The
information in this column is intended for informational
purposes only, and does not constitute medical advice or
recommendations by the author. Please consult with your
physician before making any lifestyle or medication changes, or if you
have any other concerns regarding your health.
STENTS
VS. BYPASS SURGERY
FOR CORONARY ARTERY DISEASE
Over the past 5
years or so, there has been a great deal of debate between experts
regarding
the optimal management of blocked coronary arteries in the heart. Overall, cardiovascular
disease remains the
most common cause of death in most developed countries, with cancer
coming in
as the second most common cause of mortality (and, in some demographic
groups,
cancer has already surpassed cardiovascular disease as the most
frequent cause
of early death). Relatively
recent
advances in the minimally invasive management of diseased coronary
arteries
have made it possible for millions of Americans to avoid coronary
artery bypass
graft (CABG) surgery. Instead,
clogged and
narrowed coronary arteries can often be widened with “balloon
angioplasty,” using
specialized catheters that are threaded up to the heart from veins in
the groin
or arm. Because
“ballooned” coronary
arteries rapidly begin to narrow again, most of the time, tiny
scaffold-like
meal stents are placed within the lumen of the re-expanded coronary
arteries,
helping to keep them open to the flow of heart-sustaining blood.
Currently,
the
superiority of coronary artery stents vs. CABG surgery is the topic of
enormous
debate. There is
also great controversy
regarding which type of coronary
artery stents are the best to use.
Recent research studies have called into question the
safety of at least
some types of so-called drug-eluting stents, which are coated with
drugs that
inhibit re-growth of the lining of diseased coronary arteries and,
theoretically anyway, help to keep these arteries open longer. However, most of the
recent clinical research
studies have generally found coronary artery stents to be as effective
as CABG
surgery in restoring cardiac blood flow through narrowed coronary
arteries in
many patients, although the duration of this benefit appears to be
shorter than
that provided by CABG surgery, and the need for repeat interventions is
much
more common in patients receiving stents rather than surgery. Whether or not stents
provide similar
long-term survival benefit as that obtained after CABG surgery has also
been
the topic of considerable debate, and conflicting research results,
with some
studies suggesting that, at least for blockages of the dominant
coronary
artery, the left main coronary artery, CABG surgery may indeed improve
survival
when compared to stents. A
new study,
from Korea, and just published in the New
England Journal of Medicine, therefore provides additional
important
information when comparing the outcomes of stents with those achieved
by CABG
surgery in patients with blockages of the left main coronary artery.
In
this cohort
study (which was not a prospective, randomized study), approximately
1100 stent
patients and 1100 CABG surgery patients, all with “unprotected” left
main
coronary artery narrowing, were evaluated with respect to the
post-treatment incidence
of heart attack (myocardial infarction), stroke, need for repeat
interventions
to re-open recurrent narrowing of previously treated coronary arteries,
and
death.
Overall,
there
was no statistically significant difference in the risk of death
between the
patients that received stents and those that underwent CABG surgery. When taken together as a
composite outcome,
there was also no overall significant difference in the incidence of
heart
attack or stroke between the two groups of patients.
However, as almost every previous similar
study has shown, patients who received stents were nearly 5 times as
likely to
require subsequent interventions to clear and open re-clogged coronary
arteries
after stenting, when compared to the patients that had their narrowed
coronary
arteries completely bypassed by CABG surgery.
Regarding
the
ongoing debate about the relative safety of “bare metal” stents versus
“drug-eluting” stents, a trend towards an increased risk of death was
observed
in this study among patients who received drug-eluting stents (when
compared to
the patients who received bare metal stents), although this trend did
not reach
accepted levels of statistical significance.
The
results of
this study are generally consistent with previous studies, although its
focus
on left main coronary artery disease makes it somewhat unique. Also, this study’s
findings that patients
receiving drug-eluting stents experienced a trend towards higher
mortality than
those who received bare metal stents may be cause for added concern,
although
experts in the field of coronary artery revascularization continue to
debate
each other regarding the adverse effects, if any, of drug-coated stents.
Unfortunately,
this clinical research trial does suffer from a few serious limitations. First, and foremost, it
was not a
prospective, randomized clinical trial.
Therefore, it is subject to the same “selection biases”
inherent in all
non-randomized, non-prospective studies.
Secondly, the average duration of patient follow-up in
this clinical
trial was about 3 years, which is a relatively long time for research
trials
looking at coronary artery stents.
