-associated coronary endothelial dysfunction and increment of natriuretic peptides (NP) in the circulation. Objective: We verified hypothesis that the etiopathogenesis of PH involves the oxytocin receptor (OTR) because of its functional association with inflammatory cytokines and release of atrial natriuretic peptide (ANP) and NO. Methods: Male Sprague-Dawley rats weighing 220-250g received a single subcutaneous injection of 60 mg/kg of MCT. Six to 7 weeks (46±1 days) following the injection, rats were sacrificed and gene and protein expression were detected by real-time PCR and western-blot analysis, respectively, in the RV and LV (left ventricle). Results: MCT-treated rats displayed significant increases in RV weight. RV hypertrophy was evident as the ratio of the RV to LV plus septum weight was nearly 77% higher in MCT-treated rats compared to control rats. MCT treatment increased transcripts of ANP (3.7-fold in the LV and 8-fold in RV) and brain NP (2.7-fold in the LV and 10-fold in RV). Transcripts for three NP receptors significantly increased (0.3-2 fold) only in the RV. iNOS (inducible NO synthase) protein expression also increased selectively in the RV. In contrast, the endothelial NOS and neural NOS transcripts heightened (0.5-2 fold) in the LV. Both OTR mRNA and protein were decreased by 50% in the RV, whereas an up-regulation of cytokines IL-1β and IL-6 was observed. Nab1 mRNA, a marker of pathological hypertrophy, increased two-fold in the RV. Conclusion: Increased gene expression of NP in the RV of the MCT-treated rat correlates with upregulation of NP receptor transcripts indicating local NP action in the RV during PH. OTR expression is decreased in the RV possibly by inflammatory cytokines, IL-1 and IL-6 because OTR promoter region contains multiple putative interleukin-response elements. Lowering OTR in RV during pulmonary hypertension can influence cardiac function since OT regulates heart rate and cardiac contractility and is linked with cardioprotective system ANP and NO. Keywords: pulmonary hypertension, right ventricular hypertrophy, monocrotaline, oxytocin receptor, inflammation, natriuretic peptides.

La circulation extracorporelle (CEC) déclenche une réaction inflammatoire systémique, un dommage d’ischémie-reperfusion (I-R) et une dysfonction de l’endothélium dans la circulation pulmonaire. L’hypertension pulmonaire (HTP) est la conséquence de cette cascade de réactions. Cette HTP augmente le travail du ventricule droit et peut causer sa dysfonction, un sevrage difficile de la CEC et une augmentation des besoins de vasopresseurs après la chirurgie cardiaque. L’administration de milrinone et d’époprosténol inhalés a démontré une réduction de la dysfonction endothéliale dans l’artère pulmonaire. Le but de ce travail est d’évaluer différents types de nébulisateur pour l’administration de la milrinone et d’évaluer l’effet du traitement préventif de la combinaison de milrinone et époprosténol inhalés sur les résultats postopératoires en chirurgie cardiaque. Deux études ont été conduites. Dans la première, trois groupes de porcelets ont été comparés : (1) groupe milrinone avec nébulisateur ultrasonique ; CEC et reperfusion précédées par 2,5 mg de milrinone inhalée, (2) goupe milrinone avec nébulisateur à simple jet ; CEC et reperfusion précédées par 2,5 mg de milrinone inhalée et (3) groupe contrôle ; CEC et reperfusion sans traitement. Durant la procédure, les paramètres hémodynamiques, biochimiques et hématologiques ont été mesurés. Après sacrifice, la relaxation endothélium dépendante de l’artère pulmonaire à l’acétylcholine et à la bradykinine a été étudiée en chambres d’organe. Nous avons noté une amélioration de la relaxation de l’endothélium à la bradykinine et à l’acétylcholine dans le groupe avec inhalation de milrinone avec le nébulisateur ultrasonique. Dans la deuxième étude, une analyse rétrospective de 60 patients à haut risque chirurgical atteints d’HTP et opérés à l’Institut de Cardiologie de Montréal à été effectuée. Deux groupes ont été comparés : (1) 40 patients ayant reçu la combinaison de milrinone et d’époprosténol inhalés avant la CEC (groupe traitement) et (2) 20 patients avec des caractéristiques préopératoires n’ayant