{'fraction_non_alphanumeric': 0.02739018087855297, 'fraction_numerical': 0.02118863049095607, 'mean_word_length': 6.143911439114391, '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}}
Randomized study on the effect of collagen impregnation of knitted Dacron® velour aortoiliac prostheses on blood loss during aortic reconstruction

Intraoperative blood loss is an important factor in reconstructive surgery for aortoiliac disease because it is clearly associated with an increase in the operative morbidity and mortality rates. To minimize intraoperative blood loss, a blood‐tight vascular prosthesis has been developed by impregnating a knitted Dacron™ prosthesis with bovine collagen. To study a potential reduction of intraoperative blood loss using these collagen‐impregnated prostheses, we conducted a prospective randomized trial involving the collagen‐impregnated prosthesis and its non‐impregnated substrate, the Dacron knitted non‐impregnated prosthesis. During a 2·5‐year period, 123 consecutive patients (undergoing 81 procedures for aneurysmal disease and 43 procedures for occlusive disease) were admitted for elective aortic reconstructive surgery. Equal numbers of the two prostheses were randomly implanted. Various parameters were monitored: intraoperative blood loss before aortic cross‐clamping (phase 1), during implantation of the prosthesis (phase 2) and after release of aorta cross‐clamping (phase 3); the number of intraoperative and postoperative blood transfusions; and, finally, all preoperative and intraoperative factors that might contribute to intraoperative blood loss. A significant overall difference in intraoperative blood loss between the collagen‐impregnated (2425 ml) and the non‐impregnated (1907 ml) group was found (P = 0·003). However, this difference could not be attributed to collagen impregnation because no statistically significant difference in blood loss was found in the relevant period of operation (phase 3). Similar results were observed in patients operated on for both aneurysmal and occlusive disease (2600 versus 2195 ml and 2105 versus 1344 ml respectively).