The NVR is commissioned by the Healthcare Quality Improvement Partnership (HQIP) as part of the National Clinical Audit and Patient Outcomes Programme and is designed to promote quality improvement within NHS hospitals performing vascular surgery by providing information on their performance. In this summary we present data with direct relevance to vascular anaesthetists. The full report is available at 2024 NVR State of the Nation Report | VSQIP
Carotid Endarterectomy
In 2023, a total of 3,324 carotid endarterectomies were performed in the UK, compared to 3,257 in 2022. This number still remains significantly lower from 2019, when 4,162 procedures were performed.
A summary of patient characteristics is shown below.
Anaesthetic Type and Operative Details
Operative details of unilateral carotid endarterectomies performed during 2023:
- 64.4% were performed under General anaesthesia (GA) alone
- 6.9% were performed under local anaesthetic (LA) alone
- 11.9% Combined GA/LA or block was used
- 16.8% were performed under block or regional
- 64.9% of procedures involved the use of a shunt
Table 7.4 shows the operative details of unilateral carotid endarterectomies performed from 2021 to 2023.
Table 7.4: Operative details of carotid endarterectomies performed from 2021 to 2023
In 2023, the most common source of referral was the stroke physician (88.1%), vascular surgeons (2.9%), followed by neurologists (2.1%), and ophthalmologist (1.4%).
There were 3,130 patients (94.2%) with symptomatic disease.
- TIA was the most common symptom (42.9%), followed by stroke (40.6%).
- Over 70% of patients had at least 70% stenosis in their ipsilateral carotid artery at the time of operation.
- Only 0.8% of patients had a previous ipsilateral treatment
Medication for cardiovascular conditions was common among patients prior to surgery. Overall:
- 91.1% were on antiplatelet medication
- 48.1% on single and
- 51.9% on dual therapy,
- 82.4% were taking statins.
Treatment Pathways
The NICE target time from symptom to operation is 14 days in order to minimise the chance of a high-risk patient developing a stroke.
The median time from symptom to surgery for patients who had CEA in 2023 was 15 days and 49% were treated within 14 days. This is slightly worse than in 2022, when the median time was 14 days and 53% of patients were treated within 14 days. The 14-day treatment figure was 56% in 2019 (prior to the pandemic).
The median time from symptom onset to surgery for symptomatic patients in 2023 was 15 days
(IQR 9-26). For the three distinct phases within this pathway, the median time delays were:
- 4 days (IQR 2-10) from symptom to first medical referral
- 1 day (IQR 0-5) from first medical referral to being seen by the vascular team, and
- 6 days (IQR 3-11) from being seen by the vascular team to undergoing CEA.
There is considerable variation among NHS trusts in the median time to surgery during 2023. The median time exceeded 20 days at eight NHS organisations, which is more than in 2021, although this is half of the number of NHS organisations in 2016.
- 31 of the 63 NHS organisations had a median time of 14 days or less
- The median exceeded 20 days for 6 vascular units, an increase from 4 in 2021
- 31 Trusts had less than half of their patients operated on within 14 days.
Outcomes After Carotid Endarterectomy
The complication rates for the 3,324 procedures performed in NHS hospitals in 2023 are summarised in Table 7.5. The rates of the different complications tended to be around 0.2-2.0% and have remained fairly consistent over the last few NVR Annual Reports.
Over this 12-month period:
- 1.9% of people died and/or had a stroke within 30 days (95% CI 1.5-2.4)
- 1.7% of people had a cranial nerve injury during their admission (95% CI 1.3-2.2)
- The median length of stay was 2 days (IQR: 1 to 4 days)
- The rate of return to theatre was 2.5% (95% CI 2.0 to 3.1), and
- The rate of readmission within 30 days was 4.2% (95% CI 3.6 to 5.0).
Table 7.5: Postoperative outcomes following carotid endarterectomy for 2023
The primary measure of safety after carotid endarterectomy is the rate of death or stroke within 30 days of the procedure. The risk-adjusted values for each NHS trust for this outcome indicator are shown in Figure 7.2. Between 2021 and 2023, all NHS organisations were within the expected distance of the overall national average rate of 2.0% (i.e., they were within the 99.8% control limits).
Figure 7.2: Funnel plot of risk-adjusted rates of stroke/death within 30 days for NHS trusts, for carotid endarterectomies between January 2021 and December 2023
Recommendations:
- Ensure timely referral and expedited surgery for patients with symptomatic carotid disease with measures to reduce waiting times to carotid endarterectomy.