reçu aucun traitement inhalé avant la CEC (groupe contrôle). Nous avons observé que les besoins en support pharmacologique vasoactif était réduit à 12 heures et à 24 heures postopératoires dans le groupe traitement. L’utilisation de la nébulisation ultrasonique a un impact favorable sur l’endothélium de l’artère pulmonaire après la CEC lorsque comparée à la nébulisation standard à simple jet. Le traitement préventif des patients atteints d’HTP avec la combinaison de milrinone et d’époprosténol inhalés avant la CEC est associé avec une diminution importante des besoins de support vasoactif aux soins intensifs dans les 24 premières heures après la chirurgie. / Cardiopulmonary bypass (CPB) triggers a systemic inflammatory response, an ischemia-reperfusion (I-R) injury and endothelial dysfunction in the pulmonary circulation. Pulmonary hypertension (PH) is a consequence of this insult. The latter increases right ventricle work and may cause difficult separation from cardiopulmonary bypass (CPB) and increased vasoactive requirements after cardiac surgery. Administration of inhaled milrinone or epoprostenol has been shown to reduce endothelial dysfunction in the pulmonary artery. The aim of this work is to evaluate different nebulisators for the administration of milrinone and to evaluate the effect of pre-emptive treatment with inhaled milrinone and epoprostenol on postoperative outcome in cardiac surgery. Two different studies were done. In the first, three groups of swine were compared: (1) ultrasonic nebulisator inhaled milrinone group; CPB and reperfusion preceded by 2.5 mg inhaled milrinone, (2) simple jet nebulisator inhaled milrinone group; CPB and reperfusion preceded by 2.5 mg inhaled milrinone, and (3) control group; CBP 90 minutes followed by 60 minutes of reperfusion without treatment. During the procedure, hemodynamic, biochemical and hematologic parameters were measured. After sacrifice, pulmonary arterial endothelium-dependent relaxations to acetylcholine and bradykinin were studied in organ chamber experiments. There was a greater improvement in endothelium-dependent relaxations to bradykinin and acetylcholine in the ultrasonic nebuliser inhaled milrinone group compared with the control group and the simple jet nebulisator inhaled milrinone group. In the second study, a retrospective analysis of 60 high-risk surgical patients with PH operated at the Montreal Heart Institute was conducted. Two groups were compared: (1) 40 patients received both inhaled milrinone and inhaled epoprostenol before CPB (treatment group); (2) 20 patients with equivalent preoperative data did not receive any inhaled medication before CPB during the same period (control group). Post-operative vasoactive requirement was reduced at 12 hours and 24 hours post-operatively in the treatment group. Use of ultrasonic nebulisation has a favourable impact on the pulmonary endothelial dysfunction induced by CPB when compared to the simple jet nebulisation traditionally used. Pre-emptive treatment of PH with a combination of inhaled milrinone and epoprostenol prior to CPB was associated with a significant reduction in vasoactive support in the intensive care unit during the first 24 hours after cardiac surgery.

Introduction: La circulation extracorporelle (CEC) peut entraîner une dysfonction endothéliale pulmonaire et l’hypertension pulmonaire. Le SN50 agit au niveau de la signalisation cellulaire pour prévenir ces réactions à la CEC et pourrait renverser la dysfonction endothéliale pulmonaire post-CEC sans effets néfastes sur l’hémodynamie. Méthodes: Quatre groups de porcs ont reçu un parmi quatre traîtements avant de subir 90 minutes de CEC et 60 minutes de reperfusion: (1) milrinone nébulisé; (2) sildenafil nébulisé; (3) placebo nébulisé; et (4) SN-50 intraveineux. Un monitoring hémodynamique invasif a été utilisé. La réactivité vasculaire des artères pulmonaires de deuxième ordre a été évaluée face à l’acétylcholine et la bradykinine. Résultats: Le sildénafil produit une augmentation significative de la pression de l’artère pulmonaire (PAP) moyenne à 60 minutes de reperfusion par rapport au début de la chirurgie. Les relaxations dépendantes de l’endothélium face à la bradykinine étaient