Influence of aspirin or heparin on platelet function and postoperative blood loss after coronary artery bypass surgery

Platelet mapping as part of modified thromboelastography (TEG®) in patients undergoing cardiac surgery and cardiopulmonary bypass

The platelet-mapping assay of the thromboelastograph was used to measure platelet aggregation and to examine the effect of cardiopulmonary bypass on multiple platelet receptors and the role of altered receptor activity in postoperative bleeding. The percentage platelet aggregation for collagen, adenosine diphosphate and arachidonic acid was measured in 40 patients divided post-hoc into high- or low-bleeding groups depending on postoperative 24-h chest tube output. Platelet aggregation was lower after cardiopulmonary bypass compared to before it using collagen (mean (SD) 45 (25) vs 19 (12)%, p<0.001), adenosine diphosphate (76 (23) vs 35 (24)%, p<0.001), and arachidonic acid (61 (33) vs 31 (35)%, p<0.001). Only platelet aggregation as measured using collagen pre- and post-cardiopulmonary bypass was significantly less in the high- compared to the low-bleeding group. This finding was significantly correlated with the 24-h chest tube drainage, and it predicted postoperative bleeding with a sensitivity of 83% and a specificity of 68%. Therefore, platelet aggregation is reduced following cardiopulmonary bypass, and this may play a role in predicting postoperative blood loss.

Effects of opium addiction on bleeding after coronary artery bypass graft surgery: report from Iran

PURPOSE

Opium abuse is a major type of drug abuse in Iran. This study was designed to find the possible relation between opium addiction and excessive bleeding after coronary artery bypass graft (CABG) surgery.

METHODS

In a historical cohort study during a 1.5-year period, consecutive patients scheduled for elective CABG surgery were assigned to two group on the basis of having or not having the criteria for inhalational opium addiction. Before and after operations, the complete blood count, bleeding time, prothrombin time, partial thromboplastin time, and platelet count were checked for all patients. The volumes of infused red blood cells during and after the operation were recorded. After operations, the volumes of bleeding through the patients' chest tubes were recorded. The recorded data were analyzed using SPSS software version 11.5. Independent t, chi-square and repeated measure tests were used; and P < 0.05 was considered statistically significant.

RESULTS

In total, 84 nonaddicted patients were assigned in group 1, and 110 patients who fulfilled the addiction criteria were assigned in group 2. Total bleeding from the three chest tubes was significantly different between the two groups (P = 0.001). The mean hemoglobin level, prothrombin time, partial thromboplastin time, and platelet counts before and after the operations were similar in the two groups. Opium-addicted patients received more packed red blood cells during and after the operations.

CONCLUSION

Inhalational opium addiction might lead to more hemorrhage after CABG surgery. It is recommended that cardiac surgeons consider these patients at high risk for major complications after surgery.

Biological and pharmacological aspects of perioperative hemorrhagic complications associated with oral platelet-directed antithrombotic agents. Focus on isolated coronary artery bypass grafting and oral irreversible P2Y(12) receptor antagonists

Coronary arterial bypass grafting (CABG)-the most common heart surgery performed worldwide-is an effective procedure for treating patients with advanced, obstructive atherothrombotic coronary artery disease, prolonging survival in selected high-risk patients. However, CABG is also associated with hemorrhagic complications, which can impact outcome measures such as perioperative morbidity, mortality, length of hospital stay, and health care expenditures. Recent observations have expanded our understanding of the complex process of hemostasis, fostering a more informed view of CABG-associated bleeding complications. Additional research is warranted to determine whether new antithrombotic drug treatment options, such as reversible P2Y12 receptor antagonists among patients with acute coronary syndromes, will favorably impact these clinically relevant complications.