Risk of perioperative stroke and cerebral autoregulation monitoring: a systematic review / Risco de acidente vascular cerebral perioperatório e monitoramento de autorregulação cerebral: uma revisão sistemática

Abstract Background Perioperative stroke, delirium, and cognitive impairment could be related to management and to variations in blood pressure control, cerebral hypoperfusion and raised blood volume. Cerebral autoregulation (CAR) is a mechanism to maintain cerebral perfusion through the control of the vascular tone and hemodynamic reactions in the circulation. Objective The present systematic review addresses the relationship between impaired CAR and perioperative stroke by evaluating the rate of neurological complications after surgery in studies in which perioperative CAR was tested or monitored. Methods We included randomized clinical trials and prospective observational studies. All studies had adjusted the relative risk, hazard ratio or 95% confidence interval (95%CI) values. These estimation effects were tested using random-effects models. Heterogeneity among the selected studies was assessed using the Higgins and Thompson I2 statistics. Results The Web of Science, PubMed and EMBASE electronic databases were searched to retrieve articles. A total of 4,476 studies published between 1983 and 2019 were analyzed, but only 5 qualified for the data extraction and were included in the final analysis. The combined study cohort comprised 941 patients who underwent CAR monitoring during surgical procedures. All studies provided information about perioperative stroke, which equated to 16% (158 of 941) of the overall patient population. Conclusion The present meta-analysis showed evidence of the impact of CAR impairment in the risk of perioperative stroke. On the pooled analysis, blood fluctuations or other brain insults large enough to compromise CAR were associated with the outcome of stroke (odds ratio [OR]: 2.26; 95%CI: 1.54-2.98;p < 0.0001).

Resumo Antecedentes Acidente vascular cerebral (AVC) perioperatório, delírio e comprometimento cognitivo podem estar relacionados ao manejo e à variações no controle da pressão arterial, à hipoperfusão cerebral, e ao aumento do volume sanguíneo. A autorregulação cerebral (ARC) é um mecanismo para manter a perfusão cerebral por meio do controle do tônus vascular e das reações hemodinâmicas na circulação. Objetivo Este trabalho aborda sistematicamente a determinação da relação entre a falha da ARC e o AVC perioperatório, com uma avaliação da taxa de complicações neurológicas pós-cirúrgicas em estudos em que a ARC perioperatória foi monitorada. Métodos Esta revisão sistemática incluiu ensaios clínicos randomizados e estudos observacionais prospectivos. Todos os estudos ajustaram o risco relativo, a razão de risco ou os valores de intervalo de confiança de 95% (IC95%). Esses efeitos de estimativas foram testados usando modelos de efeitos aleatórios. A heterogeneidade entre os diferentes estudos foi avaliada por meio das estatísticas de Higgins e Thompson I2. Resultados As bases de dados eletrônicas Web of Science, PubMed e Embase foram pesquisadas para selecionar os artigos. Um total de 4.476 estudos publicados entre 1983 e 2019 foram analisados, mas apenas 5 se qualificavam para a extração de dados e foram incluídos na análise final. A coorte combinada do estudo foi composta por 941 pacientes. Todos os estudos forneceram informações sobre AVC perioperatório, o que equivaleu a 16% (158 de 941) da população geral de pacientes. Conclusão Esta meta-análise mostrou evidências do impacto do prejuízo da ARC no risco de AVC perioperatório. Na análise conjunta, as flutuações sanguíneas ou outros insultos cerebrais grandes o suficiente para comprometer a ARC foram associados ao resultado do AVC (razão de probabilidades [RP]: 2,26; IC95%: 1,54-2,98;p < 0,0001).

Superior vena cava obstruction after the Glenn procedure

Acute obstruction of superior vena cava anastomosis right after the Glenn procedure may lead to tragic consequences. We describe the case of a one-year-old child with tricuspid atresia and a previous Blalock-Taussig shunt procedure, who presented severe low cardiac output syndrome right after the Glenn procedure and died forty-four hours after the procedure. The autopsy showed obstruction of the superior vena cava anastomosis. Patients that present superior vena cava syndrome and low cardiac output right after the Glenn procedure should have the surgical anastomosis revised immediately.

