Testing Real-World Application of Appropriateness Criteria of Single Photon Emission Computed Tomography (SPECT) In Two Egyptian Hospitals
The American College of Cardiology pioneered appropriateness criteria for single-photon emission computed tomography myocardial perfusion imaging in 2005 to account for evidence-based clinical relevance of stress perfusion imaging.
Our aim was to assess and compare appropriateness use criteria in in Kobry al Kobba military hospital and Ain Shams University hospitals.
All patients were subjected to thorough history taking, calculation of pretest probability and Framingham risk score, determination of appropriateness use criteria and stress-rest Tc 99m imaging to detect the presence of ischemia and one day Tc 99m imaging to detect viability.
The study included 442 patients with mean age of 56.5 years, with male predominance (77%), 38% were diabetics and 58% had hypertension.
Seventy-eight percent of patients had appropriate tests, uncertain tests in 12% and 10% inappropriate studies. 47% of appropriate tests show positive results of SPECT.
We concluded that appropriateness criteria are effective in identifying appropriateness of SPECT in a diverse patient population.
KeywordsSPECT MPI stress Coronary artery disease viability test
Single-photon emission computed tomography
Myocardial perfusion imaging
Coronary artery disease
The Framingham Risk Score
Summed stress score
Summed rest score
summed difference score
Percutaneous coronary intervention
Coronary artery bypass graft
There has recently been an explosive growth in cardiovascular imaging, with stress testing demonstrating 6.1% annual increase versus 2% for cardiac catheterization, 0.8% for percutaneous intervention, and 0.1% for acute myocardial infarctions in population-based study of the United States Medicare patients  .
The American College of Cardiology pioneered appropriateness criteria for single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) in 2005 . The criteria were developed to account for evidence-based clinical relevance of stress perfusion imaging and were the first cardiology specific document to address appropriateness. The criteria relied on the modified RAND/UCLA methodology to identify 52 common clinical scenarios and was divided into appropriate, uncertain, and inappropriate indications [1, 3].
Despite these developments, the clinical use of the appropriateness criteria has not become standard of practice for physicians . Overall, approximately 64% of stress studies are appropriate. Approximately 14% of SPECT and 18% of stress echocardiography studies are performed for inappropriate indications, and approximately 10% of all patients are unclassifiable .
In a prospective multicenter trial, the appropriateness criteria were evaluated in 7 physician practices of various size in partnership with United HealthCare. Overall, 14% of all studies were inappropriate, most in asymptomatic individuals .
Aim of the work
Was to assess and compare appropriateness use criteria and the downstream use of resources as defined by patient outcomes in two different nuclear centers in Cairo.
All patients older than 18 years undergoing SPECT in Kobry al Kobba military hospital and Ain Shams University hospitals and capable of primary decision making were included throughout the period from February 2012 to august 2012.
Chronic illnesses or malignancy with estimated life expectancy of less than 1 year,
Unwilling to give informed consent,
Not accepting record access and phone call follow up.
The final cohort consisted of 442 patients.
After having a verbal consent of including the patients’ data in the study, the following were recorded:
Age in years.
Cardiovascular risk factors: arterial hypertension, diabetes mellitus, smoking and positive family history of premature cardiovascular diseases.
Known history of ischemic heart disease (defined as prior myocardial infarction demonstrated whether by ECG changes or revascularization history).
Pretest probability of CAD according to age, gender and chest pain
With High meaning greater than 90% pretest probability. Intermediate: Between 10% and 90% pretest probability, low: Between 5% and 10% pretest probability, and very low: Less than 5% pretest probability. Modified from the ACC/AHA Exercise Testing Guidelines to reflect all age ranges .
Framingham Risk Score Calculation
Presence of left bundle branch block.
Healed infarction: e.g. Q waves in the ECG.
Non-specific ST and T wave changes.
Appropriateness use criteria: see Additional file 1
Single photon emission computed tomography
Stress-rest gated Tc99m Sestamibi scan:
To detect the presence, severity and distribution of ischemia. For all stress imaging, the mode of stress testing was exercise for patients able to exercise.
For patients unable to exercise, pharmacologic stress testing was used. Further background on the rationale for the assumption of exercise is available in the ACC/AHA 2002 guideline Update for Exercise Testing .
After fasting for at least 4 hours and abstinence from nitrates, beta blockers and calcium channel blockers; images were taken approximately 45-60 min after injection of 22-30 mCi of technetium99m Sestamibi through an indwelling intravenous cannula.
Mode of stress
Exercise stress testing: the radiotracer was injected at peak exertion at target heart rate (85% of age predicted maximum heart rate), proper analysis of stress data was done as follows:
Duration of exercise.
Percent of heart rate achieved.
Blood pressure response.
Cause of termination: Occurrence of chest pain or significant stress induced ECG changes.
Pharmacological stress test: indications:
Inability to exercise.
Left bundle branch block.
