Very high coronary artery calcium score with normal myocardial perfusion SPECT imaging is associated with a moderate incidence of severe coronary artery disease

Abstract

PurposeMyocardial perfusion imaging (MPI) has limitations in the presence of balanced multivessel disease (MVD) and left main (LM) coronary artery disease, occasionally resulting in false-normal results despite the high cardiovascular risk associated with this condition. The purpose of this study was to assess the incidence of severe coronary artery disease (CAD) in the presence of a very high Agatston coronary artery calcium (CAC) score (>1,000) in stable symptomatic patients without known CAD but with normal MPI results.MethodsA total of 2,659 prospectively acquired consecutive patients were referred for MPI and evaluation of CAC score by CT. Of this patient population, 8 % (222/2,659) had ischemia without myocardial infarction (MI) on MPIand 11 % (298/2,659) had abnormal MPI (MI and/or ischemia). On presentation 1 % of the patients (26/2,659) were symptomatic, had a CAC score >1,000 and normal MPI results. The definition of normal MPI was strict and included a normal hemodynamic response without ischemic ECG changes and normal imaging, particularly absence of transient ischemic dilation. All of these 26 patients with a CAC score >1,000 and normal MPI findings underwent cardiac catheterization.ResultsOf these 26 patients, 58 % (15/26) had severe disease (≥70 % stenosis) leading to revascularization. Of this group, 47 % (7/15) underwent percutaneous intervention, and 53 % (8/15) underwent coronary artery bypass grafting. All of these 15 patients had either MVD (14/15) or LM coronary artery disease (1/15), and represented 0.6 % (15/2,659) of all referred patients (95 % CI 0.3 – 0.9 %). The majority, 90 % (8/9), had severe CAD with typical chest pain.ConclusionA very high CAC score (>1,000) with normal MPI in a small subset of symptomatically stable patients was associated with a moderate incidence of severe CAD (95 % CI 37 – 77 %). Larger studies and/or a meta-analysis of small studies are needed to more precisely estimate the incidence of CAD in this population. This study also supports the concept that a normal MPI result in patients with severe CAD may be due to balanced MVD.Electronic supplementary materialThe online version of this article (doi:10.1007/s00259-015-3072-z) contains supplementary material, which is available to authorized users.

Coronary artery calcium scanning in symptomatic patients: Ready for use as a gatekeeper for further testing?

“…If a normal MPI study is found in a patients with very high CAC scores (e.g., over[1000), the possibility of residual high risk may exist. 20 These proposals require ''real world'' testing to determine their validity in the form of comparative effectiveness research that would compare such proposed paradigms vs the usual standard of care for the work-up patients presenting with chest pain.…”

SPECT/CT in der Nuklearkardiologischen Bildgebung

“…Eine weitere Anwendung der kombinierten Evaluierung von CACS und Ischämielast scheint sich bei der Diagnose einer Mehrgefäß-KHK mit balancierter Ischämie abzuzeichnen [76]: hier konnte in einem kleinen Patientenkollektiv gezeigt werden, dass bei Patienten mit unauffälliger myokardialer Perfusion bei gleichzeitig hohem CACS > 1000 ein moderates Risiko für das Vorliegen einer ausgeprägten Mehrgefäß-KHK besteht. Das zusätzliche CACS zur MPS könnte also hilfreich sein, balancierte Ischämien zu detektieren, welche unauffällige Perfusions-Scans vortäuschen.…”

“…Ein interessantes Anwendungsgebiet quantitativer SPECT/CT-Datensätze in der Nuklearkardiologie stellt sicherlich der Nachweis balancierter Ischämien bei Mehrgefäß-KHK dar, welche in der konventionellen, "nicht-quantitativen" Myokard-SPECT einer Detektion entgehen können [76]. Grund hierfür ist die gleichmäßige Absenkung des myokardialen Tracer-Uptakes in sämtlichen Perfusionsarealen und eine relative Normierung auf den max.…”

Use of coronary artery calcium scanning as a triage for invasive coronary angiography

“…17 Quantification of CAC also provides incremental prognostic value in patients with non-significant myocardial perfusion deficit or normal MPI and high CAC score is associated with moderate incidence of severe CAD. [18][19][20] One of the major strength of the work proposed by Yokota et al 11 is the correlation between CAC score values, obtained by SPECT/CT, and angiographic data, considering that the relationship between the extent of coronary calcification and the likelihood of significant CAD in patients with normal MPI findings has not been fully clarified and should be not underestimated. The presence of a significant correlation between CAC score and obstructive CAD may offer an opportunity to use CAC scanning in patients with suspected CAD.…”