- The target time from symptom to operation is 14 days in order to minimise the chance of a high-risk patient developing a stroke.
Elective infra-renal AAA repair
The organisation of vascular services undertaking AAA repair continues to evolve. The number of NHS vascular units performing any AAA repairs decreased from 71 in 2021 to 66 in 2023.
Table 4.3: Split of open and endovascular elective infra-renal AAA procedures by year
Figure 4.1: Distribution of elective infra-renal AAA repairs by age group between 2021 and 2023
Table 4.6 describes various aspects of postoperative care for 2023.
- For EVAR, 70% of patients went to a standard ward after surgery, and the median length of postoperative stay was 2 days.
- For patients undergoing open repair, over 95% of patients were admitted to a level 2 or level 3 critical care unit after surgery. Patients typically remained in critical care for 2-3 days and the median total postoperative stay was 7 days.
The in-hospital mortality rate for open repair in 2023 was 2.7% (95% CI 1.8 to 3.9), a little less than 2.9% (95% CI 2.0 to 4.0) for 2022. The in-hospital mortality rate for EVAR was 0.3% for 2023.
Patients undergoing open repair were more susceptible to cardiac, renal and respiratory complications, and the rate of return to theatre was also higher.
For open repair, the rate of respiratory complications was 9.0% (95% CI 7.3 to 10.8) in 2023, a slight fall from 10.0% (95% CI 8.4 to 11.9) observed in 2021. For EVARs, respiratory complications remained around 1.3% between 2022 and 2023.
Table 4.6: Postoperative details of elective infra-renal repairs undertaken in 2023
Table 4.5: Overall compliance with standards related to the VSGBI elective AAA care pathway
Anaesthetic Types for elective infra-renal AAA repairs in 2023
Other elective repair of aortic conditions
Aneurysms can occur at various locations along the aorta. In addition to infra-renal aneurysms, a distinction is made between three other types:
- Juxta-renal (that occur near to the renal arteries)
- Supra-renal (that occur above the renal arteries), and
- Thoraco-abdominal (more extensive aneurysms involving the thoracic and abdominal aorta).
The two most common procedures are Fenestrated EVAR (FEVAR), performed when aneurysms are close to the renal arteries, and branched EVAR (BEVAR), performed when other arteries branching from the aorta are involved. For the period 2021-2023, 81% of the endovascular elective procedures were FEVARs and 16% were BEVARs. Furthermore, endovascular cases tended to be older and less likely to smoke.
Table 5.1: Characteristics of patients who had other primary open elective and endovascular repairs between January 2021 and December 2023
Table 5.2: Postoperative details of other elective repairs undertaken between January 2021 and December 2023
Repair of thoracic aortic conditions
Patients who suffer from a thoracic aortic aneurysm or aortic dissection are increasingly treated using a thoracic endovascular aortic repair (TEVAR). This procedure is performed in either a cardiothoracic unit or specialist vascular unit. Within this section, thoracic repairs included records entered as a complex procedure with a TEVAR type of complex repair indicated or a standard EVAR with a TEVAR procedure code specified. Of the thoracic repairs, non-elective patients were younger and more likely to smoke. ASA fitness was worse for non-electives while elective cases had more comorbidities.
Table 5.3: Characteristics of patients who had TEVARs between January 2021 and December 2023
Table 5.4: Postoperative details of TEVARs undertaken between January 2021 and December 2023
For elective cases, over 50% were admitted to level 2 care where they stayed for 2 days. Nearly half of non-electives procedures were admitted to level 3 care with a median length of stay of 4 days. Median postoperative length of stay was 4 days for elective TEVARs in the last three years compared with 9 days for non-elective patients. Non-elective mortality was nine times more than elective cases. However, 30-day readmissions were similar for both admission modes.
The disparity in the coding practice of TEVAR procedures should be improved by designating all cases under one type of repair.
Ruptured AAA
Table 6.2: Postoperative details of emergency repairs for ruptured AAAs undertaken between January 2021 and December 2023
For NHS organisations undertaking repair of a ruptured AAA between 1 January 2021 and 31 December 2023, the risk-adjusted postoperative mortality rates are shown in Figure 6.3. The in-hospital postoperative mortality rates for the years 2021, 2022 and 2023 for open procedures were 45.0%, 46.2% and 45.6% respectively. For EVARs, the corresponding rates were 23.8%, 21.2% and 21.4%.
