Objectives: The study compared cardiac scintigraphy stress scanning practices applied in a National Maltese Nuclear Medicine centre and in international centres. This was achieved through the design of an online survey which investigated participant knowledge of stress testing, and current procedural practice. Methods: An online survey comprising 12 questions was prepared using Survey Monkey. Professional Nuclear Medicine groups such as the <i>Medical-Physics-Engineering</i> community and Virtual Radiopharmacy were targeted. Access to the survey remained open for eight months during which a periodic reminder was sent to optimise the response rate. Forty-three members responded from across Europe and Australasia. Chi-square tests and comparisons between multiple responses using IBM SPSS 20 were used to evaluate the results. Information related to Maltese practice was collated separately for review and comparative purposes. Results: The online survey participants comprised United Kingdom [72%], other European countries [18%] and Australasia [9%]. The majority of respondents [n = 39] reported pharmacological stress testing as being performed either alone or in conjunction with exercise stress testing as the preferred option. Most participants [60%] were aware of local stress test protocols but had limited knowledge in relation to guidelines designed for cases where patients were not suitable for pharmacological stress testing. Conclusion: The survey provided information about procedures within participating centres for scintigraphic cardiac stress scanning. Differences were identified with regards to the preferred radiopharmaceutical tracers and procedural protocols. Further investigation of examination techniques is warranted, with the aim of increasing standardisation of protocol compliance and the application of more suitable practice.
Chronic and noncommunicable diseases, especially cardiovascular disease and cancer, are now leading causes of mortality [
This paper outlines through an online survey that several common trends in practice exist between regions when performing NM myocardial perfusion stress tests. Cardiac tracers, types of cardiac stress tests performed, pharmacological agents used, protocols applied during cardiac stress scanning and the staff injecting the radiopharmaceutical were discussed.
Data were collected through an online survey comprising 12 questions in Survey Monkey which was posted on two international websites, the VirRAD and the Medical-Physics-Engineering homepages. The chosen international websites were indicated to the researcher by British and European Nuclear Medicine Societies, as a means for nuclear medicine radiographers of exchanging professional views and information through forums, chat groups or individual discussions for professionals working within the field globally. Questions focussed on: the frequency of myocardial stress examinations, cardiac tracers employed, pharmacological versus exercise stress protocols, pharmacological stress agents, written procedural protocols including staff knowledge and staff responsibilities. Access to the survey was open for 8 months in total for respondents with periodic reminders to encourage greater participation. Additional information related to current practice in Malta was gathered. Data were collated and transcribed to IBM SPSS version 20. Comparisons between multiple responses were carried out using Chi-square tests and cross tabulations. When studying the variances in practice between the regions, the p value was set at a level of significance of 0.05 [5%].
Forty-three respondents from centres across Europe and Australasia participated in the online survey. Geographical categorisation following statistician review resulted in 3 regions namely, United Kingdom (UK), rest of Europe and Australasia, for the purpose of comparing the data collected. The majority of participants (72%) were from the UK, 18% from various European countries and 9% from Australasia. The number of cardiac scintigraphy stress scans performed weekly by each of the responding centres is summarised in
Literature identifies Technetium-99m (Tc-99m) as the most widely used radionuclide for diagnostic scans being performed in developing countries [
The online survey identified 64.4% of responding UK centres as performing scintigraphic cardiac stress imaging using pharmacological vasodilators more frequently than other online survey respondents, as summarised in
The two preferred pharmacological agents of choice identified across the three geographical regions were [±]-4-[2-[[3-[p-Hydroxyphenyl]-1-methylpropyl]amino]ethyl]-pyrocatechol hydrochloride (Dobutamine) and 6-amino-9-β-D-ribofuranosyl-9-H-purine (Adenosine) as demonstrated in
Number of Procedures | Region | ||
---|---|---|---|
United Kingdom | Rest of Europe | Australasia | |
1 – 10 | 25.8% | 75.0% | 25.0% |
11 – 20 | 41.9% | 12.5% | 25.0% |
More than 20 | 32.3% | 12.5% | 50.0% |
p value 0.106.
tients being treated with Dipyridamole or taking caffeine products prior to the test, as being the most significant contraindications to the performance of pharmacological stress testing.
Participants were asked to confirm the presence of written protocols for scintigraphic cardiac stress scanning, the findings are outlined in
In Malta, the ECG stress test component of the myocardial scintigraphy examination is performed by the NM nurse and the ECG technician; an assigned NM Consultant, though not directly present in the room, is always on the premises during the cardiac stress testing.
All online survey findings were reviewed, descriptive analysis was performed and the responses compared with existing literature and with current practice in Malta. Comparisons between multiple responses were carried out using Chi-square testing. p values higher than the set level of significance were taken to indicate that there was no significant difference between the regions for that particular response.
