{'fraction_non_alphanumeric': 0.022034520749173704, 'fraction_numerical': 0.011384502387073081, 'mean_word_length': 5.219178082191781, '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}}
Know the Guard of Coronary Sinus Before Cannulation.

CORONARY SINUS cannulation during cardiac surgery used to be a blind procedure until the advent of tranesophageal echocardiography (TEE). TEE guides the passage of retrograde cannulation and identifies the cause of difficult retrograde cannulation. A 58-year-old male patient was scheduled for aortic valve replacement due to severe aortic stenosis and aortic regurgitation. After smooth induction of anesthesia, aortic and bicaval cannulation were done, and cardiopulmonary bypass was established. Considering severe aortic regurgitation (Clip 1), the surgical plan was to insert a coronary sinus (CS) cannula for administering retrograde cardioplegia. There was difficulty in placing a transatrial retrograde cannula after repeated attempts. Transesophageal echocardiography (TEE) revealed a large Thebesian valve at the coronary sinus ostium (Fig 1) (Video Clips 2 and 3), which was obstructing entry of the retrograde cannula into the coronary sinus. Retrograde cannulation was abandoned, and the heart was arrested using coronary ostial cardioplegia. Coronary sinus cannulation commonly is used for retrograde cardioplegia administration in cardiac surgery and for interventional cardiology procedures like lead placement and electrophysiologic procedures. Coronary sinus is an anatomically short venous trunk that extends from the valve of Vieussens, at the confluence of the oblique vein of the left atrium (vein of Marshall) and the great cardiac vein, to the CS ostium in the right atrium. The coronary sinus (CS) drains almost 60% of the venous blood from the heart to the right atrium. The CS opens into the right atrium posteromedially between the right atrioventricular orifice and the inferior vena cava. Adam Christian Thebesius, in 1708 in his monograph, De circulo sanguinis in corde, first described the guard of the coronary sinus, the Thebesian valve. It is a fold of endocardial tissue derived from the embryologic caudal remnant of the right sinoatrial valve. Although it is present in almost 70% to 80% of the population, its significant anatomic variations still play an unclear role in normal physiology. Proper cannulation of the CS is influenced by the presence of the Thebesian valve and coronary sinus ostial size and its entrance from the right atrium. CS cannulation has been reported to be unsuccessful in 5% to 10% of the patients undergoing invasive cardiac procedures. Mateusz et al suggested classification of the Thebesian valves according to their shapes in a study of 273 autopsied human hearts of both sexes aged from 6 months to 94 years. That authors concluded that Thebesian valve type-III folds (17.4% of all TVs and 14.3% of