[The bidirectional cavo-pulmonary anastomosis: a clinico-functional assessment in a medium-term follow-up]

The bidirectional cavo-pulmonary anastomosis is a useful surgical procedure for patients with complex congenital heart disease characterized by univentricular physiology. This operation significantly increases effective pulmonary blood flow and rarely causes distortion of the main pulmonary arterial branches. The aim of this study was to evaluate the clinical and pathophysiologic consequences of bidirectional cavo-pulmonary anastomosis as well as the effectiveness of this surgical approach as a definitive palliation.

Clinical, hemodynamic and functional data of 12 patients who had undergone a bidirectional cavo-pulmonary anastomosis were reviewed. Each patient underwent clinical examination, chest x-ray, ambulatory EKG, bidimensional color-Doppler echocardiography, spirometric analysis, lung perfusion scintigraphy, cardiac catheterization and angiography, and stress test. Stress test data were compared to those obtained by a normal population of age-matched children.

After a mean follow-up interval of 28 +/- 20 months all patients showed a good clinical condition. Improved oxygenation, exercise tolerance and growth velocity were noted in all patients. Only 34% of patients showed abnormalities of chest x-ray, 29% manifested significant arrhythmias during ambulatory EKG and 20% showed abnormal ventricular function echocardiographically. Spirometry was normal in all patients, while lung perfusion scintigraphy was constantly abnormal with right/left and upper/lower perfusion mismatch. At cardiac catheterization a reduction of end diastolic volume (from 106.9 +/- 50.6 to 67.3 +/- 41.6 ml, p < 0.05) and end systolic volume (from 58.0 +/- 27.9 to 32.5 +/- 33.5 ml, p < 0.05) was noted. The functional evaluation of these patients was highly abnormal due to an impaired response to effort as evidenced by work time (p < 0.0001 vs normal) and stress-induced cardiovascular modifications.

On the basis of these findings, we suggest that: 1) bidirectional cavo-pulmonary anastomosis is useful as an intermediate step towards a Fontan procedure, as it improves the hemodynamic performance of the systemic ventricle; 2) conversely, bidirectional cavo-pulmonary anastomosis should not be considered a form of definitive palliation for complex congenital heart disease because in these patients the response to exercise remains unsatisfactory.