NHS hospital readiness to embrace the proposed NICE guidelines on abdominal aortic aneurysm: a public perspective

Abstract

Introduction

The National Institute for Health and Care Excellence published a draft consultation update on abdominal aortic aneurysm, which was expected to be published on 7 November 2018. This article analyses the readiness of NHS hospitals and their workforce to embrace the proposed guidelines.

Methods

The trust and individual surgeon-level anonymised data in the public domain for elective, rupture and complex abdominal aortic aneurysm cases were collected and analysed for all the acute care trusts providing these services from the Vascular Society of Great Briton and Ireland’s prospective National Vascular Registry database.

Results

Of the 95 acute care trusts providing the service for the year 2017, the annual volume of infrarenal abdominal aortic aneurysm (both endovascular and open repairs) ranged between 0 and 137. Of these, 64 (67.36%) trusts had an annual volume of fewer than 60 cases.

A total of 366 (approximately 75% of 490) vascular surgeons have performed 10 or fewer open abdominal aortic aneurysm repairs in three years (2014–2016) with a mean operating volume of 1.452 procedures per surgeon per three years (n = 254, median 0, interquartile range, IQR, 0–3, 0.484 procedures per surgeon per year) and about 51% of the vascular surgeons have only performed five or fewer procedures in those three years with a mean operating volume of 3.455 per surgeon per three years (n = 367, median 3, IQR 0–3, 1.151 per surgeon per year).

Conclusion

The observations show that most UK acute hospitals lack the optimum case volume necessary to embrace the proposed change in the guideline.

Introduction

Abdominal aortic aneurysm affects around 4% of men aged between 65 years and 74 years in England (approximately 80,000 men). Abdominal aortic aneurysm results in approximately 6000 deaths per year in England and Wales as shown in statistics from the British Society of Interventional Radiology. The overall prevalence of abdominal aortic aneurysm is estimated to be 1.3–12.7% in the UK.¹

The incidence of symptomatic abdominal aortic aneurysm in men is around 25 per 100,000 at the age of 50 years, which rises significantly to a figure of 78 per 100,000 at the age of 70 years.¹ Abdominal aortic aneurysm accounts for around 2% of all deaths in men aged 65 years and over in the USA.² The US Centers for Disease Control and Prevention ranks abdominal aortic aneurysm as one of the top 15 causes of mortality for people between 85 and 89 years in the United States.^3–5

Over the first two decades of the 21st century, the management of abdominal aortic aneurysm has undergone technological revolution, and most vascular centres in developed countries treat the condition with endovascular aneurysm repair (EVAR).⁶ Most vascular units in the UK adopted this technique and treated patients with abdominal aortic aneurysm by EVAR. However, the National Institute for Health and Care Excellence (NICE) has published a draft consultation update on the diagnosis and management of abdominal aortic aneurysm (Box 1) and this draft consultation was initially expected to be published in November 2018.⁷ However, the publication date has been delayed and is yet to be confirmed. We analyse the readiness of NHS hospitals and their workforce to embrace the proposed NICE guidelines on abdominal aortic aneurysm management and review the impact of the proposed guideline on public perception.

Box 1.

The National Institute for Health and Care Excellence draft guideline on abdominal aortic aneurysm: diagnosis and management, with consultation closure originally dated 29 June 2018.⁷

Repairing ruptured aneurysms

• Consider endovascular repair (EVAR) or open surgical repair for people with a ruptured infrarenal abdominal aortic aneurysm. Be aware that:

  • EVAR provides more benefit than open surgical repair for most people, especially for women and for men over the age of 70.

  • Open surgical repair is likely to provide a better balance of benefits and harms in men under the age of 70.

  • Consider open surgical repair for people with a ruptured complex abdominal aortic aneurysm.

• Do not offer complex EVAR to people with a ruptured abdominal aortic aneurysm if open surgical repair is suitable, except as part of a randomised controlled trial comparing complex EVAR with the open surgical repair.

