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Introduction: Recently resistance to an acetylsalicylic acid (ASA) administration has been a frequently mentioned problem. However, to identify ASA nonresponsive patients (ASA resistance) is difficult and common examination procedures can contain important preanalytic, analytic and postanalytic mistakes. Recently a possibility to use aggregometry after induction with cationic propyl gallate (CPG) has been discussed in this context; it's a robust, highly sensitive, and specific method for ASA resistance estimates. We asked ourselves following questions during our work:, Goal: a) Experience patients with acute coronary syndrome (ACS) ASA resistance more often than healthy volunteers?; b) Are aggregation values in both patients with different metabolic homeostasis disorders and patients with risk factors for atherosclerotic complications different?; c) Change results of measured aggregation induced by CPG in patients treated with identical ASA therapy during a several years long monitoring; respectively are patients assessed differently during the monitoring?; d) Is it possible to use one-shot aggregation assessment following CPG to estimate ASA resistance or is it necessary to repeat the examinations?; e) Is recurrence of ACS complications more frequent during two years of monitoring of patients with ACS history resistant to 100 mg doses of ASA per day?, Method: 103 patients of an average age 69 were assessed. All of them suffered from ACS without ST segment elevations and were treated conservatively; in addition to it all of them were treated with 100 mg ASA/day. They were assessed at the onset of ACS and after 3, 12 and 24 months. The examination consisted of taking patient history, clinical examination, BMI determination, laboratory test for cholesterol, HDL, LDL, triacylglycerols, and glucose, and of an aggregation of thrombocytes assessment under standard conditions (spontaneous and after CPG induction)., Results and Conclusion: a) ASA resistance is more frequent in patients with ACS compared to healthy volunteers (45% to 6%, p < 0.001). b) Patients with type II DM, smokers, patients with low HDL cholesterol levels or high triacylglycerols levels are ASA resistant more often (< 0.05). c) Results of measured aggregation of thrombocytes don't change during administration of the identical dose of 100 mg ASA/day during 2 years of monitoring. Respondents usually are assessed identically during monitoring (responsive/ASA nonresponsive). d) ASA resistance can be estimated from one-shot aggregation assessment following induction with CPG. e) Two years after diagnosing the ASA resistance a percentage of cardiovascular complications recurrence is higher in patients with history of ACS (p < 0.001). One-shot assessments of the CPG induced thrombocytes aggregation and the spontaneous aggregation are sensitive in 81% of patients with ACS history and specific in 100% of patients at risk of recurrence of cardiovascular complications. If these results are confirmed it could lead to a change in interventions in patients with ASA resistance proved by this method.

Introduction and Aim of the Study: Acetylsalicylic acid (ASA) is one of basic preparations used in the therapy of cardiovascular diseases. Application of ASA leads to irreversible reduction of platelet aggregation. The aim of the present study was to verify monitoring of effectiveness of ASA therapy using the measurement of platelet aggregability in vitro after induction by cationic propyl gallate (CPG), which is considered to be a highly potent inducer of aggregation., Methods: We examined a group of 27 healthy volunteers, divided into two subgroups (n = 19, n = 8). The first subgroup was examined for thrombocyte aggregation before and 24 hours after administration of 400 mg of ASA after induction by ADP, collagen, adrenalin and CPG. The second subgroup was examined for thrombocyte aggregation before and after a three-day administration of ASA in a dose of 100 mg/day., Results and Conclusion: In the group of 27 healthy volunteers we determined normal values of aggregability for individual inducers. Low stability of the used methods was proved (weak or insignificant correlation of results of the same method before and after administration of ASA). The most advantageous parameter for monitoring of effectiveness of 400 and 100 mg of ASA was CPG slope (paired t test, p < 0.00000002, resp. p < 0.001). The parameter of CPG slope we determined in both subgroups the cut-off value (< 53s), by means of which it is possible to discriminate probands according to ASA therapy (in contrast to other routinely used inducers). The obtained results indicate that measurement of thrombocyte aggregation after CPG induction reveals a significantly lower percentage of ASA non-responders ASA than after other inducers. Measurement of thrombocyte aggregation after CPG induction is predicted to be highly promising for monitoring the effectiveness of anti-aggregation therapy.

Introduction and Objective: Acetylsalicylic acid (ASA) is one of the basic preparations which are used in the treatment of cardiovascular diseases. ASA administration leads to irreversible restriction of platelet aggregation. The objective of our work was to test possibilities of monitoring the effectiveness of ASA therapy by measuring the platelet aggregability in vitro after induction with cationic propyl gallate (CPG) which is considered a very potent aggregation inductor., Method: We examined a group of 27 healthy volunteers divided into two sub-groups (n = 19, n = 8). In the first sub-group the platelet aggregation was examined before and after 24 hours following ingestion of 400 mg ASA after induction with ADP, collagen, adrenaline and CPG. In the second sub-group the platelet aggregation was examined before and after three-day administration of ASA--100 mg/day., Results and Conclusion: In a group of 27 volunteers we assessed normal values of aggregation after different inductors. A low stability of the methods used was proved (low stability or insignificant correlation of results of the same method before and after ASA ingestion. The most useful parameter by means of which it was possible to monitor the effectiveness of administration of 400 or 100 mg ASA was the C/G slope (paired t-test, p < 0.0000002, and p < 0.001 resp.). In parameter CPG slope we were able to assess in both groups the cut-off value (< 53%/min.) by means of which it is possible to discriminate probands according to ASA therapy (contrary to the other commonly used inductors). From the results ensues that when assessing the thrombocyte aggregation after CPG induction we find a significantly lower percentage of so-called ASA non-respondents than after other inductors. We consider the use of assessment of thrombocyte aggregation after CPG induction when monitoring antiaggregation therapy a very promising procedure.