Page 859 - Cardiac Nursing

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C HAPTER 36 / Lipid Management and Cardiovascular Disease 835
consumed during a stable weight period and during a 5-week influence on endothelial function. Research has shown that regu-
weight-loss period. 108 They observed significant increases in HDL lar exercise can improve vasodilation responses and reduce platelet
60
after the weight-loss period for all diets combined with the largest adhesion. Given these beneficial effects, regular physical activity
decreases in lipid parameters including small dense LDL occur- should be a part of the TLC interventions used to manage dys-
ring with the 54% carbohydrate diet as compared to the 26% car- lipidemia (see Chapter 37). 116
bohydrate diet with low saturated fat content. The diet with the
high-saturated fat content showed the smallest decrease in LDL
cholesterol level as well as the lowest amount of weight loss 108 HORMONES AND
highlighting the importance of dietary restrictions of saturated fat. LIPOPROTEINS
Of note, the DASH diet reported a 21% increase in HDL among
men and a 33% increase among women. 109 The mechanisms pos- CHD develops in women almost a decade later in life than in men
tulated to account for these alterations in lipoproteins include de- for reasons not entirely well understood. Several mechanisms have
creased HMG-CoA reductase activity and enhanced cholesterol been suggested to account for this beneficial effect. Estrogen de-
excretion in bile acids. The release of cholesterol from adipose tis- creases LDL and increases HDL and apo A-I levels. 117 Estrogen use
sues is also thought to inhibit hepatic synthesis of cholesterol. has been associated with lower Lp(a), reduced LDL oxidative sus-
For all patients with dyslipidemia, the secondary goal of diet ceptibility, and improved endothelial vasodilation responses. 117,118
intervention is weight reduction. Patients with dyslipidemia Large, randomized, placebo-controlled clinical trials have examined
should be counseled to expect an initial reduction in HDL during the effect of hormone replacement therapy (HRT) for primary and
active weight loss. Increased levels of physical activity may mini- secondary coronary artery disease prevention.
mize the HDL reduction and facilitate weight loss. 110 The Heart and Estrogen/Progestin Replacement Study
(HERS) evaluated the influence of Premarin plus medroxyproges-
terone acetate (MPA) versus placebo in 2,763 women with CVD
ALCOHOL AND LIPOPROTEINS at baseline. 119 After an average follow-up of 4.1 years, no differ-
ences were detected in acute MI and coronary death between the
Moderate alcohol intake has been reported to be protective for two groups. In addition, there was a pattern of early increased risk
CVD. France, a country with a low rate of CVD, has a markedly of CVD and thrombotic events with a pattern of late benefit in
higher per capita consumption of alcohol, particularly of wine. 111 the women randomized to HRT. This increased risk seemed to oc-
One possible mechanism for this protective effect may be related cur primarily in the first year of treatment and there was a sug-
to the increase in HDL observed with alcohol intake. Researchers gestion of potential benefit with long-term treatment (i.e., more
have established that moderate alcohol intake increases HDL 3 , than 4 years). 119 Because of this interesting potential late benefit,
apo A-I, and apo A-II. 112,113 a follow-up study was undertaken. The investigators found that
Alcohol may also alter platelet aggregation and lower fibrino- after 6.8 years of follow-up, use of estrogen–progestin did not sig-
gen levels. Alcohol also increases catabolism of VLDL, the triglyc- nificantly decrease the risk of primary or secondary CVD events
eride-carrying lipoprotein. Patients with elevated triglyceride lev- in postmenopausal women with CVD. The effect of other doses
els may have dramatic improvements in triglyceride levels with and types of estrogen or estrogen only on CVD was not investi-
cessation of alcohol. Most researchers agree that the inverse asso- gated in this trial; therefore, these conclusions can only be applied
ciation between alcohol intake and CVD risk is a consistent but to women using this specific estrogen–progestin combination. 120
weak association. 114 Recommendations to consume alcohol must The Women’s Health Initiative (WHI), the largest study of pri-
therefore be considered cautiously, given the potential side effects mary and secondary prevention of heart disease in women ever un-
of impaired judgment, decreased motor coordination, and possi- dertaken reported a negative influence of HRT on breast cancer
ble addiction associated with alcohol use. The American Heart and cardiovascular risk in women. The WHI was a double-blind,
Association’s recent “scientific advisory” on Wine and Your Heart randomized, placebo-controlled primary and secondary prevention
concluded that until randomized clinical trials are undertaken, trial examining the effects of estrogen and estrogen–MPA combi-
there is “little justification to recommend alcohol (specifically nation therapy on various cardiovascular, vascular, breast cancer,
wine) as a cardioprotective strategy.” 115 and other health outcomes. The Data and Safety Monitoring
Board stopped the combined estrogen- plus-MPA arm of the trial
because the rates of breast cancer in this group were significantly
PHYSICAL ACTIVITY higher compared with placebo. They also found that the overall
AND LIPOPROTEINS health risks of the estrogen–MPA combination, including in-
creased risks for acute MI, thromboembolism, and stroke, far ex-
The American Heart Association has added physical inactivity to ceeded the benefits of the combination therapy. 121 This combined
dyslipidemia, smoking, and hypertension as the fourth major HRT was terminated 3 years earlier than its planned completion
modifiable risk factor for coronary artery and other vascular dis- date of 2006. The increasing risk of breast cancer was the key fac-
eases. 71 Physical activity works through a variety of mechanisms tor that led the National Heart, Lung, and Blood Institute
to lower coronary risk. Regular physical activity aids in weight loss (NHLBI) to terminate the combined HRT arm of the study. 122
by increasing caloric output. Weight loss decreases serum triglyc- The breast cancer findings along with the negative CVD outcomes
erides, which can result in increased levels of HDL cholesterol. discredit short-term or long-term estrogen-plus-progestin use for
Exercise improves glycemic control in type II diabetes by lessen- women with and without CVD. 121,122 Women in the WHI with
ing insulin resistance and improving insulin sensitivity. In some prior hysterectomy were randomized to the group receiving conju-
people, exercise also lowers LDL cholesterol, although LDL re- gated equine estrogen only versus the placebo group. After 6.8
ductions usually are modest. Regular physical activity has a positive years of follow-up, the use of conjugated equine estrogen was