Effect of procedure volume on outcomes after iliac artery angioplasty and stenting (Br J Surg 2013: 100: 1189–1196)

Abstract

Goode and colleagues report on the relationship between the annual caseload (volume) of iliac artery angioplasties undertaken within English hospitals and the outcome of these interventions. The work is significant in its role to benchmark national radiological outcomes. The key finding was that there appeared to be little relationship between volume and outcome in either elective or emergency procedures when assessing mortality, length of stay or procedural complication rates. Second, women and older patients fared worse from intervention, most impressively in the elective setting. There have been few previous attempts to quantify volume–outcome relationships in the radiological literature, other than for carotid artery stenting, which is highly volume-dependent1. This is due to difficulties in defining appropriate outcome measures, and procedural heterogeneity. In undertaking these analyses, the authors faced a number of challenges that are complex to resolve using administrative data and cloud interpretation of the results. One major confounder is the lack of granularity within the data that makes it impossible to determine the case mix undertaken in individual units. For example, a full-length external and common iliac occlusion would be expected to have a worse outcome than a short common iliac stenosis, but would be coded similarly. There are also complexities in outcome selection. Although mortality and length of stay are valid outcomes for procedures such as open aneurysm repair2, as the authors demonstrated, few patients die or have prolonged admissions after elective iliac intervention. The most appropriate measures, such as health status and symptom-based patient-reported outcome measures, are unlikely to be realistic endpoints in the near future.