Management of Coronary Sinus Ostial Atresia during a Staged Operation of a Functional Single Ventricle

Coronary sinus ostial atresia (CSOA) with persistent left superior vena cava (LSVC) in the absence of an unroofed coronary sinus is a benign and rare anomaly that may be taken lightly in most instances. However, if overlooked in patients undergoing univentricular heart repair such as bidirectional Glenn or Fontan-type surgery, fatal surgical outcomes may occur due to coronary venous drainage failure. We report a case of CSOA with a persistent LSVC that was managed through coronary sinus rerouting during a total cavopulmonary connection, and provide a review of the literature regarding this rare anomaly.

The outcomes of superior cavopulmonary connection operation: a single center experience

Abstract Introduction: The superior cavopulmonary connection operation is one of the stages of the palliative surgical management for patients with functionally single ventricle. After surviving this stage, the patients are potential candidates for the final palliative procedure: the Fontan operation. Objectives: This study aimed to analyze the outcomes of superior cavopulmonary connection operations in our center and to identify factors affecting the survival and the progression to Fontan stage. Methods: The outcomes of 161 patients were retrospectively analyzed after undergoing superior cavopulmonary connection operation in our center between 2005 and 2015. Results: The early mortality rate was 2.5%. Five (3.1%) patients underwent takedown of the superior cavopulmonary connection. The rate of exclusion from the Fontan stage was 8.3%. Statistical analysis revealed that elevated mean pulmonary artery pressure preoperatively and the prior palliation with pulmonary artery banding were risk factors for both early mortality and takedown; however, the age, the morphology of the single ventricle and the type of operation were not considered risk factors. Conclusion: The superior cavopulmonary connection operation can be performed with low rate mortality and morbidity; however, the elevated mean pulmonary artery pressure preoperatively and the prior pulmonary artery banding are associated with poor outcomes.

Effective analysis on cool-tipped catheter ablation of epicardial accessory pathway / 重庆医学

Objective To investigate the efficacy and safety of cool-tipped saline-irrigated catheter ablation of epicardial accesso-ry pathway in the patients after failure of conventional radiofrequency ablation .Methods 30 patients with epicardial accessory path-way after failuer of conventional radiofrequency ablation were included in this study ,among them ,25 cases of the left accessory pathway and 5 cases of the right accessory prathway used the cool-tipped catheter for conducting ablation through the endocardium (ventricular side or atrial side) or coronary sinus .Results All patients achieved success ,no intraoperative and postoperative related complications occurred .Conclusion The cool-tipped saline-irrigated catheter ablation of epicardial accessory pathway is effective and safe in the patients after failure of conventional radiofrequency ablation ,which may improve the success rate of epicardial acces-sory pathway ablation .

Anastomose cavo-pulmonar associada ao suporte circulatório esquerdo comparada à assistência biventricular na falência cardíaca aguda / Cavo-pulmonary anastomosis associated with left ventricular in comparison with biventricular circulatory support in acute heart failure

OBJETIVO: Este estudo avaliou o desempenho hemodinâmico e as alterações miocárdicas decorrentes do emprego de dispositivos de assistência ventricular esquerda (DAVE), associado ou não à descompressão do ventrículo direito por meio de derivação cavo-pulmonar, sendo esses achados comparados ao emprego de assistência circulatória biventricular. MÉTODOS: Vinte e um suínos foram submetidos à indução de insuficiência cardíaca através de fibrilação ventricular, sendo a atividade circulatória mantida por DAVE durante 180 minutos. No grupo controle, foi apenas implantado o DAVE. No grupo derivação, além do DAVE foi realizada cirurgia de derivação cavo-pulmonar. No grupo biventricular, foi instituída assistência biventricular. Foram monitoradas as pressões intracavitárias por 3 horas de assistência e amostras do endocárdio dos dois ventrículos foram coletadas e analisadas à microscopia óptica e eletrônica. RESULTADOS: O lactato sérico foi significativamente menor no grupo biventricular (P=0,014). A diferença observada entre o fluxo do DAVE nos grupos derivação e controle (+55±14 ml/kg/min, P=0,072) não foi significativa, enquanto que o fluxo no grupo biventricular foi significativamente maior (+93±17 ml/kg/min, P=0,012) e se manteve estável durante o experimento. A pressão arterial média (PAM) se manteve constante apenas no grupo biventricular (P<0,001), que também apresentou diminuição significativa das pressões em câmaras direitas. Na análise ultraestrutural, notou-se menor presença edema miocárdico no ventrículo direito no grupo biventricular (P=0,017). CONCLUSÃO: Os resultados apresentados demonstram que o desempenho hemodinâmico da assistência ventricular esquerda associada à derivação cavo-pulmonar, neste modelo experimental, não foi superior ao observado com a assistência de ventrículo esquerdo isolada e não substituiu a assistência biventricular de maneira efetiva.

