Page 2423 - Hematology_ Basic Principles and Practice ( PDFDrive )

Chapter 148 Peripheral Artery Disease 2163

Reduction of Atherothrombosis for Continued Health (REACH)
registry, which enrolled patients with established PAD on the basis
of clinical symptoms, abnormal ABI, and prior revascularization,
demonstrated a 23.6% rate of new adverse limb events over 4 years
including new revascularization procedures as well as ischemic ampu-
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tations. These data are consistent with findings from the TRA2°P-
TIMI 50 trial, which evaluated the impact of the novel agent
vorapaxar in patients with PAD, where the rate of peripheral artery
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revascularization in the placebo treated group was 22.2% over a
median period of three years. Prognosis is worst for those with CLI,
where mean amputation-free survival at 1 year is only 50%. Out-
comes are worse for patients with PAD who continue to smoke or
have coexisting diabetes; such patients have even higher rates of
ischemic ulceration and amputation.
Given the high risk of concomitant coronary and cerebral artery
disease, individuals with PAD are also at increased risk of MI, stroke,
and cardiovascular death. The mortality rate is increased two- to
fourfold in patients with PAD compared with those without PAD,
Fig. 148.3 DUPLEX ARTERIAL ULTRASOUND DEMONSTRATING as confirmed in a meta-analysis of 16 cohort studies from the ABI
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DOPPLER INTERROGATION OF THE POPLITEAL ARTERY. Turbu- collaboration. Furthermore, a graded association has been noted
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lence of color Doppler flow indicates possible stenosis, confirmed by elevated with lower ABI associated with increased mortality. In patients with
peak systolic velocity, monophasic waveform, and spectral broadening. PAD, the risk of MI is increased by 20% to 60%, and the risk of
stroke is increased by 40%. The REACH registry found that the
1-year event rate for the composite of cardiovascular death, MI, and
stroke was 6.2% in individuals with PAD. The highest event rates
were in those with polyvascular disease compared with rates in
patients with atherosclerosis involving only one vascular bed. 15

THERAPY

The major goals in the management of patients with PAD are to (1)
reduce the risk of cardiovascular morbidity and mortality and (2)
improve lower extremity symptoms and preserve limb viability.
Aggressive cardiovascular risk factor modification is indicated for all
patients with PAD. This includes treatment of dyslipidemia, hyper-
tension, and diabetes (including regular foot care) and the use of
antiplatelet therapy. Encouragement of healthy lifestyle habits remains
a cornerstone of the management of individuals with PAD; these
include smoking cessation, a diet enriched in fruits and vegetables
and limited in saturated fats, and regular physical activity. 1

Dyslipidemia

Treatment of dyslipidemia with statins decreases major cardiovascular
events in patients with all manifestations of atherosclerosis. The 4S
study (Scandinavian Simvastatin Survival Study) was one of the
first to demonstrate a clear benefit of lipid-lowering therapy for
secondary prevention in patients with atherosclerosis and dyslipid-
emia. Subsequently, the Heart Protection Study demonstrated that
statin therapy was associated with a 22% relative risk reduction
in adverse cardiovascular events in patients with vascular disease,
Fig. 148.4 Representative projection imaging from a gadolinium-enhanced including PAD. Recent practice guidelines recommend the use of
magnetic resonance angiogram demonstrating segmental occlusion of the left high-intensity statin therapy, such as atorvastatin 80 mg daily or rosu-
common iliac artery (indicated by dashed white line), as well as nonobstructive vastatin 20 mg daily, for individuals with established atherosclerotic
atherosclerotic disease in the distal aorta and more distally in the external iliac vascular disease, including those with PAD to lower cholesterol and
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arteries. to reduce the risk of atherosclerotic events in this population. Statin
use is not only associated with lower cardiovascular event rates, but
also with approximately 18% lower rates of adverse limb outcomes,
PROGNOSIS including worsening symptoms, peripheral revascularization, and
amputations.
Prognostic considerations are broadly divided into limb outcomes The appropriate management of non-LDL cholesterol (HDL and
and overall cardiovascular outcomes. Limb prognosis is dependent on triglycerides) is less clear. Although reduced HDL levels are a risk
the severity of symptoms at initial presentation; concurrent risk factor for atherosclerosis, studies with medications that increase HDL
factors, such as cigarette smoking and diabetes; and the likelihood of levels and lower triglyceride levels have yielded conflicting results.
successful revascularization in those with threatened limb viability. The VA-HIT study (Veterans Affairs High-Density Lipoprotein
Among patients with claudication symptoms, leg discomfort remains Intervention Trial) showed that gemfibrozil reduced the risk of fatal
stable in the majority (≈70%–80%), worsens in about 10% to 20%, coronary disease or nonfatal MI by 22% over a median of 5.1 years
1
and progresses to CLI in a small percentage. Data from the in patients with known CAD. However, in a study of patients with