Introdução: O tromboembolismo é uma grave complicação da fibrilação atrial (FA), particularmente em pacientes que vão se submeter à cardioversão, química ou elétrica. Para reduzir esse risco, os pacientes submetem-se à anticoagulação clássica, que vem sendo praticada há várias décadas. Apesar desta abordagem, em pacientes plenamente anticoagulados, não se conhece a prevalência de trombo ou contraste espontâneo no átrio esquerdo (AE). Por essa razão, alguns autores sugerem a realização do ecotransesofágico (ECOTEE) para confirmar o sucesso do tratamento e reduzir o risco de complicações tromboembólicas após a reversão. Os objetivos deste estudo foram: a) avaliar a prevalência de trombos e contraste espontâneo ao ECOTEE em pacientes que vão ser submetidos à cardioversão sob regime de anticoagulação plena; b) avaliar a incidência de tromboembolismo até 30 dias após o procedimento; c) avaliar a influência das variáveis clínicas (doenças associadas) e do ECOTEE (tamanho e volume indexado do AE, fração de ejeção ventricular; velocidade de fluxo no apêndice atrial esquerdo), além do escore CHA2DS2VASc e níveis de pró-BNP plasmático sobre a formação de trombo/contraste espontâneo. Métodos: Foram incluídos 85 pacientes (62 homens; média de idade 61±12 anos) com FA não valvar com indicação para cardioversão. Todos receberam varfarina com controle da taxa de INR. Quando se considerava o paciente plenamente anticoagulado (INR ente 2 e 3 por três semanas consecutivas), era prescrito um fármaco antiarrítmico (propafenona, sotalol ou amiodarona) cuja escolha se baseou em critérios clínicos. Na ausência de normalização do ritmo, eram encaminhados para cardioversão elétrica (CVE). No dia da CVE, os pacientes submetiam-se ao ECOTEE cujo resultado só era conhecido no dia seguinte após a cardioversão. Os pacientes recebiam alta com anticoagulante e retornavam ao ambulatório após 30 dias quando realizavam outro ECOTEE. Resultados: Todos os pacientes foram cardiovertidos com INR na faixa terapêutica (2,9±0,7). A reversão com fármacos ocorreu em 9/85 pacientes (10,6%); 67/76 pacientes submeteram-se à CVE e, destes, 58/67 (86%) reverteram ao ritmo sinusal. O ECOTEE antes da CVE evidenciou trombo no AE em 8/85 pacientes (9,4%) e contraste espontâneo em 36/85 pacientes (42,3%). Nenhuma variável clínica, escore CHA2DS2VASc, níveis plasmáticos de pró-BNP ou variáveis ecocardiográficas identificou pacientes com maior probabilidade de apresentar trombo/contraste espontâneo no AE. Após 30 dias, houve normalização das variáveis do ECOTEE. Em 5/8 (62,5%) pacientes, os trombos desapareceram e surgiu em outros dois pacientes (2,3%). O contraste espontâneo desapareceu em 24/38 (63%) pacientes. Não houve registro de nenhum caso de tromboembolismo sistêmico em 30 dias. A taxa de recorrência de FA foi de 21%. Conclusões: a) trombo atrial/contraste espontâneo foi detectado em 9,4% da população e nenhuma variável clínica ou ecocardiográfica identificou pacientes de risco; b) houve melhora das variáveis do ECOTEE após a reversão ao ritmo sinusal; d) o sucesso global da cardioversão foi de 88% e a taxa de recorrência de FA de 21% em 30 dias; c) não houve registro de tromboembolismo sistêmico em 30 dias, em ritmo sinusal ou em FA. / Introduction: Thromboembolism is a serious complication of atrial fibrillation (AF), particularly in patients who will undergo chemical or electrical cardioversion. To reduce this risk patients receive classic anticoagulant therapy, which has been practiced for several decades. Despite this approach, it is not known the prevalence of thrombus or spontaneous contrast in the left atrium (LA) in patients fully anticoagulated. For this reason, some authors have recommended the transesophageal echocardiogram (TEECHO) to reduce the risk of thromboembolic complications after cardioversion. The objectives of this study were: a) to evaluate the prevalence of thrombus and spontaneous contrast by TEECHO in patients about to undergo cardioversion under full anticoagulation regime; b) evaluate the incidence of thromboembolism within 30 days after the procedure; c) evaluate