Contraindication to exercise stress test e.g. severe bronchial asthma.
One day rest imaging: was done to assess viability after the injection of 70 mg of Trimetazidine 1 hour before injection of the radiotracer.
All radionuclide perfusion imaging indications used electrocardiogram (ECG) gating, whenever possible, with the determination of global ventricular function (i.e., left ventricular ejection fraction) and regional wall motion as part of the evaluation.
In the setting of a known acute coronary syndrome (ACS), the use of stress testing was performed in conjunction with pharmacologic stress testing, not exercise.
Image acquisition and reconstruction
Tomographic images were obtained using a rotatory dual head cardiac dedicated gamma camera (cardio MD, Phillips medical equipment’s) in Ain Shams University hospitals and (dual head symbia II, Simens) in Kobry Al Kobba hospital with a low energy, general purpose collimator interfaced to a computer.
An arc of 180 degree was used, spanning from the 45 degree right anterior oblique projection to the 45 degrees left posterior projection.
Basal myocardial perfusion was assessed using the semiquantitative analysis on the 17-segment scoring system, as standardized by the cardiac imaging committee of the council on clinical cardiology of the American Heart Association .
Nomenclature and location of the myocardial segments
Perfusion analysis was translated into
Segmental perfusion score: Perfusion was graded within each segment on a scale of 0 to 4, with 0 representing normal perfusion and 4 representing a very severe perfusion defect.
The summed stress score (SSS): which was the sum of the 17 segmental scores from the stress images representing the extent and severity of stress perfusion abnormality, the magnitude of perfusion defects related to both ischemia and infarction, as shown in Table 3 .
The summed rest score (SRS): which was the sum of the 17 segmental scores from the rest images representing the extent of infarction.
The summed difference score (SDS): which was derived by subtracting SRS from the SSS and represents the extent and severity of stress – induced ischemia. The digitalized images were evaluated by an experienced reader who was unaware of the clinical outcome and ECG findings of the patients.
Summed stress score according to cedars-sinai scoring system. Other centers may use alternative scoring systems with varying cutoffs 
Summed stress score
SDS score category 
2-4 Mild ischemia
5-7 Moderate ischemia
> 7 Severe ischemia
Data was analyzed on an IBM personal computer, using statistical package for special science (SPSS) software computer program version 15.
Data was described using mean ± standard deviation (SD) and frequencies according if they were quantitative or qualitative respectively.
Independent student T test was used for comparing of quantitative variables between two groups. Chi square test was used for comparing of distribution of qualitative variables between different groups.
The significance of the results was assessed in the form of
P value differentiated into:
Non-significant: when P value > 0.05
Significant: When P value < 0.05
Highly significant: When P value < 0.001.
In the present study, 442 patients derived from two territory hospitals in Cairo (Ain Shams university hospital and Kobry El-Kobba military hospital).
The data of these patients were used to apply for the appropriateness criteria of performing myocardial perfusion scan in the two centers.
Group I: it included 245 patients derived from Ain Shams nuclear cardiology lab.
Group II: it included 197 patients recruited from Kobry El-Kobba nuclear lab.
Age and gender distribution of both groups
56.45 ± 9.47
56.49 ± 9.80
Risk factor distribution among both groups
Indications to undergo the test
Screening for CAD was the indication in 286 patients (65%), post MI angina was the indication in 80 patients (18%), post PCI angina was found in 117 patients (26%) and in 29 patients (6%) post CABG angina was the cause of referral.
Viability assessment was the referring cause in 31 patients (7%).
Indications of SPECT in both groups
Screening for CAD
By applying pretest probability, there were 296 patients with high or intermediate probabilities (67 %) and 146 patients with low probability for IHD (33%) in the whole study group.
Pretest probability in both groups
High or intermediate pretest probability
Low pretest probability
Framingham Risk Score (FRS)
After excluding patients with documented CAD, there were 54 patients eligible for FRS (42 patients in group I and 12 patients in group II)
Distribution of different categories according to FRS in both groups
Very low and low
Pre-procedural ECG findings in both groups
Pathological Q waves
99 (50 %)
Myocardial perfusion imaging
Mode of stress in both groups
Rest imaging n(%)
Treadmill stress n(%)
51 (26 %)
Development of symptoms during exercise test in both groups
Chest pain n(%)
Target heart rate n(%)
Results of MPI in both groups
Positive scan n(%)
Negative scan n(%)
Appropriateness use criteria
Appropriateness criteria in both groups
The number and percentage of each appropriateness criteria in both groups
Detection of CAD, symptomatic with intermediate pretest probability, able to exercise.
Detection of CAD, symptomatic with intermediate pretest probability, unable to exercise.
Detection of CAD, symptomatic with high pretest probability.
Risk assessment, post revascularization.
Risk assessment, with known chronic stable angina and coronary stenosis.
