DISCUSSION
We assessed the role of LA global longitudinal strain by evaluating the
LA remodeling in a Cameroonian T2DM adults. We included a group of
diabetic patients, predominantly females, with more than half of them
having coexistent hypertension. Given that global cardiovascular risk is
very high in diabetic patients, its reduction constitutes a major
treatment objective 12. Despite the high proportion of
hypertensive patients in the population, we found only à third of them
with a renin-angiotensin-aldosterone system blocker in their treatment
regimen. Thus, reflecting the difficulties in applying ESC/ESH treatment
recommendations 13 in Africa, especially in Cameroon,
which could be linked to the relative high cost of these medications in
our context, making them less available to the majority of hypertensive
patients. Mean LVEF was 63.1%, corresponding to the classical
presentation of patients with cardiac disease related to diabetes, where
diastolic dysfunction is the main abnormality at the early stage14.
LA structural remodelling is classically expressed by the measurement of
the LAVi by 2D (or 3D) echocardiography 1. Increased
LAVi is a surrogate marker of increased and chronic pressure overload
and is a key measurement used in clinical practice to assess diastolic
dysfunction of the LV 15. The mean value of LAVi (22 ±
6 ml/m²) in the study was within the normal reference range of the
American society of Echocardiography 16. However, we
observed greater alterations of the reservoir function (LA global
ejection fraction) and the contractile function.
PALS was significantly reduced in the study population compared to a
non-diabetic black African population in South Africa (29.2 ± 9 vs 39 ±
8.3, p < 0,001)11. Meanwhile this results is
similar to those found by Markman and al. in a diabetic population with
a mean PALS of 28.5 ± 11.7% 17. Concerning the role
of PALS in early detection diastolic and LA dysfunction, it is important
to highlight that LA strain was markedly reduced in many patients with
normal LAVi. In 2016, Bassam and al, had similar results in a group of
hypertensive subjects in whom LA strain measured by speckle tracking
echocardiography allowed early detection of LA dysfunction even before
LA dilatation 7.
Finally, univariate linear regression allowed to highlight a
significative negative association of PALS with age, BMI, SBP, E/E’
ratio and LAVi. The reservoir (LA expansion index and LA global ejection
fraction) and the contractile functions were positively correlated to
PALS. Cardiac disease during diabetes leads to atrial fibrosis with
consequent reduced atrial compliance 18. Muranaka and
al, also suggested that LA fibrotic modifications during T2DM are
responsible for reduced phasic functions determined by LA strain19.
This study had several limitations: (i) LA strain measurement lacks a
criterion standard - strain values vary with different software
packages; (ii) the quantitative values defined for LA strain are
vendor-specific; (iii) the software used for assessing strain does not
have a specific mode for LA strain study; and (iv) coronarography which
is the gold standard to exclude coronary artery disease could not be
performed.