Changes in platelet count, coagulation and fibrinogen associated with elective repair of asymptomatic abdominal aortic aneurysm and aortic reconstruction for occlusive disease

Background:Mortality and morbidity following aortic surgery, particularly repair of ruptured abdominal aortic aneurysm (AAA), is frequently associated with the development of coagulopathy.Objectives:To examine changes in platelet count (PC), fibrinogen, and coagulation in patients undergoing elective repair of asymptomatic abdominal aortic aneurysm (AAA) and aortic surgery for occlusive disease.Design:Prospective clinical study in a University Department of Vascular Surgery.Patients:Thirty-three patients undergoing elective repair of asymptomatic AAA and 19 patients undergoing aortic surgery for occlusive disease.Methods:Full blood count (FBC), clotting screen, and fibrinogen measured pre-operatively; 6, 12, 24, 48 h postoperatively; and thereafter as clinically indicated in 23 consecutive patients undergoing AAA repair (Group 1). Pre- and postoperative PC measured weekly for 4 weeks following operation in a further 10 consecutive patients undergoing AAA repair (Group 2) and perioperative PC measured in 19 consecutive patients undergoing aortic surgery for occlusive disease (Group 3).Results:Group 1: Preoperative haematological parameters were normal. There was no mortality. Postoperatively, 21 (91%) patients developed thrombocytopenia (PC <150 × 109/l). The postoperative fall in PC (median 90, range 12–160 × 109/l) was significantly related to the duration of aortic cross-clamp (median 46, range 20–127 min, r2 = 0.33, p<0.01). At 10 days all patients had developed thrombocytosis (PC >350 × 109/l) Postoperatively, by 48 h, 17 (74%) patients had developed hyperfibrinogenaemia. One patient suffered a myocardial infarction associated with a PC of 105 × 109/l and a fibrinogen of 7.2 g/l.Group 2:In a further 10 patients undergoing AAA repair postoperative thrombocytosis was found to persist for several weeks in five of nine survivors.Group 3:Patients undergoing aortic surgery for occlusive disease had significantly higher preoperative PC than AAA patients (median 292, range 179–251 × 109/l vs. median 204, range 140–293 × 109/l, p