الفهرس 
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Abstract
Arterial systemic embolism including cerebral embolism is one of the most important complications in patients with rheumatic mitral stenosis (RMS). In addition, it has been shown that patients with RMS have increased platelet activity as compared to healthy volunteers as well as subjects with lone AF. Moreover, elevated plasma levels of surrogate markers reflecting increased platelet activity dramatically decrease after percutaneous mitral balloon valvuloplasty (PMBV).
Previous studies proposed that a larger MPV is an indicator of increased in vivo platelet activation, and MPV correlates well with platelet activity whether measured as aggregation, thromboxane A2 or 3-thromboglobulin release, or adhesion molecule expression . Furthermore, elevated MPV can predict the outcome in vascular thrombotic events such as myocardial and cerebral infarction .
However, in Egypt there has been no study evaluating the effects of PMBV on MPV in patients with RMS. Accordingly, the present study aimed to evaluate the effects of successful percutanous balloon mitral commissurotomy “valvuloplasty” on mean platelet volume as an indicator of platelet activity, before and after one month.
Patients and methods:
This study was carried out in Cardiology department, Natiaonal Heart Institute in the period between Aug. 2012 and May 2014.
A total number of 22 consecutive patients with moderate and severe rheumatic mitral stenosis who underwent successful percutaneous balloon mitral Commissurotomy (PMC) and 22 apparently healthy subjects as a control group were included in this study.
We studied the patients population (22 cases) collectively to assess the favorable effect of successful percutaneous balloon mitral valvuloplasty on regression of mean platelet volume one month after PMC.
Patients were subjected to the following :
Electrocardiogram, transthoracic echocardiography, transeosophageal echocardiography, percuatenous ballon valvoplasty and Hematologic measurements were done just before and 1 month after the procedure. Blood samples were drawn from the antecubital vein by careful veinpuncturein a 21 G sterile syringe without stasis.
Blood samples were drawn in the morning after 20-min rest following a fasting period of 12 hour. To assess mean platelet volume (MPV), Dipotassium EDTA (ethylenediaminetetraacetic acid) based anticoagulated blood samples (2 ml) were drawn and assessed by Sysmex KX-21N (Sysmex America, Inc) within 30 minute of sampling.
1. Patients with RMS and sinus rhythm had higher mean platelet volume reflecting increased platelet activity as compared to healthy control group.
2. Mean platelet volume decreased significantly following percutaneous mitral commisurtomy(PMC) procedure.
3. There was significant negative correlation between value of mean platelet volume before PMC and mitral valve area , MV area index and Left ventricular end diastolic pressure while there was significant positive correlation between value of mean platelet volume before PMC and mitral valve score, Calcifications, Mean diastolic PG Mean left atrial pressure and pressure gradient across mitral valve.
Conclusion
Based on the results of the current study, it can be concluded that
Mean platelet volume(MPV) was significantly elevated in patients with rheumatic mitral stenosis who were in sinus rhythm compared to control subjects. Elevated MPV values may indicate that patients with MS have a higher risk of systemic thromboembolism due to increased platelet activation.
Mean platelet volume in patient with rheumatic mitral stenosis is affected mainly by mitral valve area and calcification.
Mean platelet volume decreased significantly following percutaneous mitral commisurtomy procedure.
Recommendations
Performance of percutaneous balloon mitral commissurotomy in properly selected cases of rheumatic mitral stenosis as early as possible to get the maximum benefits of the procedure.
Performance of percutaneous balloon mitral commissurotomy as early as possible in moderate and severe mitral stenosis especially if associated with increased MPV if fulfilled PMC indication criteria for prevention of systemic embolism even in patient with sinus rhythm(SR).
In patients with mitral stenosis, cheaply and easily measurable platelet indices including MPV which are associated with increased platelet activity can be ordered in routine investigation, and should not be overlooked. Our study suggests that effective anti-platelet agents may have a role in treatment of patients with MS and SR as well as in patients with MS and AF.
Further prospective studies recruiting more patients are mandatory to establish the pathophysiological and clinical significance of increased MPV in patients with MS and to evaluate effect of PM
Study limitations
The current study had the following limitations:
The sample size was rather small and the follow-up time was short-term.
The population included was only admitted to a single center.