The Role of Myocardial Perfusion Scintigraphy in Diagnosis of Patients with Coronary Artery Disease

Background: The non-invasive imaging is most valuable for patients with intermediate pretest probability of coronary artery disease (CAD) according the guidelines of the European Society of Cardiology and is employed for the diagnosis of suspected CAD and in the assessment of prognosis in a patient with known CAD.
The aim of the study was to evaluate the role of myocardial perfusion scintigraphy (MPS) in patients diagnostic algorithm and to prove its usefullness and efficacy for the initial diagnosis of CAD and for prognostification in patients with known CAD in Latvia.
Methods: Retrospective study was held at Pauls Stradins Clinical University Hospital Latvian Centre of Cardiology and included 620 patients with performed MPS in 2014. The history of CAD, symptoms, cardiovascular risk factors, pretest probability, and stress testing have been evaluated. Two groups were selected – patients with suspected and with known CAD. Cardiovascular risk was evaluated by defining the amount of myocardial ischemia on MPS and subsequent decision was made: optimal medical therapy and/or invasive diagnostics and treatment.
Results: Results show the role of MPS – there were no indications for performing coronarography in 69.9% of patients with known CAD and in 78% of patients without CAD.
The MPS value for prognosis of obstructive CAD has been proven by cardiovascular risk marker – SDS and its association with presence of obstructive CAD on coronary angiography. The higher is SDS, the higher is the rate of obstructive CAD: for patients with very high risk (SDS>12) – in 67% of cases and for patients with high risk (SDS 9-12) – in 46% of cases, in turn, for patients with intermediate (SDS 5-8) and low (SDS 0-4) CAD risk the rate of obstructive CAD is lower (43% and 5%, respectively).
Conclusions: 1) MPS is valuable and informative non-invasive modality in patients with intermediate pretest probability of CAD, which proves the need for algorithm application in Latvia defined by guidelines;
2) MPS is important test in decision making of subsequent diagnostics and management in patients with low cardiovascular risk – best performed to identify the patients who will not benefit from further invasive intervention.