Only hepatic venous blood closes intrapulmonary shunts after cavopulmonary connection

Abstract

In patients with a functional univentricular heart good results are nowadays accomplished with a staged approach to a total cavopulmonary connection (TCPC) [ [1] d'Udekem Y. Iyengar A.J. Cochrane A.D. et al. The Fontan procedure: contemporary techniques have improved long-term outcomes. Circulation. 2007; 116: I157-I164 PubMed Google Scholar ]. However, there are certain complications leading to a diminished quality of life as well as significant morbidity and mortality [ [2] Hess J. Long-term problems after cavopulmonary anastomosis: diagnosis and management. Thorac Cardiovasc Surg. 2001; 49: 98-100 Crossref PubMed Scopus (21) Google Scholar ]. Beside protein-losing enteropathy, plastic bronchitis, dysrhythmias, ventricular dysfunction and arteriovenous fistulas or venovenous collaterals due to increased venous pressure [ 2 Hess J. Long-term problems after cavopulmonary anastomosis: diagnosis and management. Thorac Cardiovasc Surg. 2001; 49: 98-100 Crossref PubMed Scopus (21) Google Scholar , 3 Lenz D. Hambsch J. Schneider P. et al. Protein-losing enteropathy in patients with Fontan circulation: is it triggered by infection?. Crit Care. 2003; 7: 185-190 Crossref PubMed Scopus (48) Google Scholar ], microscopic intrapulmonary shunts are one of the major complications [ [4] Bernstein H.S. Brook M.M. Silverman N.H. Bristow J. Development of pulmonary arteriovenous fistulae in children after cavopulmonary shunt. Circulation. 1995; 92: II309-II314 Crossref PubMed Google Scholar ]. The incidence is reported to be up to 25% [ [5] Cloutier A. Ash J.M. Smallhorn J.F. et al. Abnormal distribution of pulmonary blood flow after the Glenn shunt or Fontan procedure: risk of development of arteriovenous fistulae. Circulation. 1985; 72: 471-479 Crossref PubMed Scopus (162) Google Scholar ]. The pathophysiology of these shunts is discussed and associated with a so-called liver factor. It has been observed, that the shunts become present in lungs without direct perfusion with hepatic venous blood, which means hepatic venous drainage has to pass another capillary bed first [ [6] Srivastava D. Preminger T. Lock J.E. et al. Hepatic venous blood and the development of pulmonary arteriovenous malformations in congenital heart disease. Circulation. 1995; 92: 1217-1222 Crossref PubMed Scopus (304) Google Scholar ]. The absence of venous hepatic blood flow into the lungs then leads to development and progression of the intrapulmonary shunts. This is the case in patients with partial cavopulmonary connection (PCPC) or after completion to TCPC with the hepatic venous drainage being directed mainly to one lung. The liver-factor-hypothesis is also supported by the fact that the shunts disappear after redirecting hepatic venous blood to the affected lung [ 7 Shah M.J. Rychik J. Fogel M.A. Murphy J.D. Jacobs M.L. Pulmonary AV malformations after superior cavopulmonary connection: resolution after inclusion of hepatic veins in the pulmonary circulation. Ann Thorac Surg. 1997; 63: 960-963 Abstract Full Text Full Text PDF PubMed Scopus (154) Google Scholar , 8 Praus A. Eicken A. Balling G. Schreiber C. Hess J. Progressive intrapulmonary shunting in a child after bidirectional Glenn operation only resolved after total cavopulmonary completion. Int J Cardiol. 2008; 128: e12-e15 Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar ]. However, the exact pathophysiology or details about the hepatic factor are still not completely understood. In this study we analyzed the results of different therapeutic approaches in patients with severe intrapulmonary shunting and functional univentricular heart.