the influence of clinical variables (associated diseases) and TEECHO parameters (LA size and LA indexed volume, ventricular ejection fraction, flow velocity in the left atrial appendage), CHA2DS2VASc score and plasma pro-BNP levels on thrombus/spontaneous contrast formation. Methods: We included 85 patients (62 men; mean age 61 ± 12 years) with non-valvular AF referred for cardioversion. All received warfarin with INR control. When considering the patient fully anticoagulated (INR in the range of 2 to 3 for three weeks) it was prescribed an anti-arrhythmic drug (propafenone, sotalol or amiodarone) whose choice was based on clinical criteria. In the absence of normal rhythm, patients were referred for electrical cardioversion (ECV). On the day of ECV, all patients were submitted to the ECOTEE whose result was known only the next day after cardioversion. The patients were discharged with anticoagulant and returned to the clinic after 30 days when another ECOTEE was performed. Results: All patients were cardioverted with INR in the therapeutic range (2.9±0.7). Sinus rhythm was restored with drugs in 9/85 patients (10.6%); 67/76 patients underwent ECV and 58/67 (86%) reverted to sinus rhythm. The TEECHO before cardioversion showed a thrombus in LA in 8/85 patients (9.4%) and spontaneous contrast in 36/85 patients (42.3%). No clinical variable, CHA2DS2VASc score, pro-BNP plasma levels or echocardiography variables identified patients with an increased likelihood of thrombus/spontaneous contrast in LA. After 30 days, there was normalization of TEECHO variables. In 5/8 (62.5%) patients thrombi disappeared and appeared in two patients (2.3%). Spontaneous contrast disappeared in 24/38 (63%) patients. There were no reports of any case of systemic thromboembolism in 30 days. The AF recurrence rate was 21%. Conclusions: a) LA thrombus/ spontaneous contrast were detected in 9.4% of the population and no clinical or echocardiography variable identified patients at risk; b) there was an improvement of TEECHO variables after reversion to sinus rhythm; d) the overall success of cardioversion was 88% and the AF recurrence rate was 21% in 30 days; c) there was no systemic thromboembolism in 30 days, in patients in sinus rhythm or AF.

Abstract: Background: At present, device closure of interatrial communication has become a well established technique in order to adequately treat severe left-to-right shunt associated with ASDs. During the traditional procedure, fluoroscopy with the waist of a compliant balloon is used to determine the appropriate size of the closure device and defect sizing. Choice of adequate closure device using transthoracic echocardiography (TTE) has been hitherto unreported. Methods & Materials: Between December 2002 and October 2004, 40 patients (15 males, 25 females, mean age; 11.7 ¡Ó 7.8 years ) with secundum ASDs underwent transcatheter closure at our institution. In group 1, 30 patients had the procedure by balloon sizing and TTE sizing. In 10 patients (group 2), TTE sizing was used as the sole too l for selecting device size and the device size was chosen to be based on the Amplatzer septal occluder ( ASO ) size and TTE size ratio in group 1. The procedure was performed under continuous transoesophageal echocardiographic monitor with general anesthesia. Results: The correlation was found between TTE and stretched balloon sizing diameter SBD ( y= 1.2645x-1.4465; R²=0.9861 ), and between TTE size and ASO size ( y = 1.3412x-1.2864; R²=0.9929 ) in group 1. In group 2, statistical correlation between TTE and ASO ( y=1.3419x-0.1172; R²=0.9934 ) was also found. Good linear regression between TTE size and ASO chosen size was noted in group 1 and group 2 (R²=0.99).In group 2, successful device implantation was accomplished in all patients whose device size was chosen to be based on the ASO and TTE ratio in group 1. Conclusions: TTE sizing is a safe and ideal method to measure interatrial defect and choose the occluding device respectively. With our experience, the sizing based on the TTE is generally easier than measurement from the balloon sizing.

