Thesis (M. Phil.)--University of Hong Kong, 2009. / Includes bibliographical references (leaves 162-171) Also available in print.

published_or_final_version / Mechanical Engineering / Master / Master of Philosophy

Penetrating injuries of the intrathoracic great vessels are well recognized although uncommon. In the First World War no survivors with thoracic vascular injury were recorded among soldiers treated with penetrating injuries to the chest as recorded by Makins. The first record of successful repair of a penetrating thoracic aortic injury was in 1922 by Dshanelidze in Russia. Similar to Makins' experience, De Bakey and Simeone in the Second World War recorded no surviving patients with involvem_ent of the thoracic aorta and its branches among American soldiers. Furthermore, no injuries to the thoracic aorta and its branches were recorded in Korean war soldiers undergoing vascular surgery by both Jahnke and Hughes. Rich reported 3 survivors of aortic injuries in the Vietnam war among 1000 patients with vascular injuries. By 1969 only 43 successfully treated cases had been reported but increasing numbers of patients sustaining injuries to the great arteries at the level of the thoracic inlet have been reported subsequently in civilian practice. Experience has grown over the years but patient numbers remain small and individual surgeons may only manage 2 or 3 of these patients in his life time. The largest single reported series consists of 93 patients in Memphis over a 13 year period. All victims were rapidly transported to hospital and were resuscitated en route. As a consequence, a large number critically ill patients reached hospital who may have died in earlier years. However some of these patients inevitably died in hospital contributing to the high mortality of 16, 7% reported. Our experience is different in that most of our victims who reach hospital will survive as poor community triage facilities prevent more than 95% of penetrating thoracic vascular trauma victims reaching hospital alive, hence we have a selection of less severely injured patients who eventually reach our hospital alive producing our mortality rate of 5%. Another important difference is that most of our patients suffered stab wounds as compared to gunshot wounds noted in the Memphis. Buchan and Robbs in Durban reported on 52 patients who had penetrating cervicomediastinal vascular injury with a remarkably similar experience to our own in Cape Town with the exception of a larger number of aortic injuries (21 out of 52 patients) recorded and a higher mortality rate of 17% as a result of these aortic injuries.

O enxerto de artéria torácica interna tem demonstrado capacidade de remodelamento devido a interação com o leito arterial coronariano. O objetivo deste estudo foi analisar a influência dos fatores clínicos e angiográficos no remodelamento dos enxertos, definido como variação no calibre vascular. Casuística e métodos: No período entre 1983 e 1999, 356 pacientes realizaram cirurgia de revascularização do miocárdio utilizando a artéria torácica interna esquerda para o ramo interventricular anterior e a artéria torácica interna direita para um ramo da circunflexa. Trinta e dois pacientes foram submetidos a cineangiocoronariografia pós-operatória, a qual foi posteriormente analisada com o aplicativo CASS II®. Este estudo observacional apresentou acompanhamento médio de 42 meses(6-204 meses). As variáveis angiográficas analisadas foram os diâmetros proximal e distal dos enxertos arteriais (variável dependente), área coronariana, pontuação de fluxo TIMI, diâmetro de estenose proximal, fluxo dominante distal e ramos patentes. Fatores de risco cardiovascular também foram incluídos. Resultados: O modelo de regressão linear múltiplo demonstrou um R2ajustado=0,69 (p=0,0001) para o modelo a direita e R2ajustado=0,46 (p=0,002) para a esquerda. Os enxertos apresentaram diâmetros proximal e distal de 2,67mm ±0,085 e 2,232mm ±0,085 à esquerda; 2,458mm ±0,088 e 2,010mm ± 0,091 (média±EP) à direita, respectivamente (p>0,05). Nenhuma variável clínica obteve correlação significante estatisticamente. A área coronariana apresentou coeficiente de beta=0,42 (0,14-0,6/IC-95%) e diâmetro de estenose proximal de 0,55 (0,40-0,65/IC-95%) para o remodelamento do lado direito. A área coronariana demonstrou coeficiente de beta=0,54 (0,3- 0,68/IC-95%) para o remodelamento do lado esquerdo. Conclusões: A artéria torácica interna não demonstrou diferença de calibre em relação a lateralidade (esquerda vs direita). O diâmetro de estenose proximal da artéria coronária revascularizada demonstrou correlação positiva com o remodelamento dos enxertos do lado direito. A área da artéria coronária revascularizada foi a única variável de influência para o remodelamento bilateral dos enxertos / Internal thoracic artery grafts has demonstrated capacity for remodeling due to interaction with the coronary artery bed. The goal was to analysis the influence of clinical and angiographic factors in this remodeling as defined as grafts caliber variation. Methods: In a period from 1983 to 1999, 356 patients underwent to coronary artery bypass surgery using the left internal thoracic artery anastomosed to interventricular anterior branch and the right internal thoracic artery to circumflex branches. Thirty two patients were submitted to postoperative coronary angiography which was further analysed by CASS II® software. The mean follow-up of this observational study was 42 months(6- 204 months). Angiographic variables analyzed was proximal and distal diameters of arterial grafts(dependent variable), coronary area, TIMI flow grade, proximal stenosis diameter, dominant distal flow and patent branches. Cardiovascular risk factors were included indeed. Results: The multiple regression model demonstrated R2adjusted=0.69 (p=0.0001) for right side and R2adjusted=0.46 (p=0.002) for left side. The grafts presented proximal and distal diameters of 2.67mm ±0.085 and 2.232mm ±0.085 from left side; 2.458mm ±0.088 and 2.010mm ±0.091 (mean±SE) from right side respectively (p > 0,05). None of the clinical variables had statistical significant correlation. The coronary area presented as a beta coefficient=0.42 (0.14-0.6/CI-95%) and proximal stenosis diameter of 0.55 (0.40-0.65/CI-95%) for right side remodeling. The coronary area shown a beta coefficient=0.54 (0.3- 0.68/CI-95%) for left side remodeling. Conclusions: The internal thoracic artery did not demonstrate difference in caliber about its laterality (left vs right). The proximal stenosis degree of the bypassed coronary artery demonstrated positive correlation with remodeling for the right side grafts. Bilateral grafts remodeling was only explained by positive correlation with the bypassed coronary area

