Looking more broadly, AF with baseline antithrombotic therapy was associated with a 15% higher risk of
any vascular event (HR: 1.15; 95% CI: 1.12–1.18) and
a 69% higher risk of a fatal vascular event (HR: 1.69;
95% CI: 1.61–1.78). However, AF without antithrombotic therapy was associated with two times the risk
of any vascular event (HR: 2.15; 95% CI: 2.05 to 2.24)
and two-and-a-half times the risk of a fatal vascular
event (HR: 2.64; 95% CI: 2.43–2.86).
This topic has been of intense interest to A.
John Camm, MD, head of the Department of Cardiac and Vascular Sciences at St. George’s Hospital
at the University of London, UK. Dr. Camm, who
is also the first author of the European Society of
Cardiology AF guidelines,15 said physicians are
more concerned about the strokes their therapy
might cause than the strokes likely to be prevented
with proper anticoagulation. However, the in-
creased risk of hemorrhagic stroke in a patient
undergoing appropriate anticoagulation is roughly
one or two per 1,000 cases. Conversely, risk of
thromboembolic stroke in a patient who is not on
anticoagulant therapy is nearer 20 per 1,000. So,
Dr. Camm stresses that there is approximately a
10-fold difference between the strokes prevented
by guideline-recommended anticoagulation versus
serious strokes caused by such therapy.
Time Marches On: Dementia Lessons from Framingham
Unlike clinical trials, the real-world patient with a chronic disease like AF
analysis, with the first serving as the baseline model (and included characteris not treated for a few months or a few years, but rather decades. In this
istics such as sex and age). The second model looked at whether microbleeds
pursuit, cardiologists are probably the best served of all clinicians, because
were associated with dementia independent of ischemic MRI markers such as
clocking in as the longest of the long-term studies is the Framingham Heart
covert brain infarcts; the third looked for associations independent of vascular
Study, which began recruiting patients from Framingham, MA, in 1948.
risk factors.
What’s more, next-gen studies (the actual next generation), the Offspring
Overall, CMBs were seen in 11.1%: most were lobar (64.3%), while 17% had
Study, began in 1971, while their kids, the Generation Three cohort, had their
covert brain infarcts. Over a mean follow-up of 6.7 years, 85 (6.6%) incident
first exams in April 2002.
cases of dementia occurred. Per model 1, presence of any microbleed was
Over the years, the data-rich Framingham Study has helped identify the
associated with a higher risk of all-cause dementia (p = 0.049); the signifimajor cardiovascular risk factors, and related factors such as age, sex, psycance was lost when adjusted for ischemic MRI markers (p = 0.204), but
chosocial levels, and more, including stroke and AF.
maintained after adjusting for cardiovascular risk factors (p = 0.038).
In February of this year, Framingham researchers added to their substanLocation, location, location also applies to microbleeds: for both all-cause
tive work with an analysis of temporal trends of dementia (included as a
and Alzheimer’s-type dementia, the combination of deep and mixed CMBs,
surveillance parameter beginning in 1975) spanning 3 decades and involving but not lobar-only CMBs, was significantly associated with risk of dementia
5,205 individuals 60 years or older who collectively contributed data for a
in each model. A similar result was seen for vascular dementia, but the numtotal of 9,015 observation periods.1 These data were reviewed over 4 peribers of patients was too small for a definitive analysis. Dr. Romero noted that
the study demonstrated that CMBs were associated with increased risk of
ods, each involving more than 2,000 participants; the baseline examination
incident dementia and the research “highlighted the role of CMBs as markperiod occurred between 1977 and 1983 for Epoch 1, followed by Epochs 2
ers of adverse neurological outcomes.”
(1986-1991), 3 (1992-1998), and 4 (2004-2008). Satizabal et al. determined
In an accompanying editorial,2 David S. Jones, MD, PhD, and Jeremy A.
5-year incidence of dementia for each epoch and also examined temporal
trends in the effects of stroke and AF, coronary heart disease (CHD), and
Greene, MD, PhD, noted that history and the Framingham Heart Study offer
heart failure on risk of dementia.
reasons for hope. “Evidence of dementia’s decline shows once again that our
They saw 371 cases of dementia overall; the age-adjusted rates per 100
burden of disease is malleable,” they wrote. “Primary and secondary prevenpersons plummeted over time, from a high of 3.6 in Epoch 1 down to 2.0
tion might diminish the magnitude of the long-feared dementia epidemic.”
in Epoch 4, a 44% decrease in incidence (p for trend < 0.001). The specific
REFERENCES
cardiovascular diseases analyzed, including AF, also significantly decreased
1. Satizabal CL, et al. N Engl J Med. 2016;374:523-32.
over time (FIGURE 4) as did the risk of dementia associated with stroke, AF, or
2. Jones DS, Greene JA. N Engl J Med. 2016;374:507-9.
HF. Although none of these trends completely explained the decrease in the
incidence of dementia, the authors said prevention
may be critical to combat the suspected tsunami of
FIGURE 4 Adjusted Temporal Trends in Dementia
dementia coming with the growing segment of the
population considered elderly.
Another factor in the hunt to prevent stroke
and related dementia: cerebral microbleeds
(CMB), which indicate hemorrhage-prone small
vessel disease. At the 2016 International Stroke
Conference held in February in Los Angeles, CA,
Framingham dementia data were the subject of
a presentation to see if there was an association
between CMB location and type of dementia.
Investigators looked at brain MRIs from nearly
1,300 members of the original and offspring cohorts who were free of neurological disease.
Dementia was classified as all type, Alzheimer’s disease type, and vascular dementia, while
CMB was classified by location as lobar only, deep
only, or deep and mixed. According to J. Rafael
Romero, MD, from the Boston University School
of Medicine and the Framingham Heart Study, the
researchers created three multivariate models for
28 CardioSource WorldNews
July 2016