Marcin Makowski

Platelet reactivity and mean platelet volume as risk markers of thrombogenesis in atrial fibrillation

Atrial fibrillation (AF) is associated with increased risk of thromboembolic complications. One of the markers of the increased risk of hypercoagulable state is platelet hyperreactivity. The aim of the study was to assess impact of arrhythmia on platelet reactivity. METHODS The study included 36 (mean age 48,3; range 21-60) male patients with lone atrial fibrillation, with exclusion of concomitant diseases known to trigger hypercoagulable state. The AF patients underwent cardioversion to restore sinus rhythm and were subsequently under observation for 1month. Echocardiography, ECG and blood collection was performed before cardioversion (T0) and 4weeks after successful cardioversion (T1). During the study period patients have been contacted and examined every week and 24h ECG monitoring was performed. Platelet reactivity was assessed based on changes of CD62 and CD42b expression on platelet surface after stimulation with thrombin. Also changes in MPV were assessed. RESULTS In all patients sinus rhythm was maintained at the end of the study period, however in 14 patients recurrences of AF were observed, confirmed by 24h ECG monitoring (atrial fibrillation recurrence group - AFR) and 22 patients maintained sinus rhythm throughout the whole study period (SR group). Mean fluorescence intensity (MFI) of CD62 on thrombin stimulated platelets decreased significantly 4weeks after electrical cardioversion as compared to T0 (48.04±22.42 vs 41.47±16.03; p<0.01). Also MFI of CD42b on thrombin stimulated platelets decreased significantly 4weeks after electrical cardioversion as compared to T0 (22.16±10.82 vs 12.06±5.99; p<0.0001). Platelets reactivity estimated by CD 62 expression in SR group decreased significantly after 4weeks observation (58.01±15.26 vs 46.57±13.44; p<0.001) opposite to AFR group 35.66±21.87 vs 34.54±16.4; p-ns). Moreover there were significant differences between basal reactivity during AF between SR and AFR groups (58.01±15.26 vs 35.66±21.87; p-0.01). MFI of CD42b on thrombin stimulated platelets decreased significantly both in AFR and SR groups (22.05±11.36 vs 13.8±6.03; p<0.001 and 21.87±14.18 vs 10.04±5.09; p<0005). MPV decreased significantly 4weeks after electrical cardioversion as compared to T0 (8.81±0.19 vs 8.42±0.14; p<0.0001). CONCLUSION The changes of platelet reactivity to thrombin observed after restoration of sinus rhythm in patients prove that arrhythmia intrinsically leads to increased reactivity of platelets.

Effect of sinus rhythm restoration on platelet function in patients with lone atrial fibrillation.

Atrial fibrillation (AF) is associated with increased risk of thrombo- embolic complications. The aim of thestudywasto assessif arrhythmia, independent of other risk factors leads to increased platelet activation. The study involved 34 (mean age 50 +/� 9.03, range 21-59) male patients with lone persistent atrial fibrillation. The exclusion criteria were: age N60, coronary artery disease, left ventricular dysfunction (ejection fraction EF b 40%), congenital and acquired heart defects, artificial heart valve, diabetes, thyroid disease, inflammatory diseases, cancer, renal disease, and active smoking. The exclusion criteria precluded more than 95.4% of patients with AF hospitalized in our Department within the last 6 years. The AF patients underwent cardioversion to restore sinus rhythm and remained subsequently under observation for 1 month. Echocardi- ography, ECG and blood collection was performed before cardioversion (T0) and 4 weeks after successful cardioversion (T1). During the study period, patients were contacted and examined weekly along with 24-hour ECG monitoring. In all patients sinus rhythm was maintained at the end of the study period, however in 12 patients recurrence of AF was observed, confirmed by 24-hour ECG monitoring (atrial fibrillation recurrence group — AFR). In 10 patients the episodes of arrhythmia were asymp- tomatic, while only 2 patients complained of arrhythmia symptoms. In 22 patients no recurrence of AF in 24-hour ECG monitoring was observed (sinus rhythm group — SR). Parameters of resting platelets collected from peripheral blood activation was measured using flow cytometry. Platelet activation was assessed by expression of p-selectin (CD62) on platelets (CD61 positive cells). The platelet aggregate number was presented as a percentage of CD61+ blood elements bigger than platelets. The platelet derived microparticles (PDMPs) were assessed based on FSC histogram profile as CD61+ particles smaller than platelets. The leukocyte-platelet aggregates were detected based on coexpression of CD11b and CD62

From blood coagulation to innate and adaptive immunity: the role of platelets in the physiology and pathology of autoimmune disorders

Thrombosis and cardiovascular complications are common manifestations of a variety of pathological conditions, including infections and chronic inflammatory diseases. Hence, there is great interest in determining the hitherto unforeseen immune role of the main blood coagulation executor—the platelet. Platelets store and release a plethora of immunoactive molecules, generate microparticles, and interact with cells classically belonging to the immune system. The observed effects of platelet involvement in immune processes, especially in autoimmune diseases, are conflicting—from inciting inflammation to mediating its resolution. An in-depth understanding of the role of platelets in inflammation and immunity could open new therapeutic pathways for patients with autoimmune disorders. This review aims to summarize the current knowledge on the role of platelets in the patomechanisms of autoimmune disorders and suggests directions for future research.

NSAIDs Hypersensitivity: When and How to Desensitize?

Opinion statementNon-steroidal anti-inflammatory drugs (NSAIDs) are the most commonly used drugs and are among the major causes of hypersensitivity reactions. NSAIDs can evoke different types of both immunological and non-immunologically mediated hypersensitivity reactions, and management of these reactions depends on type of hypersensitivity reaction. As NSAIDs are comprised of several drugs with different chemical structures which can inhibit both cyclooxygenases or selectively cyclooxygenase type 2 (COX-2), in most of the cases, it is possible to find a safe non-cross-reactive drug for a patient. However, in certain situations, especially when patients require anti-platelet treatment, patients can be desensitized to aspirin.

Patients with Idiopathic Inflammatory Myopathiesand Primary involvement of Heart Muscle andCardiovascular Complications

Idiopathic inflammatory myopathies are rare connective tissue disorders, in which inflammatory process affects mainly skeletal muscles leading to their progressive weakness. However internal organs can be affected as well, deteriorating the course of disease. We present cases of two patients with cardiac manifestations as predominant symptoms of idiopathic inflammatory myopathies. In both cases arrhythmia was the leading symptom preceding diagnosis of myositis.

Platelet reactivity and mean platelet volume as new biomarkers in risk stratification in patient with atrial fibrillation

Thank you for very valuable comments to our study. We completely agree that there is still lack of methods of precise estimation of thromboembolic complications (TE) risk, especially in the group of CHA2DS2-VASc score 1. It is striking that these patients according to studies on Asian population have higher risk over 2% as compared to European studies [1,2]. According to our studies [3,4] even patients with lone atrial fibrillation have increased platelet reactivity which reflects procoagulable state. Thuswe agreewith Authors thatwe should search for more precise, reliable, easy and useful scores which include laboratory test to minimalize thromboembolic complications. Platelet activation and reactivity measured by flow cytometry could be additional marker, but in our opinion, in everyday clinical practice may be problematic due to several issues: short time to examination (optimal