Left atrial platelet activity with rheumatic mitral stenosis: correlation study of severity and platelet P-selectin expression by flow cytometry.
BACKGROUND
Previous studies have demonstrated that platelet activation, evaluated by measuring the secretory substances of platelets (ie, platelet factor 4 and beta-thromboglobulin), occurs in the peripheral blood of patients with rheumatic mitral stenosis (MS). However, the differences in platelet activation between peripheral and atrial blood, and the relationship between regional left atrial platelet P-selectin expression and the severity of MS have never been investigated.


RESULTS
A total of 16 patients with symptomatic MS undergoing percutaneous transluminal mitral valvuloplasty were studied (group 1). The fractions of platelets expressing P selectin in the prevalvuloplasty left atrial, right atrial, peripheral venous, and arterial blood were determined by flow cytometry. The mitral valve area was calculated by means of the Doppler pressure half-time method. Peripheral venous platelet activity also was evaluated in 23 control patients (including 15 healthy volunteers who were in sinus rhythm [group 2] and 8 patients who had chronic lone atrial fibrillation [group 3]). The fraction of peripheral venous platelets expressing P selectin among group 1 patients was significantly higher than that of group 2 or 3 patients (p = 0.008). In group 1 patients, the fraction of platelets expressing P selectin in the left atrium was significantly higher than that in the right atrium, the femoral vein, or the femoral artery (p < 0.01). Correlation analysis demonstrated that there was a significantly direct relationship between the severity of MS and the fraction of left atrial platelets expressing P selectin (p = 0.01; r = -0.620). The fraction of peripheral venous platelets expressing P selectin among group 2 patients did not differ from that of group 3 patients


CONCLUSIONS
In patients with rheumatic MS, increased regional left atrial platelet P-selectin expression had a significantly direct relationship with the severity of MS. The increased regional left atrial platelet P-selectin expression was not reflected in peripheral venous blood samples.
Chen
Mien-Cheng
MC
Division of Cardiology, Department of Internal Medicine, Chang Gung Memorial Hospital, Kaohsiung, Taiwan, Republic of China. chenmien@ms76.hinet.net
Wu
Chiung-Jen
CJ
Yip
Hon-Kan
HK
Chang
Hsueh-Wen
HW
Fang
Chih-Yuan
CY
Yu
Teng-Hung
TH
Fu
Morgan
M
D000328:Adult; D000368:Aged; D001792:Blood Platelets / Q000378:metabolism*; D002404:Catheterization; D005260:Female; D005434:Flow Cytometry; D006325:Heart Atria; D006801:Humans; D008297:Male; D008875:Middle Aged; D008946:Mitral Valve Stenosis / Q000097:blood* / Q000209:etiology / Q000503:physiopathology / Q000628:therapy; D019007:P-Selectin / Q000097:blood*; D015539:Platelet Activation; D012214:Rheumatic Heart Disease / Q000097:blood* / Q000150:complications / Q000503:physiopathology
D019007:P-Selectin