Jeanne Grace; Head Research Subjects Review Board
试验速览
- 阶段
- 4 期
- 状态
- 已完成
- 入组人数
- 40
- 试验地点
- 2
- 主要终点
- 1. the PFA-100, a platelet related hemostasis test which is a high shear system test of platelet function
研究概览
简要总结
It is known that patients with aortic stenosis, including those undergoing cardiac surgery for this problem, are prone to developing bleeding problems, particularly of the gastrointestinal tract. It is believed that the shear stress associated with blood flow through the abnormal aortic valve results in abnormal hemostasis. Abnormalities include increased proteolysis of the von Willebrand factor (vWF) and increased binding of the high molecular weight multimers of vWF to platelet membranes with subsequent inappropriate platelet aggregation. Thus, appropriate aggregation of circulating platelets is impaired. Cardiac surgery is associated with significant alterations in hemostasis. Patients undergoing cardiac surgery consume a significant percent of available blood products throughout the United States and are subjected to various and numerous risks associated with blood product transfusion. In addition, excessive postoperative bleeding is a common cause for the need to surgically re-explore the chest cavity in patients who have just undergone cardiac surgical procedures. Such additional surgery carries further cost and risk. Following surgical correction of aortic valve stenotic pathology, associated vWF abnormalities appear to reverse. However, this process can take several days. Although all cardiac surgical patients are at risk for postoperative bleeding, patients undergoing aortic valve surgery for aortic stenosis may be particularly at risk for this postoperative complication. In addition, patients with aortic valve stenosis who undergo noncardiac surgery may have a predisposition to bleeding because of similar underlying shear stress induced abnormal vWF and platelet function. The proposed study is a trial to evaluate the effectiveness of 2 different antifibrinolytic drugs in ameliorating the hemostatic defect associated with aortic stenosis. Aprotonin, an antifibrinolytic agent which also has platelet preserving actions4, will be compared to the currently used anti-fibrinolytic, epsilon aminocaproic acid (EACA).
详细描述
Study subjects will be competent adult patients who are scheduled to undergo elective aortic valve surgery for severe aortic stenosis. The process of informed consent will begin prior to the day of surgery either during a patient's preoperative surgery clinic visit with one of the cardiac surgeons for any patient having such a clinic visit or during the preoperative anesthesia evaluation prior to the day of surgery. At one or both of these times patients will be told of the study and given a copy of the informed consent for their reading. An opportunity for them to discuss the study at this time will be offered. Written informed consent will be obtained on the day of surgery, prior to surgery. Patients must not also require coronary artery surgery or be taking or receiving drugs that alter platelet function, including aspirin (within the past 2 weeks) or any of the modern a ADP receptor antagonists such as Plavix. As per current patient care guidelines at Strong Memorial Hospital, patients undergoing first-time single valve, non-coronary artery surgical procedures will be randomized to receive either epsilon aminocaproic acid (EACA) or aprotonin intravenously. It is anticipated that 1-3 patients will be initially enrolled as pilot subjects to get the study going smoothly and that 1-3 patients may not be completed or that their testing and/or data may be inadequate. Therefore, although the analysis will only use 40 subjects the protocol seeks permission to enroll a maximum of 24 subjects per group for a total of 48 patients.
The tests to be performed are:
- the PFA-100, a platelet related hemostasis test which is a high shear system test of platelet function
- the von Willebrand antigen test, an immunoassay
- factor VIII coagulant activity test.
- Ristocetin cofactor activity test.
- thromboelastography (TEG), a point-of-care test of hemostatic function which includes a measure of platelet function.
(Reference ranges / coefficient of variation / SD's / for the tests are as follows:
vWF-Ag: 50 - 160% normal activity / 2 - 5% / ~5%
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Single Group
- 盲法
- Double
入排标准
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Study subjects will be competent adult patients who are scheduled to undergo elective aortic valve surgery for severe aortic stenosis.
排除标准
- •Potential study subjects will be excluded if they are scheduled to undergo elective aortic valve surgery for severe aortic stenosis and any other surgery simultaneously or have been taking aspirin within 6 days of surgery.
结局指标
主要结局
1. the PFA-100, a platelet related hemostasis test which is a high shear system test of platelet function
PFA-100, a platelet related hemostasis test
2. the von Willebrand antigen test, an immunoassay
von Willebrand antigen test
3. factor VIII coagulant activity test.
Factor VIII coagulant activity test
4. Ristocetin cofactor activity test.
5. thromboelastography (TEG), a point-of-care test of hemostatic function which includes a measure of platelet function.
次要结局
- thromboelastography