The effect of increasing operator experience on procedure-related characteristics in patients undergoing carotid artery stenting.

Objectives To evaluate the efficacy and safety of carotid artery stenting for the treatment of severe carotid artery disease in our department and to investigate the effect of increasing operator experience on perioperative and procedure-related characteristics. Methods From January 2007 to February 2015 200 patients underwent 207 endovascular procedures for carotid artery stenosis. Of all, 113 arteries (56.5%) were symptomatic. Significant changes across time were calculated with the use of Change Point analysis using bootstrap and mean squared error estimates. Results The technical success was 98.6% (204/207 cases). Thirty-day neurological events included stroke in four patients (2%) and transient ischemic attack in two (1%). None of the patients died during the first 30 days. The most significant change of radiation duration occurred after the 33rd patient with a decrease from 25.31 min to 12.31 min, while for the total operative time that change occurred between the 31st and 33rd patient where mean operation time decreased from 88.89 min to 49.22 min. The most significant change of contrast media used occurred at the 40th patient with a decrease from 91.58 ml to 62 ml. During a mean follow-up period of 42 ± 20.02 months none of the patients experienced any cerebrovascular event. There was one case of significant recurrent stenosis, which was successfully treated by endovascular means. Conclusions Endovascular treatment of carotid artery stenosis performed in a single center with the use of a cerebral protection device seems to consist a safe therapeutic choice with acceptable results, within the referenced benchmarks proposed in the latest guidelines. Certain perioperative parameters such as the amount of contrast media used, the fluoroscopy and operation time, seem to decline overtime indicating increasing operator's experience. A number of performed cases above 40 was related to the significant decrease of those parameters and may represent the learning curve of the procedure.