Introdução: O tromboembolismo é uma grave complicação da fibrilação atrial (FA), particularmente em pacientes que vão se submeter à cardioversão, química ou elétrica. Para reduzir esse risco, os pacientes submetem-se à anticoagulação clássica, que vem sendo praticada há várias décadas. Apesar desta abordagem, em pacientes plenamente anticoagulados, não se conhece a prevalência de trombo ou contraste espontâneo no átrio esquerdo (AE). Por essa razão, alguns autores sugerem a realização do ecotransesofágico (ECOTEE) para confirmar o sucesso do tratamento e reduzir o risco de complicações tromboembólicas após a reversão. Os objetivos deste estudo foram: a) avaliar a prevalência de trombos e contraste espontâneo ao ECOTEE em pacientes que vão ser submetidos à cardioversão sob regime de anticoagulação plena; b) avaliar a incidência de tromboembolismo até 30 dias após o procedimento; c) avaliar a influência das variáveis clínicas (doenças associadas) e do ECOTEE (tamanho e volume indexado do AE, fração de ejeção ventricular; velocidade de fluxo no apêndice atrial esquerdo), além do escore CHA2DS2VASc e níveis de pró-BNP plasmático sobre a formação de trombo/contraste espontâneo. Métodos: Foram incluídos 85 pacientes (62 homens; média de idade 61±12 anos) com FA não valvar com indicação para cardioversão. Todos receberam varfarina com controle da taxa de INR. Quando se considerava o paciente plenamente anticoagulado (INR ente 2 e 3 por três semanas consecutivas), era prescrito um fármaco antiarrítmico (propafenona, sotalol ou amiodarona) cuja escolha se baseou em critérios clínicos. Na ausência de normalização do ritmo, eram encaminhados para cardioversão elétrica (CVE). No dia da CVE, os pacientes submetiam-se ao ECOTEE cujo resultado só era conhecido no dia seguinte após a cardioversão. Os pacientes recebiam alta com anticoagulante e retornavam ao ambulatório após 30 dias quando realizavam outro ECOTEE. Resultados: Todos os pacientes foram cardiovertidos com INR na faixa terapêutica (2,9±0,7). A reversão com fármacos ocorreu em 9/85 pacientes (10,6%); 67/76 pacientes submeteram-se à CVE e, destes, 58/67 (86%) reverteram ao ritmo sinusal. O ECOTEE antes da CVE evidenciou trombo no AE em 8/85 pacientes (9,4%) e contraste espontâneo em 36/85 pacientes (42,3%). Nenhuma variável clínica, escore CHA2DS2VASc, níveis plasmáticos de pró-BNP ou variáveis ecocardiográficas identificou pacientes com maior probabilidade de apresentar trombo/contraste espontâneo no AE. Após 30 dias, houve normalização das variáveis do ECOTEE. Em 5/8 (62,5%) pacientes, os trombos desapareceram e surgiu em outros dois pacientes (2,3%). O contraste espontâneo desapareceu em 24/38 (63%) pacientes. Não houve registro de nenhum caso de tromboembolismo sistêmico em 30 dias. A taxa de recorrência de FA foi de 21%. Conclusões: a) trombo atrial/contraste espontâneo foi detectado em 9,4% da população e nenhuma variável clínica ou ecocardiográfica identificou pacientes de risco; b) houve melhora das variáveis do ECOTEE após a reversão ao ritmo sinusal; d) o sucesso global da cardioversão foi de 88% e a taxa de recorrência de FA de 21% em 30 dias; c) não houve registro de