Detection of CAD, asymptomatic, high FRS
Evaluation of ventricular function, with use of cardiotoxic drugs
Detection of CAD, symptomatic, with low or intermediate FRS.
Known CAD, prior test result with normal coronary angiography
Detection of CAD, symptomatic with low pretest probability.
Post revascularization, asymptomatic.
Risk assessment, known CAD.
Risk assessment, post revascularization.
Acute coronary syndrome, primary PCI, asymptomatic.
The number and percentage of each appropriateness criteria in relation to results of MPI in both groups
The objective of the current study is to identify clinical value of appropriateness use criteria in various patient and physician groups and to focus on downstream use of resources in relation to appropriateness.
This study evaluated SPECT appropriateness criteria in a diverse patient population. It included all patients undergoing SPECT in Kobry al Kobba military hospital and Ain Shams University hospitals throughout the period from February 2012 to august 2012.
It was noted that men were predominantly higher than women with 77% versus 23% respectively. Furthermore, men were higher in the group of Kobry Al Kobba military hospital (94%) than patients of Ain Shams University (62%).
This is higher than the results found by Regina et al. who investigated 570 patients with 55% of men and 45 % of women .
Diabetes, hypertension and smoking were investigated in our study as risk factors for ischemic heart disease and we found that 28% of patients were smokers, 58% hypertensive patients and 38% diabetics.
This is compared to Raymond J. et al., who investigated 284 patients undergoing SPECT imaging and found that 48% of patients were smoking, 71% with hypertension and 27% with diabetes .
Most of our patients had high or intermediate pretest probability 66%. It was noted that more patients with high or intermediate pretest probability were found in Kobry Al Kobba military hospital (79%) versus (58%) in Ain Shams university hospital.
On the other hand Regina et al. 2011 found that 51% of patients had low pretest probability and only 6% had high pretest probability .
FRS was calculated for asymptomatic patients with no history of CAD which predict 10-year incidence of CAD, most of the patients are in the low risk groups (57%).
This is supported by Regina et al. who found that 51% of the patients fall in the low risk category .
In the present study, the overall percent of appropriate studies was 78%. This is within the range found by Gibbons et al. 2008 who investigated the performance of appropriateness criteria for stress SPECT in 284 patients and found that 64% of SPECT studies were appropriate.
Also, Regina et al. found overall appropriate studies in the range of 63% .
On the other hand, we found that the overall inappropriate studies were forming 10% of all the studies done.
In our work, the uncertain or unclassified studies were found to be 15% of all studies.
This is supported Gibbons et al. who found that 10% of his studies were unclassified, but our findings were higher than that reported by Regina et al. who reported a 3% of unclassified studies [6, 12].
As regards center related findings, it was notable that the uncertain and inappropriate studies were higher in the university nuclear lab than that done in the military nuclear lab (15% versus 7%) respectively. This may be explained by the inclusion of more females in the university.
This finding was explained by Gibbons et al. who reported that almost 50% of inappropriate test were asymptomatic patients with a low FRS who were referred for screening for CAD .
The second large group of inappropriate tests was done in patients under consideration of intermediate risk surgery who had good exercise capacity and no or minor risk factors, and the third group of inappropriate patients were symptomatic patients with low pretest probability, and the final group were patients for low risk non-cardiac surgery .
These findings prove that specific scenarios may differ from institution to institution and the recognition of these general patterns in appropriateness criteria should be helpful to clinicians.
Women were more symptomatic that men and had a lower prevalence of known CAD.
Smaller number of included patients derived from 2 centers only over a relatively short period.
The inherited defects of FRS and its applicability on different ethnic groups such as Egyptians.
Appropriateness criteria are effective in identifying appropriateness of SPECT in a diverse patient population. More appropriate studies were observed in patients obtained from both sides of examination.
This study demonstrates the application of appropriateness criteria to attempt quality improvement in the clinical use of stress cardiac imaging.
Other long-term studies that include larger number of patients.
We encourage others to perform similar studies in their own institutions, hospitals, and private practices. Such efforts are only a first step towards the ultimate goal of quality improvement in this area and thereby contribute to increased efficiency in our healthcare system.
Authors would like to thank all staff, assistants and residents in both hospitals without whose help doing study would have not been possible.
We also like to thank administration in both hospital for facilitating collection of data.
AA: contributed in assessing patients and doing stress tests, main role in writing manuscript. HM: role was collecting data, doing stress tests and follow up of patients, helped in manuscript writing. MR: role was interpretation of test data and helping in data collection and analysis. All authors have read and approved the manuscript.
No special funding sources were obtained.
Ethics approval and consent to participate
Ain Shams University ethical committee approval was obtained prior to doing research.
Verbal consent was obtained from all participants (veterinary officers and farmers). Verbal consenting was approved from ethical committees as no personal data was declared and our trial is an observational trial with no intervention done to the patients other than what was already to be done.
Consent for publication
The authors declare that they have no competing interests.
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