All NHS trusts had a risk-adjusted rate of in-hospital postoperative mortality that fell within the expected range around the national average of 36.1%, given the number of procedures performed.
The rate among NHS trusts typically ranged from 20% to 60%, which reflects the relatively low volumes used to calculate these rates.
Anaesthetic types for rAAA 2021-2023
Vascular units should evaluate how access to endovascular repair can be improved for emergency repair of ruptured aneurysms. This may require:
- Network pathways for vascular surgery working in collaboration with interventional radiology and vascular anaesthesia
- 24/7 access to hybrid operating theatres
- Developing teams with the required expertise qualified to deliver in and out of hours care including nursing staff and radiographers addressing workforce for both vascular surgery and interventional radiology.
Lower Limb Revascularisation
In 2023, over 16,500 revascularisation procedures for chronic limb threatening ischemia (CLTI) (endovascular, hybrid and open bypass) were performed, compared to 14,000 in 2022.
Estimated case ascertainment rates in 2023 were 93% for bypass and 60% for angioplasty. A summary of patient characteristics is shown below.
The majority of patients for open surgical procedures were over the age of 70 years presenting for elective and non-elective procedures, 48.2% and 51% respectively. Most had comorbidities, the commonest being hypertension (68% elective, 65.7% non-elective), followed by diabetes (36.2% elective, 45.7% non-elective) and then ischaemic heart disease (30.1% elective, 32.6% non-elective). A small proportion of patients had no comorbid disease (11.4% elective, 11% non-elective).
With regards to anti-platelet therapy, 84.6% of elective patients and 72.9% of non-elective patients were recorded as being on one anti-platelet agent, and 82.8% of elective patients and 75% of non-elective patients were recorded as being on a statin.
The following table summarises the patient characteristics undergoing lower limb revascularisation in 2023.
Table 2.3: Characteristics of patients undergoing lower limb revascularisation in 2023
Most endovascular procedures in 2023 (90.0%) were performed under local anaesthetic, with 3.0% under regional and 7.0% under general anaesthetic. For open procedures in 2023, 87.3% were performed under general anaesthetic, 10.3% under regional and 2.4% under local.
The following table (2.6) shows the characteristics of lower limb revascularisation procedures undertaken in 2023.
Table 2.6: Characteristics of lower limb revascularisation procedures undertaken in 2023
During 2023, there were 5,200 patients with chronic limb threatening ischaemia (CLTI) who were admitted non-electively, compared to 4,624 in 2022. Of these, the median time (IQR) from admission to intervention was 5 (3-9) days.
The proportion of patients revascularised within 5 days was 50.3% in 2023., compared to 51.1% in 2022 and 53.9% in 2021. Among the 60 NHS organisations that performed 10 or more procedures for non-elective CLTI:
- 27 units had at least 50% of their patients wait more than 5 days
- 16 vascular units had at least 25% of their patients wait more than 10 days
- 20 vascular units had more than 50% of their non-elective CLTI patients operated on within 5 days.
There was an 11% increase in open surgical procedures for CLTI in 2023 (n= 4,066) compared to 2022 (n=3,647). There was a small increase in non-elective procedures, with 3,048 performed in 2023, compared to 2,929 in 2022 and 2,801 in 2021.
In 2023, 93.9% (n=6,574) of open procedures (elective 98.6% and non-elective 87.7%) were performed between 8am and 6pm on a weekday. The percentage of open surgical procedures performed on planned lists was at least 75% for all but three NHS trusts that submitted 10 or more procedures in the NVR in 2023 (62 out of 63 NHS trusts, 95.5%).
The proportion of patients revascularized within 5 days from admission has deteriorated slightly from 51% in 2022 (the PAD QIF standard). The timing to revascularisation for CLTI was:
- Median wait from admission to intervention was 5 days (IQR 3-9 days) in 2023, 5 days (IQR:3-9 days) in 2022 compared to 4 days (IQR 2-8 days) in 2020
The overall length of stay for open procedures was 5 days (IQR 3-8) for elective procedures and 14 days (IQR 9-25) for non-elective procedures.
Complications were relatively uncommon; however, those undergoing non-elective procedures had a higher complication rate and re-intervention rates than those undergoing elective procedures, with limb ischaemia (7.3% non-elective, 2.3% elective), and respiratory (4.4% non-elective and 2.1% elective) complications being the highest. Table 2.7 shows the postoperative outcomes after lower limb revascularisation for 2023 by procedure type.
