Effect of cardiopulmonary bypass on platelet mitochondrial respiration and correlation with aggregation and bleeding: a pilot study

Cold stored platelets in the management of bleeding: is it about bioenergetics?

When platelet concentrates (PCs) were first introduced in the 1960s as a blood component therapy, they were stored in the cold. As platelet transfusion became more important for the treatment of chemotherapy-induced thrombocytopenia, research into ways to increase supply intensified. During the late 1960s/early 1970s, it was demonstrated through radioactive labeling of platelets that room temperature platelets (RTP) had superior post-transfusion recovery and survival compared with cold-stored platelets (CSP). This led to a universal switch to room temperature storage, despite CSP demonstrating superior hemostatic effectiveness upon being transfused. There has been a global resurgence in studies into CSP over the last two decades, with an increase in the use of PC to treat acute bleeding within hospital and pre-hospital care. CSP demonstrate many benefits over RTP, including longer shelf life, decreased bacterial risk and easier logistics for transport, making PC accessible in areas where they have not previously been, such as the battlefield. In addition, CSP are reported to have greater hemostatic function than RTP and are thus potentially better for the treatment of bleeding. This review describes the history of CSP, the functional and metabolic assays used to assess the platelet storage lesion in PC and the current research, benefits and limitations of CSP. We also discuss whether the application of new technology for studying mitochondrial and glycolytic function in PC could provide enhanced understanding of platelet metabolism during storage and thus contribute to the continued improvements in the manufacturing and storage of PC.

The effect of the relationship between post-cardiotomy neutrophil/lymphocyte ratio and platelet counts on early major adverse events after isolated coronary artery bypass grafting

Background

In this study, we aimed to investigate the role of postcardiotomy neutrophil, lymphocyte, and platelet counts in predicting major adverse events after coronary artery bypass grafting.

Methods

A total of 373 patients (257 males, 116 females; median age 63, range 33 to 85 years) who underwent isolated coronary artery bypass grafting under cardiopulmonary bypass between January 2015 and January 2020 were retrospectively analyzed. The patients who did not develop any postoperative major adverse event were included in Group 1, while those who did constituted Group 2. Preoperative neutrophil-to-lymphocyte ratio, postcardiotomy neutrophil-to-lymphocyte ratio, postoperative Day 1 neutrophil-to-lymphocyte ratio, and neutrophil-to-lymphocyte x platelet ratio were calculated.

Results

Preoperative neutrophil counts, C-reactive protein values, neutrophilto- lymphocyte ratio, total perfusion time, and length of intensive care unit and hospital stay were significantly higher in Group 2 (p=0.019, p=0.028, p<0.001, p=0.027, p<0.001, and p<0.001, respectively). Post-cardiotomy neutrophil, neutrophil-to-lymphocyte ratio, and neutrophil-to-lymphocyte x platelet ratio, along with the postoperative first day white blood cell count, neutrophil, C-reactive protein, neutrophil-to-lymphocyte ratio, and neutrophil-to-lymphocyte x platelet ratio were significantly higher in Group 2 (p=0.004, p<0.001, p<0.001, p=0.019, p=0.003, p=0.001, p<0.001, and p=0.041, respectively). The post-cardiotomy platelet and lymphocyte counts and postoperative first day lymphocyte counts were significantly lower in Group 2 (p<0.001, p=0.007, and p=0.009, respectively).

Conclusion

Post-cardiotomy neutrophil-to-lymphocyte ratio and neutrophilto- lymphocyte x platelet ratio can be easily accessible, inexpensive complete blood count parameters and may be more valuable in predicting major adverse events in patients undergoing coronary artery bypass grafting.

Assessment of platelet respiration as emerging biomarker of disease

Mitochondrial dysfunction is currently acknowledged as a central pathomechanism of most common diseases of the 21(st) century. Recently, the assessment of the bioenergetic profile of human peripheral blood cells has emerged as a novel research field with potential applications in the development of disease biomarkers. In particular, platelets have been successfully used for the ex vivo analysis of mitochondrial respiratory function in several acute and chronic pathologies. An increasing number of studies support the idea that evaluation of the bioenergetic function in circulating platelets may represent the peripheral signature of mitochondrial dysfunction in metabolically active tissues (brain, heart, liver, skeletal muscle). Accordingly, impairment of mitochondrial respiration in peripheral platelets might have potential clinical applicability as a diagnostic and prognostic tool as well as a biomarker in treatment monitoring. The aim of this minireview is to summarize current information in the field of platelet mitochondrial dysfunction in both acute and chronic diseases.

The combined effects of the microcirculatory status and cardiopulmonary bypass on platelet count and function during cardiac surgery

BACKGROUND

Cardiac surgery with cardiopulmonary bypass is associated with important changes in the microcirculation, usually attributed to endothelial dysfunction. Another common finding of cardiac surgery is postoperative thrombocytopenia and platelet loss of function.

OBJECTIVE

To investigate the association between microvascular flow pattern and postoperative changes in platelet count and function in cardiac surgery patients.

METHODS

Twelve adult cardiac surgery patients received microvascular circulation (sidestream darkfield sublingual mucosa analysis) and platelet count and function (multiple electrode aggregometry ADPtest and TRAPtest) assessment before and after cardiopulmonary bypass.

RESULTS

After cardiopulmonary bypass, sublingual microcirculation showed a significantly (P = 0.001) decreased microvascular flow index and increased heterogeneity index (P = 0.006). Platelet function significantly decrease after cardiopulmonary bypass both at ADPtest (P = 0.011) and TRAPtest (P = 0.002). Preoperative patterns of poor microvascular perfusion (low perfused vessels density and total vessels density) were significantly associated with lower values of post-cardiopulmonary bypass platelet function (ADPtest, P = 0.009, TRAPtest, P = 0.031) and count (P = 0.048).

CONCLUSIONS

A preoperative disturbance of the microcirculation is associated with a greater postoperative platelet dysfunction. Endothelial damage, chemical and mechanical stimuli are the possible link between the two patterns.

Perioperative management and monitoring of antiplatelet agents: a focused review on aspirin and P2Y12 inhibitors

Platelets play pivotal roles in hemostasis as well as pathological arterial thrombosis. The combination of aspirin and a P2Y₁₂ inhibitor has become the mainstay therapy in the ageing population with cardiovascular conditions, particularly during and after percutaneous coronary intervention. A number of novel P2Y₁₂ inhibitors has become available in the recent years, and they markedly vary in pharmacokinetic and pharmacodynamic properties. Perioperative physicians today face a challenge of preventing hemorrhage due to platelet inhibitors, while minimizing thrombotic risks. There are several point-of-care platelet function tests available in the peri-procedural assessment of residual platelet aggregation. However, these platelet function tests are not standardized in terms of sample processing, agonist type and potency as well as methods of detecting platelet activity. Understanding the differences in pharmacological properties of antiplatelet agents, principles of platelet function tests, and pertinent hemostatic strategies may be useful to anesthesiologists and intensivists who manage perioperative issues associated with antiplatelet agents. The objectives of this review are: 1) to discuss clinical data on aspirin and P2Y₁₂ inhibitors relating to perioperative bleeding, 2) to outline different features of point-of-care platelet function tests, and 3) to discuss therapeutic options for the prevention and treatment of bleeding associated with antiplatelet agents.