Immediate and late effects of coronary angiography on soluble endothelial cell markers and P-selectin in patients with and without coronary artery disease

Soluble Platelet Release Factors as Biomarkers for Cardiovascular Disease

Platelets are the main players in thrombotic diseases, where activated platelets not only mediate thrombus formation but also are involved in multiple interactions with vascular cells, inflammatory components, and the coagulation system. Although in vitro reactivity of platelets provides information on the function of circulating platelets, it is not a full reflection of the in vivo activation state, which may be relevant for thrombotic risk assessment in various disease conditions. Therefore, studying release markers of activated platelets in plasma is of interest. While this type of study has been done for decades, there are several new discoveries that highlight the need for a critical assessment of the available tests and indications for platelet release products. First, new insights have shown that platelets are not only prominent players in arterial vascular disease, but also in venous thromboembolism and atrial fibrillation. Second, knowledge of the platelet proteome has dramatically expanded over the past years, which contributed to an increasing array of tests for proteins released and shed from platelets upon activation. Identification of changes in the level of plasma biomarkers associated with upcoming thromboembolic events allows timely and individualized adjustment of the treatment strategy to prevent disease aggravation. Therefore, biomarkers of platelet activation may become a valuable instrument for acute event prognosis. In this narrative review based on a systematic search of the literature, we summarize the process of platelet activation and release products, discuss the clinical context in which platelet release products have been measured as well as the potential clinical relevance.

Laboratory assessment of anti-thrombotic therapy in heart failure, atrial fibrillation and coronary artery disease: insights using thrombelastography and a micro-titre plate assay of thrombogenesis and fibrinolysis

As heart failure, coronary artery disease and atrial fibrillation all bring a risk of thrombosis, anti-thrombotic therapy is recommended. Despite such treatment, major cardiovascular events such as myocardial infarction and stroke still occur, implying inadequate suppression of thrombus formation. Accordingly, identification of patients whose haemostasis remains unimpaired by treatment is valuable. We compared indices for assessing thrombogenesis and fibrinolysis by two different techniques in patients on different anti-thrombotic agents, i.e. aspirin or warfarin. We determined fibrin clot formation and fibrinolysis by a microplate assay and thromboelastography, and platelet marker soluble P selectin in 181 patients with acute or chronic heart failure, coronary artery disease who were taking either aspirin or warfarin. Five thromboelastograph indices and four microplate assay indices were different on aspirin versus warfarin (p < 0.05). In multivariate regression analysis, only microplate assay indices rate of clot formation and rate of clot dissolution were independently related to aspirin or warfarin use (p ≤ 0.001). Five microplate assay indices, but no thrombelastograph index, were different (p < 0.001) in aspirin users. Three microplate assay indices were different (p ≤ 0.002) in warfarin users. The microplate assay indices of lag time and rate of clot formation were abnormal in chronic heart failure patients on aspirin, suggesting increased risk of thrombosis despite anti-platelet use. Soluble P selectin was lower in patients on aspirin (p = 0.0175) but failed to correlate with any other index of haemostasis. The microplate assay shows promise as a tool for dissecting thrombogenesis and fibrinolysis in cardiovascular disease, and the impact of antithrombotic therapy. Prospective studies are required to determine a role in predicting thrombotic risk.

Effect of Remote Ischemic Preconditioning on Platelet Activation Induced by Coronary Procedures

In this study, we aim to assess whether remote ischemic preconditioning (RIPC) reduces platelet activation during coronary angiography (CA) and/or percutaneous coronary interventions. We studied 30 patients who underwent CA because of a suspect of stable angina. Patients were randomized to RIPC (3 short episodes of forearm ischemia) or sham RIPC (controls) before the procedure. Blood samples were collected at baseline, at the end of the procedure, and 24 hours later. Monocyte-platelet aggregate (MPA) formation and platelet CD41 in the MPA gate and CD41 and CD62 expression in the platelet gate were assessed by flow cytometry, in the absence and in the presence of adenosine diphosphate (ADP) stimulation. A significant increase in platelet activation occurred during the invasive procedure in controls, which persisted at 24 hours. However, compared with controls, RIPC group showed no or a lower increase in platelet variables, including MPA formation (p <0.0001) and CD41 (p = 0.002) in the MPA gate and CD41 (p <0.0001) and CD62 (p = 0.002) in the platelet gate. ADP increased platelet activation at baseline, but did not further increase platelet reactivity during the invasive procedure in either groups. Percutaneous coronary interventions, performed in 10 patients (6 in the RIPC group and 4 in controls), did not have any further significant effect on platelet activation and reactivity compared with CA alone. In conclusion, RIPC reduces platelet activation occurring during CA. In contrast, no effects were observed on platelet response to ADP stimulation, probably related to the administration of an ADP antagonist in all patients.

