126
VOLUME 9 NUMBER 3 • SEPTEMBER 2012
EVIDENCE IN PRACTICE
SA JOURNAL OF DIABETES & VASCULAR DISEASE
Left ventricular remodelling after antihypertensive treatment
Salt intake falling: still too high
R
educing dietary salt intake has major health benefits and significant
cost savings, but a new review shows that salt intake is still 9–12
g per day.
Reduction of salt intake in the population to the recommended
level of < 5–6 g per day could result in improvements similar to the
provision of clean water and drains in the late nineteenth century.
The review also recommends that salt intake in patients with heart
failure should be reduced to < 5 g per day.
A meta-analysis of randomised salt-reduction trials suggests that
a reduction of 6 g/day in salt intake would reduce stroke by 24%
and coronary heart disease by 18%.
Originally from
PCCJ
2011;
4
(4): 142.
SAJDVD recommended action
This review suggests that ongoing encouragement by healthcare workers to
their patients to reduce salt added during cooking and to reduce the con-
sumption of prepared foods will reap benefits. This approach, together with
the food industry reducing salt content in prepared foods, will result in signifi-
cant improvements in public health.
Reference
He F, Burnier M, Macgregor G. Nutrition in cardiovascular disease: salt in hyper-
tension and heart failure.
Eur Heart J
2011;
doi:10.1093/eurheartj/ehr194
T
here is a substantial body of evidence that suggests left ventricular
(
LV)geometricpatternsmayrefinetheabilitytopredictcardiovascular
events beyond LV hypertrophy (LVH). The change in geometry of the
heart in hypertensive LVH is heterogeneous. Concentric remodelling
occurs in some patients, where increases in wall thickness are out of
proportion to the chamber diameter. Eccentric LVHmay occur inothers,
with wall thickness increases in parallel with chamber diameters.
From this, it is evident that an important goal of hypertensive
therapy is to reduce the prevalence of concentric and eccentric
LVH, and LV remodelling. One year of antihypertensive therapy
may normalise LV structure in 51% of hypertensive patients of
European descent.
A study by Libhaber and colleagues examined whether
similar effects could be achieved in Africans, who have a high
prevalence of concentric LVH and LV remodelling. LV relative wall
thickness is higher in groups of African ancestry than in other
patient populations. Included in the study aims was to identify
the ability of 13 months of antihypertensive therapy to normalise
LV structure in hypertensives of African ancestry.
Results evaluated from 103 hypertensive patients in the
Baragwanath Hypertension study revealed that after more than
a year of stepwise antihypertensive therapy, the proportion of
patients with normal LV mass or geometry did not significantly
increase. Despite 64% of patients achieving clinic blood pressure
control and 47% achieving 24-hour blood pressure control by 13
months of therapy, 25% of patients remained with concentric LVH
and 25% with eccentric LVH. Moreover, concentric remodelling
increased from 12 to 23% (p < 0.05).
These residual abnormalities in LV structure were noted
despite antihypertensive therapy resulting in a decreased LV
M-mode echocardiogram and relative wall thickness. The results
were unable to show a relationship between residual LV structural
changes and control of clinic and 24-hour blood pressure.
This study reported similar results to those of the LIFE study
(
patients of European descent) in terms of mean decrease
in LV relative wall thickness at one year of antihypertensive
therapy, however LV structural abnormalities still persisted in
the Baragwanath study population, with a reported increase
in concentric remodelling. This suggests that concentric LVH is
difficult to normalise in the hypertensive African population.
Confounding considerations when comparing these results
to those encountered in the LIFE study included the higher
proportion of patients with increased baseline concentric LVH
and a higher mean baseline LV relative wall thickness. This was
consistent with previously reported ethnic disparities in concentric
LV modelling, as well as with the high prevalence of obesity in the
study sample.
Other considerations raised by Libhaber et al. included the
large proportion of female participants, social demographic
factors resulting in low 13-month retention rates, and the inability
to draw conclusions as to whether the results of this study apply
to all antihypertensive agents.
Source: Libhaber EN, Norton GR, Libhaber CD,
et al
.
Prevalence of residual left
ventricular structural changes after one year of antihypertensive treatment in
patients of African descent: role of 24-hour pulse pressure.
Cardiovasc J Afr 2012
;
23
(3): 147–152.
