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Setting up a screening service for abdominal aortic aneurysm

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VOL: 101, ISSUE: 05, PAGE NO: 36

Elaine Townsend, RGN, is vascular nurse, Royal Glamorgan Hospital, Llantrisant

Grant Griffiths, MRCS, is consultant radiologist, University Hospital of Wales, Cardiff;Mike Rocker, MRCS, is SPR vascular surgeon, University Hospital of Wales, Cardiff;Richard Winter, FRCS, FRCR, is FPR radiologist, Royal Glamorgan Hospital Llantrisant;Mike Lewis, MD, FRCS, is consultant vascular surgeon, Royal Glamorgan Hospital, Llantrisant.

Abdominal aortic aneurysm (AAA) is a disease associated with life-threatening consequences following rupture. A large proportion of AAAs are asymptomatic and are unknown until the point of rupture. The spontaneous rupture of an abdominal aortic aneurysm is associated with overall mortality as high as 83 per cent (Johansson and Swedenborg, 1986; Fielding, 1981; Armour, 1977). Identifying patients with AAAs before they become symptomatic or rupture offers the opportunity for elective repair. There is also data showing regular ultrasound review offers a safe period of preliminary observation.

Abdominal aortic aneurysm (AAA) is a disease associated with life-threatening consequences following rupture. A large proportion of AAAs are asymptomatic and are unknown until the point of rupture. The spontaneous rupture of an abdominal aortic aneurysm is associated with overall mortality as high as 83 per cent (Johansson and Swedenborg, 1986; Fielding, 1981; Armour, 1977). Identifying patients with AAAs before they become symptomatic or rupture offers the opportunity for elective repair. There is also data showing regular ultrasound review offers a safe period of preliminary observation.

Elective repair may be appropriate after the AAA has expanded to 5.5cm in a man, and possibly 4.5-5cm in a woman (Greenhalgh, 1998). Initial growth rate of an AAA is low and often takes several years to reach significant size (Collin et al, 1991; Delin, 1985) (Fig 1).

Elective AAA repair is associated with a published mortality of 5-9 per cent (Collin, 1988; Campbell et al, 1986). This offers a substantial cut in mortality compared with emergency repair and avoids the disruption to hospital working needed for the care of ruptured AAA. After successful surgery patients can usually expect a long-term survival only slightly less than the normal population of the same age (Fielding, 1981; Bardram et al, 1980).

History of the nurse specialist post
In the mid-1980s a review was conducted of local, and later regional, results of AAA rupture repair (Basnyat et al, 1999). This showed obvious differences in the results of elective AAA repair compared with rupture. Following this a screening programme was set up within the hospital using a small grant funded by the local health authority. Patients attending radiology were looked at. The efficiency of patient attendance and the pickup rate of AAA in hypertensive patients was studied. Eventually central funding from the Welsh Office was obtained and the nurse specialist post was created.

Initial results
Preliminary results demonstrated that in hypertensive males over 60, the incidence of AAA was eight per cent and in hypertensive females it was two per cent. Attendance rates within the hospital were relatively low at 60 per cent and the authors felt they could improve this by screening patients in GP surgeries. A decision was made to conduct screening sessions in the GP surgeries located throughout the hospital catchment area.

As the nurse specialist was to implement this she was provided with a car allowance and a mobile ultrasound machine. Both were funded by the local health authority.

The initial target group of patients were hypertensive men over 60 and hypertensive women over 65. Selection criteria arose from a pilot study in the hospital. Furthermore, there was preliminary data in the literature showing hypertensive patients as four times more likely to have AAA than normotensive patients (Collin, 1988).

Patient literature and organising recalls
Before screening was started the content of the screening invitation had to be formulated. It was important to get the balance right between providing information about the reason for screening and not frightening the patient. AAA information sheets and patient questionnaires were sent to all patients being screened. The questionnaire asked about common cardiovascular disease risk factors, such as smoking and diabetes, and previous vascular problems. The nurse specialist used the GPs' computerised lists to identify the target patients. Having access to these lists made it easy to obtain patient information such as addresses.

Personal training
A major part of the training for the nurse specialist was to learn to perform ultrasound scans of the abdominal aorta. A consultant radiologist agreed to train the nurse specialist for a two-month period. Patients were invited to attend and were called to one of the surgical wards. The letter openly explained what the scan entailed and that the meeting was for training purposes only. It also explained to the patient the advantage of excluding an AAA. There was no problem with recruitment.

Each abdominal aorta was examined in the transverse and longitudinal planes using the portable ultrasound machine. The maximum transverse and anteroposterior diameters were recorded in the same way as for a normal aortic scan. The nurse specialist found the training relatively straightforward and her only initial concern was the difficulty in distinguishing between the inferior vena cava and the abdominal aorta. However, after performing 15 scans she was confident in reliably being able to locate the abdominal aorta.

To be certain of collecting quality data any patient with an aorta of 3cm or over was sent to the hospital for a further scan by the consultant radiologist.

Data collection and analysis
All the screening data had to be collected and recorded for analysis and to coordinate recall. A laptop computer was used because of ease of transporting it to practices.

All the questionnaire data was entered, as was aortic size. The database allowed information to be extracted with ease. Statistical analyses, trend recognition and patient demographics were available as required. This made it easier to back up the data on a desktop computer. Funding for IT equipment came from the local health authority. Advice on the appropriate equipment came from the hospital IT department. The programme used was a Borland Paradox Database.

