Operator Experience and Carotid Stenting Outcomes in Medicare Beneficiaries

Abstract

Context Although the efficacy of carotid stenting has been established in clinical trials, operator experience and outcomes with the procedure in routine clinical practice are less certain. Objectives To correlate outcomes with 2 measures of operator experience: (1) annual volume; and (2) experience at the time of the procedure among new operators who first performed carotid stenting after a national coverage decision by the Centers for Medicare & Medicaid Services (CMS). Design, Setting, & Patients Observational study using administrative data on fee-for-service Medicare beneficiaries 65 years or older undergoing carotid stenting between 2005 and 2007. Main Outcome Measure 30-day mortality stratified by very-low, low, medium, and high annual operator volumes (<6, 6 to 11, 12 to 23, and ≥24 procedures per year) and treatment early versus late during a new operator’s experience (1st to 11th procedure and 12th procedure or higher). Results 24,701 procedures were performed by 2339 operators. Of these, 11,846 were performed by 1792 new operators who first performed carotid stenting after its national coverage decision. Overall, 30-day mortality was 1.9% and rate of failure to use an embolic protection device was 4.8%. The median annual operator volume in Medicare beneficiaries was 3.0 per year (IQR, 1.4 to 6.5) and 11.6% of operators performed ≥12 procedures per year during the study period. Observed 30-day mortality was higher among patients treated by operators with lower annual volumes (2.5% [95% CI, 2.1%-2.9%], 1.9% [95% CI, 1.6%-2.3%], 1.6% [95% CI, 1.3%-1.9%], and 1.4% [95% CI, 1.1%-1.7%] across the 4 categories; P<0.001) and among patients treated early versus late during a new operator’s experience (2.3% [95% CI, 2.0%-2.7%] and 1.4% [95% CI, 1.1%-1.9%]; P=0.001). After multivariable adjustment, patients treated by very-low volume operators had a higher risk of 30-day mortality when compared with patients treated by high volume operators (adjusted OR, 1.9; 95% CI, 1.4 to 2.7; P<0.001). Similarly, we found a higher risk of 30-day mortality in patients treated early versus late during a new operator’s experience (adjusted OR, 1.7; 95% CI, 1.2 to 2.4; P=0.001). Conclusion Among older patients undergoing carotid stenting, lower annual operator volume and early experience were associated with increased 30-day mortality.

The impact of regulatory approval and Medicare coverage on outcomes of carotid stenting

“…This confirms previous reports indicating a learning curve for carotid stenting [21][22][23][24], and is in keeping with multiple reports of the same phenomenon in CEA and other endovascular therapies [25][26][27].…”

Why Calls for More Routine Carotid Stenting Are Currently Inappropriate

“…1 We would add that key indicators (such as 30-day periprocedural stroke/death rates) must be accurately measured in routine (real-world) practice, particularly as stroke and death rates here may be unacceptably higher than in trials. [3][4][5] Therefore, it is most appropriate, as suggested by White and Jaff, 1 that coverage for carotid procedures be dependent on facility accreditation and audited measurement of key standards indicators in all practices performing these procedures. This is a priority issue.…”

Centers for Medicare and Medicaid Services Medicare Data and Stroke Research

“…Another study using national Medicare fee-for-service data from 2005 to 2007 found higher 30-day mortality rates after carotid artery stenting for patients treated by low-versus high-volume operators (odds ratio, 1.9; 95% confidence interval, 1.4-2.7) and patients treated by operators early in their careers versus later (odds ratio, 1.7; 95% confidence interval, 1.2-2.4) among a sample of 24 701 patients who underwent the procedure by 2339 operators. 16 Hospital certification programs have been embraced as one means of optimizing stroke quality of care and outcomes, 17,18 but national data assessing their effect on outcomes are limited. Because Medicare data can be aggregated to different units of analyses (eg, patient, hospital, and region), their use provides the opportunity to assess organizational aspects of care and outcomes.…”