OBJECTIVE: Right ventricular (RV) failure during left ventricular assist device (LVAD) support can result in severe hemodynamic compromise with high mortality. This study investigated the acute effects of cavo-pulmonary anastomosis on LVAD performance and RV myocardial compromise in comparison with biventricular circulatory support, in a model of biventricular failure. METHODS: LVAD support was performed by centrifugal pump in 21 pigs with severe biventricular failure obtained by FV induction. Animals were randomized to be submitted to cavo-pulmonary anastomosis, to biventricular circulatory support or to control group. They were maintained under circulatory support and hemodynamic monitoring for 3h. Venous lactate and cytokines serum levels were also obtained. Endocardium samples were analyzed by electronic microscopy. RESULTS: FV maintenance was responsible for acute LVAD impairment after 180 min in the control group. cavo-pulmonary anastomosis resulted in non-significant improvement of LVAD pump flow in relation to control group (+55±14 ml/kg/min, P=0.072), while animals under biventricular support maintained higher LVAD flow (+93±17 ml/kg/min, P=0.012). Mean arterial pressure remained constant only in biventricular group (P<0.001), which also presented decrease of right atrial and ventricular pressures. Similar increases in lactate and cytokines levels were observed in the three groups. Ultra-structural analysis documented low levels of myocardial swelling in the biventricular group (P=0.017). CONCLUSION: The concomitant use of cavo-pulmonary anastomosis during LVAD support in a pig model of severe biventricular failure resulted in non-significant improvement of hemodynamic performance and it did not effectively replace the use of biventricular support.

The study of pulmonary arterial development in patients after 5 years of extracardiac tota cavopulmonary connection / 中华胸心血管外科杂志

ObjectiveTo study the pulmonary arterial development over five years in patients underwent extracardiac total cavopulmonary connection (ETCPC).Methods43 survived patients,who had undergone ETCPC were examined with pulmonary perfusion at one month and five year following the operation.Central venous pressure (CVP) and arterial oxygenation saturation (SatO2 ％ ) were measured by right cardiac catheter,pulmonary arterial index (PAI) and pulmonary vascular resistance (PVR) were calculated.Pulmonary blood distribution were measured and calculated by 99m Tc-MAA perfusion imaging.ResultsThe PAI and PVR of the follow-up group reduced significantly ( t =2.41,P ＜ 0.05 ; t =2.08,P ＜ 0.05 ),CVP also reduced significantly ( t =2.69,P ＜ 0.05 ),but SatO2 ％ did not changed significantly.Total radionuclide counts and the ratio of rightorleft pulmonary perfusion did not change significantly.( t =0.38,P ＞ 0.05 ;t =1.12,P ＞ 0.05 ),but the ratio of the superior and inferior lobe decreased significantly( t =2.54,P ＜ 0.05 ).ConclusionThe weak pulsation and low dynamic of Fontan circulation also can promote pulmonary vascular development.However,the improvement of hemodynamic in pulmonary circulation at mid-term follow will not lead to an increased amount of pulmonary perfusion or oxygen supply,which is probably due to the massive opening of the arteriovenous shunt and increased futile circulation.

Assessment of ventricular function in children with single ventricle after cavopuimonary connection using velocity vector imaging / 中华超声影像学杂志

ObjectiveTo evaluate the feasibility and accuracy of velocity vector imaging (VVI) in assessing ventricular function in children with single ventricle after cavopulmonary connection.Methods Thirty children with single ventricle after cavopulmonary connection were enrolled in this study,30 agematched normal children were served as control group.The systolic peak velocity,displacement,strain and strain rate in this two groups measured in 6 segments by VVI were compared.dp/dt of single ventricle was estimated by atrioventricular regurgitation using simplified Bernoulli equation.Results Strain and strain rate were significantly lower in all 6 segments in children with single ventricle after cavopulmonary connection compared with values in normal children( P ＜0.05,respectively),strain rate of the basal segment at the rudimentary chamber correlated best with dp/dt (r =0.72,P ＜0.01).Conclusions Segmental ventricular dysfunction was observed in children with single ventricle after cavopulmonary connection,and could be assessed accurately using velocity vector imaging.

