CARDIOVASCULAR NEWS
A randomized comparison of primary
angioplasty and thrombolytic therapy study sought
to determine the short- and long-term outcome
of primary coronary angioplasty and thrombolytic
therapy for acute myocardial infarction (AMI)
in patients older than 75 years of age. 87 patients
with an AMI who were older than 75 years were
randomly assigned to treatment with angioplasty
or intravenous (IV) streptokinase. Clinical outcome
was measured by taking the end points of death
and the combination of death, reinfarction or
stroke during follow-up. The primary end point,
a composite of death, reinfarction or stroke,
at 30 days had occurred in 4 (9%) patients in
the angioplasty group as compared with 12 (29%)
in the thrombolysis group (p = 0.01, relative
risk [RR]: 4.3, 95% confidence interval [CI]:
1.2 to 20.0). At one year the corresponding figures
were 6 (13%) and 18 (44%), respectively (p = 0.001,
RR: 5.2, 95% CI: 1.7 to 18.1). The authors concluded
that in patients with AMI who were older than
75 years, primary coronary angioplasty had a significant
clinical benefit when compared with IV streptokinase
therapy.
(J Am Coll Cardiol 2002; 39:1723-1728)
The Pathobiological Determinants of Atherosclerosis
in Youth (PDAY) evaluated the association of obesity
and atherosclerosis in young patients dying of
external causes. The study collected arteries,
blood, and other tissue from 3000 persons aged
15 to 34 years dying of external causes and autopsied
in forensic laboratories. The investigators measured
gross atherosclerotic lesions in the right coronary
artery (RCA), American Heart Association (AHA)
lesion grade in the left anterior descending coronary
artery (LAD), serum lipid concentrations, serum
thiocyanate (for smoking), intimal thickness of
renal arteries (for hypertension), glycohemoglobin
(for hyperglycemia), and adiposity by body mass
index (BMI) and thickness of the panniculus adiposus.
BMI in young men was associated with both fatty
streaks and raised lesions in the RCA and with
AHA grade and stenosis in the LAD. The effect
of obesity (BMI>30 kg/m2) on RCA raised lesions
was greater in young men with a thick panniculus
adiposus. Obesity was associated with non-HDL
and HDL (inversely) cholesterol concentrations,
smoking (inversely), hypertension, and glycohemoglobin
concentration. These variables accounted for 15%
of the effect of obesity on coronary atherosclerosis
in young men. BMI was not associated with coronary
atherosclerosis in young women although there
was a trend among those with a thick panniculus
adiposus. The study concluded that obesity is
associated with accelerated coronary atherosclerosis
in adolescent and young adult men. These observations
support the current emphasis on controlling obesity
to prevent adult coronary heart disease.
(Circulation 2002; 105 2712-2718)
Restenosis of a treated vessel remains the main
limitation of percutaneous coronary revascularization.
Sirolimus (rapamycin) inhibits the proliferation
of lymphocytes and smooth-muscle cells. The RAVEL
study compared a sirolimus-eluting stent with
a standard uncoated stent in patients with angina
pectoris. The investigators performed a randomized,
double blind trial to compare the two types of
stents for revascularization of single, primary
lesions in native coronary arteries. The trial
included 238 patients at 19 medical centers. The
primary end point was in-stent late luminal loss
(the difference between the minimal luminal diameter
immediately after the procedure and the diameter
at six months). Secondary end points included
the percentage of in-stent stenosis of the luminal
diameter and the rate of restenosis (luminal narrowing
of 50 percent or more). The investigators analyzed
the composite clinical end point consisting of
death, myocardial infarction, and percutaneous
or surgical revascularization at 1, 6, and 12
months. At six months, the degree of neointimal
proliferation, manifested as the mean (±SD) late
luminal loss, was significantly lower in the sirolimus-stent
group than in the standard-stent group (P<0.001).
None of the patients in the sirolimus-stent group,
as compared with 26.6 percent of those in the
standard-stent group, had restenosis of 50 percent
or more of the luminal diameter (P<0.001). There
were no episodes of stent thrombosis. During a
follow-up period of up to one year, the overall
rate of major cardiac events was 5.8 percent in
the sirolimus-stent group and 28.8 percent in
the standard-stent group (P<0.001). The difference
was due entirely to a higher rate of revascularization
of the target vessel in the standard-stent group.
The study concluded that a sirolimus-eluting stent
shows considerable promise for the prevention
of neointimal proliferation, restenosis, and associated
clinical events.
