Surgical palliation of primary pulmonary arterial hypertension by a unidirectional valved Potts anastomosis in an animal model.

OBJECTIVE: Patients with idiopathic pulmonary hypertension are at risk for right-sided heart failure and sudden death. Despite improvement in pharmacologic management, some still require lung transplantation. Potts anastomosis has been demonstrated as a good palliation in children to alleviate symptoms and medical therapy despite desaturation in the lower part of the body. Young adult patients with pulmonary hypertension and isosystemic pressure remain at risk, particularly at exercise. The goal of this research was to find a palliation for patients in whom suprasystemic pulmonary hypertension developed at exercise. Creating a Potts anastomosis involved a unidirectional valve between the left pulmonary artery and the descending aorta. METHODS: Experimental study was performed on 14 pigs. A prosthetic patch of polytetrafluoroethylene (Gore-Tex; WL Gore & Associates Inc, Newark, Del) was used to create the unidirectional valve and implanted in the Potts anastomosis. Via a left thoracotomy, an aorto-aortic shunt between the aortic isthmus and the distal descending thoracic aorta was instituted, allowing a safe surgical procedure. Intrapulmonary injection of Erciplex glue (Peters Surgical, Bobigny, France), diluted in 70% alcohol, was used to create acute pulmonary hypertension. The right to left shunt across the unidirectional valvular patch was evaluated after clamping the aorta in the acute phase of pulmonary hypertension by echo-pulsed Doppler at the level of the descending thoracic aorta by withdrawal of blood gas (arterial carbon dioxide tension, alveolar carbon dioxide tension) and assessment of peripheral oxygen saturation. Similar reevaluation of the shunt was performed at a mean interval of 13 ± 2.5 weeks. RESULTS: In the first series, Erciplex glue increased pulmonary artery pressure from 15.3 ± 3.1 mm Hg to 38.7 ± 6.0 mm Hg. Mean peripheral oxygen saturation decreased from 100% to 85% ± 1.5%. Mean partial pressure of carbon dioxide increased from 31.9 ± 9.1 mm Hg to 46.2 ± 12.5 mm Hg after shunt opening (P < .01), and mean peripheral oxygen decreased from 435.1 ± 109.4 mm Hg to 261.9 ± 77.9 mm Hg (P < 0.05), indicating right to left shunt through the Potts valve (P < .013). Pulsed Doppler showed a mean peak laminar flow of 133.3 ± 35.3 cm/s before aortic clamping, turbulent flow of 234.9 ± 40.1 cm/s after glue injection, and return of laminar flow 128.5 ± 30.1 cm/s after aortic isthmus unclamping. In the second series, the same results were obtained but with a lesser peak flow velocity because of the endothelialization on the valvular patch. Gross analysis of the patch did not show thrombosis, aneurysm, or fissure. CONCLUSIONS: Palliation of exercise suprasystemic pulmonary hypertension was demonstrated by a unidirectional valved Potts anastomosis. This technique can be of help in young adult patients with pulmonary hypertension and isosystemic pressure but with exercise intolerance.

Plasma concentrations of N-terminal pro-brain natriuretic peptide in control children from the neonatal to adolescent period and in children with congestive heart failure.

OBJECTIVE: To determine plasma levels of N-terminal pro-brain natriuretic peptide (N-BNP) in control children to establish a normal age-dependent range from the neonatal period to adulthood. In addition, plasma concentrations of N-BNP were measured in children with congestive heart failure (CHF) and correlated with ejection fraction and clinical symptoms of heart failure. METHODS: For establishing a normal age-dependent range of plasma N-BNP, venous blood samples were taken in 133 control patients from the neonatal period to adulthood (10 days-32 years) and in 31 children with CHF. Plasma N-BNP levels were determined by an enzyme immunoassay. In children (1 month-14 years) with CHF, plasma N-BNP levels were correlated to ejection fraction measured by echocardiography and clinical symptoms of heart failure using the Ross Score. RESULTS: N-BNP levels in control children, adolescents, and adults did not show a significant age-related difference. In control children, the normal range was established between 150 (10th percentile) and 430 fmol/mL (90th percentile). Mean plasma N-BNP in control children was 311 fmol/mL (range: 74-654 fmol/mL). In 31 children with CHF, the plasma N-BNP levels were significantly higher (mean: 846; range: 219-2718) than in control children. N-BNP levels showed a negative correlation with the ejection fraction (r = -0.53) and a positive correlation with the clinical heart failure score (r = 0.74). CONCLUSIONS: Plasma N-BNP levels reflect the severity of symptoms of heart failure and the impairment of cardiac function in children with CHF. In the future, determination of plasma N-BNP levels may be used as a helpful adjunct to monitor the effect of various treatments for CHF in children.