THE IMPACT OF THE ABLATION BY EXCIMER LASER SYSTEM ON THE LONG-TERM OUTCOME IN IN-STENT RESTENOSIS

Multimodality Imaging of Aortic Valve Calcification and Function in a Murine Model of Calcific Aortic Valve Disease and Bicuspid Aortic Valve

Calcific aortic valve disease (CAVD) is a prevailing disease with increasing occurrence and no known medical therapy. Dcbld2-/- mice have a high prevalence of bicuspid aortic valve (BAV), spontaneous aortic valve calcification, and aortic stenosis (AS). 18F-NaF PET/CT can detect the aortic valve calcification process in humans. However, its feasibility in preclinical models of CAVD remains to be determined. Here, we sought to validate 18F-NaF PET/CT for tracking murine aortic valve calcification and leveraged it to examine the development of calcification with aging and its interdependence with BAV and AS in Dcbld2-/- mice. Methods: Dcbld2-/- mice at 3-4 mo, 10-16 mo, and 18-24 mo underwent echocardiography, 18F-NaF PET/CT (n = 34, or autoradiography (n = 45)), and tissue analysis. A subset of mice underwent both PET/CT and autoradiography (n = 12). The aortic valve signal was quantified as SUVmax on PET/CT and as percentage injected dose per square centimeter on autoradiography. The valve tissue sections were analyzed by microscopy to identify tricuspid and bicuspid aortic valves. Results: The aortic valve 18F-NaF signal on PET/CT was significantly higher at 18-24 mo (P < 0.0001) and 10-16 mo (P < 0.05) than at 3-4 mo. Additionally, at 18-24 mo BAV had a higher 18F-NaF signal than tricuspid aortic valves (P < 0.05). These findings were confirmed by autoradiography, with BAV having significantly higher 18F-NaF uptake in each age group. A significant correlation between PET and autoradiography data (Pearson r = 0.79, P < 0.01) established the accuracy of PET quantification. The rate of calcification with aging was significantly faster for BAV (P < 0.05). Transaortic valve flow velocity was significantly higher in animals with BAV at all ages. Finally, there was a significant correlation between transaortic valve flow velocity and aortic valve calcification by both PET/CT (r = 0.55, P < 0.001) and autoradiography (r = 0.45, P < 0.01). Conclusion: 18F-NaF PET/CT links valvular calcification to BAV and aging in Dcbld2-/- mice and suggests that AS may promote calcification. In addition to addressing the pathobiology of valvular calcification, 18F-NaF PET/CT may be a valuable tool for evaluation of emerging therapeutic interventions in CAVD.

Risk factors and outcomes with surgical bioprosthetic mitral valve dysfunction

BACKGROUND

There are insufficient data regarding the risk factors associated with valve dysfunction of bioprosthetic valves in the mitral position This study aimed to investigate the factors associated with bioprosthetic mitral valve (MV) dysfunction (MVD).

METHODS

A total of 245 patients (age 67.2±11.2 years, 74.9% women) who were followed up for more than 5 years after surgical bioprosthetic MV replacement were analysed in the setting of retrospective study design. MVD was defined as an increased mean gradient of >5 mm Hg with limited leaflet motion and/or newly developed MV regurgitation of at least moderate severity on follow-up echocardiography. The clinical outcome was defined as a composite of cardiovascular mortality, redo MV surgery or intervention and heart failure-related hospitalisations.

RESULTS

During a median of 96.0 months (IQR 67.0-125.0 months), bioprosthetic MVD occurred in 66 (27.6%) patients. Factors associated with bioprosthetic MVD detected by multivariate regression analysis were age at surgery (HR 0.98, 95% CI 0.96 to 0.99, p<0.001), chronic kidney disease (HR 3.27, 95% CI 1.74 to 6.12, p<0.001), elevated mean diastolic pressure gradient >5.5 mm Hg across the bioprosthetic MV early after operation (HR 2.02, 95% CI 1.08 to 3.78, p=0.028) and average haemoglobin level after surgery (HR 0.80, 95% CI 0.67 to 0.96, p=0.015). Patients with bioprosthetic MVD showed significantly poorer clinical outcomes than those without bioprosthetic MVD (log-rank p<0.001).

CONCLUSIONS

Young age at operation, chronic kidney disease, elevated pressure gradient across the bioprosthetic MV early after surgery and postsurgical anaemia are associated with bioprosthetic MVD. Bioprosthetic MVD is associated with poor clinical outcomes.

Latest Advances in Multimodality Imaging of Aortic Stenosis

Aortic stenosis is a common condition associated with major morbidity, mortality, and health-care costs. Nevertheless, we currently lack any effective medical therapies that can treat or prevent disease development or progression. Modern advances in echocardiography and CT have helped improve the assessment of aortic stenosis severity and monitoring of disease progression, whereas cardiac MRI informs on myocardial health and the development of fibrosis. In a series of recent studies, 18F-NaF PET/CT has been shown to assess valvular disease activity and progression, providing mechanistic insights that can inform potential novel therapeutic approaches. This review will examine the latest advances in the imaging of aortic stenosis and bioprosthetic valve degeneration and explore how these techniques can assist patient management and potentially accelerate novel therapeutic developments.

Machine Learning with 18F-Sodium Fluoride PET and Quantitative Plaque Analysis on CT Angiography for the Future Risk of Myocardial Infarction

Coronary 18F-sodium fluoride (18F-NaF) PET and CT angiography-based quantitative plaque analysis have shown promise in refining risk stratification in patients with coronary artery disease. We combined both of these novel imaging approaches to develop an optimal machine-learning model for the future risk of myocardial infarction in patients with stable coronary disease. Methods: Patients with known coronary artery disease underwent coronary 18F-NaF PET and CT angiography on a hybrid PET/CT scanner. Machine-learning by extreme gradient boosting was trained using clinical data, CT quantitative plaque analysis, measures and 18F-NaF PET, and it was tested using repeated 10-fold hold-out testing. Results: Among 293 study participants (65 ± 9 y; 84% male), 22 subjects experienced a myocardial infarction over the 53 (40-59) months of follow-up. On univariable receiver-operator-curve analysis, only 18F-NaF coronary uptake emerged as a predictor of myocardial infarction (c-statistic 0.76, 95% CI 0.68-0.83). When incorporated into machine-learning models, clinical characteristics showed limited predictive performance (c-statistic 0.64, 95% CI 0.53-0.76) and were outperformed by a quantitative plaque analysis-based machine-learning model (c-statistic 0.72, 95% CI 0.60-0.84). After inclusion of all available data (clinical, quantitative plaque and 18F-NaF PET), we achieved a substantial improvement (P = 0.008 versus 18F-NaF PET alone) in the model performance (c-statistic 0.85, 95% CI 0.79-0.91). Conclusion: Both 18F-NaF uptake and quantitative plaque analysis measures are additive and strong predictors of outcome in patients with established coronary artery disease. Optimal risk stratification can be achieved by combining clinical data with these approaches in a machine-learning model.

Positron emission tomography imaging in cardiovascular disease

Positron emission tomography (PET) imaging is useful in cardiovascular disease across several areas, from assessment of myocardial perfusion and viability, to highlighting atherosclerotic plaque activity and measuring the extent of cardiac innervation in heart failure. Other important roles of PET have emerged in prosthetic valve endocarditis, implanted device infection, infiltrative cardiomyopathies, aortic stenosis and cardio-oncology. Advances in scanner technology, including hybrid PET/MRI and total body PET imaging, as well as the development of novel PET tracers and cardiac-specific postprocessing techniques using artificial intelligence will undoubtedly continue to progress the field.