Abstract
OBJECTIVE:
This study aimed to retrospectively analyze the blood protective effect of autologous platelet separation in operations for acute aortic dissection.
METHODS:
A total of 130 patients with acute aortic dissection were enrolled into the present study. The average age of these patients was 52.962±10.5061 years old. These patients underwent the modified aortic arch replacement with the elephant trunk technique or endovascular aortic exclusion with covered stent. Among these patients, 68 patients who underwent autologous platelet separation were assigned to the platelet separation group, while the remaining patients were assigned to the control group. All operations were performed under deep hypothermic circulatory arrest. After anesthesia, 1–2 therapeutic doses of autologous platelets were isolated from patients in the platelet separation group, and these platelets were quickly infused back to these patients after heparin was neutralized by protamine at the end of the cardiopulmonary bypass. The preoperative and postoperative indexes in these two groups were compared.
RESULTS:
There were no statistically significant differences in age, gender, smoking history, drinking history and hypertension history between these two groups. Compared with controls, the transfusion volume of allogeneic platelets in the perioperative period significantly decreased in the platelet separation group (1.919±1.6226 vs. 0.794±1.1789, P < #x003C;< #x200A;0.05), and the use rate of allogeneic platelets also significantly decreased (74.19% vs. 45.59%, P < #x003C;< #x200A;0.05).
CONCLUSION:
The intraoperative auto transfusion of platelets significantly reduced the volume of allogeneic platelet transfusion after the operation for aortic dissection, which has a significant blood protective effect.
Keywords
Introduction
Aortic dissection refers to the state where the true and false separation of two lumens of the aortic wall are formed by blood entering the aortic media from the tear of the aortic intima, separating the media and extending along the long axis of the aorta [1]. Acute aortic dissection (AAD) is a rare but life-threatening disease, and the mortality rate in patients who do not receive timely surgical treatment ranges within 1–2% per hour [2, 3].
Most aortic dissection operations need to be performed under cardiopulmonary bypass (CPB). CPB is a non-physiological arteriovenous process. Its long term use can aggravate the destruction of blood platelets and coagulation factor, and increase the bleeding volume during and after the operation. Therefore, a significant amount of allogeneic blood products and powerful hemostatic drugs, especially allogeneic platelets, are often infused during the perioperative period, which significantly increase perioperative complications and mortality [4–6]. Platelets are immunogenic. However, in the present blood transfusion process, merely antigens and antibodies of red blood cells are matched, while platelets are not matched. Therefore, antigen antibody reaction may occur during blood transfusion, which forms a complex of platelets and glycoprotein IIb/IIIa. This accordingly damages and destroys their own platelets, and reduces the number of platelets in the body [7–10]. Therefore, it is very important to reduce bleeding, save blood, and reasonably and effectively use allogeneic platelets. Hence, there is an urgent need to explore effective blood protection measures during an operation. Auto transfusion can avoid the antigen antibody reaction of allogeneic transfusion, and is safer and more effective. Furthermore, this can reduce perioperative complications and mortality by separating the platelets of patients before the operation, and transfusing these back to patients during the operation, and avoid disease transmission [11].
From January to December 2017, 130 patients with aortic dissection were operated by the same group of surgeons, and the effect of platelet isolation on allogeneic platelet transfusion was retrospectively analyzed, in order to investigate the blood protective effect of this technique during the aortic dissection operation.
Materials and methods
General information of patients
The data of 130 patients with aortic dissection from January to December 2017 were retrospectively analyzed. The Ethics Committee of our hospital approved the present study, and all patients provided a signed informed consent.
Exclusion criteria: The administration of anticoagulant and antiplatelet drugs was stopped for <7 days, and patients who presented with liver and kidney dysfunction were not considered for autologous platelet separation, so they were excluded from the analysis for both groups. Among these 130 patients, 101 (77.69%) were male and 29 (22.31%) were female, and the age of these patients ranged within 26–77 years old. Among these patients, 68 patients (52.31%) who underwent autologous platelet separation were assigned to the platelet separation group, while 62 patients (47.69%) who did not use the technique of platelet separation were assigned to the control group. All these patients underwent the modified aortic arch replacement with the elephant trunk technique or endovascular aortic exclusion with covered stent for aortic dissection. All the operations were performed under deep hypothermic circulatory arrest.