tromboembolismo sistêmico em 30 dias, em ritmo sinusal ou em FA. / Introduction: Thromboembolism is a serious complication of atrial fibrillation (AF), particularly in patients who will undergo chemical or electrical cardioversion. To reduce this risk patients receive classic anticoagulant therapy, which has been practiced for several decades. Despite this approach, it is not known the prevalence of thrombus or spontaneous contrast in the left atrium (LA) in patients fully anticoagulated. For this reason, some authors have recommended the transesophageal echocardiogram (TEECHO) to reduce the risk of thromboembolic complications after cardioversion. The objectives of this study were: a) to evaluate the prevalence of thrombus and spontaneous contrast by TEECHO in patients about to undergo cardioversion under full anticoagulation regime; b) evaluate the incidence of thromboembolism within 30 days after the procedure; c) evaluate the influence of clinical variables (associated diseases) and TEECHO parameters (LA size and LA indexed volume, ventricular ejection fraction, flow velocity in the left atrial appendage), CHA2DS2VASc score and plasma pro-BNP levels on thrombus/spontaneous contrast formation. Methods: We included 85 patients (62 men; mean age 61 ± 12 years) with non-valvular AF referred for cardioversion. All received warfarin with INR control. When considering the patient fully anticoagulated (INR in the range of 2 to 3 for three weeks) it was prescribed an anti-arrhythmic drug (propafenone, sotalol or amiodarone) whose choice was based on clinical criteria. In the absence of normal rhythm, patients were referred for electrical cardioversion (ECV). On the day of ECV, all patients were submitted to the ECOTEE whose result was known only the next day after cardioversion. The patients were discharged with anticoagulant and returned to the clinic after 30 days when another ECOTEE was performed. Results: All patients were cardioverted with INR in the therapeutic range (2.9±0.7). Sinus rhythm was restored with drugs in 9/85 patients (10.6%); 67/76 patients underwent ECV and 58/67 (86%) reverted to sinus rhythm. The TEECHO before cardioversion showed a thrombus in LA in 8/85 patients (9.4%) and spontaneous contrast in 36/85 patients (42.3%). No clinical variable, CHA2DS2VASc score, pro-BNP plasma levels or echocardiography variables identified patients with an increased likelihood of thrombus/spontaneous contrast in LA. After 30 days, there was normalization of TEECHO variables. In 5/8 (62.5%) patients thrombi disappeared and appeared in two patients (2.3%). Spontaneous contrast disappeared in 24/38 (63%) patients. There were no reports of any case of systemic thromboembolism in 30 days. The AF recurrence rate was 21%. Conclusions: a) LA thrombus/ spontaneous contrast were detected in 9.4% of the population and no clinical or echocardiography variable identified patients at risk; b) there was an improvement of TEECHO variables after reversion to sinus rhythm; d) the overall success of cardioversion was 88% and the AF recurrence rate was 21% in 30 days; c) there was no systemic thromboembolism in 30 days, in patients in sinus rhythm or AF.

