Evaluation of the National Infarct Angioplasty Project Pilots

Evaluation of the National Infarct Angioplasty Project Pilots

Version 00118/11/2005

EVALUATION OF THE NATIONAL INFARCT ANGIOPLASTY PROJECT PILOTS

A. Background, Aims & Objectives

The Department of Health is currently funding up to ten pilot sites as part of the National Infarct Angioplasty Project (NIAP) to test the feasibility of implementing a countrywide primary angioplasty service for patients presenting with acute ST-elevation myocardial infarction (AMI). We aim to evaluate the pilot sites and address the five elements of the brief produced by the NHS Service Delivery and Organisation (SDO) R&D Programme.

The specific objectives will be: To gain an in depth understanding of patient and carer experience of receiving care at the pilot sites, and measure differences in satisfaction between the pilot sites and sites providing standard, thrombolysis-based care. To assess the workforce implications of setting up an angioplasty service at the pilot sites, and measure the effect of providing the service upon the angioplasty team, support staff, and related staff groups. To describe the models of service delivery established at the pilot sites in terms of their setting (geography, population, transport and communications), structure (hospitals, referral networks, transfer and access points) and components (staff, facilities, and equipment). To explore implementation and feasibility issues by describing the processes involved in establishing primary angioplasty (particularly the development of teams and leadership roles), identifying facilitating factors and barriers to implementation, and assessing the implications of establishing primary angioplasty for cardiology and other services. To compare the costs and outcomes of providing angioplasty and thrombolysis, and estimate the incremental cost-effectiveness of a comprehensive primary angioplasty service, compared to standard, thrombolysis-based care, for the different organisational service models adopted in the pilot sites.

B. Relevance to SDO Call for Proposals

This proposal is submitted directly in response to the SDO call for proposals “Evaluation of the National Infarct Angioplasty Project Pilots” and addresses the specific issues outlined in the brief.

C. Background, including NHS context and relevant literature

Acute ST-elevation myocardial infarction (heart attack) occurs when a coronary artery is occluded by a blood clot. Treatment with an intravenous thrombolytic agent to break down the clot is cheap, simple and effective, and can be provided in all acute hospitals and by some ambulance services. Primary angioplasty, where a catheter and a stent and/or balloon is used to restore blood flow, is more effective for many patients, probably more costly and delivery requires specialist staff and facilities.

Meta-analysis of randomised trials comparing primary angioplasty to intravenous thrombolysis has established that primary angioplasty is associated with reduced mortality, reinfarction, stroke and need for coronary artery bypass grafting, compared to thrombolysis.1-3 Economic analyses suggest that, if both interventions are routinely available, then primary angioplasty is likely to be cost-effective, although this cost-effectiveness is likely to be dependent on the additional time it takes to initiate angioplasty compared to thrombolysis.4 Although, on average, primary angioplasty is likely to be considered cost-effective, the costs and benefits of the two alternative reperfusion strategies are likely to vary according to the type of centre (e.g. rural versus urban setting).

These data provide evidence that, if both interventions are routinely available, then primary angioplasty is likely to be the appropriate choice for most patients. However, primary angioplasty is currently not routinely available to patients presenting to the National Health Service (NHS) with AMI. It is available to some patients, depending upon where and when they present to hospital, but routine provision of primary angioplasty will require substantial re-organisation of services to ensure widespread availability 24 hours per day. Establishing such a service requires a number of organisational and economic questions to be addressed.[cjm1]

What models of service delivery could be used?

Primary angioplasty requires specialist staff and facilities. Several models have been suggested for providing widespread access to primary angioplasty,5,6 but little data exist to compare these models. Meta-analysis suggests that angioplasty is superior to thrombolysis even when it requires inter-hospital transfer.7[cjm2] Data from the United States (US) suggest that centres with a higher volume of angioplasty procedures have a lower mortality rate,8 and that the advantages of angioplasty over thrombolysis are limited to hospitals with a high or intermediate volume of cases[cjm3].9 Meanwhile, regionalisation of angioplasty services does not appear to increase travel distances for most patients.10 This has prompted researchers to suggest a network model similar to US trauma networks,6 in which patients bypass or are transferred from local hospitals to specialist centres, although this approach does not appear to be appropriate to the NHS.11

What are the barriers to implementing a primary angioplasty service?

A number of barriers to implementation of primary angioplasty have been identified,6 mainly related to the difficulty of providing timely access to appropriate staff and facilities, and strategies have been suggested to overcome these barriers. However, both the barriers and solutions identified have been based on a paucity of empirical data and those identified in other health care systems may not be transferable to the NHS. For example, there are important international differences in the professional groups delivering services and in the way health services are funded and organised.

