Polymer Free Stent in Acute Coronary Syndrome

One of the treatment options for CAD is a percutaneous coronary intervention through balloon angioplasty or stent insertion . Although the restenosis rate can be reduced by using bare metal stents , the in-stent restenosis (ISR) rate is still high at around 20%-30% .

increased rates of stent thrombosis were reported with first-generation DESs.(5) The high rate of late and very late stent thrombosis is caused by a long duration of drug elution, which can delay endothelial healing and prolong metallic structure exposure to blood vessel .

Conventionally, DES (drug eluting stents ) are coated with permanent polymers that facilitate drug release and remain long after drug elution is complete. These permanent polymers can cause delayed healing, impaired stent strut endothelialization , and a hypersensitivity reaction, which can culminatein ST (stent thrombosis ).

Research has led to the design of the newer DES (drug eluing stents) that have biodegradable polymers, novel coatings, or are completely polymer free. The polymer-free technology has the potential advantage to reduce the inflammatory and prothrombotic risks related to the utilization of polymers .

• Our study will be conducted on at least thirty patients with non-ST-segment elevation acute coronary syndromes (NSTE-ACS)who will be subjected to the early invasive strategy . Polymer-free drug eluting stents will be used for these patients instead of the usually used polymer-permanent drug eluting stents .
• Patients with NST-ACS who will meet the inclusion and exclusion criteria will be subjected to the following during the admission in the ICU :
• History of the patient concerning :
• Analysis of presenting complaint . Past history of previous similar complaints or the coarse of his illness if he is known to have IHD(ischemic heart disease ) before . Risk factors ( Diabetus mellitus , hypertension , smoking ,....) .Any other co-morbidities and therapeutic history .
• Examination will be done with special concern payied for:
• Blood pressure, heart rate, respiratory rate, Jugular Venous Pressure (JVP), cardiac examination and chest auscultation .
• Investigations in the form of:
• Serial 12 lead ECG .
• Laboratory investigations : (Complete Blood Count (CBC) , Prothrombine time and concentration ,Kidney function ,HCV-Ab , HBs-Ag , HIV Ab , Creatine kinase (CK and CK-MB ) and Troponin at admission and 6 hours later ) .
• Imaging:
• Echocardiographic evaluation with certain emphasis on the following parameters (Wall motion abnormalities ,systolic function , diastolic function and cardiac dimensions).
• TIMI (Thrombolysis in Myocardial Infarction ) risk score will be calculated to every patient .
• Each of the following criteria constitutes one point for TIMI scoring :
• Age ≥65 years
• Three or more risk factors for coronary artery disease (CAD) (family history of CAD, hypertension, hypercholesterolemia, diabetes mellitus, tobacco use)
• Known CAD (stenosis >50%)
• Aspirin use in the past 7 days
• Severe angina (≥2 episodes in 24 hours)
• ST deviation ≥0.5 mm
• Elevated cardiac marker level
• Syntax score will be caiculated during PCI .
• Early invasive strategy with percutaneous coronary intervention will be done for these patients using Polymer-free drug eluting stents instead of the polymer-permanent drug eluting stents .
• The patients will be followed for 6 months after the intervention .
• The patients included in the study will be followed up and re-evaluated at one month and six months after the intervention ( by telephon calls and office visits )
• Re-evaluation will include asking about and analysing symptoms of IHD after the PCI , compliance to the medications .
• Examination: Vital signs , JVP , chest and heart examination .
• 12-lead ECG and cardiac enzymes if needed .
• Follow up Echocardiography will be done at six months .
• Patients will be subjected to follow up diagnostic coronary angiography six months of PCI (whenever possible).
• Six months views after the index procedure coronary angiography will be evaluated by quantitative coronary angiography (QCA) with edge detection method used for evaluation of coronary lesion in index and follow up procedures. Minimal luminal diameter (MLD), Reference vessel diameter (RVD), Percent diameter stenosis %DS), Acute Gain, Late loss and Late loss index will be estimated.