The re-intervention rate (angioplasty/stent, bypass, minor and major amputation, 30-day amputation) was 6.1% for elective procedures and 26.7% for non-elective procedures. This was lower from 2022, where the re-intervention rate was 7.5% for elective procedures and 28% for non-elective procedures.
The In-hospital postoperative mortality rate was 2.1% for elective patients and 5.1% for non-elective patients. The report highlighted that all NHS trusts had a risk adjusted in-hospital mortality following lower limb bypass that deck within the expected range of the overall national average of 1.6% (95% CI: 1.5 to 1.8) in this cycle.
Table 2.7: Postoperative outcomes after lower limb revascularisation for 2023 by procedure type
Recommendations:
- Patients admitted with non-electively with chronic limb ischaemia should have a revascularisation procedure within 5 days.
- Improved data entry for this group especially for those who require a second unplanned procedure during the same admission.
- Trusts should aim to perform at least 75% of lower limb revascularisation on planned operating lists.
Lower Limb Amputation
This chapter describes the patterns of care and outcomes for patients undergoing unilateral major lower limb amputations due to vascular disease during the audit period from January 2023 to December 2023.
During this period, 3,688 primary major unilateral amputations were recorded in the NVR, which consisted of 1,993 (54%) below the knee amputations (BKAs) and 1,695 (46%) above the knee amputations (AKAs). Through knee amputations (TKAs) have been analysed as part of the BKA group. TKAs accounted for 3.1% of all major amputations recorded on the NVR during the 1-year audit period. The case ascertainment rate has remained stable, and the overall level exceeds the recommended 85% target by GIRFT vascular surgery report 2018.
In addition, NHS hospitals submitted information on 1,417 minor amputations, and other types of major amputation (65 bilateral, 35 due to trauma and 584 that were performed within 30 days of a lower limb revascularisation procedure). This chapter focuses on major unilateral lower limb amputations that were primary procedures, and these of other types of procedure were not included in the analysis.
An increase trend in the number of unilateral major amputations were undertaken between 2020 and 2023 within the NHS (Table 3.1). Explanation for this requires further investigation, although partly it could be an indirect impact from COVID 19.
A summary of patient characteristics is shown below.
BKA’s were more common in those under the age of 60 (28.8%), while AKA were more common in those over the age of 80 (17.7%). Most patients in both groups were mainly men, and were either current or ex-smokers.
Most patients had one or more comorbidities. The majority of patients requiring a BKA were diabetic (73.3%), compared to the majority being hypertensive (59.6%) in those requiring an AKA. It was common for patients to be on multiple medications, antiplatelet agents, statins, antibiotic and DVT prophylaxis being the commonest. Oral anticoagulants were taken by 20-25% of patients.
Prophylactic antibiotics were recorded in 93.7% of BKAs and 92.6% of AKAs, and and DVT prophylaxis was recorded in 68.3% of BKAs and 64.7% of AKAs.
Table 3.3 shows the characteristics of patients undergoing lower limb amputation in 2023, and table 3.4 shows the pre-operative risk factors among patients undergoing lower limb amputation in 2023.
Table 3.3: Characteristics of patients undergoing major unilateral lower limb amputation in 2023
Table 3.4: Preoperative risk factors among patients undergoing lower limb amputation in 2023
In 2023, there were 1,993 above knee and 1,695 below knee amputations, giving an overall AKA:BKA ratio of 0.85 (95% CI 0.80-0.91). Most NHS organisations had a ratio of less than one (43 out of 61 trusts), but 18 organisations had a ratio above one. No units had a ratio above 2 in 2023.
Future research should investigate factors associated with high ratios and lead to design of interventions aimed to reduce this ratio. Improvement in outcomes for patients undergoing major lower limb amputation has been identified as a top research priority by vascular patients and clinicians.
Overall, in 2023:
- The proportion of below knee and above knee major amputations performed during the day (8am - 6pm) was 91.4% and 90.9%, respectively, which were similar to annual rates in years 2020 to 2022.
- A consultant surgeon was present for just over 75% of the procedures. The consultant presence rates were improved slightly compared to 2022 (BKA=75.1%; AKA=73.3%) and 2021 (BKA=72.9%; 72.2%).
The median time from vascular assessment to amputation in 2023 was:
- 7 days (IQR: 3 to 19 days) for non-elective patients
- 39 days (IQR: 12 to 98 days) for elective patients, and
- 9 days (IQR: 3 to 28 days) for all patients
Outcomes After Major Amputation
Patient outcomes immediately following a major lower limb amputation are summarised in table 3.6.