What are the workforce implications of implementing a primary angioplasty service?

One of the principal barriers to implementation of a primary angioplasty service is the 24-hour requirement for specialist medical and nursing staff.12 As outcomes from AMI are related to staffing levels and staff specialisation,13,14 appropriate staffing is essential to achieve anticipated outcomes. However, successful implementation may take trained staff away from other important roles, such as on-call commitments and emergency cover, and may have some negative consequences for the NHS. [cjm4]

What is the most cost-effective approach to providing primary angioplasty?

A number of cost-effectiveness analyses have established that, if both services are routinely available, then primary angioplasty is likely to be considered a more cost-effective use of resources than thrombolysis.3,15,16 However, these studies assume that primary angioplasty is routinely available and use an average angioplasty cost based upon current angioplasty service costs, which does not vary according to the specific circumstances under which it is performed. This assumption is unlikely to represent the true cost of providing emergency primary angioplasty. If provision requires a substantial re-organisation of services, rearrangement of staff rosters or knock-on effects for other services then the true cost of an emergency primary angioplasty may be much higher than the average cost. Furthermore, it is probably inappropriate to consider primary angioplasty and thrombolysis to be distinct, mutually exclusive strategies. Instead, the most cost-effective alternative to a comprehensive angioplasty service will probably involve some selective, opportunistic use of primary angioplasty, with thrombolysis as a back up. Therefore the more appropriate comparison would be between a strategy that seeks to maximise use of primary angioplasty (intervention), and one that only provides it in an opportunistic manner (standard care). Finally, it is possible that costs and additional time it takes to initiate angioplasty (compared to thrombolysis) may vary between different models of service provision, such that some models may be more cost-effective than others.[cjm5]

What do patients think of primary angioplasty and thrombolysis?

The views of service users should help determine the development of NHS services. It is self-evident that patients and carers want effective services, but other factors may have an important influence upon their experience. For example, implementation of primary angioplasty may require centralisation of services, which may run counter to patient and carer preferences. Patient views have been sought in developing cardiac care,17 in the attempt to weigh the risks and benefits of reperfusion strategies for myocardial infarction,18-20 and in comparing diagnostic strategies for chest pain.21,22 The patient experience of angioplasty has been explored,23 but comparison of primary angioplasty to thrombolysis has focussed upon mortality, morbidity and cost-effectiveness.

The National Infarct Angioplasty Pilots

The British Cardiac Society (BCS) and the Department of Health have established a joint working group to establish the feasibility of implementing a countrywide primary angioplasty service. Up to ten pilot sites will be funded to set establish a service and collect data. Meanwhile, other hospitals will continue to collect data from patients with acute myocardial infarction as part of the Myocardial Infarction National Audit Project (MINAP) database. We propose to evaluate the pilot sites and address the issues outlined above.

D. Plan of investigation

Evaluation of changes to the organisation and delivery of emergency services requires a multidisciplinary approach, involving researchers with experience of working in this challenging area. We will use a mixture of qualitative and quantitative methods, involving health service research, organisational research, work psychology, epidemiology, and health economics. Members of our research team have evaluated the role of chest pain units in the NHS (SG, SJC, KS, SC), the influence of organisational factors upon waiting times in Accident and Emergency (AC, SG), the role of NHS Direct (AOC), human resources in the health sector (SW), and the value of revascularisation (RS,MJ).

A core research team of Steve Goodacre, Fiona Sampson, Alicia O’Cathain, Katherine Stevens, Mark Sculpher (University of York), and Angela Carter will undertake the project, with expert guidance from Simon Capewell (epidemiology), Stephen Campbell (cardiology), Rod Stables (cardiology), Stephen Wood (work psychology and organisational research), James Wardrope (prehospital care) and Mark Jackson (Clinical Audit). A consumer representative (Enid Hirst) is helping to develop the project and will establish a consumer group of people who have experience of heart attack and/or angioplasty. A Steering Group comprising of an independent Chair, independent member, consumer representative, stakeholder representatives and the co-applicants will guide the project.

We plan to compare the pilot (intervention) sites to four control sites that do not formally establish a primary angioplasty service. Evaluation will take a whole-system approach. We anticipate that even pilot sites that successfully implement 24-hour primary angioplasty will still use thrombolysis for at least a residual proportion of patients. Likewise, control sites that do not develop a primary angioplasty service may still use angioplasty opportunistically for some patients arriving during working hours. Our evaluation will compare the overall effect on all patients with AMI at each site, rather than focussing upon those who received the intended or principal service.

