Mechanisms of Cerebrovascular Events as Assessed by Procoagulant Activity, Cerebral Microemboli, and Platelet Microparticles in Patients With Prosthetic Heart Valves

Geiser, Thomas; Sturzenegger, Matthias; Genewein, Urs; Haeberli, André; Beer, Jürg H.

doi:10.1161/01.str.29.9.1770

Cited by 86 publications

(48 citation statements)

References 45 publications

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“…This contrasts with the findings of others. 20 In our study, other coagulation and platelets parameters such as F1ϩ2, soluble CD62P values, and platelet counts were not associated with solid emboli. A nonsignificant increase in PMPs without a soluble CD62P or F1ϩ2 increase cannot exclude platelet activation in patients with solid emboli, but our results suggest that if present, this activation did not reach the secondary irreversible phase of platelet aggregation.…”

Section: Discussionsupporting

confidence: 40%

Solid Cerebral Microemboli and Cerebrovascular Symptoms in Patients With Prosthetic Heart Valves

Skjelland

Michelsen

Brosstad

et al. 2008

Stroke

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Background and Purpose-Although cerebral microemboli are often detected by transcranial Doppler ultrasonography in mechanical heart valve patients, the clinical significance of such microemboli is unclear. The aim of this study was to determine the frequency and composition of cerebral microemboli in a prosthetic heart valve population and to correlate these findings to cerebrovascular symptoms, blood inflammation, and coagulation parameters. Methods-Seventy-six consecutive patients with a total of 81 prosthetic (54 mechanical, 27 biologic) heart valves were monitored for cerebral microemboli by multifrequency transcranial Doppler ultrasonography 1 year after valve replacement. Cerebrovascular events in the first year were recorded by a neurologist. Inflammation and coagulation markers were measured by immunoassays. Results-Microemboli were detected in mechanical heart valve patients only (28 patients, 56%). Twelve percent were solid, occurring in 17 (34%) of the mechanical heart valve population. The presence of solid cerebral microemboli was the only variable that was associated with cerebrovascular symptoms after a final regression analysis (Pϭ0.026). The plasma monocyte chemotactic protein-1 level was raised in patients with solid microemboli (Pϭ0.014). Conclusions-Solid cerebral microemboli were detected by multifrequency transcranial Doppler ultrasonography in 35% of a mechanical heart valve population, and the frequency was higher in patients who experienced cerebrovascular events during the first year after valve replacement. The results suggest that the detection of solid cerebral microemboli may be helpful in predicting the risk of ischemic stroke in mechanical heart valve patients.

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Section: Discussionsupporting

confidence: 40%

Solid Cerebral Microemboli and Cerebrovascular Symptoms in Patients With Prosthetic Heart Valves

Skjelland

Michelsen

Brosstad

et al. 2008

Stroke

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“…After fixation, the number of PMP was diluted with 2 mL of PBS, then measured with flow cytometry 35 Soluble ICAM-1, soluble vascular adhesion molecule-1s (VCAM-1), and von Willebrand Factor (vWF) were measured as follows. 46 Soluble ICAM-1 and sVCAM-1 were quantified by a colorimetric sandwich ELISA (R&D Systems), using monoclonal murine antihuman sVCAM-1 and soluble intercellular adhesion molecule-1 (sICAM-1) capture antibodies.…”