meilleurs dans les groupes milrinone et SN-50 et surtout dans le groupe sildénafil par rapport au groupe placébo. Le SN-50 produisait de moins bonnes relaxations dépendantes de l’endothélium face à l’acétylcholine que les autres traitements incluant placébo. Conclusion: Le sildénafil prévient mieux la dysfonction endothéliale pulmonaire que les autres traitements. Les bénéfices du SN-50 sont possiblement sous-estimés vu que la dose n’a pas pu être ajustée à la durée de CEC. Le sildenafil inhalé mérite une étude plus importante chez l’humain et le SN-50 dans un model de CEC animal. / Background: Cardiopulmonary bypass (CPB) can lead to pulmonary endothelial dysfunction and consequent pulmonary hypertension. The novel agent SN-50 acts at the level of the transduction pathway to prevent these responses and may limit or reverse post-CPB pulmonary endothelial dysfunction and pulmonary hypertension without the untoward effects on hemodynamics seen with other known therapies. Methods: Four groups of Landrace-Yorkshire swine that received one of four treatments before undergoing 90 minutes of normothermic CPB and 60 minutes of reperfusion were compared: (1) Nebulized milrinone; (2) nebulized sildenafil; (3) placebo consisting of nebulized NaCl solution; and (4) intravenous SN-50. Invasive hemodynamic monitoring was used throughout all experiments. Vascular reactivity of second-degree pulmonary arteries was evaluated in response to acetylcholine and bradykinin. Results: Sildenafil produced a significant increase in mean pulmonary artery pressure (PAP) at 60 minutes after CPB compared to baseline. Both the sildenafil and milrinone groups had increased mean PAP/MAP ratio at 60 minutes after CPB compared to baseline, however this ratio was not different between the groups. Endothelial-dependent relaxations to bradykinin were improved in the SN-50 and milrinone groups and especially the sildenafil group as compared to placebo. SN-50 produced worse endothelium-dependent relaxations in response to acetylcholine compared to the other groups including placebo. Conclusion: Sildenafil better prevented pulmonary endothelial dysfunction than all other treatments. The improvements seen with SN-50 may be suboptimal as dose could not be titrated to length of CPB. Inhaled sildenafil and SN-50 both merit further study in human trials and animal models, respectively.

La circulation extracorporelle (CEC) est une technique utilisée en chirurgie cardiaque effectuée des milliers de fois chaque jour à travers le monde. L’instabilité hémodynamique associée au sevrage de la CEC difficile constitue la principale cause de mortalité en chirurgie cardiaque et l’hypertension pulmonaire (HP) a été identifiée comme un des facteurs de risque les plus importants. Récemment, une hypothèse a été émise suggérant que l'administration prophylactique (avant la CEC) de la milrinone par inhalation puisse avoir un effet préventif et faciliter le sevrage de la CEC chez les patients atteints d’HP. Toutefois, cette indication et voie d'administration pour la milrinone n'ont pas encore été approuvées par les organismes réglementaires. Jusqu'à présent, la recherche clinique sur la milrinone inhalée s’est principalement concentrée sur l’efficacité hémodynamique et l'innocuité chez les patients cardiaques, bien qu’aucun biomarqueur n’ait encore été établi. La dose la plus appropriée pour l’administration par nébulisation n'a pas été déterminée, de même que la caractérisation des profils pharmacocinétiques (PK) et pharmacodynamiques (PD) suite à l'inhalation. L'objectif de notre recherche consistait à caractériser la relation exposition-réponse de la milrinone inhalée administrée chez les patients subissant une chirurgie cardiaque sous CEC. Une méthode analytique par chromatographie liquide à haute performance couplée à un détecteur ultraviolet (HPLC-UV) a été optimisée et validée pour le dosage de la milrinone plasmatique suite à l’inhalation et s’est avérée sensible et précise. La limite de quantification (LLOQ) était de 1.25 ng/ml avec des valeurs de précision intra- et inter-dosage moyennes (CV%) <8%. Des patients souffrant d’HP pour lesquels une chirurgie cardiaque sous CEC était prévue ont d’abord été recrutés