However, clinical studies involving CABG surgery
frequently include
patient follow-up durations of 5 or more years, and 10 years in some
studies. Whether or
not the results achieved with
coronary artery stents, as observed in this non-randomized,
non-prospective
clinical study, will remain stable for 5 years, or even 10 years,
remains to be
seen. In my view,
this clinical trial
provides interesting and potentially useful clinical information, but
because of
these significant limitations, it is probably best viewed as an
indication to
proceed with a larger prospective, randomized clinical trial with
long-term
follow-up. It will
only be through such
a clinical research trial that the results of this particular study can
be
definitively affirmed.
THE
“DASH” HYPERTENSION
DIET & CARDIOVASCULAR DISEASE PREVENTION
High blood
pressure (hypertension), like diabetes, is often referred to as “the
silent
killer.” Patients
with hypertension are
usually unaware of their elevated blood pressure, and of hypertension’s
insidious adverse effects on vital organs throughout the body,
including the
brain, the heart and the kidneys.
Over
time, untreated hypertension can cause serious, irreversible damage to
these
and other organs, resulting in an increased risk of stroke, heart
attack, heart
failure and kidney failure. Multiple
treatment
approaches to hypertension have been advocated by experts, including
diet,
exercise, avoidance of obesity and, when necessary, the use of
medications to
lower elevated blood pressure.
The
DASH diet
(“Dietary Approaches to Stop Hypertension” diet) has been shown to be a
valuable adjunct in the treatment of high blood pressure. The DASH diet plan
involves eating more
fruits and vegetables, whole grain foods, fish, poultry, nuts and
low-fat dairy
products, as well as foods that are good sources of magnesium,
potassium and
calcium. At the
same time, the DASH diet
calls for significantly decreasing dietary intake of red meat and other
high-fat foods, sugary foods, and salt.
While previous studies of the DASH diet have shown it to
be effective in
helping to lower blood pressure, the effects of the DASH diet, if any,
on
reducing the risk of coronary artery disease and stroke is not well
understood. A new
prospective study, from Harvard
University and the American Cancer Society, and just published in the
journal Archives of Internal Medicine,
looks at
the long-term impact of the DASH diet on the risk of coronary artery
disease
and stroke in otherwise healthy adult women.
In this study, the
enormous Nurses’ Health Study, more than 88,000 female nurses, aged 33
to 59,
were closely followed between 1980 and 2004.
At the time of entry into this landmark public health
study of women,
study volunteers had to be free of any clinical evidence of
cardiovascular
disease or diabetes. During
an average
of 24 years of follow-up, dietary intake was assessed a total of 7
times. Lifestyle
and medical histories were also
collected every other year. Although
the
women participating in this huge prospective epidemiological study were
not required
to follow the DASH diet, a “DASH dietary score” was used to assess the
diets of
these nurses, based upon the specific recommendations contained within
the DASH
diet’s guidelines.
Among
this very
large cohort of study volunteers, 2,129 were diagnosed with a heart
attack
(myocardial infarction) during the course of this study, 976 women
actually
died from complications of coronary artery disease, and 3,105 women
suffered a
stroke. When all of
the women in this
study were graded according to how closely their individual diets
corresponded
with the DASH diet’s guidelines, 5 levels of adherence (from very poor
adherence to excellent adherence) were derived.
Using this “DASH diet score,” the researchers found that
the women with
the best adherence to the DASH diet guidelines, when compared to those
with the
worst adherence, experienced a 24% reduction in the relative risk of
developing
coronary artery disease and heart attack (both fatal and non-fatal
heart
attacks). Similarly,
patients who
followed a “DASH-like” diet had an 18% reduction in the relative risk
of stroke
when compared to the women who did not follow DASH diet guidelines. Interestingly, when blood
tests for the inflammatory
markers C-reactive protein and Interleukin-6 were measured, the women
who
followed DASH diet guidelines had significantly lower levels of these
pro-inflammatory substances, which have been linked by other studies to
an
increased risk of coronary artery disease and cancer.
While
the
absolute level of risk reduction for coronary artery disease, heart
attack
(both fatal and non-fatal), and stroke observed with strict adherence
to the
DASH diet, in this study, were relatively small, these findings are
still
clinically significant. This
study
specifically enrolled clinically healthy middle-aged women, and then
followed
them for more than two decades (at the time that this study was
published). Using
their extensive health database on
these nearly 90,000 women, the study’s authors statistically corrected
their
data for differences in age, smoking status and other known
cardiovascular risk
factors before reaching their conclusions, in an effort to isolate the
effects
of diet, alone, on cardiovascular illness and mortality rates. Taken together, this study
provides strong
evidence that a healthy diet, along the guidelines established by the
DASH
diet, can, over time, reduce the risk of heart disease and stroke, even
in
already healthy adult women (and, presumably, men as well). These apparent DASH diet
benefits are, of
course, additive to the known benefit of the DASH diet in reducing
elevated
blood pressure in hypertensive adults as well.