Simulation based education has been shown to increase the task-specific capability of medical trainees. Transesophageal echocardiography training greatly benefits from the use of simulators. They allow real time scanning of a beating heart and generation of ultrasound images side by side with anatomically accurate virtual model. These simulators are costly and have many limitations. 3D printing technologies have enabled the creation of bespoke phantoms capable of being used as task-trainers. This study aims to compare the ease of use and accuracy of a low-cost patient-specific, Computer-tomography based, 3D printed, echogenic TEE phantom compared to a commercially available echocardiography training mannequin. We hypothesized that a low-cost, 3D printed custom-made, cardiac phantom has comparable image quality, accuracy and usability as existing commercially available echocardiographic phantoms. After Institutional Ethic Research Board approval, we recruited ten American Board – Certified cardiac anesthesiologists and conducted a blinded comparative study divided into two stages. Stage one consisted of image assessment. A set of basic TEE views obtained from the 3D printed and commercial phantom were presented to the participants on a computer screen in random order. For each image, participants will be asked to identify the view, identify the quality of the image on a 1-5 Likert scale compared to the corresponding human view and guess with which phantom it was acquired (1 not at all realistic to patients view and 5 realistic to patients view). Stage two, participants will be asked to use the 3D printed and the commercially available phantom to obtain basic TEE views. In a maximum of 30 minutes. Each view was recorded and assessed for accuracy by two certified echocardiographers. Time needed to acquire each basic view and number of correct views was recorded. Overall usability of the phantoms was assessed through a questionnaire. For all continuous variables, we will calculate mean, median and standard deviation. We use Wilcoxon Signed-Rank test to assess significant differences in the rating of each phantom. All ten participants completed all part of the study. All participants could recognize all of the standard views. The average Likert scale was 3.2 for the 3D printed and 2.9 for the commercial Phantom with no significant difference. The average time to obtain views was 24.5 and 30 sec for the 3D printed and the commercial phantoms respectively statistically significantly in favor of the 3D printed phantom. The qualitative user assessment for ease to obtain the views, probe manipulation, image quality and overall experience were in great favor of the 3D printed phantom. Our Study suggest that the quality of TEE images obtained on the 3D printed phantom are not significantly different from those obtained on the commercial Phantom. The ease of use and time required to complete a basic TEE exam were in favor of the 3D Printed phantom.:Table of Content 1. Bibliographic Description 3 2. Introduction 4 2.1. Perioperative transesophageal echocardiography 4 2.2. Transesophageal echocardiography training 5 2.3. Transesophageal echocardiography simulation 6 2.4. 3D Heart Printing 13 2.5. 3D Segmentation 16 2.6. Development of the study phantom 17 2.7. Study Rationale 18 3. Publication 22 4. Summary 30 5. References 33 6. Appendices 37 6.1. Darstellung des eigenes Beitrags 38 6.2. Erklärung über die eigenständige Abfassung der Arbeit 39 6.3. Lebenslauf 40 6.4. Publikationen und Vorträge 44 6.5. Danksagung 61

<p>Transesophageal echocardiography (TEE) has become a useful tool in monitoring the heart in patients during open-heart surgery. This study was undertaken to evaluate whether it is feasible to use TEE to assess left ventricular myocardial viability in anesthetized patients scheduled for coronary artery bypass grafting (CABG).</p><p>A total of 84 patients were studied. To test myocardial viability, TEE and a low-dose dobutamine stress regimen were used. Echocardiographic data were analyzed off-line using a visual or semiautomatic analysis of segmental left ventricular wall motion (LVWM). Visual assessment was performed by readers blinded to the sequence of events. The agreement between readers in visual analysis of segmental LVWM in the transgastric short-axis view was 73% or higher. Segmental LVWM assessed by TEE was compared to hemodynamic data obtained by thermodilution pulmonary artery catheter (PAC) and coronary angiographic data. Also, using the same low-dose dobutamine stress regimen, TEE findings in the anesthetized patient perioperatively were compared with preoperative transthoracic echocardiography (TTE) findings in the awake patient.