Perspectives and Conclusions
Half of patients with the clinical syndrome of heart failure are
presented with preserved ejection fraction. The pathophysiology of HFpEF
is complex but increased LV stiffness is proved to play a key role.
Additive information about LV stiffness may be helpful in the early
diagnosis and management of patients with HFpEF. Determination of LV
stiffness has previously relied on invasive cardiac catheterization. The
echocardiographic imaging has increasingly been applied recently for
non-invasive evaluation of LV chamber and myocardial stiffness. LV
chamber stiffness indices such as E/e’/LVEDV, E/SRe/LVEDV, and DPVQ were
derived on the basis of the relationship between echocardiographic
parameters of LVFP and LV size. However, all these methods are surrogate
and lumped measurements, relying on E/e’ or E/SRe for evaluating LVFP.
The limitations of E/e’ or E/SRe in assessment of LVFP may contribute to
the moderate correlation between E/e’/LVEDV or E/SRe/LVEDV and LV
stiffness constant. Even the best validated measurement (DPVQ) is
considered unreliable in the individual patient by Kass and Burkhoff
themselves. Compared to E/e’/LVEDV and E/SRe/LVEDV,
IPVA/IA and FPVA/FA may display better
performance in assessing LV chamber stiffness as evidenced by a higher
correlation with LV stiffness constant. However, only one study has been
conducted in the literature on the exploration and application of
IPVA/IA and FPVA/FA, and its accuracy in
assessing LV chamber stiffness remains to be confirmed. In terms of
echocardiographic indices for LV myocardial stiffness evaluation, the
parameters of EMI/DWS, iVP and SWI were proposed. Despite alteration of
DWS and its predictive value of adverse outcomes in various populations
have been widely validated, it was found that DWS may be better
considered as an overall marker of cardiac function performance instead
of pure myocardial stiffness. As for the iVP and SWI, the validities of
these two indices in assessing LV myocardial stiffness have not been
confirmed in invasive studies.
Taken together, it seems that no echocardiography-derived indices could
be currently used to reliably and accurately assess LV stiffness despite
several parameters were developed. Therefore, the comprehensive
evaluation of LV stiffness using all these available parameters may be
more accurate and earlier to detect the alterations of LV stiffness.
Despite there is a long way to go, indices from STE such as FRe/SRe and
PALS have been proved to show good correlations with LVFP and have the
potential to become promising indexes for LV stiffness assessment. More
echocardiographic indices with higher sensitivities and specificities
warrant to be further uncovered to evaluate LV stiffness. Additionally,
further cross-sectional and longitudinal studies with large sample size
and prospective design of nature are also required to confirm their
utilities in different populations and their prognostic values.