Platelet activation in acute pulmonary embolism.
BACKGROUND
Platelet activation is implicated in thrombotic disorders, but has not been described in acute clinical pulmonary embolism (PE).


OBJECTIVE
To investigate the natural history of platelet activation in PE and associated markers of inflammation, thrombosis and cardiac dysfunction.


METHODS
Thirty-five consecutive patients (age 62 +/-17 years) with acute PE were prospectively enrolled and followed for 6 months. Platelet activation was assessed by flow cytometry [measuring expression of platelet P-selectin, conformational activation of glycoprotein IIb/IIIa complex (PAC-1) and formation of platelet-leukocyte complexes] and by plasma soluble P-selectin. Platelet activation, right ventricular (RV) function (assessed as RV ejection area by transthoracic echocardiography), D-dimer and high-sensitivity C-reactive protein (hs-CRP) were measured at presentation and repeated over 6 months follow-up.


RESULTS
Soluble P-selectin (56 +/-19 ng mL(-1), anovaP < 0.0001) and PAC-1 (1.5 +/- 1.8%, anovaP = 0.005) were mildly but significantly increased in patients with acute PE relative to healthy young men (soluble P-selectin 33 +/- 13 ng mL(-1), P < 0.001; PAC-1 binding 0.5 +/- 0.6%, P < 0.01) and age-matched controls (soluble P-selectin 31 +/- 9 ng mL(-1), P < 0.001; PAC-1 binding 0.4 +/-0.4%, P < 0.05). Platelet P-selectin expression and platelet-leukocyte complexes were not increased during acute PE. Echocardiographic RV ejection area correlated inversely with soluble P-selectin (r = -0.47, P = 0.007) and positively with platelet P-selectin (r = 0.49, P = 0.0007), suggesting P-selectin is shed from activated platelets in proportion to the severity of RV dysfunction. Elevated soluble P-selectin, D-dimer and hs-CRP demonstrated a time-dependent return to normal during 6 months follow-up.


CONCLUSIONS
Platelet activation is evident after acute PE. Platelet activation correlates with the severity of RV dysfunction, and can persist for several months after acute PE.
Chung
T
T
Department of Cardiology, Concord Hospital, ANZAC Research Institute, University of Sydney, Sydney, Australia.
Connor
D
D
Joseph
J
J
Emmett
L
L
Mansberg
R
R
Peters
M
M
Ma
D
D
Kritharides
L
L
D000208:Acute Disease; D000328:Adult; D000368:Aged; D001792:Blood Platelets / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D008875:Middle Aged; D019007:P-Selectin / Q000097:blood; D015539:Platelet Activation; D011655:Pulmonary Embolism / Q000503:physiopathology*
D019007:P-Selectin