{'fraction_non_alphanumeric': 0.023117569352708058, 'fraction_numerical': 0.007926023778071334, 'mean_word_length': 5.3125, '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}}
Arterial injury during perfusion preservation: a possible cause of posttransplantation renal artery stenosis.

To evaluate the effect of perfusion preservation upon renal arteries, 10 sets of porcine kidneys were removed en bloc and flushed in iced Sacks' solution via an aortic cannula. Preservation at 4 degrees C was by ice storage without perfusion (10 kidneys), perfusion with cannulation of the aortic segment (five kidneys), or perfusion with direct cannulation of the renal artery (five kidneys). After 48 to 72 hours the renal arteries and their primary branches were examined histologically. No intimal changes were evident by light microscopy. By scanning electron microscopy the endothelium of all renal arteries preserved by ice storage or aortic perfusion remained intact with only occasional deposits of particulate matter. By contrast, three distinct lesions appeared in all arteries subjected to direct cannulation: (1) full-thickness crushing at the site of the securing ligature, (2) intimal flattening at the site of contact with the cannula, and (3) marked disruption of intimal architecture extending several millimeters beyond the cannula tip. The latter injury, presumably caused by turbulent flow, is not apparent to the unaided eye. If this abnormal intima is not adequately excised at the time of transplantation, fibrin and platelet deposition may lead to fibrosis and localized arterial stenosis. The injury can be avoided by ice storage or by indirect perfusion via an aortic cannula.