The ultimate success of bypass surgery depends on the construction of a technically perfect bypass graft to an appropriate coronary vessel using a conduit which will remain durable for the lifetime of the patient. This thesis explores methods to improve coronary surgery by enhancing intraoperative imaging and conduit selection in the operating room. It is known that technical errors in graft construction cause failure of up to 12% of coronary bypass grafts in the operating room. We performed investigations of a new technique of intraoperative fluorescence angiography using indocyanine green dye to determine graft patency. We developed optimal methods of obtaining images and preliminary investigations revealed the technique was highly reproducible. In a follow-up trial, we demonstrated that over 80% of technical errors which would otherwise have been missed were identifiable with indocyanine green angiography, while only 25% of these errors were identified by transit-time ultrasonic flow measurement, the current clinical standard. We also determine that coronary surgery with indocyanine green angiographic graft patency verification was associated with less perioperative myocardial injury than bypass surgery without graft patency assessment. The long term graft patency of saphenous vein grafts is sub-optimal, with over 40% of such grafts totally occluded and a further 30% significantly diseased at ten years. We attempted to improve these outcomes by increasing the use of arterial grafts, which are less prone to intimal hyperplasia. In a multicentre clinical trial, we demonstrated a 40% relative risk reduction in graft occlusion at one year when radial arteries were used as bypass conduits versus saphenous veins. We identified that women and patients with small coronary vessels maximally benefited from radial artery bypass grafts. Conversely, in settings of less severe target vessel stenosis or concomitant peripheral vascular disease, saphenous veins performed as well as radial arteries. We have demonstrated that high quality imaging to identify technical errors during the operation, increased use of radial artery grafts and careful consideration of individual patient and target vessel characteristics can all improve graft patency. Future studies will be aimed at identifying the role of intraoperative imaging and arterial grafting in improving long-term clinical outcomes.

The ultimate success of bypass surgery depends on the construction of a technically perfect bypass graft to an appropriate coronary vessel using a conduit which will remain durable for the lifetime of the patient. This thesis explores methods to improve coronary surgery by enhancing intraoperative imaging and conduit selection in the operating room. It is known that technical errors in graft construction cause failure of up to 12% of coronary bypass grafts in the operating room. We performed investigations of a new technique of intraoperative fluorescence angiography using indocyanine green dye to determine graft patency. We developed optimal methods of obtaining images and preliminary investigations revealed the technique was highly reproducible. In a follow-up trial, we demonstrated that over 80% of technical errors which would otherwise have been missed were identifiable with indocyanine green angiography, while only 25% of these errors were identified by transit-time ultrasonic flow measurement, the current clinical standard. We also determine that coronary surgery with indocyanine green angiographic graft patency verification was associated with less perioperative myocardial injury than bypass surgery without graft patency assessment. The long term graft patency of saphenous vein grafts is sub-optimal, with over 40% of such grafts totally occluded and a further 30% significantly diseased at ten years. We attempted to improve these outcomes by increasing the use of arterial grafts, which are less prone to intimal hyperplasia. In a multicentre clinical trial, we demonstrated a 40% relative risk reduction in graft occlusion at one year when radial arteries were used as bypass conduits versus saphenous veins. We identified that women and patients with small coronary vessels maximally benefited from radial artery bypass grafts. Conversely, in settings of less severe target vessel stenosis or concomitant peripheral vascular disease, saphenous veins performed as well as radial arteries. We have demonstrated that high quality imaging to identify technical errors during the operation, increased use of radial artery grafts and careful consideration of individual patient and target vessel characteristics can all improve graft patency. Future studies will be aimed at identifying the role of intraoperative imaging and arterial grafting in improving long-term clinical outcomes.

