الفهرس 
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Abstract
Introduction: ual antiplatelet therapy combining aspirin and clopidogrel is the standard care for patients who have acute coronary syndromes (ACS) or are undergoing percutaneous coronary intervention (PCI), according to the current ACC/AHA and ESC guidelines (Kushner et al., 2009). However, despite the administration of dual antiplatelet therapy, some patients do develop recurrent cardiovascular ischemic events, with stent thrombosis being the most catastrophic (Pyrgakis and Goudevenos, 2010). It is well established that the antiplatelet response to clopidogrel varies widely among patients (Dupont et al., 2010). Patients who display little attenuation of platelet reactivity under clopidogrel therapy are recognized as low- or non-responders, or clopidogrel-resistant (Papathanasiou et al., 2007). Aim of the current study: The current study aims to detect the predictors and in hospital outcome of the responsiveness to the loading dose of clopidogrel in a random sample of Egyptians undergoing an elective PCI using the FDA approved P2Y12 platelet response assay (Verify Now test). Patients and methods: This study was conducted on a random sample of 60 Egyptian patients who were undergoing elective Percutaneous Coronary Intervention (PCI).
All patients were subjected to:
• Complete medical history, full clinical examination, a base line twelve leads surface resting electrocardiogram, laboratory investigations (CBC, Coagulation profile and serum creatinine level).
• All patients were loaded with 300 mg of clopidogrel as a single dose.
• P2Y12 platelet response test (Verify Now test) was performed to all patients after taking the loading dose with an interval ranging from 7-10 hours.
• The patients were classified according to the test results into two groups:
Group A: Non responders PRU > 240 or the platelet inhibition < 40%
Group B: Responders PRU < 230 or the platelet inhibition > 40%
Both groups were compared as regard the clinical & the demographical data.
• They were subjected to elective Percutaneous Coronary Intervention (PCI).
• The patients were followed up for 24 hours during their hospital stay for the clinical outcome & acute stent thrombosis presented with STEMI or sudden cardiac death.
• A twelve leads electrocardiogram and cardiac enzymes (troponin) were done immediately to the patient who complaint of typical chest pain.
• The patient with ECG showed new ST elevation in the area supplied by the stented artery and with cardiac troponin reviled positive results would detect an acute stent thrombosis.
• All the results were tabulated and statistically analyzed using IBM© SPSS© Statistics version 21 (IBM© Corp., Armonk, NY).
Results:
The age of all patients ranged from 42 to 70 years with the mean age of (55.4 ± 7.4 years). There were 22 female patients (36.7%) and 38 male patients (63.3%).The BMI of all patients ranged from 18 to 28 with the mean BMI of (23.2 ± 2.6). 29 patients were diabetics (48.3%). 41 patients were hypertensive (68.3%).
30 patients were smokers (50%). 31 patients were dyslipidemic (51.7%). 7 patients had performed pervious PCI (11.7%). 36 patients had a previous attack of ACS (Acute Coronary Syndrome) (60%). None of patients had performed pervious CABG.
Drug to test interval: the median is 8 hours and the interquartile range is (8-9). Base line PRU: The median is 344 and the interquartile range is between 296.5 and 378. PRU (Platelet Reactive Unit) after clopidogrel: the median is 220 and the interquartile range is (198.5 – 263). Platelet percent of inhibition (%): the median is 41.5% and the interquartile is between (12.5% - 44%).
Selected target vessel for PCI was: LAD in 35 patients (58.3%) with bare metal stent in 14 patients (40%) and Drug eluted stent in 21 (60%). LCX stent in 13 patients (21.7%) with bare metal stent in 7 patients (53.8%) and Drug eluted stent in 6 patients (46.2%). OM in 6 patients with bare metal stent in 3 patients (50%) and Drug eluted stent in 3 (50%). RCA stent in 14 patients (23.3%) with bare metal stent in 6 patients (42.9%) and Drug eluted stent in 8 patients (57.1%).
Number of target vessels: 52 patients had a single targeted vessel for PCI with percentage (86.6%), 8 patients had two targeted vessels for PCI with percentage (13.4%), while none of patients had three targeted vessels for PCI.
Among the whole study population one patient had a typical chest pain with percentage (1.7%), one patient) the same patient) had an ST segment elevation with percentage (1.7%) and the same patient also had a positive troponin test with percentage (1.7%).
The whole population study was classified into two groups according to the response to the clopidogrel. Group A: (Non-responders) 22 patients were non-responders with percentage of (36.7%) and Group B: (Responders) 38 patients were responders with percentage (63.3%).
Regarding the gender distribution There was a statistical significant higher incidence of female patients in group A versus group B with percentage of 54.5% versus and 26.3% with (P = 0.029).
There was a statistical significant higher incidence of smoking in group B versus group A with percentage 63.2% versus 27.3% with (P = 0.007).
There was a statistical significant higher incidence of hypertension in group A versus group B with percentage 90.9% versus 55.3% with (P= 0.004).
There was a statistical significant higher incidence of diabetes in group A versus group B with percentage 81.8% versus 28.9% with (P ˂ 0.0001).
There was no significant statistical difference among the studied groups as regard to age (p=0.613) or BMI (p=0.112).
There was no significant statistical difference among the studied groups as regard to dyslipidemia (p=0.158), history of previous PCI (p=0.405) or history of ACS (p=0.662).
Among the whole variables discussed before only Diabetes mellitus was the determinant of clopidogrel non responsiveness between the two groups using the multivariable logistic regression model showing a (P ˂ 0.0001).
We had only one patient who had Acute stent thrombosis in the form of typical chest pain, ST segment elevation in the stented artery and positive troponin test in group B in the first 24 hours post PCI versus none of the patients in group A with (P=1.0).