Clinical and structural aspects of tracheal stenosis and a novel embryological hypothesis of left pulmonary artery sling.

OBJECTIVES: To identify the imaging features peculiar to congenital tracheal stenosis (CTS) complicated with left pulmonary artery sling (LPAS) with the aim of presenting a hypothesis of tracheal stenosis embryology in LPAS. METHODS: We retrospectively reviewed CTS patients (with complete cartilaginous rings) admitted between April 2010 and July 2018. All the patients were classified into the LPAS or non-LPAS group, and their clinical characteristics and qualitative variables on computed tomography (CT) imaging were compared. RESULTS: Of the 72 patients enrolled, 61 had bilateral lungs. Among the bilateral lung patients, 26 (43%) had LPAS. The tracheal bifurcation was significantly deeper, the stenotic region was longer, and the bronchial angle (especially in the right) was wider, in the LPAS group. The cut-off values for the thoracic vertebral level at the tracheal bifurcation (>4.8), subcarinal angle (>118.1), and right bronchial angle (>61.9) were useful for diagnosing suspected cases of LPAS. In the time-dependent course, LPAS complicated with a congenital heart defect was a statistically significant risk factor of respiratory symptoms (hazard ratio, 3.01; 95% confidence interval, 1.23-7.37; P = .02). CONCLUSIONS: The CT findings described here should immediately raise suspicion of LPAS on chest X-ray and also suggest tracheal "squeezing and milking" by the surrounding vessels in the embryo. Patients with LPAS complicated with a heart defect should be followed carefully to determine the optimal timing of intervention.

Development of reference equations for spirometry in Japanese children aged 6-18 years.

BACKGROUND: Spirometry is the most widely used pulmonary function test and the measured values of spirometric parameters need to be evaluated using reference values predicted for the corresponding race, sex, age, and height. However, none of the existing reference equations for Japanese children covers the entire age range of 6-18 years. The Japanese Society of Pediatric Pulmonology had organized a working group in 2006, in order to develop a new set of national standard reference equations for commonly used spirometric parameters that are applicable through the age range of 6-18 years. METHODS: Quality assured spirometric data were collected through 2006-2008, from 14 institutions in Japan. We applied multiple regression analysis, using age in years (A), square of age (A(2)), height in meters (H), square of height (H(2)), and the product of age and height (AH) as explanatory variables to predict forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV(1)), peak expiratory flow (PEF), forced expiratory flow between 25% and 75% of the FVC (FEF(25-75%)), instantaneous forced expiratory flow when 50% (FEF(50%)) or 75% (FEF(75%)) of the FVC have been expired. RESULTS: Finally, 1,296 tests (674 boys, 622 girls) formed the reference data set. Distributions of the percent predicted values did not differ by ages, confirming excellent fit of the prediction equations throughout the entire age range from 6 to 18 years. Cut-off values (around 5 percentile points) for the parameters were also determined. CONCLUSIONS: We recommend the use of this new set of prediction equations together with suggested cut-off values, for assessment of spirometry in Japanese children and adolescents.

Radionuclide imaging study of long-term pulmonary function after lobectomy in children with congenital cystic lung disease.

PURPOSE: We evaluated the long-term pulmonary function after lobectomy for congenital cystic lung disease, in both infants and children, using radionuclide imaging (RI). METHODS: We performed a retrospective review of 93 patients who underwent resection of cystic lung lesions between 1974 and 2001. The results of postoperative lung volume/perfusion scintigraphy at 1 (n = 64), 5 (n = 32), and 10 years (n = 18) after surgery (V1, 5, 10/Q1, 5, 10) and mean transit time (MTT-a marker for air-trapping) at 1, 5, and 10 years after surgery (MTT1, 5, 10) were compared with respect to age at operation, preoperative infection, underlying disease, and type of surgery. RESULTS: Patients who were younger than 1 year at the time of surgery showed a significantly lower MTT5 (1.09 +/- 0.08) and MTT10 (1.15 +/- 0.11) than patients who were older than 1 year at the time of surgery (MTT5, 1.49 +/- 0.67; MTT10, 1.54 +/- 0.33). The noninfected group had significantly higher Q10 and lower MTT10 values (P < .05) compared to the infected group. No significant differences were observed between patients with single lobe vs multiple lobe resection. CONCLUSIONS: The optimal age for surgery in patients with congenital cystic lung disease appears to be less than 1 year.

Hepatopulmonary syndrome can show spontaneous resolution: possible mechanism of portopulmonary hypertension overlap?

Hepatopulmonary syndrome (HPS) (hypoxaemia due to intrapulmonary vasodilation and a right-to-left shunt associated with liver disease) resolves after liver transplantation. The authors describe a case of spontaneous resolution of HPS prior to liver transplantation. This patient was diagnosed with HPS associated with extra-hepatic biliary atresia when she was 10 years old. She exhibited digital clubbing, facial vascular dilation, cyanosis, and suffered from dyspnoea during exercise. The patient's PaO(2) at rest was 53.8 mm Hg in room air and a Technetium-99m macro-aggregated albumin lung perfusion scan demonstrated a right-to-left shunt. Although her symptoms and laboratory data supported a diagnosis of HPS, she nevertheless showed spontaneous resolution within 2 years. When she was 14 years old, pulmonary hypertension was evident upon examination of her echocardiogram. HPS may be improved or masked by an accidental overlap with pulmonary hypertension in the terminal stage of liver disease.