The IAEA created a NM online database (NUMDAB-http://nucmedicine.iaea.org/details.asp) in 2003, with the aim of investigating current protocol trends across global regions in NM, this site is continually updated. This database represents responses from NM centres in 99 IAEA member states and provides information about the
Are written procedures available? | Region | ||
---|---|---|---|
United Kingdom | Rest of Europe | Australasia | |
No | 3.2% | 0% | 25.0% |
Yes | 64.5% | 62.5% | 25.0% |
Do not know | 32.3% | 37.5% | 50.0% |
p value 0.255.
Staff injecting the radiopharmaceutical | Region | ||
---|---|---|---|
United Kingdom | Rest of Europe | Australasia | |
Doctor or consultant | 6.1% | 25.0% | 75.0% |
Nurse | 18.2% | 37.5% | 0% |
Radiographer | 75.8% | 37.5% | 25.0% |
p value 0.003.
extent and type of practice in NM centres worldwide. The NUMDAB currently contains data from 760 Asian NM centres and 50 centres from Western Europe [
This online survey in comparison to the NUMDAB received responses from 31 UK centres and these findings therefore are potentially more indicative of practices within the United Kingdom. The response from Asia, in direct contrast to the NUMDAB survey returned a low number of participants [n = 2].
NUMDAB figures currently report that 52,287 cardiovascular (CV) scans are performed yearly in the NM centres within Western Europe. This data aligns to the findings of this online survey, which indicated that in 41.9% of the participating UK centres 11 - 20 cardiac scans were performed weekly (
Despite some disadvantages for usage for both Tc-99m Sestamibi and Tc-99m Tetrofosmin, published literature supports their use for cardiac stress scintigraphy [
Due to the relatively longer physical half-life of Thallium-201 (3.05 days), patients being injected with this tracer have been shown to still have residual biological activity even after 5 half-lives (15.2 days) [
Literature has shown that 50% of all myocardial perfusion imaging is performed by pharmacological stress testing rather than exercise methods [
Research also suggests that the inability to exercise may be indicative of a poor prognostic outcome [
Dobutamine and Adenosine were identified as the preferred pharmacological stress agents in comparison to Di- pyridamole and 2-{4-[[methylamino]carbonyl]-1H-pyrazol-1-yl}adenosine (Regadenoson) according to the responses from the three participating geographical regions. One explanation for this may be due to the pharmacological characteristics of the drugs. In 51% of the participating UK centres Dobutamine is the pharmacological stress agent of choice, as it is considered to be safe even in patients with contraindications to pharmacological stress testing [
Interesting to note that literature reported a two-fold higher cardiac event rate in patients undergoing Dobutamine stress myocardial perfusion imaging (DSMPI) when compared to the event rates reported after a normal exercise SPECT study [
Regadenoson is a new agent on the market, which unlike Adenosine, targets only A2A receptors, and can therefore be used in patients with mild-to-moderate airway disease and obstructive lung pathology [
Through the online survey, the participant’s knowledge of contraindications to pharmacological stress testing was also investigated; the answers given by the majority of the respondents suggested uncertainty regarding the use of pharmacological stress agents. Participants were asked which of the options given would be a contraindication to pharmacological stress testing (
Literature notes that a large variety of cardiac imaging procedures exist across NM and it is the responsibility of individual departments to design suitable protocols [
Professional bodies across countries uniformly agree that a physician must be in attendance while performing cardiac exercise stress testing due to the possible related patient complications, even if guidelines pertaining to the performance of this test exist [
As shown in
Due to the uneven geographical spread of results the findings, whilst providing an insight into practices in NM in specific geographical regions, present clustering of participant responses in a limited number of countries. This may impact upon the ability to apply the findings to the international population with NM facilities. The information does however provide detail against which current Maltese practice can be compared and offers a good insight into UK practice which was not evident following previous international surveys [
Other technical factors play a role in the set-up of a myocardial scintigraphy stress test protocol such as patient position, the type of acquisition set up, the number of ECG leads utilised during the stress test, and also the type of software used to analyse the data acquired. The scope of this survey was to investigate the incidence of common variances and trends present across centres performing myocardial stress testing rather than to assess the technical details in the different protocols that can be used.
The results of this online survey confirm that several common trends in practice exist between regions when performing NM myocardial perfusion stress tests. Technetium-99m Tetrofosmin appears to be more in use within the UK as is pharmacological stress testing, with Dobutamine being the preferred pharmacological agent in this region. With so many different combinations of tracers, pharmacological agents to choose from and constantly developing new technology, it is essential that guidelines or protocols exist, which leads to more efficient and improved patient care [
Despite 64.5% of the UK and 62.5% of the European survey participants indicating the existence of written procedures for cardiac scintigraphy stress testing, a number of participants in all the 3 regions pointed out that they did not know or were unsure if such written procedures existed. It is critical that procedures and protocols are known, particularly in scenarios where the radiographer is taking on more leading roles in myocardial stress testing. Further research is justified to investigate optimisation of practice for patients attending for cardiac scintigraphic stress test examinations in the national Maltese NM unit.