{'fraction_non_alphanumeric': 0.02188183807439825, 'fraction_numerical': 0.0032822757111597373, 'mean_word_length': 4.903225806451613, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
[Right aortic arch with retro-esophageal component. 2 cases].

Right-sided aortic arch with a retro-oesophageal segment is much rarer than right-sided aortic arch without a retro-oesophageal segment. As opposed to the latter situation which is always associated with congenital heart disease, it is usually an isolated finding. The left subclavian artery arises from a posterior diverticulum and may be stenosed at its origin, giving rise to a systolic murmur as in one of the reported cases, or to a subclavian steal syndrome. The ligamentum arteriosum completes the aortic ring and may give rise to respiratory problems at varying ages and of variable severity, sometimes attributed to asthma. In one of the cases followed up over 15 years chronic respiratory problems and late tracheal lesions were observed. Although the possibility of a double aortic arch may be raised, early surgical treatment is desirable.