INTRODUÇÃO: A ecocardiografia com perfusão miocárdica em tempo real (EPMTR) é uma técnica que permite a avaliação da perfusão miocárdica e a quantificação do fluxo miocárdico regional. Existem poucos dados na literatura a respeito da acurácia da EPMTR na detecção de viabilidade miocárdica e predição da melhora da qualidade de vida proporcionada pela revascularização miocárdica. MÉTODOS: Vinte e quatro pacientes com doença arterial coronária e disfunção ventricular esquerda crônica foram submetidos à EPMTR e questionário de qualidade de vida antes e após revascularização miocárdica. EPMTR foi realizada com injeção intravenosa contínua de PESDA ou Definity® e energia modulada. Recuperação funcional regional foi considerada padrão de referência (miocárdio hibernante), viabilidade miocárdica foi definida como presença de perfusão homogênea em pelo menos 1 segmento miocárdico no território revascularizado à avaliação qualitativa e a análise do fluxo miocárdico foi realizada nos 17 segmentos do ventrículo esquerdo obtendo-se índices de volume de sangue no miocárdio (A), da velocidade do fluxo () e do fluxo miocárdico absoluto (Ax) na condição de repouso no pré-operatório. Todos territórios revascularizados foram analisáveis. RESULTADOS: Presença de miocárdio hibernante foi observada em 77% dos territórios com viabilidade miocárdica pela EPMTR e em 44% dos territórios sem viabilidade (p=0,03). A presença de viabilidade pela EPMTR qualitativa apresentou sensibilidade, especificidade, valor preditivo positivo (VPP) e valor preditivo negativo (VPN) de 74%, 60%, 77% e 56%, respectivamente. Análise combinada (reserva contrátil e/ou perfusão miocárdica) resultou sensibilidade, especificidade, VPP e VPN de 89%, 40%, 73% e 67%, respectivamente. O valor de Ax 1,76 conferiu sensibilidade de 91,3%, especificidade de 50%, VPP de 75% e VPN de 77,8%, resultando em uma acurácia de 75,7%. O escore de qualidade de vida foi de 36,4 (29,1-43,6) para 18,1 (12,8-23,4; p =0,001) no pós-operatório. Entretanto, não houve correlação estatística com análise de perfusão miocárdica.CONCLUSÃO: Concluímos que a avaliação da perfusão miocárdica pela EPMTR apresenta boa acurácia para detecção de miocárdio hibernante em pacientes com DAC crônica e DVE. A presença de miocárdio viável pela EPMTR não foi capaz de prever a melhora da qualidade de vida após a cirurgia de revascularização miocárdica / BACKGROUND: Real-time perfusion echocardiography (RTPE) is an emerging modality for assessing myocardial perfusion and allows noninvasive quantification of regional myocardial blood flow. Little is known about the accuracy of the RTPE for the assessment of myocardial viability and the possibility of prediction of quality of life improvement after myocardial revascularization. METHODS: Twenty four patients with coronary artery disease and ventricular dysfunction underwent RTPE and answered Minnesota Quality of Life Questionnaire before and repeated after myocardial bypass coronary surgery. RTPE was performed using continuous PESDA or Definity intravenous infusion with power modulation image. Regional function recovery after surgical procedure was considered the standard reference (hibernating myocardial). Qualitatively, viability was defined as presence of homogeneous opacification in at least one myocardial segment in a rest revascularized territory, according coronary distribution. For myocardial blood flow evaluation, the left ventricle was divided into 17 segments, and indexes of myocardial blood volume (A), blood flow velocity (), and myocardial blood flow (Ax) were obtained for each myocardial segment at rest condition. All revascularized territories were analyzed. RESULTS: Hibernating myocardial was observed in 77% of RTPE viable territories and in 44% in non-viable ones (p=0.03). Sensitivity, specificity, predictive positive and negative values of qualitative RTPE viability detecting were 74%, 60%, 77% and 56%, respectively. A combined analysis (contractile reserve and/or myocardial perfusion) provided sensitivity, specificity, predictive positive and negative values of 89%, 40%, 73% e 67%, respectively. The sensitivity, specificity, predictive positive and negative values of Ax1.76 for recovery of function were 91%, 50%, 75% and 78%, respectively, with an accuracy of 76%. Quality of life score improved from 36.4 (29.1-43.6) to 18.1 (12.8-23.4; p =0.001). However, there was no statistical correlation with RTPE. CONCLUSION: In conclusion, RTPE provides good accuracy of detecting hibernating myocardial in patients with coronary artery disease and ventricular dysfunction. Nevertheless, it couldnt predict the quality of life improvement after myocardial revascularization

