Anaerobic threshold diastolic function as a novel prognostic marker in older HFpEF patients without requiring peak stress

Background

Simultaneous cardiopulmonary exercise testing and stress echocardiography (CPET-SE) non-invasively assesses cardiac function and metabolism, but its prognostic value in older adults with HFpEF remains unclear. Left ventricular diastolic function, measured by tissue Doppler e’, predicts cardiac events and peaks near the anaerobic threshold (AT), when metabolism shifts to anaerobic. Since older patients may be hard to reach peak stress, we hypothesized that e’ immediately after AT (e’AT) could serve as a practical marker of maximal diastolic function and predict HF worsening.

Purpose

To evaluate whether e’AT obtained during CPET-SE predicts worsening HF in older adults.

Methods

We enrolled 58 consecutive HFpEF patients aged ≥65 years hospitalized at the hospital (2020–2022). All received guideline-directed HF therapy. Worsening HF was defined as hospitalization, unplanned diuretic therapy, or intensified cardioprotective therapy. Cardiac events included worsening HF or cardiovascular death. Frailty was assessed using the Clinical Frailty Scale. Serum biomarkers including hemoglobin, albumin, aspartate aminotransferase, creatinine, and BNP were measured.

CPET-SE was performed on recumbent cycle ergometers with breath-by-breath gas analysis. AT was determined using VE/VO2, VCO2/VO2, end-tidal gas trends, and V-slope method. Echocardiography measured EF, E/A, E/e’, left ventricular outflow tract velocity-time integral, cardiac output, left ventricular mass index, left atrial volume index, tricuspid regurgitant pressure, and e’ from septal/lateral annuli. e’AT and related indices were recorded immediately after AT.

Results

During 1-year follow-up, 11 patients (19%) experienced cardiac events. There were no significant differences between the two groups in age, sex, or EF, while there was a significant difference in e’AT. ROC analysis showed that an e'AT<5.8 cm/s was the optimal cutoff for predicting the occurrence of cardiac events. The area under the ROC curve was 0.83. The sensitivity and specificity of e'AT <5.8 cm/s were 0.73 and 0.85, respectively.

Conclusions

Assessment of anaerobic threshold diastolic function via e’AT during CPET-SE predicts 1-year outcomes in older adults with HFpEF and may serve as a novel prognostic marker, without requiring peak stress.ESC Abstract