</p><p>TEE was found to be feasible and adequate for testing left segmental ventricular viability. A concomitant increase in stroke volume assessed by PAC and decrease in LVWM-score assessed by TEE was found with dobutamine stimulation. Abnormal segmental LVWM corresponded to angiographically stenosed supplying coronary artery vessels. During dobutamine stimulation, 69% of the corresponding segments responded which is a sign of viability. The LVWM response to preoperative TTE and perioperative TEE dobutamine stress was comparable except for a significant difference in the apical segments.</p><p>This study showed that perioperative TEE dobutamine stress could be used to test left ventricular viability and was also a valuable supplement to PAC, angiography and TTE. The acquired knowledge is important and suggest that further development of transesophageal ultrasound technology is warranted.</p>

Transesophageal echocardiography (TEE) has become a useful tool in monitoring the heart in patients during open-heart surgery. This study was undertaken to evaluate whether it is feasible to use TEE to assess left ventricular myocardial viability in anesthetized patients scheduled for coronary artery bypass grafting (CABG). A total of 84 patients were studied. To test myocardial viability, TEE and a low-dose dobutamine stress regimen were used. Echocardiographic data were analyzed off-line using a visual or semiautomatic analysis of segmental left ventricular wall motion (LVWM). Visual assessment was performed by readers blinded to the sequence of events. The agreement between readers in visual analysis of segmental LVWM in the transgastric short-axis view was 73% or higher. Segmental LVWM assessed by TEE was compared to hemodynamic data obtained by thermodilution pulmonary artery catheter (PAC) and coronary angiographic data. Also, using the same low-dose dobutamine stress regimen, TEE findings in the anesthetized patient perioperatively were compared with preoperative transthoracic echocardiography (TTE) findings in the awake patient. TEE was found to be feasible and adequate for testing left segmental ventricular viability. A concomitant increase in stroke volume assessed by PAC and decrease in LVWM-score assessed by TEE was found with dobutamine stimulation. Abnormal segmental LVWM corresponded to angiographically stenosed supplying coronary artery vessels. During dobutamine stimulation, 69% of the corresponding segments responded which is a sign of viability. The LVWM response to preoperative TTE and perioperative TEE dobutamine stress was comparable except for a significant difference in the apical segments. This study showed that perioperative TEE dobutamine stress could be used to test left ventricular viability and was also a valuable supplement to PAC, angiography and TTE. The acquired knowledge is important and suggest that further development of transesophageal ultrasound technology is warranted.

Die chirurgische Mitralklappenrekonstruktion (MKR) ist der konservativen Therapie bei signifikanter Mitralklappeninsuffizienz (MI) überlegen. Bisher fehlen sensitive präoperative Parameter zur Detektion latenter linksventrikulärer Funktionsstörungen. Aufgrund der pathophysiologisch bedingten Nachlastreduktion und Vorlaststeigerung bei MI bergen die konventionell verwendeten Ejektionsindices, Ejektionsfraktion (EF) und Fractional Area Change (FAC), die Gefahr der Überschätzung der effektiven Pumpfunktion des linken Ventrikels (LV). Der dopplersonographisch erhobene Tei Index gilt als ein Marker globaler myokardialer Funktion. Ziel der vorliegenden Studie war es, mit dem Tei Index (bzw. dem Myokardialen Performance Index, MPI) einen sensitiveren präoperativen Parameter zur Prädiktion der postoperativen linksventrikulären Funktion zu finden. Hierzu wurden im Rahmen einer prospektiven klinischen Studie 130 Patienten mit signifikanter MI am Herzzentrum Leipzig entsprechend den ASE/SCA Leitlinien vor und nach kardiopulmonaler Bypass-Operation mittels transösophagealer echokardiographischer (TEE) Bildgebung untersucht. Die Quantifizierung der MI erfolgte durch Messung der Vena contracta (VC). Die FAC wurde in der transgastrischen midpapillären kurzen Achse und die EF im midösophagealen Zwei- sowie Vier-Kammer-Blick erfasst. Die Zeitintervalle zur Berechnung des Tei Index wurden im tiefen transgastrischen und midösophagealen Vier-Kammer-Blick erfasst. Eine statistische Korrelation zwischen präoperativen Tei Index und postoperativer EF und FAC konnte zur Validierung unserer Hypothese nicht detektiert werden. Folgend kann der Tei Index nicht als Prädiktor der effektiven linksventrikulären Funktion vor MKR gewertet werden.