(As always, please remember to consult your physician
before making any
significant changes in your diet!)
TESTOSTERONE
THERAPY FOR
WOMEN WITH DECREASED SEXUAL DESIRE & FUNCTION
While an
objective definition of decreased libido in women is generally lacking
in most
publications on the subject, by some estimates, more than 60% of women
have
been estimated to experience lowered levels of libido, or other forms
of
“sexual dysfunction,” by experts in the field of sexual health. Various treatments, both
pharmacological and
behavioral, have been advocated for women who themselves perceive—or
who are
perceived by their partners—to have a decreased level of sexual desire
or
interest. Testosterone,
the sex hormone
that appears to underlie interest in sexual behavior in both men and
women, has
increasingly been used to treat women with decreased libido (and men
complaining of decreased desire too, for that matter).
Although normal blood levels of testosterone
in women are much lower than in men, testosterone still appears to
mediate
libido in both sexes, and so interest in testosterone supplementation
for women
with decreased libido is a logical treatment to consider. A new prospective,
randomized,
placebo-controlled, double-blinded study in the Annals
of Internal Medicine, from Australia,
adds to our
understanding of at least the short-term risks and benefits of
supplemental
testosterone therapy in women with low testosterone levels who also
experience
decreased libido.
In
this study,
261 women, aged 35 to 46, with documented low blood levels of
testosterone and
decreased libido, were randomized to receive one of 3 different doses
of
testosterone, or a placebo (an inactive substitute for testosterone),
for a
duration of 16 weeks. An
absorbable
spray applied to the skin, on a daily basis, was used in each case, and
neither
the patient nor the person administering the spray knew if the spray
contained
testosterone or the placebo spray.
In
yet another
demonstration of the “placebo effect,” the women in all treatment
groups,
including those receiving the inert placebo spray, reported a
significant
increase in satisfactory sexual events (as defined by the researchers
conducting this study) during the course of this study.
However, women receiving the intermediate
dose of testosterone spray reported the greatest increase in
satisfactory
sexual events (SEEs) when compared to the women who had, unknowingly,
received
the placebo spray (2.48 “SSEs” vs. 1.70 “SSEs” within a 28-day period,
respectively, to be precise…). Interestingly,
the women receiving the highest dose of testosterone did not appear to
derive
any benefit, in terms of increased “SSEs,” when compared to women
receiving the
placebo spray.
This
interesting
study suggests that, for premenopausal middle-aged women reporting low
sexual
desire, at least among those with documented low blood levels of
testosterone,
a daily 90 microliter spray of absorbable testosterone on the skin can
significantly improve sexual interest and satisfaction, while both
lower and
higher doses of transdermal testosterone appear to be less effective. At the same time, this
study also confirms
what is already well known about human sexual behavior, and that is the
fact
that the most important sexual organ is the brain.
All
of the women in this placebo-controlled double-blinded study reported
improved
sexual interest and function after enrolling in this clinical research
trial,
including the women who only received (unknown to them) an inert
placebo
spray.
Unfortunately,
while there were no apparent significant side effects associated with
transdermal
testosterone supplementation in this 16-week research trial (except for
the
manageable tendency to develop increased hair growth at the application
site),
this study did not continue long enough to assess for long-term side
effects
(nor did the researchers measure the effects of testosterone
supplementation on
blood cholesterol levels or cardiovascular function, both of which are
directly
affected by testosterone). The
authors
are to be congratulated, however, on their use of a stringent
prospective,
randomized, double-blinded, placebo-controlled design for their
research trial,
which provides clinical research data of the highest attainable
objectivity and
quality. The next
step, it would be
appear, is to repeat this clinical trial with larger numbers of
patients, and
to follow them longer, and in more detail, in order to fully assess the
risks
and benefits associated with chronic transdermal testosterone
supplementation
in women with low serum testosterone levels who simultaneously report
diminished
libido and sexual function.
Disclaimer:
As always, my advice to readers is to seek the advice of your physician
before making any significant changes in
medications, diet, or level of physical activity.