pour une étude pilote (n=12) et, par la suite, pour une étude à plus grande échelle (n=28) où la milrinone (5 mg) était administrée par inhalation pré-CEC. Dans l'étude pilote, nous avons comparé l'exposition systémique de la milrinone peu après son administration avec un nébuliseur pneumatique ou un nébuliseur à tamis vibrant. L’efficacité des nébuliseurs en termes de dose émise et dose inhalée a également été déterminée in vitro. Dans l'étude à plus grande échelle conduite en utilisant exclusivement le nébuliseur à tamis vibrant, la dose inhalée in vivo a été estimée et le profil pharmacocinétique de la milrinone inhalée a été pleinement caractérisé aux niveaux plasmatique et urinaire. Le ratio de la pression artérielle moyenne sur la pression artérielle pulmonaire moyenne (PAm/PAPm) a été choisi comme biomarqueur PD. La relation exposition-réponse de la milrinone a été caractérisée pendant la période d'inhalation en étudiant la relation entre l'aire sous la courbe de l’effet (ASCE) et l’aire sous la courbe des concentrations plasmatiques (ASC) de chacun des patients. Enfin, le ratio PAm/PAPm a été exploré comme un prédicteur potentiel de sortie de CEC difficile dans un modèle de régression logistique. Les expériences in vitro ont démontré que les doses émises étaient similaires pour les nébuliseurs pneumatique (64%) et à tamis vibrant (68%). Cependant, la dose inhalée était 2-3 fois supérieure (46% vs 17%) avec le nébuliseur à tamis vibrant, et ce, en accord avec les concentrations plasmatiques. Chez les patients, en raison des variations au niveau des facteurs liés au circuit et au ventilateur causant une plus grande dose expirée, la dose inhalée a été estimée inférieure (30%) et cela a été confirmé après récupération de la dose de milrinone dans l'urine 24 h (26%). Les concentrations plasmatiques maximales (Cmax: 41-189 ng/ml) et l'ampleur de la réponse maximale ΔRmax-R0 (0-65%) ont été observées à la fin de l'inhalation (10-30 min). Les données obtenues suite aux analyses PK sont en accord avec les données publiées pour la milrinone intraveineuse. Après la période d'inhalation, les ASCE individuelles étaient directement reliées aux ASC (P=0.045). Enfin, notre biomarqueur PD ainsi que la durée de CEC ont été identifiés comme des prédicteurs significatifs de la sortie de CEC difficile. La comparaison des ASC et ASCE correspondantes a fourni des données préliminaires supportant une preuve de concept pour l'utilisation du ratio PAm/PAPm comme biomarqueur PD prometteur et justifie de futures études PK/PD. Nous avons pu démontrer que la variation du ratio PAm/PAPm en réponse à la milrinone inhalée contribue à la prévention de la sortie de CEC difficile. / Cardiopulmonary bypass (CPB) is a technique used during cardiac surgery performed thousands of times each day worldwide. Hemodynamic complications associated with difficult separation from CPB represent a leading cause of mortality in cardiac surgery and pulmonary hypertension (PH) was identified as one of the most important predictor and risk factor. Recently, inhaled milrinone administration prior to CPB was hypothesized to have a preventive effect and facilitate separation from CPB in patients with PH. However, this indication and route of administration have not yet been approved by regulatory agencies for milrinone. So far, research efforts on inhaled milrinone have mainly focused on evidence supporting hemodynamic efficacy and safety in cardiac patients although no biomarker has been established. The most appropriate dose for nebulization has never been determined, nor have pharmacokinetic (PK) and pharmacodynamic (PD) profiles been characterized after inhalation. The objective of the current research consisted of characterizing the exposure-response relationship for milrinone administered by inhalation in patients undergoing cardiac surgery. An improved high-performance liquid chromatography (HPLC) analytical assay using UV detection was validated for the quantification of milrinone in plasma after inhalation and proved to be sensitive and accurate. The lower limit of quantification (LLOQ) was 1.25 ng/ml with mean intra-assay and inter-assay precisions (CV%) <8%. Pulmonary hypertensive patients scheduled