Die chirurgische Mitralklappenrekonstruktion (MKR) ist der konservativen Therapie bei signifikanter Mitralklappeninsuffizienz (MI) überlegen. Bisher fehlen sensitive präoperative Parameter zur Detektion latenter linksventrikulärer Funktionsstörungen. Aufgrund der pathophysiologisch bedingten Nachlastreduktion und Vorlaststeigerung bei MI bergen die konventionell verwendeten Ejektionsindices, Ejektionsfraktion (EF) und Fractional Area Change (FAC), die Gefahr der Überschätzung der effektiven Pumpfunktion des linken Ventrikels (LV). Der dopplersonographisch erhobene Tei Index gilt als ein Marker globaler myokardialer Funktion. Ziel der vorliegenden Studie war es, mit dem Tei Index (bzw. dem Myokardialen Performance Index, MPI) einen sensitiveren präoperativen Parameter zur Prädiktion der postoperativen linksventrikulären Funktion zu finden. Hierzu wurden im Rahmen einer prospektiven klinischen Studie 130 Patienten mit signifikanter MI am Herzzentrum Leipzig entsprechend den ASE/SCA Leitlinien vor und nach kardiopulmonaler Bypass-Operation mittels transösophagealer echokardiographischer (TEE) Bildgebung untersucht. Die Quantifizierung der MI erfolgte durch Messung der Vena contracta (VC). Die FAC wurde in der transgastrischen midpapillären kurzen Achse und die EF im midösophagealen Zwei- sowie Vier-Kammer-Blick erfasst. Die Zeitintervalle zur Berechnung des Tei Index wurden im tiefen transgastrischen und midösophagealen Vier-Kammer-Blick erfasst. Eine statistische Korrelation zwischen präoperativen Tei Index und postoperativer EF und FAC konnte zur Validierung unserer Hypothese nicht detektiert werden. Folgend kann der Tei Index nicht als Prädiktor der effektiven linksventrikulären Funktion vor MKR gewertet werden.

Chaque année, environ 1 à 1,25 million d’individus subiront une chirurgie cardiaque. [1] Environ 36 000 chirurgies cardiaques sont effectuées au Canada et 8000 procédures au Québec (http://www.ccs.ca). Le vieillissement de la population aura pour conséquence que la chirurgie cardiaque sera offerte à des patients de plus en plus à risque de complications, principalement en raison d’une co-morbidité plus importante, d’un risque de maladie coronarienne plus élevée, [2] d’une réserve physiologique réduite et par conséquent un risque plus élevé de mortalité à la suite d’une chirurgie cardiaque. L’une des complications significatives à la suite d’une chirurgie cardiaque est le sevrage difficile de la circulation extracorporelle. Ce dernier inclut la période au début du sevrage de la circulation extracorporelle et s’étend jusqu’au départ du patient de la salle d’opération. Lorsque le sevrage de la circulation extracorporelle est associé à une défaillance ventriculaire droite, la mortalité sera de 44 % à 86 %. [3-7] Par conséquent le diagnostic, l’identification des facteurs de risque, la compréhension du mécanisme, la prévention et le traitement du sevrage difficile de la circulation extracorporelle seront d’une importance majeure dans la sélection et la prise en charge des patients devant subir une chirurgie cardiaque. Les hypothèses de cette thèse sont les suivantes : 1) le sevrage difficile de la circulation extracorporelle est un facteur indépendant de mortalité et de morbidité, 2) le mécanisme du sevrage difficile de la circulation extracorporelle peut être approché d’une façon systématique, 3) la milrinone administrée par inhalation représente une alternative préventive et thérapeutique chez le patient à risque d’un sevrage difficile de la circulation extracorporelle après la chirurgie cardiaque. / Every year, 1 million to 1.25 million patients worldwide undergo cardiac surgery. [1] Up to 36,000 cardiac surgeries are performed each year in Canada and close to 8000 in Quebec (http://www.ccs.ca). Because of the aging of the population, cardiac surgery will increasingly be offered to patients at a higher risk of complications. Indeed, elderly patients have increased co-morbidities, and aging is also a significant risk factor in the prevalence of coronary artery disease. [2] The consequence is a reduced physiologic reserve, hence an increased risk of mortality. These issues will have a significant impact on future healthcare costs, because our population undergoing cardiac surgery will be older and more likely to develop postoperative complications. One of the most dreaded complications in cardiac surgery is difficult separation from cardiopulmonary bypass (CPB). The definition of difficult separation from CPB includes the time period from when CPB is initiated and until the patient leaves the operating room. When separation from CPB is associated with right ventricular failure, the mortality rate will range from 44% to 86%. [3-7] Therefore the diagnosis, the preoperative prediction, the mechanism, prevention and treatment of difficult separation from CPB will be crucial in order to improve the selection and care of patients and to prevent complications for this high-risk patient population. The hypotheses of this thesis are the following: 1) difficult separation from CPB is an independent factor of morbidity and mortality, 2) the mechanism of difficult separation from CPB can be understood through a systematic approach, 3) inhaled milrinone is a preventive and therapeutic approach in the patient at risk for difficult weaning from CPB after cardiac surgery.