Platelet separation before the operation
The requirement for allogenic blood transfusions depended on the clinical condition of the patient, thromboelastogram (TEG), and tissue perfusion/oxygenation rather than a fixed threshold of the level of haemoglobin(Hb), hematocrit (HCT), red cell volume or platelet count/function. It was determined by the operative team (cardiothoracic surgeon, perfusionist, and anesthesiologist). Generally, the haematocrit of 21–24% may be maintained during cardiopulmonary bypass (CPB). The HCT was maintained above 16% under deep hypothermic circulatory arrest. The HCT was maintained between 25% and 28% after CPB. The HCT of patients in the intensive care unit was usually dependent on the patient’s clinical parameters.
In the platelet separation group, after anesthesia and deep vein catheterization, the platelets were separated using the COM.TEC blood cell separator (Fresenius Kabi AG, Germany), which was equipped with disposable separator pipeline consumables of Fresenius C5L. The anticoagulant of Freenius Acsncoo blood preservation solution I glucose citrate (ACD) was used. The rate of collection and transfusion was 60–80 ml/min. At the same time, normal saline was replenished from another vein access. The donor’s blood and blood preservation solution were mixed at a ratio of 9 : 1, and centrifuged at 2,200 rpm. The acquisition process was carried out according to its setting procedure. The isolated platelets were continuously maintained at 22±2°C, and continuously oscillated at a frequency of 60 times/min. At the end of the CPB, and after heparin was neutralized by protamine, the collected platelets were quickly infused back into the patient.
Specimen and data collection
General situation of patients: The age, gender, smoking history, drinking history and hypertension history of the patient were collected. Blood transfusion: The amount of allogeneic platelets (1 therapeutic dose = 1 unit) used during and after the operation was recorded for these two groups.
Statistical analysis
Data were analyzed using statistical software SPSS 22.0. Count data were compared using X2-test. Measurement data were expressed as mean±standard deviation (x±SD), and compared between two groups using independent samples t-test. P < #x003C;< #x200A;0.05 was considered statistically significant.
Results
General data of patients
There were no significant differences between these two groups in terms of preoperative clinical data, which included gender, age, smoking history, drinking history and hypertension history (P > #x003E;> #x200A;0.05, Table 1). For platelet count, there was no significant difference between the two groups before operation, and were significantly decreased in both groups after operation. There were no significant differences in adverse events, mortality or hospital stay.
Comparison of general data between two groups
Comparison of general data between two groups
Table 2 presents the data for the allogeneic platelet dosage in these two groups during the perioperative period. Compared with the control group, the transfusion volume of allogeneic platelets in the perioperative period significantly decreased in the platelet separation group (1.919±1.6226 vs. 0.794±1.1789, P < #x003C;< #x200A;0.05).
The allogeneic platelet dosage in these two groups
The allogeneic platelet dosage in these two groups
Table 3 presents the data for the allogeneic platelet utilization rate in these two groups during the perioperative period of aortic dissection. Among these patients, 16 patients (25.81%) in the control group and 37 patients (54.41%) in the platelet separation group did not use allogeneic platelets, while 46 patients (74.19%) in the control group and 31 patients (45.59%) in the platelet separation group used allogeneic platelets (Table 3).
Rate of utilization of allogeneic platelets [cases (%)]
AAD is a devastating cardiovascular disease. There are approximately 2.6–3.6 new cases per 100,000 persons each year. AAD is a life-threatening disease, which has high mortality and more complications during hospitalization and before the operation [1, 2]. As the incidence of aortic dissection increases and the onset age becomes younger, this has become the key to study the operation method of aortic dissection and determine how to reduce the complications. With the maturity of the corresponding operation for aortic dissection, many patients have been saved [1, 2]. Therefore, the adverse outcome after an operation remains as an urgent problem to be solved in cardiac surgery at home and abroad. Furthermore, it has become a hotspot to reduce the complications of the disease, and improve the survival rate of patients [3, 4].