O enxerto de artéria torácica interna tem demonstrado capacidade de remodelamento devido a interação com o leito arterial coronariano. O objetivo deste estudo foi analisar a influência dos fatores clínicos e angiográficos no remodelamento dos enxertos, definido como variação no calibre vascular. Casuística e métodos: No período entre 1983 e 1999, 356 pacientes realizaram cirurgia de revascularização do miocárdio utilizando a artéria torácica interna esquerda para o ramo interventricular anterior e a artéria torácica interna direita para um ramo da circunflexa. Trinta e dois pacientes foram submetidos a cineangiocoronariografia pós-operatória, a qual foi posteriormente analisada com o aplicativo CASS II®. Este estudo observacional apresentou acompanhamento médio de 42 meses(6-204 meses). As variáveis angiográficas analisadas foram os diâmetros proximal e distal dos enxertos arteriais (variável dependente), área coronariana, pontuação de fluxo TIMI, diâmetro de estenose proximal, fluxo dominante distal e ramos patentes. Fatores de risco cardiovascular também foram incluídos. Resultados: O modelo de regressão linear múltiplo demonstrou um R2ajustado=0,69 (p=0,0001) para o modelo a direita e R2ajustado=0,46 (p=0,002) para a esquerda. Os enxertos apresentaram diâmetros proximal e distal de 2,67mm ±0,085 e 2,232mm ±0,085 à esquerda; 2,458mm ±0,088 e 2,010mm ± 0,091 (média±EP) à direita, respectivamente (p>0,05). Nenhuma variável clínica obteve correlação significante estatisticamente. A área coronariana apresentou coeficiente de beta=0,42 (0,14-0,6/IC-95%) e diâmetro de estenose proximal de 0,55 (0,40-0,65/IC-95%) para o remodelamento do lado direito. A área coronariana demonstrou coeficiente de beta=0,54 (0,3- 0,68/IC-95%) para o remodelamento do lado esquerdo. Conclusões: A artéria torácica interna não demonstrou diferença de calibre em relação a lateralidade (esquerda vs direita). O diâmetro de estenose proximal da artéria coronária revascularizada demonstrou correlação positiva com o remodelamento dos enxertos do lado direito. A área da artéria coronária revascularizada foi a única variável de influência para o remodelamento bilateral dos enxertos / Internal thoracic artery grafts has demonstrated capacity for remodeling due to interaction with the coronary artery bed. The goal was to analysis the influence of clinical and angiographic factors in this remodeling as defined as grafts caliber variation. Methods: In a period from 1983 to 1999, 356 patients underwent to coronary artery bypass surgery using the left internal thoracic artery anastomosed to interventricular anterior branch and the right internal thoracic artery to circumflex branches. Thirty two patients were submitted to postoperative coronary angiography which was further analysed by CASS II® software. The mean follow-up of this observational study was 42 months(6- 204 months). Angiographic variables analyzed was proximal and distal diameters of arterial grafts(dependent variable), coronary area, TIMI flow grade, proximal stenosis diameter, dominant distal flow and patent branches. Cardiovascular risk factors were included indeed. Results: The multiple regression model demonstrated R2adjusted=0.69 (p=0.0001) for right side and R2adjusted=0.46 (p=0.002) for left side. The grafts presented proximal and distal diameters of 2.67mm ±0.085 and 2.232mm ±0.085 from left side; 2.458mm ±0.088 and 2.010mm ±0.091 (mean±SE) from right side respectively (p > 0,05). None of the clinical variables had statistical significant correlation. The coronary area presented as a beta coefficient=0.42 (0.14-0.6/CI-95%) and proximal stenosis diameter of 0.55 (0.40-0.65/CI-95%) for right side remodeling. The coronary area shown a beta coefficient=0.54 (0.3- 0.68/CI-95%) for left side remodeling. Conclusions: The internal thoracic artery did not demonstrate difference in caliber about its laterality (left vs right). The proximal stenosis degree of the bypassed coronary artery demonstrated positive correlation with remodeling for the right side grafts. Bilateral grafts remodeling was only explained by positive correlation with the bypassed coronary area