for cardiac surgery with CPB were first recruited for a pilot (n=12) and, subsequently, a full-scale (n=28) study where milrinone (5mg) was administered by inhalation pre-CPB. In the pilot study, milrinone early systemic exposure was investigated using a jet nebulizer or a mesh nebulizer. Nebulizers performance in terms of emitted and inhaled doses were also determined in vitro. In the full-scale study, using a mesh nebulizer exclusively, in vivo inhaled dose was estimated and milrinone definite pharmacokinetics fully characterized based on blood sampling and urine collection. Mean arterial pressure to mean pulmonary arterial pressure ratio (mAP/mPAP) was selected as the PD biomarker. Milrinone exposure-response relationship was characterized during the inhalation period by studying the relationship between individual area under the effect-time curve (AUEC) and corresponding area under the plasma concentration-time curve (AUC). Finally, the mAP/mPAP ratio, among other variables, was explored as a potential predictor of difficult separation from bypass in a multiple logistic regression model. In vitro experiments demonstrated that emitted doses were similar for the jet (64%) and the mesh (68.0%) nebulizers. However, the inhaled dose was 2-3 fold higher (46% vs 17%) after mesh nebulization, which was in agreement with plasma concentrations. In patients, due to variations in circuit-related and ventilator-related factors, the inhaled dose was estimated to be lower (30%) and this was confirmed by 24-h recovery in urine (26%). Milrinone peak plasma concentrations (Cmax: 41-189 ng/ml) and magnitude of peak response ΔRmax-R0 (0-65%) were observed at the end of inhalation (10-30 min). Data obtained from PK analysis agreed with published data for intravenous milrinone. After the inhalation period, individual AUEC were directly related to AUC (P=0.045). Finally, our PD biomarker, expressed as ΔRmax-R0, as well as CPB duration, were both identified as significant predictors of DSB. The comparison of corresponding AUC and AUEC provided preliminary evidence of a proof of concept for the use of the mAP/mPAP ratio as a promising PD biomarker and warrants future PK/PD studies. Indeed, mAP/mPAP ratio variation in response to inhaled milrinone was found to contribute in the prevention of DSB.

INTRODUÇÃO: A hipertensão pulmonar tromboembólica crônica (HPTEC) é uma doença vascular pulmonar progressiva, cuja incidência varia de 0,56% a 3,2% em indivíduos com embolia pulmonar aguda (EPA) recorrente. Apesar do avanço nas opções de tratamento para HPTEC, a tromboendarterectomia pulmonar (TEAP) continua sendo padrão ouro, levando a melhora hemodinâmica e aumento da sobrevida. OBJETIVOS: Avaliar o impacto que mudanças técnicas intraoperatórias implementadas tiveram na evolução dos pacientes submetidos à TEAP em relação à morbimortalidade imediata e tardia, e também sobre o desenvolvimento do ato operatório. MÉTODOS: Estudo retrospectivo em portadores de HPTEC, submetidos à TEAP, no período de janeiro/2007 a maio/2016, divididos em 3 grupos, de acordo com intervenções implementadas. A 1ª intervenção consistiu em mudanças na circulação extracorpórea (CEC) e no tempo de parada circulatória total (PCT), e a 2ª intervenção incluiu alterações na CEC, técnicas anestésica e cirúrgica. A avaliação dos dados incluiu análise univariada para associações entre intervenções com variáveis de morbimortalidade e técnica operatória. O modelo de regressão multivariado foi aplicado para validar se as melhorias resultaram das intervenções implementadas. A análise de sobrevida foi feita por Kaplan-Meier. RESULTADOS: Foram avaliados 102 indivíduos, 62,8% mulheres, idade média de 49,1±14,8 anos, 65,7% estavam em classe funcional III-IV (NYHA). A avaliação hemodinâmica demonstrou hipertensão pulmonar importante, com valores médios elevados de pressão média na artéria pulmonar (PmAP; G1=52,9±14,45mmHg; G2=53,2±12,4mmHg; G3=53,3±12,5mmHg, p=0,992) e resistência vascular pulmonar (RVP; G1=828,4±295,13 dynas.s.cm-5; G2=838,9±428,4 dynas.s.cm-5; G3=969±417,3 dynas.s.cm-5, p=0,313). Os pacientes submetidos à TEAP mostraram aumento do tempo total de CEC entre os grupos (G1=192,3±39,4min; G2=251,7±33,4min; G3=298,2±40,2min, p < 0,001), como resultado da padronização dos tempos de esfriamento (G1=47,9±18,5min; G2=66,9±5,9min; G3=70,6±3,7min, p < 0,001), aquecimento (G1=66,8±17,7min; G2=87,2±8,1min; G3=107,7±23,5min, p < 0,001) e reperfusão (G1=25,5±7,6min; G2=20,7±8,4 min; G3=18,6±9,4min, p=0,007). A diminuição do número de operações com mais de 2 PCT (G1= 89%; G2= 60%; G3: 55%, p=0,002) foi decorrente do aumento da duração média de cada PCT (G1=15,5±2,9min; G2=17,8±1,7min; G3=19,2±2,0min, p < 0,001). Complicações pós-operatórias foram observadas em 88,5% dos pacientes, havendo redução significativa das complicações cirúrgicas (p=0,035), infecciosas (p=0,017) e neurológicas com sintomas permanentes (p=0,048) na comparação entre os 3 grupos. No seguimento após a alta, 85% estavam em classe funcional I-II (NYHA), sem melhora hemodinâmica significativa entre os grupos. Após a análise multivariada, o G3 apresentou 4,7 menos chances de complicação cirúrgica que G1 (p=0,034) e tempo de aquecimento menor que 83 minutos aumentou 4 vezes a chance de complicação infecciosa (p=0,002). A redução da mortalidade hospitalar e da sobrevida não foi significativa entre os grupos. CONCLUSÕES: Em relação à morbimortalidade imediata e tardia, o impacto das intervenções foi evidenciado pela redução das complicações neurológicas com sintomas permanentes, complicações cirúrgicas e infecciosas. Em relação ao ato operatório, o impacto foi evidenciado pelo aumento dos tempos totais de CEC, de esfriamento, de aquecimento, tempo médio das PCT, redução nos números de PCT e no tempo total de reperfusão / INTRODUCTION: Chronic thromboembolic pulmonary hypertension (CTEPH) is a progressive pulmonary vascular disease which incidence varies from 0.56% to 3.2% in individuals with recurrent acute pulmonary embolism (APE). Despite advances in treatment options for CTEPH, pulmonary endarterectomy (PE) remains a gold standard, leading to hemodynamic improvement and increased survival. OBJECTIVES: Evaluate the impact of intraoperative technical changes on the evolution of patients submitted to PE related to immediate and late morbimortality, as well as on the development of the operative procedure. METHODS: Retrospective study of patients with CTEPH, submitted to PE, between January 2007 and May 2016, divided into 3 groups, according to the implemented interventions. The first intervention consisted of changes in cardiopulmonary bypass (CPB) and total circulatory arrest time (CAT), and the second intervention included changes in CPB, anaesthetic and surgical techniques. The data analysis included a univariate analysis for associations between interventions with morbidity variables and operative technique. The multivariate regression model was applied to validate whether the improvements resulted from the interventions implemented. Survival analysis was performed using Kaplan-Meier. RESULTS: We evaluated 102 individuals, 62.8% were women, mean age was 49.1 ± 14.8 years, and 65.7% were in functional class III-IV (NYHA). The hemodynamic evaluation showed significant pulmonary hypertension, with mean values of mean pulmonary artery pressure (mPAP, G1 = 52.9 ± 14.45 mmHg, G2 = 53.2 ± 12.4 mmHg, G3 = 53.3 ± 12.5 mmHg, p = 0.992) and pulmonary vascular resistance (PVR, G1 = 828.4 ± 295.13 dynas.s.cm-5, G2 = 838.9 ± 428.4 dynas.s.cm-5, G3 = 969 ± 417.3 dynas.s.cm-5, p = 0.313). The patients submitted to PE showed an increase in the total CPB time between the groups (G1 = 192.3 ± 39.4min, G2 = 251.7 ± 33.4min, G3 = 298.2 ± 40.2min, p < 0.001), as a result of the standardization of cooling times (G1 = 47.9 ± 18.5min, G2 = 66.9 ± 5.9min, G3 = 70.6 ± 3.7min, p < 0.001), heating (G1 = 66.8 ± 17.7min, G2 = 87.2 ± 8.1min, G3 = 107.7 ± 23.5min, p < 0.001) and reperfusion (G1 = 25.5 ± 7.6min, G2 = 20.7 ± 8.4 min, G3 = 18.6 ± 9.4min, p = 0.007). The decrease in the number of operations with more than 2 CAT (G1 = 89%, G2 = 60%, G3: 55%, p = 0.002) was due to the increase in the average duration of each CAT (G1 = 15.5 ± 2, 9min, G2 = 17.8 ± 1.7min, G3 = 19.2 ± 2.0min, p < 0.001). Postoperative complications were observed in 88.5% of the patients, with a significant reduction in surgical (p = 0.035), infectious (p = 0.017) and neurological