[Alterations in certain indices of the haemostasis system following aortic surgery]

A total of 24 patients were examined after surgery on the thoracic or abdominal aorta. Depending on the level of the aortic clamping at the main stage of the operation, the patients were subdivided into three groups: Group One was composed of 7 patients with aortic coarctation in whom the level of artery clamping was located just below the subclavian artery, Group Two comprised 7 patients with an aneurysm of the infrarenal aortic portion, with the clamp applied immediately underneath the renal arteries, and Group Three consisted of 10 patients with type IV thoracoabdominal aortic aneurysm according to Crawford's classification, with the artery being clamped above the diaphragm. The studies were carried out at the following stages: before and at the end of surgery, then 6 hours thereafter, and at 24 hours postoperatively.

The alterations in the indices of plasma-thrombocytic haemostasis at all the stages were insignificant and did not differ reliably between the groups. In Group One patients, the time of XHa-kallikrein-dependent fibrinolysis (XIIaKDF) at the end of the operation was found to be within the range of the normal values(657.5+/-92.3 s) and had no statistically reliable differences from the baseline value (612.0+/-63.7 s). After 6 hours and on day 1 after the operation, we observed inconsiderable inhibition of the fibrinolytic activity (903.0+/-142.3 and 848.9+/-149.5 s, respectively). In Group Two patients at the end of the operation, we registered a statistically reliable, as compared with the baseline value, shortening of the time of XIIaKDF (from 990.0 +/-81.0 to 510.0 +/- 103.6 s, p<0.05). However, the subsequent stages of the follow-up revealed a dramatic decrease in the fibrinolytic activity (to1.388.0+/-183.1 s). Group Three patients demonstrated a considerable activation of fibrinolysis at the end of the operation (348.2 +/-48.5 s), which was noted to remain unchanged during the first 24 postoperative hours, with the alterations in the D-dimer's concentration in patients of all groups at the stages of observation being of a unidirectional pattern, i. e. increasing maximally after 6 hours to be then decreasing on the first 24 hours after the operation.

To prevent postoperative haemorrhage associated with hyperfibrinolysis in aortic operations, it is necessary to administer antifibrinolytic drugs with due regard for the level of aortic clamping.