Patient cooperation and concerns
An initial major concern was how to tell a patient her or his aorta was enlarged, and in some patients significantly so to the degree of 8-9cm. This is where experience as a registered nurse and patient carer was invaluable. Because the nurse specialist was used to talking with patients she did not find discussing their results particularly difficult and their reactions were very positive.

A joint study was undertaken with a university psychology department into the trauma felt by patients after being told they had an aneurysm. Patients were assessed by questionnaire about anxiety levels after diagnosis of aneurysm. On average their anxiety score returned to a normal psychological level after six months. This reassured the authors that screening for aneurysms is not a cause of major long-term psychological stress.

GP visits
In order to obtain their cooperation and help reduce any disruption to the GPs, the nurse specialist visited each surgery and explained the reason for screening and how the programme works. Initially this was done with the consultant vascular surgeons, but the nurse specialist now does it alone. Written information was also provided for the general practices about the programme and the various studies supporting screening for GPs to review. Patients for screening may be selected based on age or specific risk factors such as hypertension and are readily obtainable from the computerised lists.

Having completed the hypertensive study the programme now selects men over 65 and women over 70 for screening. Invitation letters are despatched to all patients who match the screening criteria, and times are allocated for each one to attend their GP surgery. The authors have found that screening in the surgeries has achieved a marked increase in the attendance rate (upwards of 80 per cent) compared with hospital scanning (60 per cent).

For each screening session the nurse specialist allowed up to three hours and initially screened 10 men and 10 women per session. This gave sufficient time to scan each patient and talk to them without feeling rushed. In order for this to run smoothly a room was needed with a trolley for the ultrasound machine and a couch. The nurse specialist can now undertake three separate screening sessions a week in three different surgeries.

Patients are sent the invitation two weeks before the allocated screening session. The hospital provides the nurse specialist with a mobile phone and this number is available on the letter inviting the patient for screening. If they have any questions or anxieties about the appointment they can call the nurse specialist for reassurance. This also helps keep attendance figures up.

General practice sessions
Practical details

On arrival at each practice the screening equipment is set up. This takes about 10 minutes. Each patient is called one by one and their questionnaire is collected. The nurse specialist then explains again to every patient individually the reason for the programme. Patients do not need to get fully undressed for the procedure but simply expose their abdomen. The length of the time for each scan varies but does not usually take more than 5-10 minutes. Most sessions are completed within the allotted three hours. They overrun only occasionally.

Non-attendees are recalled again a year later so they have a second chance to participate in the programme.

Results

Patients found to have an abdominal aortic diameter of less than 2.5cm are not followed up. The specialist nurse reassures them that all is well and suggests that it is highly unlikely they will ever develop an abdominal aortic aneurysm of any significance.

On finding an enlarged abdominal aorta a still picture of the scan is taken and the patient is informed immediately of the result. The nurse specialist gives them the opportunity to ask any questions they may have and encourages them to ring later that day or the next day if they wish. This allows the patient time for reflection and the opportunity to discuss things with their family who may also have questions.

Patients found to have an AAA of 2.5-2.9cm diameter are re-screened in one year's time. Abdominal aortas of more than 3cm in diameter are referred for a repeat ultrasound scan in the hospital radiology department by the consultant radiologist. This repeat scan has two purposes: to confirm the diagnosis and to scrutinise the relationship of the AAA to the renal arteries.

The diameter of the iliac arteries is also measured. If the aneurysm is found to be saccular, with a theoretically higher risk of rupture, the patients are referred to the vascular surgeon in the hospital. However, all GPs are asked if this is acceptable and their preference of consultant vascular surgeon is always taken.

For patients with AAAs of 3-4cm diameter, annual screening within the radiology department and follow-up in the surgical outpatient department is arranged. Those with AAAs of 4-5cm diameter are scanned every 3-6 months depending on whether the aneurysm is tender and/or saccular on ultrasonography.

Patients with aortas of over 5.5cm are seen in the outpatient department within 2-3 weeks, and are assessed for surgical intervention and anaesthetic review.

After each screening session the nurse specialist leaves the details of any abnormal findings on a preprinted letter for the GPs. Any further ultrasound scans are arranged within the radiology department at the Royal Glamorgan Hospital. Any outpatient referral forms are taken to the vascular surgeon's secretary along with the ultrasound scan results. An outpatient appointment is then arranged for as soon as possible.

Allaying patient anxieties

People who require arterial surgery are encouraged to visit patients already undergoing surgery in the hospital. The nurse specialist is able to answer most of the queries or anxieties they may have about what to expect both before and after surgery, as she has seen the operation and understands what it entails and the sort of problems patients may experience. Patients frequently want to know what type of graft is used and are surprised to learn it is a man-made material.

There are often further anxieties about the length of the hospital stay and return to normal life. Patients are commonly concerned about their life-expectancy and when they will be able to return to a relatively normal, active life. Having worked on a busy vascular ward the nurse specialist is able to describe in great detail the nature of the procedure, potential complications, and the advantages and disadvantages of vascular surgery.

Problems with the programme
Inevitably there have been teething problems encountered in developing the screening posts, including difficulties with the database. These were remedied with advice and assistance from the hospital IT department.

A further problem was the lack of a permanent base in the hospital for the screening position. While most administration and IT work was carried out by the nurse specialist at home, it is important to have access to an office, telephone link, organised filing and data storage.

A minor problem encountered with the process of screening was the amount of clothing many patients wear. Removing excessive clothing such as girdles can be time consuming. This is the sort of minor problem that it is very difficult to predict.

- This article has been double-blind peer-reviewed.

- For related articles on this subject and links to relevant websites see www.nursingtimes.net

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