complications with permanent symptoms (p = 0.048) in the comparison between the three groups. In the post-discharge follow-up, 85% were in functional class I-II (NYHA), with no significant hemodynamic improvement between groups. After the multivariate analysis, G3 presented 4.7 less chance of surgical complication than G1 (p = 0.034) and warming time less than 83 minutes increased 4 times the chance of infectious complication (p = 0.002). The reduction in hospital mortality and survival was not significant between the groups. CONCLUSIONS: Regarding immediate and late morbimortality, the impact of interventions was evidenced by the reduction of neurological complications with permanent symptoms, surgical and infectious complications. Regarding the operative event, the impact was evidenced by the increase in total CPB, cooling, heating, mean CAT time, CAT reduction and total reperfusion time

INTRODUÇÃO: Pacientes pediátricos portadores de defeitos septais cardíacos não restritivos podem apresentar, em cerca de 5% a 10% dos casos, remodelamento vascular pulmonar progressivo, com evolução para hipertensão arterial pulmonar (HAP) de grau moderado ou acentuado. A inflamação e a imunidade exercem papel central na patogênese da HAP, porém são ainda pouco exploradas neste grupo específico de pacientes. O presente estudo, prospectivo, longitudinal e de coorte, teve como objetivo avaliar níveis circulantes de mediadores inflamatórios segundo grupos de pacientes hemodinamicamente distintos. Concomitantemente foram analisadas possíveis correlações com dados histopatológicos e com resposta à intervenção medicamentosa. MÉTODOS: Estabelecida a forte suspeita de hipertensão pulmonar por exame à beira leito, foram incluídos no estudo 47 pacientes, com idade de dois a 37 meses (mediana 10 meses), sendo 32 portadores de síndrome de Down. Pacientes classificados como Grupo 1 (n=16) apresentavam sinais clínicos de hiper-resistência pulmonar e foram aqueles submetidos ao cateterismo cardíaco, com níveis comprovadamente elevados de resistência vascular pulmonar (5,2 (4,2-8,9) U x m2, mediana e intervalo interquartílico). Pacientes classificados como Grupo 2 (n=31) apresentavam sinais clínicos de hiperfluxo com congestão pulmonar, não necessitando de cateterismo pré-operatório. A relação entre fluxo pulmonar e sistêmico (Qp/Qs), estimada por ecocardiografia, foi de 1,9 (1,3-2,6) no Grupo 1 e 2,8 (2,3-3,3) no Grupo 2 (p=0,008). Foram analisadas 36 citocinas séricas através de quimioluminescência. RESULTADOS: Observando-se os pacientes como um todo (n=47), os níveis séricos da quimiocina MIF (macrophage migration inhibitory factor) estavam aumentados (7510±2755 pixels x 5697±2051 pixels em controles pediátricos, média±desvio padrão). Entretanto, os níveis de MIF estiveram especificamente aumentados no Grupo 1 quando comparados ao Grupo 2 e controles (respectivamente, 8494±619 pixels, 6618±477 pixels e 6548±726 pixels, média ajustada para idade±erro padrão, p=0,037). Por outro lado, níveis da quimiocina RANTES (regulated on activation, normal T cell expressed and secreted) estavam aumentados especificamente no Grupo 2 quando comparados ao Grupo 1 e controles (respectivamente, 74183±3865 pixels, 60130±6455 pixels e 59332±3970 pixels, média±erro padrão, p=0,039). Este comportamento foi semelhante quando analisados apenas os pacientes com síndrome de Down. Em todos os pacientes, a quimiocina GRO-Alfa (growth-regulated oncogene alpha) esteve aumentada nos primeiros meses de vida, com subsequente declínio exponencial (R2= -0,47, p < 0,001), enquanto a interleucina 17E (também conhecida como IL-25) apresentou relação direta com a idade (R2=0,44, p=0,002). A interleucina 16 apresentou relação inversa com o fluxo sanguíneo pulmonar (rs= -0,34, p=0,018) e níveis mais elevados em pacientes com evidência de doença vascular avançada em biópsia realizada no intra-operatório (p=0,021). Pacientes do Grupo 1 receberam sildenafila no pré-operatório, o que resultou em aumento do fluxo sanguíneo pulmonar (p=0,012) e da saturação periférica de oxigênio (p=0,010), além de redução dos níveis de interleucina 6 (p=0,027) e ICAM-1 (intercellular adhesion molecule 1) (p=0,011). Não foi observado comportamento