Overall, 25.4% of patients suffered one or more complication following major limb amputation; these were commonly respiratory (6.2% BKA, 8.2% AKA), cardiac (3.6% BKA, 5.1% AKA) complications and surgical site infections (4.7% BKA, 2.8% AKA), which were similar to the rates in 2022: respiratory (5.9% BKA, 9.6% AKA), cardiac (3.5% BKA, 5.6% AKA) complications and surgical site infections (4.9% BKA, 4.4% AKA). 8.5 % of BKA and 5.6% AKA had a return to theatre during their admission.
Most patients returned to the ward following an amputation, while 11% of BKA and 15.6% of AKA patients were admitted to critical care (level 2 or 3)
The overall median length of hospital stay for major lower limb amputation was 22 days (IQR: 13 to 387 days)
The overall rate of 30-day in-hospital death for major lower limb amputations in 2023 was 5.6%. As expected, it was higher for AKA (7.8%) than BKA (3.9%). Rates of readmission within 30 days were 9.6% for AKAs and 9.1% for BKAs.
All NHS organisations had an adjusted 30-day in-hospital mortality rate that fell within the expected range of the overall 30-day in hospital mortality rate (national average = 6.1% for 3 years from 2021 to 2023).
Table 3.6: Patient outcomes following major lower limb amputations undertaken in 2023
Anaesthetic Type
Anaesthetic data showed 48.1% of procedures were done under GA alone, 20.4% were combined GA with LA/RA and 31.4% were under LA/RA alone.
The following table summarises the anaesthetic types for major amputations undertaken in 2023
Recommendations:
- All patients undergoing elective major lower limb amputation should be admitted in a timely fashion to a recognised arterial centre with agreed protocols and timeframes for transfer from spoke sites and non-vascular units.
- Below knee amputations should be undertaken whenever appropriate.
- Vascular units should aim to have an above knee amputation to below knee amputation ratio below one.
- Major amputations should be undertaken on a planned operating list during normal working hours.
- A consultant surgeon should operate or at least be present in the theatre to supervise a senior trainee (ST4 or above) undertaking the amputation.
- The patient should have routine antibiotic and DVT prophylaxis according to local policy.
Commentary
The State of the Nation report highlights a number of important aspects of vascular care across the UK. Firstly, the mix of procedures continues to change. Over the last three years, the number of procedures for elective infra-renal AAA repair and repair of ruptured AAA have decreased. The number of carotid endarterectomies has remained stable since 2021 but is almost half of the number performed in 2014. A greater number of lower limb endovascular revascularisations are being entered onto the NVR, but the case-ascertainment rate could be improved. NHS vascular units and vascular networks should aim to identify barriers and facilitators to the efficient collection of data on endovascular revascularisation, particularly for day case procedures.
The increasing number of major lower limb amputations observed last year continued into 2023 (case ascertainment rates have remained the same). Research to investigate and explain these findings is urgently required. Potential explanations which merit further investigation include the increasing prevalence of diabetes, challenges in the prevention and management of diabetic foot conditions and the delivery of timely revascularisation. These findings also have implications for rehabilitation and community services.
The times from vascular assessment and admission to treatment for lower limb revascularisation, AAA and CEA have all increased within the last year (which were all higher than in 2019 in the pre-pandemic period), although there is variability across the UK. Urgent action is required, particularly for those organisations with the most significant delays. QI projects to improve referral pathways, capacity and working arrangements across vascular surgery, interventional radiology and anaesthesia are essential. For people with CLTI, services should (i) ensure times to revascularisation do not depend upon whether people initially present at a spoke or hub hospital, and (ii) ensure endovascular procedures are performed as day cases where possible.
The outcomes following all vascular procedures remained similar to last year. The mortality rate for open repair of rAAA is high at 45.6%, but these may represent the more complex cases that are unsuitable for EVAR. However, vascular networks should ensure there is access to EVAR for people with rAAAs and this may require (i) reviewing working arrangements across vascular surgery, interventional radiology and anaesthesia, (ii) having hybrid operating theatres available on 24/7 basis, (iii) developing teams to deliver EVAR for rAAA out of hours, which may include EVAR trained clinicians, nursing staff and radiographers with vascular anaesthetic support.
The interpretation of figures on all open and endovascular aortic procedures would benefit from improved coding. This would be particularly helpful for TEVARs, in order to distinguish between those performed for aneurysms or dissections, and also for FEVARs for juxta or supra renal aneurysms.