Perioperative management of antiplatelet-drugs in cardiac surgery

Intraoperative ventricular septal rupture: A case report

Ventricular septal rupture (VSR) is a rare complication of myocardial infarction that requires surgical repair. Herein, we describe a case of intraoperative VSR requiring patch repair and postoperative extracorporeal membrane oxygenation (ECMO) support. This case highlights the risk factors, patient presentation, and management recommendations for this potentially lethal pathology.

Point-of-Care Platelet Function Monitoring: Implications for Patients With Platelet Inhibitors in Cardiac Surgery

Although most physicians are comfortable managing the limited anticoagulant effect of aspirin, the recent administration of potent P2Y₁₂ receptor inhibitors in patients undergoing cardiac surgery remains a dilemma. Guidelines recommend discontinuation of potent P2Y₁₂ inhibitors 5- to- 7 days before surgery to reduce the risk of postoperative hemorrhage. Such a strategy might not be feasible before urgent surgery, due to ongoing myocardial ischemia or in patients at high risk for thromboembolic events. Recently, different point-of-care devices to assess functional platelet quality have become available for clinical use. The aim of this narrative review was to evaluate the implications and potential benefits of platelet function monitoring in guiding perioperative management and therapeutic options in patients treated with antiplatelets, including aspirin or P2Y₁₂ receptor inhibitors, undergoing cardiac surgery. No objective superiority of one point-of-care device over another was found in a large meta-analysis. Their accuracy and reliability are generally limited in the perioperative period. In particular, preoperative platelet function testing has been used to assess platelet contribution to bleeding after cardiac surgery. However, predictive values for postoperative hemorrhage and transfusion requirements are low, and there is a significant variability between and within these tests. Further, platelet function monitoring has been used to optimize the preoperative waiting period after cessation of dual antiplatelet therapy before urgent cardiac surgery. Furthermore, studies assessing their value in therapeutic decisions in bleeding patients after cardiac surgery are scarce. A general and liberal use of perioperative platelet function testing is not yet recommended.

Ticagrelor Removal by CytoSorb® in Patients Requiring Emergent or Urgent Cardiac Surgery: A UK-Based Cost-Utility Analysis

BACKGROUND

Acute coronary syndrome patients receiving dual antiplatelet therapy who need emergent or urgent cardiac surgery are at high risk of major bleeding, which can impair postoperative outcomes. CytoSorb^®, a blood purification technology based on adsorbent polymer, has been demonstrated to remove ticagrelor from blood during on-pump cardiac surgery.

OBJECTIVE

The aim of this study was to evaluate the cost utility of intraoperative removal of ticagrelor using CytoSorb versus usual care among patients requiring emergent or urgent cardiac surgery in the UK.

METHODS

A de novo decision analytic model, based on current treatment pathways, was developed to estimate the short- and long-term costs and outcomes. Results from randomised clinical trials and national standard sources such as National Health Service (NHS) reference costs were used to inform the model. Costs were estimated from the NHS and Personal Social Services perspective. Deterministic and probabilistic sensitivity analyses (PSAs) explored the uncertainty surrounding the input parameters.

RESULTS

In emergent cardiac surgery, intraoperative removal of ticagrelor using CytoSorb was less costly (£12,933 vs. £16,874) and more effective (0.06201vs. 0.06091 quality-adjusted life-years) than cardiac surgery without physiologic clearance of ticagrelor over a 30-day time horizon. For urgent cardiac surgery, the use of CytoSorb was less costly than any of the three comparators-delaying surgery for natural washout without adjunctive therapy, adjunctive therapy with short-acting antiplatelet agents, or adjunctive therapy with low-molecular-weight heparin. Results from the PSAs showed that CytoSorb has a high probability of being cost saving (99% in emergent cardiac surgery and 53-77% in urgent cardiac surgery, depending on the comparators). Cost savings derive from fewer transfusions of blood products and re-thoracotomies, and shorter stay in the hospital/intensive care unit.

CONCLUSIONS

The implementation of CytoSorb as an intraoperative intervention for patients receiving ticagrelor undergoing emergent or urgent cardiac surgery is a cost-saving strategy, yielding improvement in perioperative and postoperative outcomes and decreased health resource use.

