| Total cavopulmonary connection (TCPC) has been proposed as a rational alternative to atriopulmonary connection for complex cyanotic congenital heart disease. But because of its only ten years' clinical application, the study of its animal model, postoperative hemodynamics, cardiovascular and neuroendocrine is deficiency. By improving the vascular anastomosis of venae cavac-pulmonary connection, we successfully created its animal model, and by following up the clinic patients, we discussed the mechanism of the interactionbetween hemodynamics and cardiovascular-neuroendocrine. This study includes two parts:Part I Experimental study of the total cavopulmonaryconnectionBy improving on the vascular anastomosis of venae cavae梡ulmonary connection, we have built a new animal model of total cavopulmonary connection (TCPC). Our methods is to construct a Y-shaped conduit with tube grafts (1.4cm in diameter), each limb of the conduit was anastomosised with the vena cava and the main pulmonary artery in the end-to-side way with a side clamp, then ligated the proximal vena cava. It can drain the blood flow to pulmonary artery directly, being accordance with the pathophysiology of clinic TCPC operations. We have observed the relationship between the different central venous pressure and the hemodynamics postoperation. Using hespan to keep the cava pressure at 20mrnHg, we observed the hemodynamic changes along with the time. Using electromagnetic flowmeter, we measured the pulmonary perfusion, and investigated the relationship between pulmonary perfusion and hemodynamic characteristics.Results: All dogs tolerated the operative procedure. No pressure gradients were observed between the pulmonary artery and venae cavae. We found that cardiac output can be increased with the central venous pressure, and the circulation with this model can be sufficiently sustained with the CVP at 20mmHg. The mean time that dogs alive is 14 hours, and the longest is 5 days. After the operation, pulmonary vascular resistance stepped up and CO decreased significantly, CO has a positive correlation with CVP, and has a negative correlation with PVR. After TCPC operation, the- IX -distribution of pulmonary perfusion changed remarkable, the ratio of left/right pulmonary blood flow is approach to 1:1, and has a negative correlation with PVR.Conclusions: Our new model was successfully developed without the use of cardiopulmonary bypass, the tricuspid valve and pulmonary artery valve was left untouched. The operation is easy, and we can get stable hemodynamic characteristics. After operation, CO has an intimate correlation with CVP and PVR, the distribution of pulmonary perfusion has a negative correlation with PVR. It will be useful for studying the circulation after TCPC operation that result in total exclusion of the right heart.Part II Clinical study of the total cavopulmonaryconnectionSince 1990, 50 patients have undergone TCPC in our departments, including all kinds of pattern, such as intracardiac tunnel, intracardiac canal, extracardiac lateral tunnel, and extracardiac canal TCPC. Between March 1993 and November 2000, 16 patients underwent total right heart bypass by means of a superior vena cava梤ight pulmonary artery anastmosis and an extracardiac Gore-Tex conduit from the inferior vena cava to the main pulmonary artery in our departments. We reviewed these patients to investigate the hemodynamic characteristics, pulmonaryperfusion, and some vasoactive factors.Results: seventeen patients with complex congenital heart disease underwent this surgical procedure. Three patients died (early mortality, 12.5%). Mean follow-up was 13.8 months. The incidence of postoperative pleural effusion and chylothorax are 21.4%, cardiac arrthymia is 13.4%. The ECT results showed that right lung has the relative superior blood perfusion. The patients underwent this procedure are associated with abnormal distribution of flow to the lower lung lobes. Hemodynamic data were satisfactory, a preferential direction... |
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