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CARDIOLOGY
- Publications
CONTROLLING
HEART DISEASE
a
strategy update
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Reduced
HDL levels
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Extensive epidemiologic and clinical studies have established
that HDL levels are inversely associated with cardiovascular
disease risk. More importantly, the risk associated
with HDL is totally independent of LDL (Figure 2).10
These results have also been confirmed by the PROCAM
study. Studies have also suggested that a low level
of HDL may be more of a CHD risk than a moderately increased
LDL.11
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A low level of HDL may be more of a CHD risk than a
moderately increased LDL
The PROCAM study also suggested that
a high concentration of HDL is more protective than
a low level of LDL.12 Further, a meta-analysis
of 4 large trials showed that for every 1 mg/dl increase
in HDL, the CHD risk decreases by 2% in men and 3% in
women.10
The classification of HDL as
per NCEP guidelines9
is given in Table 3.
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Table
3: Classification of HDL
(as per NCEP guidelines)
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< 40 mg/dl
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Low
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> 60 mg/dl
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High
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Management (as per NCEP guidelines)9
- In all persons with low HDL,
the primary target of therapy is LDL
- When a low HDL is associated
with high triglycerides (200-499 mg/dl), secondary
priority goes to achieving the non-HDL cholesterol
goal.
- If triglycerides are <
200 mg/dl, drugs for HDL raising (fibrates or nicotinic
acid) can be considered.
Drugs
for raising HDL include fibrates and nicotinic acid
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| Small
dense LDL |
Initial detailed analysis of plasma LDL in control subjects
and CHD patients with hypertriglyceridemia and low HDL
have revealed the presence of two distinct major lipoprotein
phenotypes based on LDL subclasses. One subclass is characterized
by a predominance of large buoyant LDL particles (pattern
A), and the second subclass is characterized by small,
dense LDL particles (pattern B). Pattern B is often associated
with hypertriglyceridemia and low HDL, and is frequently
referred to as the atherogenic lipoprotein profile.
Clinical and epidemiologic studies have indicated that
small, dense LDL is associated with an increased risk
of CHD. In the St. Thomas Atheroma Regression Study, “dense”
LDL was the best predictor of arteriographic outcome.13
Similarly, in the Stanford Coronary Risk Intervention
Project,14 the best correlation with reduction
in the rate of arteriographic progression was observed
in the patients with a decrease in dense LDL, and in the
Quebec Cardiovascular Study,15 small dense
LDL was associated with increased risk of subsequently
developing CHD.
The best correlation with
reduction in the rate of arteriographic progression was
observed in the patients with a decrease in small dense
LDL
Small dense LDL is found most frequently in patients with
combined hyperlipidemia, metabolic syndrome and in patients
with type 2 diabetes mellitus.
The increased atherogenic potential of dense LDL, when
compared with buoyant LDL, has been attributed to several
factors, including greater susceptibility to oxidative
modification and efficient infiltration into the arterial
vessel wall.
Management
Plasma concentrations of small dense LDL can be reduced
by non-pharmacological methods (restriction of animal
fats, reduction of body weight, physical activity) as
well as by pharmacological means, particularly fibrates.16
Fibrates are particularly effective in reducing plasma
concentrations of small dense LDL |
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