Drug eluting stents represent a major advance in coronary revascularization reducing neointimal hyperplasia. However, in-stent restenosis (ISR) was not completely eradicated. The aim of our study was to determine the frequency of the ISR, its angiographic and clinical patterns, the time to onset and different predictors of occurrence.

We collected retrospectively clinical and angiographic data of 749 patients hospitalized in the cardiology department of the Military Hospital of Tunis between January 2002 and June 2010 and who underwent percutaneous coronary intervention with drug-eluting stents in 1159 lesions. The exclusion of patients without follow-up reduced the size of the population to 577 patients and 936 lesions.

The average age of our patients was 59.65±10 years. The prevalence of clinical ISR was 18.9% per patient and 15.9% per lesion. Its average time to onset was 27.6±20 months. Acute coronary syndrome was the most frequent clinical presentation (83.4%). The focal angiographic form was predominant (64%).

Predictors of ISR in univariate analysis were: dyslipidemia (p=0.001), overweight (p=0.001), stenting of proximal left anterior descending artery (p=0.002), severe calcifications (p=0.001), B2 and C lesions (p=0.001), restenosis lesion (p=0.19), reference vessel diameter (p=0.003), minimal lumen diameter (p=0.006), lesion length (p=0.02), sirolimus eluting stent (p=0.001). Protective factors were: use of everolimus eluting stent (p=0.001) and inflation pressure>16 atmospheres (p=0.022). Predictors in multivariate analysis were: restenosis lesion (OR=32, p=0.012) and severe calcifications (OR=38, p=0.016). Inflation pressure>16 atmospheres was a protective factor (OR=27, p=0.017).

The ISR remains a potential risk even with drug-eluting stents. A better understanding of its characteristics could provide solutions and reduce its prevalence and complications.