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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 28, No 1, January/February 2017
AFRICA
65
confirmation in our study of the increased risk of these patients
when admitted for acute HF is important, adding to the evidence
encouraging a low threshold for evaluation and treatment of
patients with suspected aortic stenosis.
Left atrial enlargement has been increasingly suggested
in recent years to be an important indicator of increased
risk for an adverse clinical outcome. Left atrial enlargement
may serve as an indicator for persistent increased pressure
within the cardiovascular system, possibly representing longer-
term changes, such as the role of HbA
1c
in diabetes mellitus.
Furthermore, the left atrium modulates left ventricular filling
and cardiovascular performance by functioning as a reservoir for
pulmonary venous return during ventricular systole, a conduit
for pulmonary venous return during early ventricular diastole,
and a booster pump that augments ventricular filling during
late ventricular diastole. Therefore, left atrial enlargement (and
possibly associated dysfunction) may play an important role not
only in the marking of cardiovascular dysfunction but also in its
enhancement.
The finding that left atrial size is associated with adverse
outcomes begs the question of why measures of diastolic
dysfunction were not predictive of such adverse outcomes in
the current cohort. Although the reasons for that cannot be
ascertained, given the limitations of the study (see below), it
is possible that, as described by Gandhi
et al
.,
9
measures of
diastolic dysfunction improve rapidly after admission in patients
Table 4. Univariate associations between echo predictors
and 60-day death/re-admission
Echocardiographic parameter
Hazard ratio (95% CI)
p
-value
Heart rate, per increment of 5 bpm 1.07 (1.02–1.13)
0.0088
LVEDD (mm)
1.00 (0.99–1.02)
0.81
LVESD (mm)
1.00 (0.98–1.01)
0.63
IVSTd (mm)
0.96 (0.91–1.01)
0.14
PWTd (mm)
0.97 (0.91–1.03)
0.34
LV mass
1.00 (1.00–1.00)
0.63
LVEF (%), per 5% increment
1.02 (0.96–1.07)
0.58
Left atrial size (A-P) (mm)
1.01 (0.99–1.03)
0.57
Left atrial size (planimetry) mm
2
1.00 (1.00–1.00)
0.030
E/A ratio, per doubling
1.07 (0.86–1.34)
0.53
E-wave deceleration time (ms)
1.00 (0.99–1.00)
0.13
MV A-wave duration
1.00 (1.00–1.01)
0.43
MV E/A ratio grades
Grade 1: impaired relaxation
(reference group)
0.61
Grade 2: pseudonormal
1.07 (0.55–2.06)
Grade 3: restrictive filling
1.28 (0.72–2.26)
Aortic stenosis
None, mild
(reference group)
0.69
Moderate
1.83 (0.45–7.41)
Severe
0.90 (0.22–3.65)
Aortic regurgitation
None, mild
(reference group)
0.072
Moderate
1.20 (0.61–2.36)
Severe
2.42 (1.13–5.19)
Mitral stenosis
None, mild
(reference group)
0.50
Moderate
1.56 (0.58–4.22)
Severe
0.64 (0.20–2.00)
Mitral regurgitation
None, mild
(reference group)
0.95
Moderate
0.95 (0.63–1.41)
Severe
1.03 (0.60–1.76)
Tricuspid regurgitation
None, mild
(reference group)
0.23
Moderate
1.41 (0.94–2.11)
Severe
1.21 (0.66–2.21)
LVEDD, left ventricular end-diastolic diameter; LVESD, left ventricu-
lar end-systolic diameter; IVSTd, interventricular septal thickness in
diastole; PWTd, posterior wall thickness in diastole; LV, left ventricu-
lar; LVEF, left ventricular ejection fraction; A-P, antero-posterior;
MV, mitral valve. Heart rates are for an increment of one unit in the
predictor unless otherwise noted.
Table 5. Univariate associations between echo predictors
and 180-day mortality
Echocardiographic parameter
Hazard ratio (95% CI)
p
-value
Heart rate
≤ 80 bpm, per change of 5
0.90 (0.76–1.06)
0.0001
>
80 bpm, per change of 5
1.25 (1.03–1.52)
LVEDD (mm)
1.01 (0.99–1.02)
0.39
LVESD (mm)
1.01 (0.99–1.02)
0.38
IVSTd (mm)
0.94 (0.89–0.99)
0.025
PWTd (mm)
≤ 9 mm
0.77 (0.67–0.89)
0.0009
>
9 mm
1.32 (1.08–1.61)
LV mass
1.00 (1.00–1.00)
0.22
LVEF (%), per 5% increment
0.96 (0.91–1.01)
0.12
Left atrial size (A-P) (mm)
1.00 (0.98–1.01)
0.64
Left atrial size (planimetry) mm
2
1.00 (1.00–1.00)
0.50
E/A ratio, per doubling
1.13 (0.92–1.39)
0.23
E-wave deceleration time (ms)
1.00 (0.99–1.00)
0.07
MV A-wave duration
1.00 (1.00–1.01)
0.61
MV E/A ratio grades
Grade 1: impaired relaxation
(reference group)
0.19
Grade 2: pseudonormal
1.77 (0.92–3.38)
Grade 3: restrictive filling
1.67 (0.92–3.03)
Aortic stenosis
None, mild
(reference group)
0.039
Moderate
3.60 (1.33– 9.74)
Severe
0.83 (0.21–3.36)
Aortic regurgitation
None, mild
(reference group)
0.096
Moderate
0.93 (0.46–1.90)
Severe
2.30 (1.07–4.92)
Mitral stenosis
None, mild
(reference group)
0.89
Moderate
0.99 (0.31–3.10)
Severe
0.79 (0.29–2.12)
Mitral regurgitation
None, mild
(reference group)
0.87
Moderate
0.92 (0.62–1.34)
Severe
1.05 (0.63–1.74)
Tricuspid regurgitation
None, mild
(reference group)
0.53
Moderate
1.26 (0.85–1.86)
Severe
1.04 (0.57–1.89)
LVEDD, left ventricular end-diastolic diameter; LVESD, left ventricu-
lar end-systolic diameter; IVSTd, interventricular septal thickness in
diastole; PWTd, posterior wall thickness in diastole; LV, left ventricu-
lar; LVEF, left ventricular ejection fraction; A-P, antero-posterior;
MV, mitral valve. Heart rates are for an increment of one unit in the
predictor unless otherwise noted.