Materials and methods

The vascular services quality improvement programme (VSQIP) launched by the Vascular Society of Great Britain and Ireland maintains a prospective database, the National Vascular Registry, which is a national database collecting data on index procedures including abdominal aortic aneurysm repair from every hospital and vascular surgeon. VSQIP publishes surgeon-level reporting and individual trust-level data in the public domain. These data are available to the public and patients.^8,9 We have collected data on all the NHS trusts providing services for the treatment of abdominal aortic aneurysm and on every vascular surgeon who is registered with the National Vascular Registry. The NHS trust and individual surgeon data were anonymised for analysis and publication. Abdominal aortic aneurysm is divided into three categories: elective infrarenal abdominal aortic aneurysm; ruptured abdominal aortic aneurysm and complex abdominal aortic aneurysm. Data were collected on the number of cases treated with open repair and EVAR in each category. We have also collected case volumes for individual surgeon on both open surgery and EVAR from 2014 to 2016. A comparison was made between the number of open surgery and EVAR cases at the NHS trust and individual surgeon level. This is a descriptive study to analyse and discuss the individual NHS trust and surgeon case volume.

Results

Trust-level data for 2017

Of the 95 acute care trusts providing the service for the year 2017, the annual volume of infrarenal abdominal aortic aneurysm (both EVAR and open repair) ranged between 0 and 137. Of these, 64 trusts, which represented 67.36% of the total number of trusts, had an annual volume of less than 60 cases, the recommended minimum figures for the trusts to provide the service (Table 1).

Table 1.

Trusts with various ranges of infrarenal abdominal aortic aneurysm (open and endovascular repair), 2017.

Cases (n)	Trusts (n)a
< 30	17
31–59	29
60+	31

^a Total of 77 trusts.

For patients with elective infrarenal abdominal aortic aneurysm, open repair was less favoured compared with EVAR. A total of 30 trusts performed 10 open repairs per year in 2017, which amounted to 38.9% of the total (77 trusts). In this calculation, 18 trusts were excluded as there were no figures for abdominal aortic aneurysm (Table 2).

Table 2.

Elective open repair compared with emergency endovascular aneurysm repair in elective, ruptured and complex abdominal aortic aneurysm.

Trusts (n)	Elective (2017) (n)		Ruptured (2014–2016)		Complex (2014–2016)
	Open repair	EVAR	Open repair	EVAR	Open repair	EVAR
0–5	13	2	5	27	64	27
6–10	17	2	7	23	5	9
10–20	21	10	17	19	1	12
> 20	26	63	49	9	2	23
Total	77	77	78	78	72	72

The percentage of open repairs from the total of infrarenal abdominal aortic aneurysm repairs varied between 3.61% and 66.66%; 46 trusts (48.42%) performed fewer than 25% of their cases by open repair (Table 3).

Table 3.

Emergency repair for endovascular aneurysms in 2017.

Repairs (n)	Trusts (n = 66)
	(n)	(%)
< 10	37	56.06
10–20	20	30.30
21–60	9	13.63

Of 4193 elective infrarenal abdominal aortic aneurysm repairs managed by 77/95 acute care trusts, 1333 patients had an open repair (mean value 17.31, median 13, IQR 9–24, range 2–59) while 2806 cases (mean value 36.44, median 31, IQR 23–49, range 1–91) were managed by EVAR. Of the 95 trusts, 18 had no cases of abdominal aortic aneurysm. Some 2879 patients with ruptured infrarenal abdominal aortic aneurysm presented to 78 acute care trusts, of whom 2088 with a mean value of 26.76 (median 25, IQR 16–37, range 1–77) were operated by open technique while 791 cases (mean value 10.14, median 08, range 1–60, IQR 23–49) were managed by EVAR. Only 17 trusts had no cases.

For complex abdominal aortic aneurysm, 2037 patients presented to 72 acute care trusts, of whom 210 with a mean value of 2.91 (median 2, IQR 1–4, range 1–28) were operated by open technique while 1827 with a mean value of 25.37 (median 16, IQR 4 to 32, range 1 to 238) were managed by EVAR; 23 trusts had no cases.

Individual-level data

For the years 2014–2016, of the 490 vascular surgeons employed in the 95 acute care NHS trusts providing vascular surgery services, only 366 surgeons have performed 10 infrarenal open procedures as shown in the data available in the public domain (Table 4). Of these 366 surgeons, 54 were newly appointed and many of them had no reported operative volume. A total of 254/490 surgeons (51.83%) had performed 0–5 open abdominal aortic aneurysm repairs in 2017, with a mean operating volume of 1.452/surgeon/three years or (n = 254, median 0, IQR 0–3, 0.484/surgeon/year) while 367/490 surgeons (74.89%) were in the range of 0–10 procedures per year during 2014–2016, with a mean operating volume of 3.455/surgeon/three years (n = 367, median 3, IQR 0–3, 1.151/surgeon/year). Figure 1 gives the scatter of the data.

Table 4.

Operative experience of individual surgeons, 2014–2016.

