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46 Multislice CT in Coronary Heart Disease KCE Reports 82
terms of mortality and morbidity up to 6 months are not any different between the
arms.
Moreover, despite the apparent safety of both strategies (absence of adverse
complications), 10% of the patients in the MSCT arm had to undergo a radiotoxic test
twice (MSCT+nuclear testing) and 4% even three times (MSCT+nuclear testing+CCA).
Iodinated contrast also presents a potential harm in MSCT evaluation. Although 8 CCAs
out of 12 were positive in the MSCT-arm against only 1 out of 7 in the ”standard of
care”-arm, this does not necessarily mean anything for the prognosis of the patients
with a positive CCA.
The numbers of patients were too small to evaluate the true incidence of false positive
cases and false negative cases, especially in a population with a low prevalence.
Recently the Andalusian HTA agency 129 published a report on MSCT coronary
angiography including a meta-analysis of 16-SCT or more coronary angiography and an
economic model based on a decision tree. The input parameters were drawn from the
meta-analysis of studies using “patients” as units of analysis. The model was populated
with patients with a suspected coronary stenosis (>50% vessel diameter). The three
following strategies were compared:
• direct CCA,
• 16-SCT coronary angiography followed by CCA when positive,
• 64-SCT coronary angiography followed by CCA when positive
The prevalence of significant coronary stenosis was assumed to be 40%. The sensitivity
and specificity of 16-SCT were 94% and 77.9% respectively. Those of 64-SCT were
98.4% and 93.7% respectively. Complications due to CCA occurred in 2.2% of the
procedures and lead to death in 5% of the complicated procedures, AMI in 45% and
urgent surgery in the remaining 50%.
The perspective was that of the Andalusian public health system. Costs included direct
costs of equipment, consumables (including pharmaceuticals), procedures (including
ECG and blood tests in the three arms), and costs of personnel. Procedure costs and
costs of complications were obtained from the public tariffs of the SSPA (Sistema
Sanitario Público Andaluz). For the equipment cost, an average per patient was
calculated based on the purchasing price, the throughput and the lifetime of the
equipment. Costs of personnel were calculated as the legal hourly wage cost per
professional qualification multiplied by the time per test, based on a 2004 Spanish paper
comparing CCA to 16-SCT coronary angiography. Costs drawn from the literature
were validated by a radiologist and a nurse of the radiology department of two
Andalusian hospitals. The time spent by the radiologist, the technician and the nursing
auxiliary in the case of a 16-SCT coronary angiography was 45 minutes against 12
minutes for a 64-SCT coronary angiography. Total costs per patient of following the
three paths were respectively €203.96 for the 64-SCT path, €259.06 for the 16-SCT
path and €307.85 for direct CCA.
The ICER was calculated comparing CCA and 16-SCT to 64-SCT. Two denominators,
i.e. effectiveness parameters, were used: (1) number of cases correctly diagnosed with
stenosis (true positives) and (2) number of effective cases, defined as the number of
true positives minus the number of false negatives. In both methods, the 16-SCT
strategy was dominated by the 64-SCT strategy. In the CCA arm more patients were
correctly diagnosed (0.64%) than in the 64-SCT arm, but CCA was also more expensive
(€103.89 more). The ICER of CCA relative to 64-SCT was €16 596 per correctly
diagnosed case and €8 206 per ‘effective case’.