Perioperative bleeding and coagulation dysfunction are common complications in patients undergoing aortic dissection under CPB [10–14]. In the CPB process, many links, such as low temperature, mechanical extrusion, intracardiac suction, direct blood gas contact, blood flow shear stress and the side effects of anesthetics, can destroy blood cells, and reduce the number and function of platelets, resulting in coagulation dysfunctions, such as the activation of the internal and external coagulation system, the consumption of platelets, the hyperactivity of the fibrinolysis system, the activation of inflammatory cells, and the release of inflammatory mediators [15, 16]. Accordingly, these cause a systemic reaction and damage to the important organs of patients, leading to postoperative bleeding. Furthermore, its postoperative hemostasis remains difficult, and the massive infusion of allogeneic blood components and hemostatic drugs also increase postoperative complications and mortality [17]. However, even if these hemostasis measures are improved, since platelets are immunogenic, and are not matched during the allogeneic transfusion at present, an antigen antibody reaction may occur during the blood transfusion, which would accordingly damage and destroy these platelets, and reduce the number of platelets in the body [17]. Auto transfusion can prevent the antigen antibody reaction of allogeneic transfusion. Furthermore, it is safer and more effective, and can also prevent disease transmission [17].
In the present study, 130 patients with AAD, who underwent a limited operation in 2017, were enrolled as the study subjects, and the influence of platelet isolation technique on the usage and use rate of allogeneic platelets were retrospectively analyzed. The results revealed that compared with the control group, the transfusion volume of allogeneic platelets in the perioperative period significantly decreased in the platelet separation group (1.919±1.6226 vs. 0.794±1.1789, P < #x003C;< #x200A;0.05). Furthermore, the use rate of allogeneic platelets also significantly decreased (74.19% vs. 45.59%, P < #x003C;< #x200A;0.05). Therefore, the use of intraoperative platelet separation technology to separate autologous platelets to infuse back to patients can significantly reduce the transfusion volume of allogeneic platelets after aortic dissection, which has a significant blood protective effect. It has been reported in previous literatures that prospective and retrospective studies on aortic surgery have also confirmed its blood protective effect [18–20]. Furthermore, it has been reported in another previous literature that in the auto transplantation group, the platelet count significantly increased at one hour after the operation, while the 24-hour thoracic drainage volume, 24-hour allogeneic red blood cells, plasma transfusion and allogeneic platelet transfusion significantly decreased, and the indexes, such as fibrinogen, coagulation rate and platelet function, were better than those in the control group. In addition to reducing the transfusion volume of allogeneic platelets, the preoperative isolation of platelets can also reduce the destruction of autologous platelets by CPB [21].
The present study has some limitations. First, the present study has a small sample size, and was single-center study. Furthermore, the selected time span was short, and the number of patients with aortic dissection was small. Hence, further follow-up works at multiple centers with large samples are needed. Second, further studies are needed to determine whether the technique of platelet separation can be applied for all CPB operations. Finally, the role and mechanism of platelet separation in perioperative complications and mortality needs further in-depth studies and long-term follow-ups. Future prospective randomized controlled studies are needed to obtain a clearer answer.
Conclusion
The use of intraoperative platelet separation technology to separate autologous platelets and infuse these back to patients can significantly reduce the transfusion volume of allogeneic platelets after aortic dissection, and has an obvious blood protective effect. However, further studies are still needed to determine whether the platelet separation technique can be applied for all CPB operations.
Funding
National Natural Science Foundation of China (No. 81601741), the Science Foundation for young scientists of Shandong Province (No. BS2015SW026), the Initial Funding for New Clinical and Practical Techniques of Qilu Hospital of Shandong University (No. 2017-2).