Soluble but not platelet P-selectin correlates with spontaneous platelet aggregation: a pilot study

BACKGROUND

P-selectin (PS) is a marker of platelet activation measured on the platelet surface as platelet PS (pPS) or in serum as soluble PS (sPS). Controversy remains over the exact relationship between sPS, pPS, and other markers such as spontaneous platelet aggregation (SPA).

OBJECTIVE

To investigate correlations between pPS, sPS, and SPA in patients with peripheral arterial disease.

METHODS

SPA, pPS, and sPS levels were measured in venous blood sampled from patients following intermittent claudication (n = 18) or an acute stroke (n = 18).

RESULTS

SPA and sPS correlated significantly in the claudicants (Pearson correlation coefficient, r = 0.661; P = .0020) and stroke patients (r = 0.514; P = .020). No significant correlation was identified between pPS and SPA, or sPS and pPS.

CONCLUSIONS

The 2 methods of assessing PS are not comparable. Although pPS is accepted as a platelet activation marker, sPS may be a better indicator of aggregation represented by SPA.

Cellular adhesion molecules and cardiovascular disease. Part II. Their association with conventional and emerging risk factors, acute coronary events and cardiovascular risk prediction

The role of cellular adhesion molecules in the patho-genesis of atherosclerosis has now been clearly demonstrated. Plasma levels of adhesion molecules, which have been shed from the cell surface, have also been associated with the presence of clinical atherosclerotic disease, cardiovascular risk factors and acute coronary syndromes. However, there is little consensus in the literature, including between the large well-designed population studies. This may be explained either by unrecognized confounding factors or, alternatively, by the unpredictable relationship between cell surface expression and activity of cellular adhesion molecules and their shedding into the plasma under different circumstances. Probably for the latter reasons, there is at present little evidence that the measurement of circulating adhesion molecules is likely to offer any additional benefit for individual patients above the assessment of conventional cardiovascular risk factors in the assessment of either the extent of, or future risk from, cardiovascular disease.

Time course of plasma adhesion molecules in acute coronary syndromes

BACKGROUND

Atherosclerosis is an inflammatory process in which adhesion molecules play an intimate role in both the initiation and progression of lesions. It is postulated that they also play a role in the presentation of acute coronary syndromes and that plasma levels thereafter may be of potential prognostic significance. The stability of sample levels under different laboratory conditions is unknown.

METHODS

Stability of plasma levels was assessed in six healthy subjects under four different laboratory conditions. The time course of levels was studied in 57 patients with acute chest pain, 21 of non-cardiac aetiology, 23 unstable angina and 13 acute myocardial infarction, at mean times of 2.3, 8.2 and 17.3 h after the onset of pain. Samples were assayed for intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), P-selectin, E-selectin and C-reactive protein (CRP).

RESULTS

ICAM-1, VCAM-1, P-selectin and E-selectin levels did not differ under different laboratory conditions. Levels were similar at presentation in patients with acute chest pain of non-cardiac aetiology, unstable angina or acute myocardial infarction (median levels ICAM-1 269 microg/l, VCAM-1 379 microg/l, P-selectin 167 microg/l and E-selectin 53 microg/l). Levels did not change in the 24 h following the onset of pain. CRP levels did not differ at presentation between groups (median level 2.1 mg/l), but rose more than 12 h after the onset of pain in the group with acute myocardial infarction (P < 0.05).

CONCLUSION

Adhesion molecule levels are stable under normal laboratory sample handling conditions. Levels do not change in the 24 h following the onset of chest pain of non-cardiac or acute ischaemic aetiology.

Platelet and leukocyte activation during aortoiliac angiography and angioplasty

OBJECTIVE

to evaluate platelet and leukocyte activation during aortoiliac angiography and percutaneous transluminal angioplasty (PTA).

METHODS

an observational study of 14 patients with aortoiliac atherosclerotic disease, nine of whom underwent PTA. The proportion of fibrinogen-, and P-selectin positive platelets, P-selectin expression on platelets, intraplatelet cGMP and cAMP, CD18 positive granulocytes, CD18 expression on granulocytes, plasma (p)-neopterin, p-TNF alpha and p- interleukin-6 were repeatedly measured in arterial blood during angiography and in venous blood before and after.

RESULTS

compared to a previous venous sample, arterial intraplatelet cAMP was increased proximal to the atherosclerotic lesion before contrast infusion and PTA (median 18 [range: 14-22] vs 16 [15-21] pmol/10(9) platelets p<0.05), and intraplatelet cGMP was increased proximal to the lesion after contrast infusion and PTA (1.2 [0.8-3.9] vs 0.9 [0.6-2.5] pmol/10(9) platelets p<0.05). Four hours after angiography, both the proportion of P-selectin positive platelets (28[11-55]%) and platelet P-selectin expression (9[6-40]) had decreased (p<0.05), from arterial values distal to the lesion before contrast infusion and PTA (57 [24-78]% and 26 [10-83]). Granulocyte CD18 expression was lower during angiography than in a previous venous sample.

CONCLUSIONS

the results are compatible with platelet but not leukocyte activation during peripheral angiography.