Factors associated with excessive bleeding in cardiopulmonary bypass patients: a nested case-control study

<p>Abstract</p> <p>Introduction</p> <p>Excessive bleeding (EB) after cardiopulmonary bypass (CPB) may lead to increased mortality, morbidity, transfusion requirements and re-intervention. Less than 50% of patients undergoing re-intervention exhibit surgical sources of bleeding. We studied clinical and genetic factors associated with EB.</p> <p>Methods</p> <p>We performed a nested case-control study of 26 patients who did not receive antifibrinolytic prophylaxis. Variables were collected preoperatively, at intensive care unit (ICU) admission, at 4 and 24 hours post-CPB. EB was defined as 24-hour blood loss of >1 l post-CPB. Associations of EB with genetic, demographic, and clinical factors were analyzed, using SPSS-12.2 for statistical purposes.</p> <p>Results</p> <p>EB incidence was 50%, associated with body mass index (BMI)< 26.4 (25–28) Kg/m², (<it>P </it>= 0.03), lower preoperative levels of plasminogen activator inhibitor-1 (PAI-1) (<it>P </it>= 0.01), lower body temperature during CPB (<it>P </it>= 0.037) and at ICU admission (<it>P </it>= 0.029), and internal mammary artery graft (<it>P </it>= 0.03) in bypass surgery. We found a significant association between EB and 5G homozygotes for PAI-1, after adjusting for BMI (F = 6.07; <it>P </it>= 0.02) and temperature during CPB (F = 8.84; <it>P </it>= 0.007). EB patients showed higher consumption of complement, coagulation, fibrinolysis and hemoderivatives, with significantly lower leptin levels at all postoperative time points (<it>P </it>= 0.01, <it>P </it>< 0.01 and <it>P </it>< 0.01).</p> <p>Conclusion</p> <p>Excessive postoperative bleeding in CPB patients was associated with demographics, particularly less pronounced BMI, and surgical factors together with serine protease activation.</p

LEUKOCYTE PROTEINASE RELEASE DURING STORAGE OF RED-CELL CONCENTRATES

HERTFELDER HJ, SUWER V, POPOVCENIC S, Tschesche H, HANFLAND P. LEUKOCYTE PROTEINASE RELEASE DURING STORAGE OF RED-CELL CONCENTRATES. EUROPEAN JOURNAL OF CLINICAL CHEMISTRY AND CLINICAL BIOCHEMISTRY. 1994;32(6):441-447.The release of polymorphonuclear leukocyte proteinases in buffy-coat-depleted red cell concentrates was examined during a storage period of 35 days. Collagenase, gelatinase and elastase predominantly induce breakdown of connective tissue. However, when released by cell disintegration during red cell concentrate storage, the considerable proteolytic activities of these enzymes might influence the quality of the stored blood. During the observation period a considerable decrease in the polymorphonuclear leukocyte count was observed, accompanied by increases in the levels of collagenase, gelatinase and elastase. Compared with the enzyme levels on the day of red cell concentrate preparation, collagenase increased 20-fold, gelatinase 6-fold and elastase 100-fold during the storage period. When cells were treated with the chemoattractant hexapeptide, N-formyl-nle-leu-phe-nle-tyr-leu, and the degranulation promoting cytochalasin B, gelatinase exhibited the highest secreted concentration in the freshly prepared red cell concentrate, exceeding the maximum of spontaneously released elastase by 4- to 6-fold. However, these compounds stimulated enzyme release only during the first day after red cell concentrate preparation. Thereafter, no differences between stimulated and non-stimulated samples were observed. The data indicate that polymorphonuclear leukocytes contain a large storage pool of proteolytic enzymes. These enzymes together with other polymorphonuclear leukocyte enzymes, e.g. hydrolases and oxidoreductases, might alter the erythrocyte membrane surface and thus influence the storage quality of the prepared red cell concentrate