Routine data will be collected from all sites. Two intervention sites will be used for detailed evaluation of the patient and carer experience. Two other intervention sites will be selected to develop workforce and feasibility methods and identify the economic implications of providing primary angioplasty. The Research Team will meet regularly for joint discussions of methods and findings from these two pairs of sites to ensure that the project benefits from the complimentry nature of the evaluations.

We have requested an additional £25,000 to undertake micro-costing at four of the intervention sites and all four control sites, and to cross-check routine data collected at these sites. Micro-costing will allow us to accurately measure the actual costs of primary angioplasty and thrombolysis, and measure variation in costs between the different models of service delivery. Validation of MINAP data will allow us to address concerns about the quality and completeness of this dataset, particularly at the control hospitals where we would otherwise have very little control over data collection. These additions to the project will substantially improve the quality of data used in the economic model and hence the reliability of our estimates of cost-effectiveness.

Patient and carer experience

Although patient satisfaction has been measured in the context of angioplasty,17 there is no validated instrument specific to the patient and carer experience of angioplasty. Even if such an instrument existed, it might fail to fully capture experience when used in the context of an innovative service such as the NIAP pilot sites. We therefore propose a phased approach of developing an instrument, followed by the use of this instrument to describe experiences in a range of pilot sites and comparator hospitals.

Phase 1 will involve the two sites with designated special responsibility for the evaluation of patient and carer experience. We will use qualitative methods to identify key elements of the patient experience and develop NIAP-specific instruments for measuring patient and carer satisfaction. We will then test the feasibility of using this instrument, alongside a generic instrument, in a postal questionnaire. In phase 2 we will use this questionnaire to measure patient and carer satisfaction at four of the pilot sites and patient satisfaction at four control hospitals providing standard thrombolysis-based care. We will select the four pilot sites with the highest proportion of patients receiving angioplasty so that this aspect of the evaluation maximises the contrast between intervention and control care. In Phase 3 we will use qualitative interviews with patients and carers from the two original pilot sites to expand upon results from the survey and identify possible solutions to issues identified.

Workforce implications

We will use a mixture of quantitative and qualitative methods to address the questions outlined in the brief. We will administer self-complete questionnaires to staff who work with patients that have treatment for AMI. We will then conduct semi-structured interviews and focus group discussions with these staff and others who are associated with treatment for AMI, including members of the angioplasty team, emergency department staff, ambulance staff and paramedics. A two/three day site visit will be used as the principal vehicle to arrange and conduct interviews and focus groups. This visit will also be used to undertake the specialist teamworking interviews and ethnographic observation (or where not possible retrospective case discussion) that will address the implementation and feasibility issues

It is anticipated that specific material will be produced for this study. These will be developed on two sites working closely with the teams who are collecting economic data to produce a holistic model of investigation, and will involve close collaboration with researchers working at two other sites to develop the patient and carer satisfaction evaluation. Once piloted these materials and methods will be developed/edited and then used with the other intervention sites.

Description of models of service delivery

We will use data from routine sources, a telephone survey and site visits to describe the models of service delivery developed by the pilot sites in terms of the following parameters: Service setting: urban or rural; area covered; catchment population (number, age and gender, coronary heart disease morbidity and mortality rates, ethnicity and social deprivation); transport and communications networks. Service overview: participating hospitals; teaching status; referral networks between hospitals; ambulance services; other prehospital care; access route to the service. Service infrastructure: staff numbers, grades, profession and specialties; interventional cardiology skills; rostering and on-call arrangements; facilities and equipment; bed availability (general, coronary care and intensive care); cardiac surgery services. Service activity levels: number of AMI treated (prehospital thrombolysis, in-hospital thrombolysis and angioplasty), numbers of emergency and elective admissions, revascularisation procedures, and cardiac operations performed.

Implementation and feasibility

We will explore these issues alongside the evaluation of the workforce implications and address the questions outlined in the brief by using a multiple case study approach. This will involve face-to-face interviews, focus group discussions, and observational / retrospective case study methods. The vehicle for the collection of these data will be the site visit outlined in the workforce implications section.

Economic evaluation

Mark Sculpher and colleagues at the University of York have already developed a cost-effectiveness model to compare angioplasty to thrombolysis.4 It considers cost-effectiveness from the perspective of the NHS and uses data from the literature and routine sources to provide an estimate of the incremental cost per QALY. The analysis also looks at the variation in cost-effectiveness according to the time delay to angioplasty. The value of the model for the pilot evaluation is that it can be used to explore how the cost-effectiveness of primary angioplasty might vary between the different types of service configuration seen in the pilot centres. In particular, it can use centre-specific data on costs and times to reperfusion to assess variation in cost-effectiveness across different models of service delivery.