Operação de Fontan: uma técnica em evolução / Fontan operation: a technique in evolution

Objetivo: Estudos recentes de fluxo com modelos experimentais de anastomoses cavopulmonares totais (ACPTs) baseados em ressonância magnética e angiografia demonstram que este é um procedimento bem estabelecido para o tratamento de várias cardiopatias, mas o melhor arranjo espacial continua controverso. Nosso intuito é apresentar os resultados imediatos com três diferentes técnicas de ACPTs. Métodos: Ensaio clínico de ACPTs realizadas no período de janeiro de 2005 a julho de 2008 com 40 pacientes, com idade média de 6,4 ± 3,2 anos, com Glenn prévio. Os pacientes foram divididos em três grupos, dependendo da técnica cirúrgica empregada: Grupo 1 (G1) - túnel lateral; Grupo 2 (G2) - conduto extracardíaco; Grupo 3 (G3) - conduto intracardíaco dirigido para o ramo esquerdo de artéria pulmonar, todos com fenestração. Foram avaliadas variáveis pré e pós-operatórias. Resultados: Foram incluídos 11 pacientes no G1, 10 no G2 e 19 no G3. As variáveis pré-operatórias foram semelhantes nos três grupos (P>0,05). A mortalidade foi maior nos Grupos 1 e 2 (9,1 por cento e 10,0 por cento, respectivamente), comparadas ao Grupo 3 (zero), porém sem significância estatística (P=0,3841). Efusão pleural foi ausente no Grupo 3, diferença significativa (P=0,0128) em relação aos outros grupos (40,0 por cento e 33,3 por cento). A mediana do tempo de hospitalização pós-operatória foi menor no Grupo 3 (8 dias), em relação aos grupos 1 e 2 (18 e 13 dias, respectivamente) (P=0,0164). Conclusão: A técnica de conduto intracardíaco foi associada a menor morbidade pós-operatória, sendo a opção atual do nosso serviço na anastomose cavopulmonar total.

Objectives: Recent experimental flow studies based on angiography and magnetic resonance have shown that total cavopulmonary anastomosis (TCPA) is a valid concept for surgical treatment of many congenital heart defects, but there is not agreement of the best surgical arrangement. Our purpose is to analyze the immediate results with three different techniques of TCPA. Methods: We sought to analyze retrospectively all TCPA realized from January 2005 to July 2008; there were 40 patients, all with previous Glenn anastomosis, with mean age of 6.4 ± 3.2 years. Three different techniques were employed: Group 1 (G1) lateral tunnel, Group 2 (G2) extracardiac conduits, Group 3 (G3) intracardiac conduit directed to the left pulmonary artery. All patients had a fenestration done. Results: G1 had 11 patients, G2 10 patients and G3 19 patients. Preoperative data were similar in the 3 groups (P>0.05). Surgical mortality was higher in Groups 1 and 2 (9.1 percent and 10 percent) compared to Group 3 (0 percent) but there was no statistical significance (P=0.3841). Pleural effusion was absent in Group 3 (0 percent), which was statistically significant in relation to the other groups (P=0.0128). The hospitalization time was also significantly lower in G3 (8 days) in relation to G1 (18 days) and G2 (13 days) (P=0.0164). Conclusion Intracardiac TCPA was associated with lower postoperative morbidity and is currently our preferred technique.

Emprego da anastomose cavo-pulmonar associada a assistência ventricular esquerda com bomba centrífuga em modelo experimental de disfunção biventricular / Cavo-pulmonary anastomosis associated to centrifugal pump left ventricle assistance in a experimental model of biventricular heart failure