(N Eng J Med 2002; 346:1773-1780)
To better understand the role of various prophylactic
therapies against postoperative atrial fibrillation
(AF), Crystal et al conducted a systematic review
of evidence from randomized trials. Fifty-two
randomized trials (controlled by placebo or routine
treatment) of b-blockers, sotalol, amiodarone,
or pacing were identified by systematic literature
search. Results of beta-blockers, sotalol, amiodarone,
or pacing in preventing AF were analyzed. The
3 drug treatments each prevented AF. Pacing was
also effective. The incidence of stroke was 1.2%
in all the treatment groups combined and 1.4%
in controls (OR, 0.90; 95% CI, 0.46 to 1.74).
Beta-blockers, sotalol, and amiodarone all reduce
risk of postoperative AF with no marked difference
between them. There is evidence that use of these
drugs will reduce LOS. Biatrial pacing is a promising
new treatment. There was no evidence that reducing
postoperative AF reduces stroke; however, data
on stroke are incomplete.
(Circulation 2002 electronic section).
Previous studies have suggested that cardiac
resynchronization achieved through atrial-synchronized
biventricular pacing produces clinical benefits
in patients with heart failure who have an intraventricular
conduction delay. The investigators conducted
a double-blind trial to evaluate this therapeutic
approach. Four hundred fifty-three patients with
moderate-to-severe symptoms of heart failure associated
with an ejection fraction of 35 percent or less
and a QRS interval of 130 msec or more were randomly
assigned to a cardiac-resynchronization group
(228 patients) or to a control group (225 patients)
for six months, while conventional therapy for
heart failure was maintained. The primary end
points were the New York Heart Association functional
class, quality of life, and the distance walked
in six minutes. As compared with the control group,
patients assigned to cardiac resynchronization
experienced an improvement in the distance walked
in six minutes (+39 vs. +10 m, P=0.005), functional
class (P<0.001), quality of life (–18.0 vs. –9.0
points, P= 0.001), time on the treadmill during
exercise testing (+81 vs. +19 sec, P=0.001), and
ejection fraction (+4.6 percent vs. –0.2 percent,
P<0.001). In addition, fewer patients in the group
assigned to cardiac resynchronization than control
patients required hospitalization (8 percent vs.
15 percent) or intravenous medications (7 percent
vs. 15 percent) for the treatment of heart failure
(P<0.05 for both comparisons). Implantation of
the device was unsuccessful in 8 percent of patients
and was complicated by refractory hypotension,
bradycardia, or asystole in four patients (two
of whom died) and by perforation of the coronary
sinus requiring pericardiocentesis in two others.
Cardiac resynchronization results in significant
clinical improvement in patients who have moderate-to-severe
heart failure and an intraventricular
(N Eng J Med 2002; 346:1845-1853)
Dual-chamber (atrioventricular) and single-chamber
(ventricular) pacing are alternative treatment
approaches for sinus-node dysfunction that causes
clinically significant bradycardia. However, it
is unknown which type of pacing results in the
better outcome. Gervasio and colleagues randomly
assigned a total of 2010 patients with sinus-node
dysfunction to dual-chamber pacing (1014 patients)
or ventricular pacing (996 patients) and followed
them for a median of 33.1 months. The primary
end point was death from any cause or nonfatal
stroke. Secondary end points included the composite
of death, stroke, or hospitalization for heart
failure; atrial fibrillation; heart-failure score;
the pacemaker syndrome; and the quality of life.
The incidence of the primary end point did not
differ significantly between the dual-chamber
group (21.5 percent) and the ventricular-paced
group (23.0 percent, P=0.48). In patients assigned
to dual-chamber pacing, the risk of atrial fibrillation
was lower (hazard ratio, 0.79; 95 percent confidence
interval, 0.66 to 0.94; P=0.008), and heart-failure
scores were better (P<0.001). The differences
in the rates of hospitalization for heart failure
and of death, stroke, or hospitalization for heart
failure were not significant in unadjusted analyses
but became marginally significant in adjusted
analyses. Dual-chamber pacing resulted in a small
but measurable increase in the quality of life,
as compared with ventricular pacing. The authors
concluded that in sinus-node dysfunction, dual-chamber
pacing does not improve stroke-free survival,
as compared with ventricular pacing. However,
dual-chamber pacing reduces the risk of atrial
fibrillation, reduces signs and symptoms of heart
failure, and slightly improves the quality of
life. Overall, dual-chamber pacing offers significant
improvement as compared with ventricular pacing.
(N Eng J Med 2002; 346: 1854-1862)
Compiled by Dr. Jassim Al Suwaidi
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