Resistenz gegen Azetylsalizylsäure und Clopidogrel

Acetylsalicylic Acid Resistance After Simultaneous Pancreas-Kidney Transplantation

BACKGROUND

The most common conditions leading to death after simultaneous pancreas-kidney transplantations (SPKs) are cardiovascular diseases. The aim of this study was to test the platelet aggregation inhibitor acetylsalicylic acid (ASA) resistance in patients after SPKs, including investigations into the triggering factors.

METHODS

Thirty-two patients (22 men, 10 women; overall age, 47.4 ± 8.6 years) were involved in our study and took 100 mg ASA per day. We used optical platelet aggregometry to detect resistance.

RESULTS

Resistance occurred in 40.6% of the study group. However, with the use of logistic regression analysis, the examined 24 factors did not show any significant correspondence with resistance.

CONCLUSIONS

The incidence of ASA resistance seems to be higher compared with other groups, but the triggering effect is still unproved. Clarifying this question should be important regarding the mortality- and morbidity-reducing capacity of antiplatelet drugs in the management of cardiovascular conditions.

[Significance of platelet function tests]

Numerous laboratory tests are in use to detect congenital or acquired platelet function disorders. Platelet aggregometry, using ADP, collagen, arachidonic acid or ristocetin as inductor is the standard test system for diagnosis. It is also used to detect platelet non-response to antiplatelet therapy. Studies have demonstrated that laboratory assessment of platelet non response to aspirin or clopidogrel is associated with adverse outcomes, and they indicate the importance of adjusting antiplatelet therapy in patients with a low degree of platelet inhibition. Nevertheless, a standardized method for identifying these patients is still missing.

Prevalence of Platelet Dysfunction and Abnormal Coagulation: Results of a Population-Based Study

The prevalence of impairments in the hemostatic process is unknown in acutely ill people. Data on hemostasis (PFA 100®) and the coagulation cascade of 1015 people are presented here, establishing a cohort of unselected emergency patients in a population-based approach. A high prevalence of reduced platelet function (38%) was found, which was more frequent than expected. In contrast, there was a lower prevalence (20%) of abnormal plasmatic coagulation, which was almost always explained by medication, whereas medication could not predict abnormal platelet function. Moreover, a history of disproportionate bleeding did not correlate well with abnormal platelet or coagulation factor function and could not substitute for a screening in this setting. The effect of acetylsalicylic acid (ASA) on PFA-closure time was frequently missing (34%), indicating a considerable prevalence of ASA nonresponse among the study population. These data should be applicable in similar settings. The high prevalence of unexpectedly abnormal platelet function in acute illness as well as the high prevalence of possible ASA nonresponders suggests a functional platelet assay to be effective in screening certain subpopulations of emergency patients.