Introdução: A utilização de dispositivos de assistência ventricular esquerda (DAVE) proporciona melhor manejo dos pacientes que necessitam de métodos alternativos como ponte para o transplante cardíaco. Parcela significativa dos pacientes sob uso de DAVE desenvolve falência de ventrículo direito (VD), com elevada mortalidade. Propusemos estudo experimental para desenvolvimento de método de descompressão do VD em pacientes sob assistência mecânica esquerda e disfunção biventricular. Método: Foi realizado estudo experimental em cães adultos, com disfunção biventricular em fibrilação ventricular, mantidos em uso de DAVE com bomba centrífuga. Os animais foram divididos em dois grupos. No Grupo A, foi realizada descompressão do VD através de anastomose cavo-pulmonar, com anastomose da veia cava superior na artéria pulmonar direita. No grupo B, não foi realizado o "shunt". Após o preparo inicial foi iniciada assistência circulatória átrio esquerdo-aorta. Foram realizadas medidas hemodinâmicas e laboratoriais no momento inicial e aos 30, 60 e 90 minutos de assistência nos dois grupos. Resultados: Os dados hemodinâmicos e laboratoriais iniciais foram semelhantes nos dois grupos. No Grupo A, houve melhora da pressão arterial media (p<0,0001) durante a assistência. O fluxo pulmonar também foi maior no grupo A (p<0,0001), resultando em maior fluxo na bomba centrífuga, principalmente aos 90 min(1,2L/min X 0,5L/min, p<0,0001). A dosagem de lactato sérico no último momento de estudo foi menor no grupo A (27,6mg/dL versus 47,6mg/dL, p<0,05). Conclusão: Concluímos que a anastomose cavo-pulmonar promove descompressão do VD em modelo de disfunção bi-ventricular aguda sob assistência circulatória isolada do ventrículo esquerdo. A descompressão do VD leva a aumento do fluxo pulmonar e melhor desempenho hemodinâmico da assistência ao ventrículo esquerdo.

Introduction: The use of Left Ventricular Assist Devices promotes better clinical handling of patients in the need of alternative methods as bridge to heart transplant. A significant part of them develop right ventricle failure, leading to high death incidence. We have proposed an experimental study for the development of a method to decompress the right ventricle in biventricular failure patients under Left Ventricular Assist Devices . Method: Experimental study with adult dogs with acute biventricular failure in ventricular fibrillation under left assist device by centrifugal pump. The animals were divided in 2 groups. In Group A decompression of RV was made by cavo-pulmonary anastomosis between superior vena cava and right pulmonary artery. In Group B the anastomosis was not performed. After initial preparation left atrium-aorta circulatory support begun. Hemodinamic and laboratory measures were taken at start time and at 30, 60 and 90 minutes of circulatory support. Results: Initial laboratory and haemodinamic data were similar in both groups. Group A had better mean arterial pressure during support(p<0,0001). Pulmonary blood flow was higher in Group A resulting in higher pump flow, mainly at 90 minutes(1,2L/minX0,5L/min, p<0,0001). Serum lactate was lower at 90 minutes in Group A(27,6mg/dL x 47,6mg/dL, p<0,05). Conclusion: We conclude that the cavo-pulmonary anastomosis led to right ventricle decompression in an experimental model of acute biventricular failure under isolated left ventricle circulatory support. The right ventricle decompression generated enhancement in pulmonary blood flow and better circulatory support performance.

Manejo médico-quirúrgico de la hipoplasia del corazón izquierdo: Primera experiencia en Uruguay

Resumen El síndrome de hipoplasia del corazón izquierdo (SHCI) es una cardiopatía congénita compleja que representa el 7% del total de las cardiopatías congénitas y el 95% de los pacientes fallecen en el primer mes de vida si no se efectúa un tratamiento médico–quirúrgico paliativo. Se presenta la evolución de tres casos clínicos en el postoperatorio alejado. Todos se presentaron como cardiopatías ductus dependientes del recién nacido requiriendo del aporte de prostaglandinas. Un paciente asoció una coartación de aorta severa. Otro asoció una interrupción del arco aórtico tipo A. En un caso se efectuó cirugía de Norwood modificada y en los dos casos restantes se efectuó cirugía de Norwood modificada con técnica de Sano, con la corrección quirúrgica correspondiente de la coartación de aorta y de la interrupción del arco aórtico respectivamente. El seguimiento de los pacientes demostró acentuación de la hipoxemia. En el primer paciente se comprueba la permeabilidad de la fístula con ramas pulmonares hipoplásicas y falla de la contractilidad del ventrículo sistémico, se realiza la cirugía de Glenn con buena respuesta. En el segundo paciente se comprueba estenosis proximal y distal del tubo ventrículo derecho-arteria pulmonar realizándose angioplastia con catéter balón y posteriormente cirugía de Glenn, con buena evolución inicial y posterior hipoxemia progresiva, identificándose colaterales aortopulmonares hacia el pulmón derecho que se embolizan con coils, con buena evolución, saturaciones por encima de 85%, buena función del ventrículo único y recuperación ponderal. En el tercer paciente se detecta estenosis proximal del tubo protésico realizándose una angioplastia con balón y por persistir con hipoxemia se realiza cirugía de Glenn con buena evolución. Conclusiones: El esfuerzo de un equipo multidisciplinario ha permitido la sobrevida de estos pacientes portadores de una compleja y letal cardiopatía congénita, hasta completar la ...