Section: Platelet Microparticlesmentioning

confidence: 99%

Effects of Severe Hypertension on Endothelial and Platelet Microparticles

et al. 2003

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Abstract-The molecular mechanisms by which extreme blood pressure elevation leads to vascular injury are not defined.To explore the hypothesis that activation of endothelium and platelets as manifested by increased concentrations of circulating endothelial microparticles and platelet microparticles could play a role in this target organ injury, we conducted a cross-sectional study of these markers in 3 groups: (1) untreated patients referred specifically for treatment of severe uncontrolled hypertension; (2) untreated patients with established mild hypertension; and (3) normotensive volunteer subjects. By ANOVA, endothelial (Pϭ0.002) and platelet (Pϭ0.01) microparticles were greatest in the severely hypertensive group. There was a significant correlation between both of these markers and blood pressure, even in the setting of multiple risk factors. Our results suggest that these markers may be useful and specific for pressure-induced endothelial and platelet activation in hypertension. Furthermore, because of the combined effects of endothelial and platelet microparticles on coagulation, leukocytes, and endothelium, it is possible that they may play a pathogenic role in mediating target organ injury in severe hypertension. Key Words: hypertension, arterial Ⅲ endothelium Ⅲ platelets Ⅲ endothelium-derived factors Ⅲ cell adhesion molecules S evere, uncontrolled hypertension is associated with high rates of target organ complications, 1-6 but the molecular mechanisms by which extreme blood pressure elevation leads to vascular injury are not well defined. Increasing evidence suggests that hypertension confers a prothrombic state, characterized by abnormalities of endothelial function and platelet activation. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] This dysfunction is conferred by isolated systolic hypertension as well as simultaneous systolic and diastolic hypertension. 9 Consequently, investigative interest has recently focused on endothelial and platelet activation as important mediators of hypertensive vascular injury.Endothelial microparticles (EMP) are small membrane vesicles that are shed from the surface of endothelial cells in response to activation, injury, and/or apoptosis. EMP release can be caused by a number of cytokines such as interleukin-1 and tumor necrosis factor and by elevated shear pressure. [25][26][27][28][29][30] Assays for circulating EMP have recently been developed 25-26 as potential means of quantifying endothelial cell injury. EMP are also known to be elevated in thrombotic thrombocytopenic purpura, 26 a condition associated with endothelial injury, and in acute coronary syndromes. 27,30 Increased EMP release has also been associated with endothelial injury in patients with multiple sclerosis and lupus anticoagulant. 25,28 -29 Circulating platelet microparticle (PMP) concentration is a marker of platelet activation. [31][32][33] PMP are formed by platelet membrane vesicle formation and shedding. 31 PMP are known to possess procoagulant activity and are elev...

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“…27,28 Also, increased levels of platelet-derived microparticles, an increased procoagulant activity, and an increased rate of MESs were found in MHV carriers symptomatic with cerebrovascular events. 29 In 30 patients with bileaflet valves, a reduction of MESs by 16% to 41% after administration of acetylsalicylic acid of 81 to 531 MESs/h was demonstrated. 25 Additionally, a higher number of MESs was found in patients with valve obstruction.…”

Section: Mess In Prosthetic Heart Valvesmentioning

confidence: 97%

Occurrence and Clinical Impact of Microembolic Signals During or After Cardiosurgical Procedures

Dittrich

Ringelstein

2008

Stroke

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Background and Purpose-Microembolic signals (MESs) are detectable within the transcranial Doppler frequency spectrum downstream from vascular atherothrombotic or cardiothrombotic lesions. A frequent occurrence of MESs has also been shown during bypass surgery or after mechanical valve implantation. We sought to compile the knowledge on MES prevalence, the clinical impact of these cardiogenic MESs, and microemboli composition. Summary of Review-We performed a systematic MEDLINE search and summarized the currently available literature about MESs during or after cardiosurgical procedures for this state-of-the-art report. Conclusions-The nature of cardiogenic MESs is heterogeneous, and their prevalence is highly variable, reflecting their different origin from a broad spectrum of cardiosurgical conditions. The occurrence and number of MESs during cardiac catheterization and percutaneous coronary angioplasty seem to have a clinical impact but need to be explored further.In patients with prosthetic heart valves, in those with left ventricular assist devices, and during cardiac surgery, the occurrence of MESs has an important clinical impact, and MES monitoring has proven its reliability.

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Mechanisms of Cerebrovascular Events as Assessed by Procoagulant Activity, Cerebral Microemboli, and Platelet Microparticles in Patients With Prosthetic Heart Valves

Cited by 86 publications

References 45 publications

Solid Cerebral Microemboli and Cerebrovascular Symptoms in Patients With Prosthetic Heart Valves

Solid Cerebral Microemboli and Cerebrovascular Symptoms in Patients With Prosthetic Heart Valves

Effects of Severe Hypertension on Endothelial and Platelet Microparticles

Occurrence and Clinical Impact of Microembolic Signals During or After Cardiosurgical Procedures

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