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Non-invasive imaging of coronary artery disease and its functional consequences- The Hybrid SPECT and CCTA approach
- Publication date
- 4 October 2013
- Publisher
- For several decades invasive coronary angiography (CA) has been the reference
standard in the assessment of coronary artery disease (CAD) severity. Patients with
high pre-test likelihood of CAD, receive a Class 1 indication for CA. Several factors,
however, motivate the need for a reliable non-invasive imaging modality, especially
in patients with a high pre-test likelihood. Not only to rule out, but also to reliably
diagnose coronary stenosis with functional consequences (significant CAD) and
guide therapeutic decision making.
Performance of CA in all patients with high pre-test likelihood of CAD has
undeniable drawbacks. First of all, the prevalence of angiographically significant CAD
in patients with high pre-test likelihood may be as low as 44-46%. In real life,
the prevalence of significant CAD in patients referred for CA is even lower at only
36.7%, according to the national cardiovascular data registry of the United States .
Secondly, angiographic severity of CAD does not reliably predict its main functional
consequence: myocardial ischemia 6-8. Because evidence of myocardial ischemia is
needed before deciding whether revascularization is necessary, additional (non-
) invasive tests are needed . Finally, CA comes with high costs as a result of the
need for admission to a hospital or day-care facility and a low risk (0.1%) of serious
adverse events .
With the advent of computed tomography coronary angiography (CCTA) and
the known reliability of single photon emission computed tomography myocardial
perfusion imaging (SPECT-MPI) a combination of non-invasive imaging modalities
became available that potentially could reliably diagnose significant CAD. The high
diagnostic accuracy of this combination has previously been shown in highly selected
patient populations. Nevertheless, data demonstrating the applicability of hybrid
SPECT and CCTA in diagnosing significant CAD in stable patients with an intermediate
to high pre-test likelihood of CAD are still lacking. Furthermore, the contribution of
these tests to therapeutic decision making in these patients is unknown. Providing
evidence on both of these issues is the main objective of this thesis.