National Vascular Registry Context Page

The Royal College of Surgeons CEU and Vascular Society of Great Britain and Ireland (VSGBI) runs the National Vascular Registry (NVR) which examines care for patients undergoing the repair of Abdominal Aortic Aneurysms, carotid endarterectomy among stroke patients or interventions for peripheral arterial disease.   Results reported include number of procedures, mortality rates, and length of stay.

Audit website: www.vsqip.org.uk

Metrics:

Case ascertainment (elective open or endovascular infra-renal abdominal aortic aneurysm repair)

  • Rationale: the proportion of all eligible patients captured by the audit in the sampling period reflects the quality of participation of this hospital in this audit. The comparison is made against Hospital Episode Statistics data.
  • Guideline/mapping: there is no national guideline related to case ascertainment; the audit specifies an aspirational threshold of more than 90%.
  • Graph/relative performance: there is no graphical display for this metric; the hospital’s performance should be compared against the aspirational threshold.
  • Quality improvement prompt question: consider the metrics below in the context of case ascertainment – particularly where ascertainment is low – and should prompt questions about the quality of audit participation.

1. Risk-adjusted post-operative in-hospital mortality rate

  • Rationale: death is the most serious outcome after abdominal aortic aneurysm surgery and is known to vary across regions.  This metric uses case-mix adjustment to ensure that hospitals dealing with sicker patients are compared fairly against those with a less complex casemix.
  • Guideline/mapping: there is no national guideline related to mortality after elective infra-renal abdominal aortic aneurysm repair.
  • Graph/relative performance: risk-adjusted funnel-plot cross-section; this shows the position of the Trust relative to 99.8% control limits. The grey zone means that the hospital’s performance is not statistically significantly different to the national average. Outside the grey zone means that the performance is different to the national average.
  • Quality improvement prompt question: ‘red’ (alarm) outlier status should prompt questions about actions which the Trust has taken to reduce their mortality rates following carotid endarterectomy.

Case ascertainment (carotid endarterectomy)

  • Rationale: the proportion of all eligible patients captured by the audit in the sampling period reflects the quality of participation of this hospital in this audit. The comparison is made against Hospital Episode Statistics data.
  • Guideline/mapping: there is no national guideline related to case ascertainment and the audit specifies an aspirational threshold of more than 90%.
  • Graph/relative performance: there is no graphical display for this metric; the hospital’s performance should be compared against the aspirational threshold.
  • Quality improvement prompt question: consider the metrics below in the context of case ascertainment – particularly where ascertainment is low – and should prompt questions about the quality of audit participation.

2. Crude median time from symptom to surgery

Therefore this metric only applies to eligible symptomatic patients receiving surgery at NHS hospitals; it does not include asymptomatic patients or – for eligible symptomatic patients – carotid stents, independent sector operations, abandoned operations [e.g. for technical reasons] or cases performed simultaneously with heart surgery.

  • Rationale: carotid endarterectomy is performed to reduce the risk of stroke from carotid artery disease; there is good evidence that, for eligible patients, this benefit is closely related to the speed with which surgery is performed after the first symptom of stroke. Eligible patients are those with marked narrowing of the carotid artery (50-99%) and who are fit enough for surgery. Prompt surgery is more likely to be achieved by robust infra-structure (such as frequency of and ease of access to acute stroke clinics as well as effective liaison between acute medical and vascular surgical services).
  • Guideline/mapping: this metric maps exactly to NICE CG 68, section 1.2.4; accordingly, the audit specifies an aspirational threshold of 14 days between first stroke symptom and surgery (for eligible patients).
  • Graph/relative performance: there is no graphical display for this metric; the hospital’s performance should be compared against the aspirational threshold.
  • Quality improvement prompt question: hospitals with a median time greater than 14 days should prompt questions about the quality of access to specialist acute medical and vascular surgical care for patients suffering an acute stroke.

3. Risk-adjusted post-operative 30-day mortality and stroke rate 

This metric applies to all completed operations performed at NHS hospitals with complete 30-day follow-up data; it does not include carotid stents, independent sector operations, abandoned operations [e.g. for technical reasons] or cases performed simultaneously with heart surgery.

  • Rationale: death or stroke are the most serious outcomes after carotid endarterectomy and are known to vary across regions.  This metric uses case-mix adjustment to ensure that hospitals dealing with sicker patients are compared fairly against those with a less complex casemix.
  • Guideline/mapping: there is no national guideline related to death or stroke after carotid endarterectomy.
  • Graph/relative performance: risk-adjusted funnel-plot cross-section; this shows the position of the Trust relative to 99.8% control limits. The grey zone means that the hospital’s performance is not statistically significantly different to the national average. Outside the grey zone means that the performance is different to the national average.
  • Quality improvement prompt question: ‘red’ (alarm) outlier status should prompt questions about actions which the Trust has taken to reduce their mortality and stroke rates following carotid endarterectomy.