Combination of Myocardial Perfusion Imaging and Coronary Artery Calcium Scanning: Potential Synergies for Improving Risk Assessment in Subjects with Suspected Coronary Artery Disease

Abstract

For many years, the mainstay of noninvasive evaluation of patients suspected of ischemic cardiovascular disease (CVD) centered on the use of myocardial perfusion imaging (MPI). In recent years, the advent of newer modalities such as coronary artery calcium (CAC) scanning, coronary CT angiography, and MRI have broadened the means of assessing cardiac patients for this purpose. Moreover, the advent of these newer modalities has created potential synergies whereby combinations of tests may be clinically useful. In this review, we assess the potential synergies between MPI, whether assessed by single photon emission computed tomography (SPECT) or positron emission tomography (PET), and CAC scanning. Whereas MPI has long been used for diagnostic assessment and for risk stratification purposes, the emerging uses of CAC scanning now appear multifold: screening for CVD, triaging patients for diagnostic stress testing, improving risk stratification in patients following stress testing, and enhancing the direct management of patients' CVD risk following CAC scanning. Recent work suggests that CAC scanning may be emerging as the initial test of choice for most asymptomatic patients. The advent of hybrid SPECT-CT and PET-CT scanners may signify an important new opportunity for the combined use of these modalities in the higher-risk asymptomatic patient population.

Atualização da Diretriz Brasileira de Cardiologia Nuclear – 2020

“…Dados demonstram que na presença de EC com valores entre 400 e 999 a probabilidade de defeitos perfusionais alcança até 29% e para valores > 1.000 a chance será de 39%. 241 Dados nacionais de Cerci et al relataram informações semelhantes, com prevalência de isquemia de 34% em pacientes com EC acima de 400. 242 Dentro da orientação médica mostram-se evidentes os benefícios de medidas preventivas rígidas em indivíduos com EC elevado.…”

“…245,246 Portanto, no cenário delineado, com anatomia evidenciando DAC obstrutiva, mas sem preencher critérios de alto risco (lesão de tronco da coronária esquerda, ou lesões triarteriais incluindo comprometimento proximal da DA), o manejo sugerido como mais adequado é seguramente a quantificação de isquemia, considerando-se que revascularização estaria indicada na presença de carga isquêmica pelo menos moderada. 241 No caso específico, o paciente deveria ser tratado clinicamente abordando prevenção secundária agressiva, com monitoramento próximo dos fatores de risco modificáveis e atenção especial à manifestação de sintomas, postergando-se a revascularização, pelo menos neste momento em que carecem evidências de seu benefício.…”

The power of stress echocardiography and myocardial perfusion scintigraphy in predicting long-term outcome. Nothing lasts forever

“…In some occasions, very severe coronary artery calcifications can be a red flag that the test is false negative due to severe diffuse coronary artery disease and balanced hypoperfusion. 7,8 Various clinical and stress test variables have been associated with the occurrence of cardiac events despite a normal stress imaging study. These include diabetes mellitus, advanced age, inability to perform exercise stress test, and prior history of coronary artery disease.…”

“…Additionally, the use of hybrid imaging can be very useful by identifying patients with significant coronary artery calcifications. 7,8 This observation could set the requirement for closer follow-up after a normal MPI and may drive suspicion that ischemia may have been underestimated in those with severe calcification who have otherwise a small perfusion defect. This advantage is obviously not attainable by stress echocardiography.…”

Extending the Use of Coronary Calcium Scanning to Clinical Rather Than Just Screening Populations

“…CAC scanning can serve as an adjunct to predicting clinical outcomes based on the results of stress imaging [21]. For instance, Chang et al followed 1,126 generally asymptomatic patients for a median of 6.9 years for the cardiac death, nonfatal myocardial infarction and the need for coronary revascularization [22].…”