A Difference in Bleeding and Use of Blood and Blood Products in Patients who Were Preoperatively on Aspirin or Dual Antiplatelet Therapy Before Coronary Artery Bypass Grafting

Background

Postoperative bleeding in patients who underwent elective coronary artery bypass surgery (CABG) may increase due to preoperative anticoagulant therapy indicative of their disease - acute coronary syndrome or implanted coronary artery stent. Increased bleeding in many cases requires the use of blood and blood derivatives, and sometimes even reoperation. Their use poses the risk of complications, may extend the hospitalization.

Methods

Our observation retrospective study included 131 patients, 41 treated with aspirin and 90 treated with aspirin and clopidogrel. All underwent for the first time elective on-pump isolated CABG surgery at Clinic for cardiovascular surgery of Clinical Center University of Sarajevo, in period June 2016 to September 2017. The data were collected from patient's records.

Results

Out of 131 patients,73.3% were male. The average age was 62. The average total drainage during the first 48 postoperative hours in ASA group was 1027.4±404.9ml and 1049.8±371.3ml in DAPT group. The mean number of whole blood transfusions in the DAPT group washigher compared to ASAgroup. The average number of fresh frozen plasma were higher in the DAPT group 0.84±0.51 compared to the group ASA 0.39±0.07, as well the average thrombocytes transfusions were slightly higher in the DAPT group. Statistical analysis suggests that there is no significant difference between the observed groups (p>0.05). Also, our study did not show a statistically significant difference between arrhythmia onset, the length of mechanical ventilation, use of protamineand tranexamic acid. Reoperation due to postoperative bleeding was recorded in 2 cases in the DAPT group as well as 2 lethal cases.

Conclusion

In our study, we could not demonstrate less postoperative bleeding and use of blood and blood products in a group of patients who were preoperatively treated with aspirin compared to patients with dual antiplatelet therapy in the elective isolated CABG surgery.

Perioperative changes in platelet count and function in patients undergoing cardiac surgery

Background: Patients undergoing cardiac surgery are at increased risk of bleeding due to multifactorial coagulopathies. In the present study, we aimed at investigating the changes in platelet count and function during and after surgery as well as determining the association of the platelet dysfunction with bleeding and transfusion requirements in these patients.

Methods: A total of 40 adult patients scheduled for elective valve coronary cardiac surgery were included in this prospective observational study. Changes in platelet count and function with ADP, acid arachidonic, and collagen (light transmission aggregometry) were analyzed at three time points: before CPB, after CPB, and 24 hours after end of surgery. Postoperative bleeding and intraoperative transfusion requirements were recorded.

Results: There were a significant reverse correlation between CPB time and ADP-induced aggregation, particularly after CPB and postoperative AA-induced aggregation. There was not any significant correlation between platelet count and function at all-time points. Both platelet count and platelet aggregation significantly reduced during CPB. While platelet aggregation increased on postoperative Day 1, platelet count reduced by about 40% after CPB, and remained at this level postoperatively. Patients with abnormal ADP-induced aggregation had significant increased postoperative bleeding and transfusion requirements.

Conclusion: The results of this study demonstrate that platelet count and platelet aggregation are reduced during CPB. Our results emphasized the effect of platelet dysfunction on increased postoperative bleeding and transfusion requirements. Perioperative monitoring of platelet function can be considered as a bleeding management strategy for implantation of PBM programs.

Additive antithrombotic effect of ASP6537, a selective cyclooxygenase (COX)-1 inhibitor, in combination with clopidogrel in guinea pigs

Clopidogrel (Plavix^®, Sanofi-Aventis), the adenosine diphosphate P2Y₁₂ receptor antagonist, is reported to be effective in the prevention of cardiovascular events and is often used in combination with aspirin, particularly in high-risk patients. ASP6537 is a reversible cyclooxygenase (COX)-1 inhibitor that is under investigation as an anti-platelet agent. First, we investigated the reversibility of the antiplatelet effect of ASP6537 and its interaction with ibuprofen to compare the usability of ASP6537 with that of aspirin. We then evaluated the antithrombotic effect of ASP6537 in combination with clopidogrel using a FeCl₃-induced thrombosis model in guinea pigs. ASP6537 exerted reversible antiplatelet activity, and no pharmacodynamic interaction with ibuprofen was noted. When administered as monotherapy, ASP6537 exerted a significant antithrombotic effect at ≥3mg/kg, while aspirin inhibited thrombosis at 100mg/kg. ASP6537 exerted significant additive effects in combination with clopidogrel, and the minimum antithrombotic dose was reduced by concomitant administration of clopidogrel. Our study showed that ASP6537 did not interact with ibuprofen and has clear additive effects in combination with clopidogrel. ASP6537 may therefore represent a promising antiplatelet agent for use in clinical settings in combination with clopidogrel.

