035: Impact of operator learning curve on success of percutaneous coronary intervention for chronic total occlusions

Abstract

Percutaneous coronary intervention (PCI) for Chronic Total Occlusions (CTO) is associated with a higher failure rate than PCI for other lesion subsets. The aim of this study was to assess the impact of operator learning curve on success rate of PCI for CTO. The study included consecutive patients undergoing PCI for CTO at 3 tertiary cardiac centres between January 2004 and December 2011. To identify minimum case volume for optimum clinical benefit, CTO-PCI cases were chronologically ranked and stratified into 6 case volume groups, as 1 to 50 (beginner operators), 51 to 100, 101 to 150, 151 to 200, 201 to 250, >250, for several operators. A multivariable mixed effect logistic regression for clustered data was used to assess the impact of case volume on PCI failure after adjustment for patient characteristics, lesion difficulty graded by angiographic score, vessel site, procedural techniques. A total of 1261 patients, median 63 yrs-old (25th-75th percentile, 55–72), undergoing PCI for 1418 CTO were included. PCI success occurred in 1008 (71%) lesions. Crude success rate was 69.6%, 66.2%, 69.6%, 76.1%, 70.2%, 77.8% across the 6 ordered case volume groups, respectively, p=0.04. At multivariable logistic regression, increasing case volume across the six categories was significantly associated with successful PCI (odds ratio (OR) 1.22, 95% confidence interval (CI) 1.13.–1.32, p<0.001). The OR of success increased substantially and significantly with a case volume of at least 151 to 200, as compared to 1 to 50 case volume (2.09, 95% CI 1.18–3.70, p=0.012), reaching the highest value in case volume >250 (OR 2.85, 95% CI 1.87–4.34, p<0.001, while the increase in odds ratio for case volumes < 151, as compared to 1 to 50 case volume, did not reach the statistical significance. Operator experience in PCI for CTO is an independent predictor of success. A minimum case volume >150 is required to increase significantly the chance of success compared to beginner operators