Non-invasive anatomic and functional imaging of vascular inflammation and unstable plaque

Over the last several decades, basic cardiovascular research has significantly enhanced our understanding of pathobiological processes leading to formation, progression, and complications of atherosclerotic plaques. By harnessing these advances in cardiovascular biology, imaging has advanced beyond its traditional anatomical domains to a tool that permits probing of particular molecular structures to image cellular behaviour and metabolic pathways involved in atherosclerosis. From the nascent atherosclerotic plaque to the death of inflammatory cells, several potential molecular and micro-anatomical targets for imaging with particular selective imaging probes and with a variety of imaging modalities have emerged from preclinical and animal investigations. Yet, substantive barriers stand between experimental use and wide clinical application of these novel imaging strategies. Each of the imaging modalities described herein faces hurdles—for example, sensitivity, resolution, radiation exposure, reproducibility, availability, standardization, or costs. This review summarizes the published literature reporting on functional imaging of vascular inflammation in atherosclerotic plaques emphasizing those techniques that have the greatest and/or most immediate potential for broad application in clinical practice. The prospective evaluation of these techniques and standardization of protocols by multinational networks could serve to determine their added value in clinical practice and guide their development and deploymen

Heterogeneity of resting and hyperemic myocardial blood flow in healthy humans

Objective: Absolute myocardial blood flow (MBF) is not well-defined in large normal populations, and appears to be heterogeneous in both humans and animals. These factors contribute to the difficulties in defining resting MBF to hibernating myocardium. We therefore assessed absolute baseline and hyperemic MBF in a large population of normal humans. Methods: MBF was quantified by positron emission tomography with oxygen-15-labeled water at baseline and during hyperemia induced by either adenosine or dipyridamole in 131 men and 38 women, aged 21-86 (mean 46±12) years. MBF was corrected for workload using the rate-pressure product (RPP). Results: Uncorrected baseline MBF ranged from 0.590 to 2.050 (mean 0.985±0.230) ml/min/g (coefficient of variation=27%), and corrected MBF from 0.736 to 2.428 (mean 1.330±0.316) ml/min/g (coefficient of variation=24%). MBF in the inferior region was significantly (P<0.0001) lower than either the anterior or lateral regions. Baseline MBF in females was significantly (P<0.001) higher than in males. Conclusions: These results confirm the heterogeneity of MBF in normals and highlight the difficulty in establishing the lower limit of normal MB

Prognostic association of plasma NT-proBNP levels in patients with microvascular angina -A report from the international cohort study by COVADIS-

Background The aim of this study was to assess the prognostic association of plasma levels of N-terminal prohormone of brain natriuretic peptide (NT-proBNP) with clinical outcomes of patients with microvascular angina (MVA). Methods In this international prospective cohort study of MVA by the Coronary Vasomotor Disorders International Study (COVADIS) group, we examined the association between plasma NT-proBNP levels and the incidence of major adverse cardiovascular events (MACE), including cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, and hospitalization due to heart failure or unstable angina. Results We examined a total of 226 MVA patients (M/F 66/160, 61.9 ± 10.2 [SD] yrs.) with both plasma NT-proBNP levels and echocardiography data available at the time of enrolment. The median level of NT-proBNP level was 94 pg/ml, while mean left ventricular ejection fraction was 69.2 ± 10.9 % and E/e’ 10.7 ± 5.2. During follow-up period of a median of 365 days (IQR 365–482), 29 MACEs occurred. Receiver-operating characteristics curve analysis identified plasma NT-proBNP level of 78 pg/ml as the optimal cut-off value. Multivariable logistic regression analysis revealed that plasma NT-proBNP level ≥ 78 pg/ml significantly correlated with the incidence of MACE (odds ratio (OR) [95 % confidence interval (CI)] 3.11[1.14–8.49], P = 0.001). Accordingly, Kaplan-Meier survival analysis showed a significantly worse prognosis in the group with NT-proBNP ≥ 78 (log-rank test, P &lt; 0.03). Finally, a significant positive correlation was observed between plasma NT-proBNP levels and E/e’ (R = 0.445, P &lt; 0.0001). Conclusions These results indicate that plasma NT-proBNP levels may represent a novel prognostic biomarker for MVA patients

Is There Evidence Supporting Coronary Revascularization in Patients With Left Ventricular Systolic Dysfunction?

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The measurement of absolute myocardial perfusion in patients with coronary artery disease using 3T CMR and 1.5T CMR : validation against PET

Objectives: To validate absolute measurement of myocardial blood flow (MBF) with 1.5 Tesla (T) and 3T cardiovascular magnetic resonance (CMR) using positron emission tomography (PET) as the gold standard. Methods: 21 healthy subjects and 44 patients with coronary artery disease (CAD) were randomised to undergo PET scanning using oxygen 15-labeled water and CMR scanning at either 1.5T or 3T, using a saturation recovery fast-gradient echo sequence and 0.04 mmol/kg gadolinium bolus. MBF was assessed at rest and during adenosine stress. CMR MBF was determined by model independent deconvolution Results: There was no significant difference in rest and stress rate pressure product during PET and CMR scanning at either field strength. Agreement between the two methods was tested by Bland Altman plots The mean difference between PET MBF and 3T CMR MBF was 0.30 ml/g/min, limits of agreement of -1.23 and 1.89 ml/g/min. For the 3T cohort the sensitivity and specificity for the detection of coronary stenoses ≥50 % was 87% and 81 % for PET (threshold 1.93 ml/g/min) and 61% and 78% (threshold 1.73 ml/g/min) for 3T CMR. The mean difference between PET and 1.5T CMR was 0.05 ml/g/min, limits of agreement of -1.75 and 1.84 ml/g/min. For the 1.5T cohort the sensitivity and specificity for the detection of coronary stenoses ≥50 % was 84% and 94% for PET (threshold 1.98 ml/g/min) and 81% and 78% (threshold 2.29ml/g/min) for CMR. Conclusion: This study demonstrates there is no significant difference in mean MBF as measured by PET and CMR at either 1.5T or 3T CMR. However there is marked variation in values of MBF between different segments as demonstrated by the wide limits of agreements.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Prognostic impact of late gadolinium enhancement in the risk stratification of heart transplant patients

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Impairment of coronary flow reserve in aortic stenosis

International audienc