Cavopulmonary connections: comparisons between different techniques (with or without cardiopulmonary bypass).

Abstract

Patients with univentricular heart physiology present with abnormal cardiovascular physiology and, without surgery, have a poor prognosis. (17) Current surgical approaches in congenital heart disease that is characterized functionally as single ventricle are based on diverting systemic venous return to the lungs (127) The bidirectional Cavopulmonary anastomosis is used as part of this staged approach (41) Because the operation enables a substantial proportion of the venous return to flow passively into the lungs, the ventricle pumps only to the body, and the volume load is reduced. (83) Typically the oxygen saturation rises to 80% to 85% almost immediately after the procedure. (57) Performance of a BCPC procedure with CPB has a well-established risk profile, including increased lung injury and consequent prolonged mechanical ventilation requirements, hemolysis, and increased costs. Prolonged CPB has been recently identified as an independent predictor of adverse outcomes after a BCPC procedure. (18) The performance of the BCPC shunt without the use of CPB has been described using several different approaches. (18) The performance of this operation without CPB is associated with significant temporary elevation of the proximal superior vena cava (SVC) pressure that may lead to neurological injury. (74) Different techniques can be used to drain the superior vena cava (SVC) blood during clamping for BCPC anastomosis. (88) The technique of doing SBCPC without CPB has been reported by many authors. Most of these authors have reported this procedure using various techniques to drain the SVC blood during clamping. (49). Leaving additional source of pulmonary blood flow at time of BCPC may have the advantage of allowing more PA growth, supplying hepatic factors to the lungs and thus preventing arteriovenous fistula formation, facilitating future catheterization by providing access to the PA, and finally allowing a delay of Fontan by providing better oxygenation. On the other hand, disadvantages include the potential increase in volume load on SV, higher central venous pressure with subsequent facial swelling and pleural effusions, ineffective increase in oxygenation due to the high O2 concentration in the blood coming from SV, complicating future Fontan surgery and possibly increasing mortality in some reports .(84) Outcomes of SV patients continue to be largely influenced by underlying cardiac anatomy. Early and late results in patients with dominant left ventricle morphology are superior to those with dominant right ventricle morphology. The left ventricle and associated mitral valve may better equipped to tolerate volume and pressure overload imposed on the SV prior to SBCPC and to endure the continual high afterload as the ventricle assumes the responsibility of forcing the blood against the systemic vascular resistance. Subsequently, the left ventricle may be more resilient to develop systolic or diastolic dysfunction, and the mitral valve may be less prone to develop secondary regurgitation. (6) This is well reflected in our current study with better outcome achieved in patients with tricuspid atresia and double inlet left ventricle. This observation is supported by another large contemporary study from Emory in which they found that dominant right ventricle morphology continues to be a significant risk factor for adverse outcomes .(76) The prognosis of children with different SV cardiac anomalies has improved significantly due to changes in management strategy, advances in pre-operative stabilization, surgical and perfusion techniques, better post-operative care, home monitoring and progress in catheter-based intervention .(2)