Disease Activity in Mitral Annular Calcification

18F-Sodium Fluoride (18F-NaF) for Imaging Microcalcification Activity in the Cardiovascular System

Accumulating preclinical and clinical evidence suggests that calcification is one of the body's primary responses to injury and a key pathological feature of cardiovascular disease. Calcification activity can now be imaged using 18F-sodium fluoride (18F-NaF) positron emission tomography (PET) in combination with either computed tomography or magnetic resonance. These techniques allow visualization of calcification activity and, therefore, provide different information to the established macroscopic calcium imaged with computed tomography. Indeed, 18F-NaF PET has been used to investigate a wide range of valvular conditions, including aortic stenosis, mitral annular calcification, and bioprosthetic valve disease, as well as vascular conditions, including abdominal aortic aneurysm disease, coronary, and carotid atherosclerosis, peripheral vascular disease, and erectile dysfunction. In this brief review, we will focus on how 18F-NaF PET has improved our pathophysiological understanding of cardiovascular calcification and how it can be used as a marker of vascular calcification, providing a useful tool that can be utilized in clinical trials investigating the prediction of both disease progression and clinical events. Finally, we will discuss how 18F-NaF might be employed clinically to improve patient assessment and to guide decision-making.

Body mass index and peripheral artery disease

BACKGROUND AND AIMS

An independent association of body mass index (BMI) with atherosclerotic cardiovascular disease is somewhat controversial and may differ by vascular bed. Sex-specific risk factors for atherosclerosis may further modify these associations. Obesity and peripheral artery disease (PAD) are both more prevalent in women. We sought to determine the association between PAD and BMI using a very large population-based study.

METHODS

Self-referred individuals at >20,000 US sites completed medical questionnaires including height and weight, and were evaluated by screening ankle brachial indices (ABI) for PAD (ABI<0.9).

RESULTS

Among 3,250,350 individuals, the mean age was 63.1 ± 10.5 years and 65.5% were women. The mean BMI was 27.7 ± 5.8 kg/m2. 27.8% of participants were obese (BMI ≥30 kg/m2) - 27.6% females, 28.1% males. Overweight individuals (BMI 25-29.9 kg/m2) exhibited the lowest prevalence of PAD. There was a J-shaped association of BMI with prevalent PAD. After adjustment for age and cardiovascular risk factors, underweight was associated with similarly increased odds of PAD (1.72 vs. 1.39, women and men, respectively). The association of obesity with PAD was predominant in women, with only a slight association of increasing BMI with PAD in men (OR = 2.98 vs. 1.37 for BMI ≥40 kg/m2).

CONCLUSIONS

Our study suggests that increasing BMI is a robust independent risk factor for PAD only in women. This observation requires validation, but highlights the need for further research on sex-specific risk and mechanisms of atherosclerosis.

Minimally Invasive Hybrid Approach to High Risk Mitral Disease With Severe Mitral Annular Calcification

Severe circumferential mitral annular calcification (MAC) remains a significant challenge, complicating surgical treatment of mitral valve disease. Transcatheter treatment options are attractive; however, they remain fraught with risks of annular fixation, paravalvular leak, atrioventricular-groove disruption, and left-ventricular outflow tract obstruction. We describe a novel minimally invasive hybrid technique of transcatheter mitral valve replacement in a patient with severe circumferential MAC.

Molecular Imaging of Vascular Calcification with 18F-Sodium-Fluoride in Patients Infected with Human Immunodeficiency Virus

¹⁸F-Sodium Fluoride (NaF) accumulates in areas of active hydroxyapatite deposition and potentially unstable atherosclerotic plaques. We assessed the presence of atherosclerotic plaques in 50 adult patients with HIV (HIV+) who had undergone two cardiac computed tomography scans to measure coronary artery calcium (CAC) progression. CAC and its progression are predictive of an unfavorable prognosis. Tracer uptake was quantified in six arterial territories: aortic arch, innominate carotid artery, right and left internal carotid arteries, left coronary (anterior descending and circumflex) and right coronary artery. Thirty-one patients showed CAC progression and 19 did not. At least one territory with high NaF uptake was observed in 150 (50%) of 300 arterial territories. High NaF uptake was detected more often in non-calcified than calcified areas (68% vs. 32%), and in patients without than in those with prior CAC progression (68% vs. 32%). There was no correlation between clinical and demographic variables and NaF uptake. In clinically stable HIV+ patients, half of the arterial territories showed a high NaF uptake, often in the absence of macroscopic calcification. NaF uptake at one time point did not correlate with prior progression of CAC. Prospective studies will demonstrate the prognostic significance of high NaF uptake in HIV+ patients.