Physicians' Academy for Cardiovascular Education

Doppler imaging of LV diastolic function has prognostic value for CV risk

Literature - Kuznetsova T et al., J Am Heart Assoc. 2014 - J Am Heart Assoc. 2014 Apr 29;3(3):e000789

 

Prognostic value of left ventricular diastolic dysfunction in a general population

 
Kuznetsova T, Thijs L, Knez J, et al.
J Am Heart Assoc. 2014 Apr 29;3(3):e000789
 

Background

Tissue Doppler Imaging (TDI) enables measurement of myocardial velocities. Impaired myocardial relaxation, which is an early stage of left ventricular (LV) dysfunction, is characterized by decreased transmitral early (E peak), and enhanced atrial (A peak) LV filling, and less vigorous mitral annulus motion (d’) during early diastole. The E/e’ ratio reflects elevated LV filling pressure, which is another characteristic of diastolic dysfunction.
Community-based studies have revealed prevalences of up to 34.7% of LV diastolic dysfunction, when measured with comprehensive conventional and TDI echocardiographic imaging [1-4].
The prognostic role of TDI-derived indexes has been assessed in patients with cardiovascular (CV) disease. Population-based studies on the other hand are essential to determine the prognostic value of subclinical LV diastolic dysfunction. Two community-based studies evaluated the predictive value of TDI velocities [4] or LV diastolic dysfunction based on these indexes [5], but they only assessed the value for total mortality.
This study therefore used the FLEMENGHO cohort to evaluate whether Doppler diastolic indexes have prognostic value beyond traditional CV risk factors. Data of 793 white Europeans were analysed (405 women). Median follow-up time was 4.8 years (5th-95th percentile: 3.0-5.4, 3628 person-years (PY)).
 

Main results

  • 59 participants experienced a fatal or nonfatal CV endpoint (16.3 events per 1000 PY), and 40 participants had a fatal or nonfatal cardiac event (11.0 events per 1000 py).
  • After adjustment for traditional CV risk factors, TDI e’ velocity was a significant predictor of fatal and nonfatal CV (HR: 2.50, 95%CI: 1.33-4.82, P=0.004) and cardiac events (HR: 3.66, 95%CI: 1.68-7.76, P=0.001).
  • The E/e’ ratio was borderline associated with increased risk of cardiac events (HR: 1.41, 95%CI: 1.00-1.98, P=0.050), but not with CV events.
  • Three groups of LV diastolic dysfunction were defined based on mitral inflow and TDI velocities at baseline, but because the third group only represented 3.4% of the participants, whose LV filling pressure (E/e’>8.5) was increased like in the second group, group 2 and 3 were combined for the survival analysis.
    Risk of combined CV events increased with worsening of LV diastolic function: from an incidence rate of 6.9 per 1000 PY (95%CI: 3.8-10.00) in the normal group, to 53.2 per 1000 PY (95%CI: 33.5-72.9). The same trend was seen for combined cardiac events.
  • Integrated discrimination improvement (IDI) reached significance for fatal and nonfatal CV and cardiac outcomes, when TDI e’ was added to the basic model.
  • Net reclassification improvement (NRI) was seen with addition of TDI e’ to a model that already included conventional risk factors. No such improvements were seen with E/e’ ratio.
 

Conclusion

Low early diastolic mitral annulus velocity as measured by TDI is a significant predictor of fatal and nonfatal CV events in the general population, irrespective of conventional CV risk factors. Discrimination of subjects with and without events was improved in a model that included e’ velocity, as compared to a model limited to conventional risk factors. Subjects with elevated LV filling pressure, meaning moderate diastolic dysfunction, had a higher risk of combined CV and cardiac events than people with normal LV diastolic function. Thus, Doppler Imaging provides a possibility of non-invasively evaluating diastolic function and CV risk in a general population.
 
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References

1. Abhayaratna W, Marwick TH, Smith WT, et al. Characteristic of left ventricular diastolic dysfunction in the community: an echocardiographic survey. Heart. 2006;92:1259–1264.
2. Kloch-Badelek M, Kuznetsova T, Sakiewicz W, et al. Prevalences of left ventricular diastolic dysfunction in European populations based on crossvalidated diagnostic thresholds. Cardiovasc Ultrasound. 2012;10:1–9.
3. Kuznetsova T, Herbots L, L_opez B, et al. Prevalence of left ventricular diastolic dysfunction in a general population. Circ Heart Fail. 2009;2:105–112.
4. Mogelvang R, Sogaard P, Pedersen SA, et al. Cardiac dysfunction assessed by echocardiographic tissue Doppler imaging is an independent predictor of mortality in the general population. Circulation. 2009;119:2679–2685.
5. Redfield MM, Jacobsen SJ, Burnett JC Jr, et al. Burden of systolic and diastolic ventricular dysfunction in the community. Appreciating the scope of the heart failure epidemic. JAMA. 2003;289:194–202.

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