الفهرس 
Pathogenesis of In-stent restenosisOnly 14 pages are availabe for public view
 |  | from | 161 |  |  |
| | | from | 161 | | |
Abstract
Vessel size is a critical anatomic factor inversely related to restenosis rate, and Lesions in vessels with small reference diameter represent a distinct group with respect to clinical and morphologic characteristics as well as device utilization. These lesions carry relatively higher risks for restenosis after percutaneous stenting, which is a critical problem need to be solved with better stents.
Various studies have shown that stent design, stent coating and stent strut thickness may determine event-free survival.
Chromium coronary stents are increasingly being used in percutaneous coronary interventions due to it`s better properties. The aim of this study is to compare chromium coronary stents with conventional stainless steel stents when both are used for small vessel stenting.
Aim of the work
To evaluate and compare the outcome of both chromium alloy stent and bare metal stainless steel stent regarding in-hospital and intermediate term prognosis of patients when they are used in stenting lesions in small coronary vessels.
Patients selection
This study was conducted on 40 diabetic patients with symptomatic ischemic heart disease attributable to de novo or restenotic nonstented native lesions of small coronary vessels, who were referred to the cath. Lab. Department in Ain-Shams University Hospital and National Heart Institute for percutaneous stenting, in the period between April and December, 2008.
The Inclusion criteria were: Symptomatic diabetic patients with coronary artery disease who were referred for elective PCI with a target vessel being less than 2.8mm diameter as measured by QCA that is amenable to percutaneous stenting.
The Exclusion criteria were: Primary PCI and lesion not amenable for stenting as thrombus containing lesion.
Methods
Every patient was subjected to:
1. Thorough history taking.
2. Laboratory investigations.
3. 12-lead ECG.
4. Echocardiography.
5. Coronary angiography :
Pre-procedural, Post-procedural and if there are recurrent ischemic symptoms or positive stress ECG test for evaluation of the previously deployed stent.
End points
Six months follow up of all patients to detect end points.
The endpoint will be the incidence of MACE (death, myocardial infarction, emergency bypass surgery, or target lesion revascularization) 180 days after enrollment and in-stent restenosis.
Results
This study was conducted to assess in-hospital and intermediate term prognosis of 40 enrolled diabetic patients with symptomatic ischemic heart disease underwent percutaneous stenting of a lesion in a small coronary vessel less than 2.8 mm diameter in Ain shams university hospital and national heart institute cath. Lab, they were subdivided into two groups:
Group (I): Included 20 patients underwent PCI using ٍStainless steel stent.
Group (II): Included 20 patients underwent PCI using chromium alloy Stent.
Group (I) included 17 males and 3 females with mean age of 56.5±5.5 years. Group (II) included 16 males and 4 females with mean age of 55.8±8.1 years.
Variables of baseline demographic and clinical characteristics of patients including (age, sex, risk factors, history of CAD, clinical exam, labs and echocardiography) as well as baseline lesion and procedural characteristics were similar in both groups.
Every patient of the two groups underwent coronary intervention in the Ain Shams university Hospital and national heart institute Catheterization Laboratories, using either Chromium alloy stent or bare metal Stainless Steel Stent.
1. Assessment of initial success and in-hospital prognosis
The initial success including (device, lesion and procedure success) was 100% in both groups with no statistically significant difference between them, also no statistically significant difference between the two stents as regards in-hospital complications.
2. Assessment of Intermediate Term Prognosis
The intermediate term prognosis or the intermediate term follow up period which was from ( 6 months ) post procedure and included 6 months follow up ٍby stress ECG ( if positive stress ECG coronary angiogram will be done for stent evaluation and the occurrence of end points.
End points
End Point, which was the incidence of MACE (Death, MI, CABG and TLR) and in-stent restenosis at follow up period. There was no statistically significant difference between the two groups as regards the incidence of MACE and in-stent restenosis at follow up period, which might be due to limitations of the study including small number of pts. and total event rate.
ISR was 15% for chromium stent, which was much less that stainless steel stent 25% and less than other studies which revealed ISR of 27-44% after stenting small coronary vessels.
Conclusions
Using chromium alloy stent in stenting lesions in small coronary vessels < 2.8mm reference diameter, showed a better results than using stainless steel stent especially as regards event-free survival and average MACE occurrence at follow up period.
However, no significant statistical difference was found between the two stents regarding (initial procedural success, in-hospital complications, the incidence of MACE at follow up, the incidence of ISR at follow up, event-free survival at follow up). And this might be due to some limitations which the study has faced.
Recommendations
Although the results of our study shows a trend toward chromium stent, statistical analysis showed no significant difference between chromium stent and stainless steel stent in diabetic patients with small coronary vessels with reference diameter< 2.8mm.
Further multicenter studies with higher number of patients, higher total event rate and overcoming the limitations of our study are recommended to be done to complete our results, and give more significant data.