Summary Hypoplastic Left Heart Syndrome (HLHS) is a complex congenital heart malformation that represents 7% of all congenital heart defects. Without any palliative surgical treatment, 95% die in the first month of life. The evolution of three clinical cases is presented. The cases reported are newborns with ductus dependent heart disease that required prostaglandin infusion; one patient associated severe aortic coarctation and another patient type A aortic arch interruption. A modified Norwood procedure was performed in one case and a Sano procedure in the other two, together with surgical correction of associated damage. Follow-up showed evidence of increasing hypoxemia. The first patient had fistula permeability with hypoplastic pulmonary branch stenosis and deficient contractility of the systemic ventricle. A Glenn procedure was succesfully performed. In the second patient, the existence of proximal and distal stenosis of the tube between the right ventricle and pulmonary artery was demonstrated, so a balloon catheter angioplasty followed by Glenn surgery was performed, with good evolution at the beginning but progressive hypoxemia. Coil embolism was performed after noticing aortopulmonary collaterals linked to the right lung, with a good result, saturation levels over 85%, good single ventricle function and weight recovery. In the third patient, prosthetic tube proximal stenosis was confirmed which lead to balloon angioplasty and later to Glenn surgery due to hypoxemia, with good result. Conclusions: the effort of a multidisciplinary team made possible these patients survival who suffered a complex and lethal congenital heart defect, until the second stage of the Norwood procedure could be performed.

The application of inhaled nitric oxide in the early period after extracardiac total cavopulmonary connection / 中华胸心血管外科杂志

Objective To evaluate the effects of inhaled nitric oxide in the early period after extracardiac total cavopulmonary connection (ETCPC). Methods 32 patients after ETCPC were evaluated,of them 16 patients (experimental group) were administered with inhaled nitric oxide in the early postoperative period. Another 16 patients were as control. The cardiac index (CI), pulmonary vascular resistance(PVR), respiratory index(RI), pulmonary-left atrium pressure gradient(PLG), duration of ventilation, intensive care time, hydrothorax drainage and hospital stay were recorded. Results In experimental group, after inhaled NO, RI decreased from 2.61?0.32 to 1.41?0.21 (t=2.35,P

Clinical application of total cavopulmonary connection with off-pump technique / 中华胸心血管外科杂志

Objective: To evaluate the clinical application of total cavopulmonary connection with off-pump technique. Methods: Between May 2000 and December 2002, 9 patients underwent total cavopulmonary connection without cardiopulmonary bypass. The patients were 5 males and 4 females, mean age (10.3?6.4) years, ranged 4～24 years and mean body surface area (0.95?0.35) m 2, range 0.65～1.66 m 2. SpO 2 before operation was (73?6)% (60%～80%). Pulmonary pressure was (12.7?2.4) mmHg (10～16 mmHg) at operation. Results: Patient died after surgery. Chylothorax occurred in 1 patient. 2 patients were reoperated for fenestration between the extracardiac conduit and right atrial during the early postoperative period. All survivors were noncyanotic, the average SpO 2 on breathing air was (94?3)% (89%～97%). On d ischarged. Conclusion: Total cavopulmonary connection with off-pump technique is a useful procedure in management of patients with a functional univentricular heart. It is easy to perform. However, much remains to be studied about this unique physiologic status.

A study on pulmonary blood distribution in patients undergoing extracardiac total cavopulmonary connection / 中华胸心血管外科杂志

Objective: To study blood distribution in extracardiac total cavopulmonary connection (ETCPC). Methods: To combine a bidirectional cavopulmonary anastomosis with a Gore-Tex extracardiac conduit interposition between the inferior vena cava and the main pulmonary artery, and to evaluate the changes of pulmonary blood distribution with SPECT in all surviving patients. Results: The cournts of pulmonary radionuclide was (313.7?40.1)?10 3 increased significantly after surgery (t=2.23, P