Chaque année, environ 1 à 1,25 million d’individus subiront une chirurgie cardiaque. [1] Environ 36 000 chirurgies cardiaques sont effectuées au Canada et 8000 procédures au Québec (http://www.ccs.ca). Le vieillissement de la population aura pour conséquence que la chirurgie cardiaque sera offerte à des patients de plus en plus à risque de complications, principalement en raison d’une co-morbidité plus importante, d’un risque de maladie coronarienne plus élevée, [2] d’une réserve physiologique réduite et par conséquent un risque plus élevé de mortalité à la suite d’une chirurgie cardiaque. L’une des complications significatives à la suite d’une chirurgie cardiaque est le sevrage difficile de la circulation extracorporelle. Ce dernier inclut la période au début du sevrage de la circulation extracorporelle et s’étend jusqu’au départ du patient de la salle d’opération. Lorsque le sevrage de la circulation extracorporelle est associé à une défaillance ventriculaire droite, la mortalité sera de 44 % à 86 %. [3-7] Par conséquent le diagnostic, l’identification des facteurs de risque, la compréhension du mécanisme, la prévention et le traitement du sevrage difficile de la circulation extracorporelle seront d’une importance majeure dans la sélection et la prise en charge des patients devant subir une chirurgie cardiaque. Les hypothèses de cette thèse sont les suivantes : 1) le sevrage difficile de la circulation extracorporelle est un facteur indépendant de mortalité et de morbidité, 2) le mécanisme du sevrage difficile de la circulation extracorporelle peut être approché d’une façon systématique, 3) la milrinone administrée par inhalation représente une alternative préventive et thérapeutique chez le patient à risque d’un sevrage difficile de la circulation extracorporelle après la chirurgie cardiaque. / Every year, 1 million to 1.25 million patients worldwide undergo cardiac surgery. [1] Up to 36,000 cardiac surgeries are performed each year in Canada and close to 8000 in Quebec (http://www.ccs.ca). Because of the aging of the population, cardiac surgery will increasingly be offered to patients at a higher risk of complications. Indeed, elderly patients have increased co-morbidities, and aging is also a significant risk factor in the prevalence of coronary artery disease. [2] The consequence is a reduced physiologic reserve, hence an increased risk of mortality. These issues will have a significant impact on future healthcare costs, because our population undergoing cardiac surgery will be older and more likely to develop postoperative complications. One of the most dreaded complications in cardiac surgery is difficult separation from cardiopulmonary bypass (CPB). The definition of difficult separation from CPB includes the time period from when CPB is initiated and until the patient leaves the operating room. When separation from CPB is associated with right ventricular failure, the mortality rate will range from 44% to 86%. [3-7] Therefore the diagnosis, the preoperative prediction, the mechanism, prevention and treatment of difficult separation from CPB will be crucial in order to improve the selection and care of patients and to prevent complications for this high-risk patient population. The hypotheses of this thesis are the following: 1) difficult separation from CPB is an independent factor of morbidity and mortality, 2) the mechanism of difficult separation from CPB can be understood through a systematic approach, 3) inhaled milrinone is a preventive and therapeutic approach in the patient at risk for difficult weaning from CPB after cardiac surgery.