The diagnosis and prognosis of coronary microvascular disease using PET/CT

OBJECTIVE

This study aimed to evaluate the diagnostic and prognostic value of 13N-NH3·H2O positron emission tomography combined with computed tomography (PET/CT) for non-obstructive coronary microvascular disease (CMVD).

METHODS

A retrospective analysis was conducted on 70 patients with clinically suspected non-obstructive CMVD (35 males, 35 females) between March 2017 and August 2019. The average age of the patients was 53.32±7.82 years. The patients underwent 13N-NH3·H2O PET/CT and were divided into two groups based on diagnostic criteria: a CMVD group and a non-CMVD group. They were then followed up for 180-1,095 days. Data were analyzed using an χ 2 test, the logistic regression model, the multiple linear regression model, the Kaplan-Meier method, the Cox proportional hazards regression model, and a receiver operating characteristic (ROC) curve.

RESULTS

(1) The incidence of cardiovascular family history and a high calcification score (11-400) was higher in the CMVD group than in the non-CMVD group (58.8% vs. 20.8% and 29.4% vs. 5.7%, respectively; P <  0.05 for all), stress myocardial blood flow (MBF) and coronary flow reserve (CFR) values were lower in the CMVD group than in the non-CMVD group (2.280±0.693 vs. 3.641±1.365 and 2.142±0.339 vs. 3.700±1.123, respectively), and calcification score was higher in the CMVD group than in the non-CMVD group (110.18±165.07 vs. 13.21±41.68, respectively; P <  0.05 for all). Gender and diabetes were risk factors for stress MBF reduction (β= 1.287 and β= -0.636, respectively), calcification score and hypertension were risk factors for CFR reduction (β= -0.004 and β= -0.654, respectively), and hypertension, family history, and calcification score were risk factors in the CMVD group (OR = 7.323, OR = 5.108, OR = 1.012, respectively; P <  0.05 for all). (2) The prognosis of patients with CFR <  2.5 was worse than that of patients with CFR≥2.5 (x2 value: 27.404, P <  0.001). The risk of adverse cardiovascular events in diabetic patients was also increased (β= 0.328, P <  0.001). When CFR was set to 2.595, the prognostic sensitivity was 94% and the specificity was 80%.

CONCLUSION

The technology of 13N-NH3·H2O PET/CT can be used for the diagnosis and prognosis of non-obstructive CMVD. Cardiovascular risk factors are related to the occurrence and prognosis of CMVD.

Association of White Matter Hyperintensities and Cardiovascular Disease: The Importance of Microcirculatory Disease

Cardiac and cerebrovascular diseases are currently the leading causes of mortality and disability worldwide. Both the heart and brain display similar vascular anatomy, with large conduit arteries running on the surface of the organ providing tissue perfusion through an intricate network of penetrating small vessels. Both organs rely on fine tuning of local blood flow to match metabolic demand. Blood flow regulation requires adequate functioning of the microcirculation in both organs, with loss of microvascular function, termed small vessel disease (SVD) underlying different potential clinical manifestations. SVD in the heart, known as coronary microvascular dysfunction, can cause chronic or acute myocardial ischemia and may lead to development of heart failure. In the brain, cerebral SVD can cause an acute stroke syndrome known as lacunar stroke or more subtle pathological alterations of the brain parenchyma, which may eventually lead to neurological deficits or cognitive decline in the long term. Coronary microcirculation cannot be visualized in vivo in humans, and functional information can be deduced by measuring the coronary flow reserve. The diagnosis of cerebral SVD is largely based on brain magnetic resonance imaging, with white matter hyperintensities, microbleeds, and brain atrophy reflecting key structural changes. There is evidence that such structural changes reflect underlying cerebral SVD. Here, we review interactions between SVD and cardiovascular risk factors, and we discuss the evidence linking cerebral SVD with large vessel atheroma, atrial fibrillation, heart failure, and heart valve disease.

Imparied retrobulbar blood flow and increased carotid IMT in patients with Crohn's disease

Crohn's Disease [CD] is one of the Inflammatory Bowel Diseases that are chronic relapsing inflammatory diseases. Despite the major affected organ is intestine in CD, extra intestinal organs and tissues including cardiovascular system are also affected. Several studies have demonstrated that CD patients may have a higher risk of advancing atherosclerosis. The microvascular endothelial dysfunction plays an essential role for developing coronary atherosclerosis. Microvascular structural abnormalities in the retinal circulation may predict macrovascular events such as stroke and coronary heart disease. In order to assess the the microvascular circulation of the retina; retrobulbar blood flow velocities and resisitive indices [RI] of retrobulbar arteries are measured. The carotid intima media thickness [CIMT] correlates strongly with CV risk in the future. We aimed to investigate whether calculation of RI of retrobulbar arteries can be used as novel, easy and reproducible method to define atherosclerotic risk in CD patients along with CIMT. Thirty CD patients with remission period and thirty healthy volunteers were enrolled in the study. Measurement of carotid intima-media thickness and retrobulbar blood flow velocities were obtained with ultrasound scanner and colour Doppler ultrasonography. The RI of the OA [0.77 ± 0.06 vs. 0.65 ± 0.06, p < 0.001] and CIMT 0.52 [0.50-0.60] vs. 0.40 [0.40-0.50] in patients with CD was significantly higher than the control group. Increased OARI and CIMT values may reflect an increased risk of atherosclerosis and OARI measurement may be used as a screening test for microvascular circulation evaluation in patients with CD.

