RESUMO
We evaluated 54 patients with different right heart by-pass by means of contrast echocardiography with rapid venous injection of shaken saline (3 cc, < 20 k; 6cc, > 20 k), in order to detect venous collateral circulation in partial by-pass, pulmonary arteriovenous fistulae in partial and total by-pass, and right-to-left shunt in total by-pass. Forty three patients had partial by-pass: 29 had a bidirectional cavopulmonary anastomosis with additional pulmonary flow (systemic-pulmonary anastomosis and/or restrictive anterograde ventricular flow); 10 had a partial ventricular correction (bidirectional cavopulmonary anastomosis and non restrictive anterograde ventricular flow; two had classical Glenn procedures; two had Kawashima operations (bidirectional cavopulmonary anastomosis and non restrictive anterograde ventricular flow; two had classical Glenn procedures; two had kawashima operations (bidirectional cavopulmonary anastomosis with inferior vena cava interruption), and 11 with total by-pass (10 atriopulmonary anastomosis and 1 with total cavopulmonary anastomosis). The age ranged from 2.5 to 33 years (x = 12.2 years), and the mean postoperative period was 4.3 years. Venous collateral circulation: 32/43 patients (74%) with partial by-pass, specially in those without partial biventricular correction: 29/33 patients (88%) compared to those with partial biventricular correction: 3/10 (30%) p < 0.01. Pulmonary arteriovenous fistulae: 6/43 patients (14%) with partial by-pass; 6/33 (18%) with partial biventricular correction, 0/10 patients with partial biventricular correction, and 0/11 with total by-pass. Right-to-left shunt: 2/11 patients (18%) with total by-pass, all of them with atriopulmonary anastomosis. Contrast echocardiography is an excellent noninvasive method for the initial evaluation of specific dysfunctions of different right heart by-pass. We emphasize the higher frequency of collateral venous circulation in cavopulmonary anastomosis, that would explain the dysfunction with progressive hypoxia in the evolution of these patients. Pulmonary arteriovenous fistulae were detected only in partial by-pass, without partial biventricular correction (p < 0.01). The minor frequency of these fistulae in bidirectional cavopulmonary anastomosis would be due to additional pulmonary flow.
