Interventional Radiology clinical outcomes

Clinical outcomes are broadly agreed, measurable changes in health or quality of life that result from our care. Constant review of our clinical outcomes establishes standards against which to continuously improve all aspects of our practice.

About the Interventional Radiology Service

The Interventional Radiology Service at Great Ormond Street Hospital (GOSH) offers a comprehensive range of interventional radiology procedures for children as part of the diagnosis and treatment of a range of conditions. GOSH is the only hospital in the UK that employs full-time paediatric interventional radiologists.

Interventional radiology refers to a range of techniques that rely on the use and guidance of radiological images such as x-ray and ultrasound to precisely target therapy for the patient. Interventional radiology is usually performed using needles and narrow tubes called catheters rather than by making large incisions into the body as in traditional surgery. This approach has many benefits including minimising the pain for the patient, the risk of infection, hospital stay and recovery time.

The Interventional Radiology Service does not usually admit patients directly under their care. Instead we see and treat patients on behalf of other teams in the hospital who refer their patients to us for specific procedures. Currently the Interventional Radiology Service performs around 3,500 procedures per year, including central venous access, biopsy, oesophageal dilatation, airway intervention, feeding tube insertion, joint injections, angiography, angioplasty and embolisation, sclerotherapy, percutaneous urinary tract stone removal and thrombolysis. 

Clinical outcome measures


1. Central venous access (Hickman catheter) procedural outcomes

2. Renal biopsy procedural outcomes

1. Central venous access (Hickman catheter) outcomes

Central venous access procedures account for about 40 per cent of all Interventional Radiology procedures performed each year. With this procedure, the interventional radiologist aims to safely and effectively insert a thin catheter into a vein so that fluid, nutrition, or medication can enter the patient’s bloodstream and blood tests can be taken without the use of a needle.

Central venous access usually involves making two incisions, one to tunnel the catheter under the skin and the second at the site where the catheter is inserted into the vein. X-ray and ultrasound are used to perform the procedure.

Figure 1.1 Hickman catheter insertion success rates

A successful insertion is defined as a visit to the interventional radiology suite where it was possible to make the central venous access insertion, even if it was not at the first attempt.

If the procedure is not successful, the team will try again at another time and potentially try an alternative vein for access. Evidence suggests that the most common cause of the procedure not working the first time is because the child is already critically ill, so trying again is likely to be successful when the child is in better health.

As there are currently no defined success rate standards for children, the Interventional Radiology team use adult success rate standards from the Society of Interventional Radiology to compare their outcomes. Reported adult success rates are between 95 and 96 per cent. The guidance states that success rates could be expected to be lower in a paediatric population. 

The graph below shows the success rates for Hickman catheter insertions for 2009/10 to 2013/14, which is well above the adult standard:

Success rates for Hickman catheter insertion
Success rates for Hickman catheter insertion

Figure 1.2 Hickman catheter insertion procedural complication rates

The team also uses the adult standard to compare their complication rates. Reported complication rates1 in adults are between 1 to 2 per cent for haemothorax, pneumothorax, and air embolism.

1JVIR 2003; 14: S231

The table below shows the complication rates for our Hickman catheter insertions for 2009/10 to 2013/14, which is again well above the adult standard at zero complications:

Hickman catheter insertion procedural complication rates
Hickman catheter insertion procedural complication rates

2. Renal biopsy procedural outcomes

The interventional team perform around 135 renal (kidney) biopsies per year to enable diagnosis of kidney diseases and to assess problems in transplant kidneys. Renal biopsy standards2 for paediatrics enable us to have a benchmark against which to measure our quality.

2Hussain et al. Pediatr Nephrol 2003; 18: 53

Figure 2.1 Renal biopsy inadequacy rate

Ensuring that minimal tissue is taken that will enable a conclusive result by the Pathology department is crucial. If the tissue biopsied is 'inadequate', the biopsy procedure will need to be repeated. Therefore, renal biopsy inadequacy rate is an important measure of effectiveness and safety.

Studies3,4 show an inadequacy rate for renal biopsies in children of 2.5 to 3 per cent.

3Tøndel et al. Clin J Am Soc Nephrol 2012; 7: 1591

4Hussain et al. Nephrol Dial Transplant 2010; 25: 485

The table below shows the Interventional Radiology team's inadequacy rates for renal biopsies for 2012/13 to 2013/14:

Renal Biopsy Inadequacy Rate

 Year  Biopsies  Inadequate  Rate (%)
 2012/13 117  1  0.9%
 2013/14 137  2  1.5%
 Total 254  3  1.2%

Figure 2.2 Renal biopsy procedural complication rate

Renal biopsy carries risk of bleeding, which will be a higher risk for very sick patients. Reported rates1,2,3 of bleeding that requires surgery or blood transfusion range from 0.3 to 1.3 per cent.

3Rianthavorn et al. Nephrology 2014; 19: 143

Our results range from 1.9 to 0 per cent across the reporting period, with an average of 0.98 per cent. Though we are within the range of reported rates, we continue to monitor our results to seek to continuously improve our outcomes.

Renal biopsy procedural complication rate
Renal biopsy procedural complication rate

The information on this page will be reviewed and updated in June 2015.