Association of subclinical atherosclerosis using carotid intima-media thickness, carotid plaque, and coronary calcium score with left ventricular dyssynchrony: the multi-ethnic Study of Atherosclerosis

BACKGROUND

The role of atherosclerosis in the progression of global left ventricular dysfunction and cardiovascular events has been well recognized. Left ventricular (LV) dyssynchrony is a measure of regional myocardial dysfunction. Our objective was to investigate the relationship of subclinical atherosclerosis with mechanical LV dyssynchrony in a population-based asymptomatic multi-ethnic cohort.

METHODS AND RESULTS

Participants of the Multi-Ethnic Study of Atherosclerosis (MESA) at exam 5 were evaluated using 1.5T cardiac magnetic resonance (CMR) imaging, carotid ultrasound (n = 2062) for common carotid artery (CCA) and internal carotid artery (ICA) intima-media thickness (IMT), and cardiac computed tomography (n = 2039) for coronary artery calcium (CAC) assessment (Agatston method). Dyssynchrony indices were defined as the standard deviation of time to peak systolic circumferential strain (SD-TPS) and the difference between maximum and minimum (max-min) time to peak strain using harmonic phase imaging in 12 segments (3-slices × 4 segments). Multivariable regression analyses were performed to assess associations after adjusting for participant demographics, cardiovascular risk factors, LV mass, and ejection fraction. In multivariable analyses, SD-TPS was significantly related to measures of atherosclerosis, including CCA-IMT (8.7 ms/mm change in IMT, p = 0.020), ICA-IMT (19.2 ms/mm change in IMT, p < 0.001), carotid plaque score (1.2 ms/unit change in score, p < 0.001), and log transformed CAC+1 (0.66 ms/unit log-CAC+1, p = 0.018). These findings were consistent with other parameter of LV dyssynchrony i.e. max-min.

CONCLUSION

In the MESA cohort, measures of atherosclerosis are associated with parameters of subclinical LV dyssynchrony in the absence of clinical coronary event and left-bundle-branch block.

Coronary artery calcium screening: does it perform better than other cardiovascular risk stratification tools?

Coronary artery calcium (CAC) has been advocated as one of the strongest cardiovascular risk prediction markers. It performs better across a wide range of Framingham risk categories (6%-10% and 10%-20% 10-year risk categories) and also helps in reclassifying the risk of these subjects into either higher or lower risk categories based on CAC scores. It also performs better among population subgroups where Framingham risk score does not perform well, especially young subjects, women, family history of premature coronary artery disease and ethnic differences in coronary risk. The absence of CAC is also associated with excellent prognosis, with 10-year event rate of 1%. Studies have also compared with other commonly used markers of cardiovascular disease risk such as Carotid intima-media thickness and highly sensitive C-reactive protein. CAC also performs better compared with carotid intima-media thickness and highly sensitive C-reactive protein in prediction of coronary heart disease and cardiovascular disease events. CAC scans are associated with relatively low radiation exposure (0.9-1.1 mSv) and provide information that can be used not only for risk stratification but also can be used to track the progression of atherosclerosis and the effects of statins.

Coronary flow reserve estimated by positron emission tomography to diagnose significant coronary artery disease and predict cardiac events

Coronary artery disease (CAD) is a major cause of death in Japan. Coronary angiography is useful to assess the atherosclerotic burden in CAD patients, but its ability to predict whether patients will respond favorably to optimal medical therapy and revascularization is limited. The measurement of the fractional flow reserve with angiography is a well-validated method for identifying ischemic vessels. However, neither an anatomical assessment nor a functional assessment can delineate microvasculature or estimate its function. The quantitative coronary flow reserve (CFR) estimated from sequential myocardial perfusion images obtained by positron emission tomography (PET) during stress provides an accurate index of hyperemic reactivity to vasodilatory agents in the myocardium. In fact, there is growing evidence that the CFR reflects disease activity in the entire coronary circulation, including epicardial coronary artery stenosis, diffuse atherosclerosis, and microvascular dilatory function. Importantly, reduced CFR is observed even in patients without flow-limiting coronary stenosis, and its evaluation can improve the risk stratification of patients at any stage of CAD. This review focuses on the application of CFR estimated by cardiac PET for the diagnosis and risk stratification of patients with CAD.