Platelet sequestration and activation during GalTKO.hCD46 pig lung perfusion by human blood is primarily mediated by GPIb, GPIIb/IIIa, and von Willebrand Factor

BACKGROUND

Here, we ask whether platelet GPIb and GPIIb/IIIa receptors modulate platelet sequestration and activation during GalTKO.hCD46 pig lung xenograft perfusion.

METHODS

GalTKO.hCD46 transgenic pig lungs were perfused with heparinized fresh human blood. Results from perfusions in which αGPIb Fab (6B4, 10 mg/l blood, n = 6), αGPIIb/IIIa Fab (ReoPro, 3.5 mg/l blood, n = 6), or both drugs (n = 4) were administered to the perfusate were compared to two additional groups in which the donor pig received 1-desamino-8-d-arginine vasopressin (DDAVP), 3 μg/kg (to pre-deplete von Willebrand Factor (pVWF), the main GPIb ligand), with or without αGPIb (n = 6 each).

RESULTS

Platelet sequestration was significantly delayed in αGPIb, αGPIb+DDAVP, and αGPIb+αGPIIb/IIIa groups. Median lung "survival" was significantly longer (>240 vs. 162 min reference, p = 0.016), and platelet activation (as CD62P and βTG) were significantly inhibited, when pigs were pre-treated with DDAVP, with or without αGPIb Fab treatment. Pulmonary vascular resistance rise was not significantly attenuated in any group, and was associated with residual thromboxane and histamine elaboration.

CONCLUSIONS

The GPIb-VWF and GPIIb/IIIa axes play important roles in platelet sequestration and coagulation cascade activation during GalTKO.hCD46 lung xenograft injury. GPIb blockade significantly reduces platelet activation and delays platelet sequestration in this xenolung rejection model, an effect amplified by adding αGPIIb/IIIa blockade or depletion of VWF from pig lung.

Preventing deep wound infection after coronary artery bypass grafting: a review

The consequences of deep wound infections before, during, and after coronary artery bypass grafting have prompted research to clarify risk factors and explore preventive measures to keep infection rates at an irreducible minimum. An analysis of 42 studies in which investigators used multivariate logistic regression analysis revealed that diabetes mellitus and obesity are by far the chief preoperative risk factors. A 4-point preoperative scoring system based on a patient's body mass index and the presence or absence of diabetes is one practical way to determine the risk of mediastinitis, and other risk-estimate methods are being refined. Intraoperative risk factors include prolonged perfusion time, the use of one or more internal mammary arteries as grafts, blood transfusion, and mechanical circulatory assistance. The chief postoperative risk factor is reoperation, usually for bleeding. Unresolved issues include the optimal approach to Staphylococcus aureus nasal colonization and the choice of a prophylactic antibiotic regimen. We recommend that cardiac surgery programs supplement their audit processes and ongoing vigilance for infections with periodic, multidisciplinary reviews of best-practice standards for preoperative, intraoperative, and postoperative patient care.

Prevention of the renarrowing of coronary arteries using drug-eluting stents in the perioperative period: an update

The management of patients scheduled for surgery with a coronary stent, and receiving 1 or more antiplatelet drugs, has many controversies. The premature discontinuation of antiplatelet drugs substantially increases the risk of stent thrombosis (ST), myocardial infarction, and cardiac death, and surgery under an altered platelet function could also lead to an increased risk of bleeding in the perioperative period. Because of the conflict in the recommendations, this article reviews the current antiplatelet protocols after positioning a coronary stent, the evidence of increased risk of ST associated with the withdrawal of antiplatelet drugs and increased bleeding risk associated with its maintenance, the different perioperative antiplatelet protocols when patients are scheduled for surgery or need an urgent operation, and the therapeutic options if excessive bleeding occurs.