particular em pacientes com síndrome de Down. CONCLUSÕES: Os dados apresentados indicam uma relação entre níveis séricos de algumas citocinas e gravidade da doença vascular pulmonar, com potenciais implicações fisiopatológicas e clínicas. Além disso, o envolvimento da interleucina 17E e do MIF enfatizam o papel da resposta imune Th2, já descritas na HAP. Os resultados também permitem um questionamento a respeito das generalizações correntes relacionadas à vasculopatia pulmonar na síndrome de Down, anteriormente considerada como fator de risco em todos os casos / INTRODUCTION: Pediatric patients with nonrestrictive cardiac septal defects may present progressive pulmonary vascular remodeling with progression to pulmonary arterial hypertension (PAH), which might range from moderate to severe in about 5% to 10% of the patients. Inflammation and immunity play a central role in the pathogenesis of PAH, but are still poorly explored in this specific group of patients. This current study - prospective, longitudinal and cohort - was aimed at evaluating circulating levels of inflammatory mediators according to hemodynamically distinct groups of patients. At the same time, possible correlations with histopathological data and response to vasodilator intervention were analyzed. METHODS: After the establishment of a strong suspicion of pulmonary hypertension at bedside, 47 patients aged 2 to 37 months (median 10 months) were included in the study, of which 32 had Down syndrome. Patients classified as Group 1 (n = 16) had clinical signs of elevated pulmonary vascular resistance and were subjected to cardiac catheterization, with proven levels of increased pulmonary vascular resistance (5.2 (4.2-8.9) U x m2, median and interquartile range). Patients classified as Group 2 (n = 31) presented clinical signs of increased blood flow with pulmonary congestion, requiring no preoperative catheterization. The pulmonary to systemic blood flow ratio (Qp/Qs), estimated by echocardiography, was 1.9 (1.3-2.6) in Group 1 and 2.8 (2.3-3.3) in Group 2 (p = 0.008). Thirty-six cytokines and related proteins were analyzed in serum by chemiluminescence. RESULTS: Observing patients as a whole (n = 47), serum levels of the chemokine MIF (macrophage migration inhibitory factor) were increased (7510 ± 2755 pixels x 5697 ± 2051 pixels in pediatric controls, mean ± standard deviation). However, MIF levels were specifically increased in Group 1 when compared to Group 2 and controls (respectively, 8494 ± 619 pixels, 6618 ± 477 pixels and 6548 ± 726 pixels, mean age adjusted ± standard error, p = 0.037). On the other hand, RANTES (regulated on activation, normal T cell expressed and secreted) levels were specifically increased in Group 2 when compared to Group 1 and controls (respectively 74183 ± 3865 pixels, 60130 ± 6455 pixels and 59332 ± 3970 pixels, mean ± standard error, p = 0.039). This behavior was similar when only patients with Down syndrome were analyzed. In all patients, GRO-Alpha (growth-regulated oncogene alpha) was increased in the first months of life, with subsequent exponential decline (R2 = -0.47, p < 0.001), while interleukin 17E (also known as IL-25) presented a direct relationship with age (R2 = 0.44, p=0.002). Interleukin 16 was negatively related to pulmonary blood flow (rs = -0.34, p = 0.018) and was higher in patients with evidence of advanced vascular disease by intraoperative lung biopsy (p = 0.021). Patients in Group 1 received sildenafil in the preoperative period, which resulted in increased pulmonary blood flow (p = 0.012) and peripheral oxygen saturation (p = 0.010), as well as decreased levels of interleukin 6 (p = 0.027) and ICAM-1 (intercellular adhesion molecule 1) (p = 0.011). There was no particular behavior of subjects with Down syndrome at all. CONCLUSION: The presented data indicate a relationship between serum levels of some cytokines and the severity of pulmonary vascular disease, with potential pathophysiological and clinical implications. In addition, the involvement of interleukin 17E and MIF emphasizes the role of Th2 immune response, already described in PAH. The results also raise doubts if Down syndrome should be considered as a risk factor in a generalized way