Carotid artery intima-media thickness is closely related to impaired left ventricular function in patients with coronary artery disease: a single-centre, blinded, non-randomized study

Background

Atherosclerosis is the underlying cause of the majority of myocardial infarctions and ischemic strokes. Carotid intima-media thickness (IMT) is a surrogate measure of atherosclerotic cardiovascular disease. Left ventricular (LV) function can be accurately assessed by 2D speckle-tracking strain echocardiography (2D-STE). The aim of this study was to assess the relationship between carotid IMT and LV dysfunction assessed by strain echocardiography in patients with coronary artery disease (CAD).

Methods

Thirty-one patients with symptoms of CAD were examined with coronary angiography, cardiac echocardiography and carotid ultrasound. Layer-specific longitudinal strains were assessed from endo-, mid- and epicardium by 2D-STE. LV global longitudinal strain (LVGLS) was averaged from 16 longitudinal LV segments in all 3 layers. LVGLS results were compared with coronary angiography findings in a receiver operating curve (ROC) to determine the cut-off for normal and pathological strain values. The calculated optimal strain value was compared to maximal carotid IMT measurements.

Results

The ROC analysis for strain versus coronary angiography was: area under curve (AUC) = 0.91 (95% CI 0.80 – 1.0), cut-off value for endocardial LVGLS: -16.7%. Further analyses showed that increased carotid IMT correlated with low absolute strain values (p = 0.006) also when adjusted for hypertension, smoking, hyperlipidemia, diabetes and BMI (p = 0.02).

Conclusions

In this study increased carotid IMT values were associated with decreased LV function assessed by strain measurements. These findings support the use of carotid IMT measurements to predict the risk of coronary heart disease.

Sonographic evaluation for predicting the presence and severity of coronary artery disease

PURPOSE

The aim of our study was to investigate the relationship between age, sex, obesity, nonalcoholic fatty liver disease (NAFLD), carotid intima-media thickness (CIMT), and both the presence and severity of coronary artery disease (CAD) and their predictive value for the presence and severity of CAD.

METHODS

Our study population consisted of 136 patients who underwent coronary angiography for various reasons. Gensini scoring was used to determine the severity of coronary atherosclerosis. Carotid intima-media thickness was estimated by carotid duplex ultrasound. Nonalcoholic fatty liver disease was diagnosed by abdominal ultrasonography. Body mass index (BMI) was calculated as kilograms divided by meters squared.

RESULTS

Coronary artery disease was detected in 74 patients (54%). In the whole group, patients with CAD had significantly higher CIMT measurements compared with those without CAD (0.93 [SD, 0.14] and 0.72 [SD, 0.12] mm, respectively, P < 0.001). Carotid intima-media thickness was correlated with BMI (P < 0.001, r = 0.453), age (P = 0.001, r = 0.389), and grade 2-3 NAFLD (P < 0.001, r = 0.356). In the multiple logistic regression model, CIMT (odds ratio, 1.189; 95% confidence interval, 1.122-1.261; P < 0.001) was the only independent predictor of the presence of CAD. In receiver operating characteristic curve analysis, optimal cutoff value of CIMT to predict the presence of CAD was found as greater than 0.75 mm with 93.2% sensitivity and 71% specificity. In CAD group patients, Gensini score was correlated with CIMT (P < 0.001, r = 0.604), grade 2-3 NAFLD (P < 0.001, r = 0.534), BMI (P < 0.001, r = 0.498), and age (P = 0.001, r = 0.385). In the multiple stepwise linear regression model, CIMT (β = 0.444, P < 0.001) and grade 2-3 NAFLD (β = 0.353, P < 0.001) were associated with severity of CAD.

CONCLUSIONS

Our data suggest that CIMT is a strong independent predictor for the presence and severity of CAD. Furthermore, moderate to severe hepatosteatosis is also significantly associated with the severity of CAD. Therefore, detection of CIMT and NAFLD by ultrasonography, which is a very cheap, safe, and noninvasive radiological modality, can be used to improve CAD risk prediction.

The year 2012 in the European Heart Journal-Cardiovascular Imaging: Part I

The new multi-modality cardiovascular imaging journal, European Heart Journal - Cardiovascular Imaging, was started in 2012. During its first year, the new Journal has published an impressive collection of cardiovascular studies utilizing all cardiovascular imaging modalities. We will summarize the most important studies from its first year in two articles. The present 'Part I' of the review will focus on studies in myocardial function, myocardial ischaemia, and emerging techniques in cardiovascular imaging.