The Association Between a Surgeon’s Learning Curve With Endovascular Aortic Aneurysm Repair and Previous Institutional Experience

Abstract

The purpose of the present study was to determine whether an institution’s prior endovascular experience influenced the learning curve of subsequent surgeons. A prospective analysis of the initial 70 endovascular abdominal aortic aneurysm repair (EVAR) cases attempted by an individual surgeon was performed with the primary outcome variable being achievement and 30-day maintenance of initial clinical success. Along with standard statistical analyses, the cumulative sum failure method (CUSUM) was used to analyze the learning curve, with a predetermined acceptable failure rate of 10%. Seventy elective EVAR cases were performed by this surgeon during a 4-year period (2000-2004) (mean age, 73.7 ∓ 5.4 years; mean aneurysm diameter 63.3 ∓ 7.2 mm). Initial clinical success was achieved in 68 of 70 cases (97%), which differed significantly with that of our initial surgeon (88.5%, P = .01). Causes of failure in the present series included 1 early mortality (1.4%) and 1 case of conversion to open repair with no instances of type I endoleak or endograft limb thrombosis. Both surgeons’ cases were plotted sequentially with CUSUM curves revealing a significantly shorter learning curve for the second surgeon. Optimal results were achieved following 10 to 20 EVAR cases, as opposed to 60 cases in the initial series. Such an analysis confirms that as an institution’s experience with EVAR increases, an individual surgeon’s learning curve shortens considerably.

Keywords

endovascular abdominal aortic aneurysm repair (EVAR)learning curve cumulative sum failure method (CUSUM)

Get full access to this article

View all access options for this article.

References

Forbes TL , DeRose G , Kribs SW , Harris KA. Cumulative sum failure analysis of the learning curve with endovascular abdominal aortic aneurysm repair. J Vasc Surg. 2004;39: 102-108.

Lee WA , Wolf YG , Hill BB , et al. The first 150 endovascular AAA repairs at a single institution: how steep is the learning curve? J Endovasc Ther. 2002;9: 269-276.

Lobato AC , Rodriguez-Lopez J , Dietrich EB. Learning curve for endovascular abdominal aortic aneurysm repair: evaluation of a 277-patient single-center experience. J Endovasc Ther. 2002;9: 262-268.

Chaikof EL , Blankensteijn JD , Harris PL , et al , for the Ad Hoc Committee for Standardized Reporting Practices in Vascular Surgery of The Society for Vascular Surgery / American Association for Vascular Surgery . Reporting standards for endovascular aortic aneurysm repair. J Vasc Surg. 2002;35: 1048-1060.

Williams SM , Parry BR , Schlup MMT. Quality control: an application of the CUSUM. Brit Med J. 1992;304: 1359-1361.

Wohl H. The CUSUM plot: its utility in the analysis of clinical data. N Eng J Med. 1977;296: 1044-1045.

Forbes TL. A cumulative analysis of an individual surgeon’s early experience with elective open abdominal aortic aneurysm repair. Am J Surg. 2005;189: 469-473.

Forbes TL , DeRose G , Harris KA. A CUSUM analysis of ruptured abdominal aortic aneurysm repair. Ann Vasc Surg. 2002;16: 527-533.

Rehring TF , Brewster DC , Cambria RP , et al. Utility and reliability of endovascular aortouniiliac with femorofemoral crossover graft for aortoiliac aneurysmal disease. J Vasc Surg. 2000;31: 1135-1141.

10.

Faizer R , Forbes TL , Harris KA , et al. Objective scoring systems of high medical risk: a clinical tool for selecting patients for an endovascular approach to aneurysm repair. Abstract presented at the 2005 Annual Meeting of the Canadian Society for Vascular Surgery, Toronto, ON.

11.

Forbes TL , Steiner SH , Lawlor DK , et al. Risk-adjusted analysis of outcomes following elective open abdominal aortic aneurysm repair. Ann Vasc Surg. 2005;19: 142-148.

12.

Harris JR , Forbes TL , Steiner SH , et al. Risk adjusted analysis of early mortality following ruptured abdominal aortic aneurysm repair. J Vasc Surg. 2005;42: 387-391.