INTRODUÇÃO: A ecocardiografia com perfusão miocárdica em tempo real (EPMTR) é uma técnica que permite a avaliação da perfusão miocárdica e a quantificação do fluxo miocárdico regional. Existem poucos dados na literatura a respeito da acurácia da EPMTR na detecção de viabilidade miocárdica e predição da melhora da qualidade de vida proporcionada pela revascularização miocárdica. MÉTODOS: Vinte e quatro pacientes com doença arterial coronária e disfunção ventricular esquerda crônica foram submetidos à EPMTR e questionário de qualidade de vida antes e após revascularização miocárdica. EPMTR foi realizada com injeção intravenosa contínua de PESDA ou Definity® e energia modulada. Recuperação funcional regional foi considerada padrão de referência (miocárdio hibernante), viabilidade miocárdica foi definida como presença de perfusão homogênea em pelo menos 1 segmento miocárdico no território revascularizado à avaliação qualitativa e a análise do fluxo miocárdico foi realizada nos 17 segmentos do ventrículo esquerdo obtendo-se índices de volume de sangue no miocárdio (A), da velocidade do fluxo () e do fluxo miocárdico absoluto (Ax) na condição de repouso no pré-operatório. Todos territórios revascularizados foram analisáveis. RESULTADOS: Presença de miocárdio hibernante foi observada em 77% dos territórios com viabilidade miocárdica pela EPMTR e em 44% dos territórios sem viabilidade (p=0,03). A presença de viabilidade pela EPMTR qualitativa apresentou sensibilidade, especificidade, valor preditivo positivo (VPP) e valor preditivo negativo (VPN) de 74%, 60%, 77% e 56%, respectivamente. Análise combinada (reserva contrátil e/ou perfusão miocárdica) resultou sensibilidade, especificidade, VPP e VPN de 89%, 40%, 73% e 67%, respectivamente. O valor de Ax 1,76 conferiu sensibilidade de 91,3%, especificidade de 50%, VPP de 75% e VPN de 77,8%, resultando em uma acurácia de 75,7%. O escore de qualidade de vida foi de 36,4 (29,1-43,6) para 18,1 (12,8-23,4; p =0,001) no pós-operatório. Entretanto, não houve correlação estatística com análise de perfusão miocárdica.CONCLUSÃO: Concluímos que a avaliação da perfusão miocárdica pela EPMTR apresenta boa acurácia para detecção de miocárdio hibernante em pacientes com DAC crônica e DVE. A presença de miocárdio viável pela EPMTR não foi capaz de prever a melhora da qualidade de vida após a cirurgia de revascularização miocárdica / BACKGROUND: Real-time perfusion echocardiography (RTPE) is an emerging modality for assessing myocardial perfusion and allows noninvasive quantification of regional myocardial blood flow. Little is known about the accuracy of the RTPE for the assessment of myocardial viability and the possibility of prediction of quality of life improvement after myocardial revascularization. METHODS: Twenty four patients with coronary artery disease and ventricular dysfunction underwent RTPE and answered Minnesota Quality of Life Questionnaire before and repeated after myocardial bypass coronary surgery. RTPE was performed using continuous PESDA or Definity intravenous infusion with power modulation image. Regional function recovery after surgical procedure was considered the standard reference (hibernating myocardial). Qualitatively, viability was defined as presence of homogeneous opacification in at least one myocardial segment in a rest revascularized territory, according coronary distribution. For myocardial blood flow evaluation, the left ventricle was divided into 17 segments, and indexes of myocardial blood volume (A), blood flow velocity (), and myocardial blood flow (Ax) were obtained for each myocardial segment at rest condition. All revascularized territories were analyzed. RESULTS: Hibernating myocardial was observed in 77% of RTPE viable territories and in 44% in non-viable ones (p=0.03). Sensitivity, specificity, predictive positive and negative values of qualitative RTPE viability detecting were 74%, 60%, 77% and 56%, respectively. A combined analysis (contractile reserve and/or myocardial perfusion) provided sensitivity, specificity, predictive positive and negative values of 89%, 40%, 73% e 67%, respectively. The sensitivity, specificity, predictive positive and negative values of Ax1.76 for recovery of function were 91%, 50%, 75% and 78%, respectively, with an accuracy of 76%. Quality of life score improved from 36.4 (29.1-43.6) to 18.1 (12.8-23.4; p =0.001). However, there was no statistical correlation with RTPE. CONCLUSION: In conclusion, RTPE provides good accuracy of detecting hibernating myocardial in patients with coronary artery disease and ventricular dysfunction. Nevertheless, it couldnt predict the quality of life improvement after myocardial revascularization