Experience (years)	Open (2014–2016)	EVAR (2014–2016)
Newly appointed	54	54
0–5	254	126
6–10	113	72
11–20	96	132
> 20	27	160
Total	490	490

Figure 1.

The scatter of individual operating volume data for endovascular aneurysm repair.

A total of 126/490 surgeons (25.71%) had performed 0–5 EVAR in 2014–2016, with a mean operating volume of 0.73/surgeon/three years (median 0, IQR 0–0, 0.243/surgeon/year) while 198/490 surgeons (40.40%) were in the range of 0–10 procedures per year in 2017 with a mean operating volume of 3.35/surgeon/three years (median 0, IQR 0–7, 1.116/surgeon/year). Figure 2 gives the scatter of the data.

Figure 2.

The scatter of individual operating volume data for endovascular aneurysm repair.

Emergency EVAR for ruptured abdominal aortic aneurysm

For eEVAR annual volume, 29 trusts had no volume of ruptured abdominal aortic aneurysms. Only 28/66 trusts (42.42%) had more than 10 cases of emergency EVAR in one year and only 9/66 (13.63%) had a case volume of 20 in a year (Table 5). Most trusts treated the ruptured aneurysm by open techniques. The percentage of the ruptured abdominal aortic aneurysms treated by EVAR varied between 1/78 (1.28%) and 8/9 (88.88%). Of the 66 trusts, only 42 trusts were performing emergency EVAR for one-third of their patients with ruptured abdominal aortic aneurysm.

Table 5.

Total number of trusts in relation to percentage of emergency endovascular aneurysm repair in 2017.

Emergency repairs (%)	Trusts (n)a
< 34	29
34–66	42
> 66	21

^a Total of 66 trusts; 29 trusts excluded as no cases.

Discussion

Volume–outcome relationships are increasingly evident in vascular surgery since the start of the twenty-first century.^10–15 Volume–outcome and learning curve analyses show that increased experience and high surgery volume has been linked to improved patient outcomes, both at the individual surgeon and hospital level. A meta-analysis of the existing literature reviewed studies including PubMed, EMBASE and the Cochrane Library articles on the operation volume–outcome relationship in elective and ruptured abdominal aortic aneurysm surgery. These studies included 421,299 elective aneurysm repairs and reported a weighted odds ratio of 0.66 in favour of higher-volume centres dichotomised at 43 cases/year.¹⁶

The data from the volume–outcome study for elective aneurysm repair in the UK between 2001 and 2005 demonstrated that the mean mortality rate for an elective repair was 7.4%. Subgroup analysis of the data revealed that the mortality figure for the units with the lowest caseload was 8.5% compared with 5.9% reported from the units with a higher caseload. A more worrying observation was that many small-volume centres had elective mortality figure in excess of 20%.¹⁷

Another interesting study from New York State shows that the volume–outcome relationship data for abdominal aortic aneurysm repair is related to the surgeon’s annual operative volume rather than the facilities’ annual turnover. The data demonstrate higher in-hospital mortality rates for low-volume surgeons (1–4 open surgical repairs) when compared with the high-volume surgeons (more than 11 open surgical repairs) with an adjusted odds ratio of 1.87 (95% confidence interval, CI, 1.1–3.17). It is also noteworthy that there were higher odds of major complications in the low-volume surgeons with an odds ratio of 1.23 (95% CI 1–1.51). However, there is insufficient evidence as to what would be considered as optimal surgery volume for open aortic surgery to minimise the major complication and mortality rate.⁴

In this present study from the National Vascular Registry, the total number of low-volume surgeons (who perform fewer than 10 open repair procedures a year) was 74.89%. With this reality, a change of recommendation for abdominal aortic aneurysm repairs to revise practice may pose a challenge for the system, especially when 67.36% of the total number of trusts in the UK had an annual volume of fewer than 60 cases of infrarenal abdominal aortic aneurysm (both EVAR and open repair), the recommended minimum figures for the trusts.

Conclusion

These observations lead one to question whether all centres in the UK are equipped to receive the optimum case volume necessary to provide an acceptable level of postoperative complications and patient outcomes. The public will naturally be concerned about the procedural volume inexperience in most of the centres arising from the change of guidelines. While the implementation of evidence-based medicine indeed will welcomed by all, the lack of proper planning and preparedness, combined with sudden and drastic policy changes, could undermine public confidence in the process of change and undermine the whole system, should avoidable complications arise stemming from this lack of planning.