SPC365

Sliding down a Slope - The Prognostic Value of Different Methods of Measuring VE/VCO2 in Heart Failure

Session: Sessão de Posters 38 - Insuficiência cardíaca avançada
Speaker: Rita Amador

Congress: CPC 2024
Topic: D. Heart Failure
Theme: 10. Chronic Heart Failure
Subtheme: 10.6 Chronic Heart Failure - Clinical
Session Type: Cartazes
FP Number: ---
Authors: Rita Amador; Joana Certo Pereira; Sérgio Maltês; Bruno Rocha; Mariana Paiva; Rita Carvalho; Miguel Mendes; Anaí Durazzo; Pedro Adragão; Gonçalo Lopes da Cunha

<p><span style="font-size:11pt"><span style="font-family:Aptos,sans-serif"><strong>Background and objetives:</strong></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Aptos,sans-serif">The Cardiopulmonary exercise testing (CPET) is the gold standard for evaluation of cardiorespiratory and metabolic function during exercise and provides strong prognostic indicators in patients with heart failure (HF), particularly the VE/VCO2 slope. However, VE/VCO2 slope measurement methods differ, producing dissimilar results and hindering comparability. There are only small studies that approached this problem and were performed in populations with low prevalence of guideline directed medical therapy (GDMT) and excluded patients who had not reached VT2. </span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Aptos,sans-serif">Thus, we aim to evaluate the prognostic power of VE/VO2 measurement methods in a broader contemporary cohort of patients with HF. </span></span></p>

<p><span style="font-size:11pt"><span style="font-family:Aptos,sans-serif"><strong>Methods: </strong></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Aptos,sans-serif">Single centre retrospective study of patients with HF with LVEF &lt; &nbsp;50% who underwent CPET between 2015-2021. VE/VCO2 was measured using 1) VE/VCO2 up to VT2 (Pre-VT2 Slope) and after VT2 (Post-VT2 Slope); 2) VE/VCO2 from rest to peak exercise (Total Slope) and 3) as fitted to a power curve (f(x) = a.x<sup>b</sup>) (Figure 1-A). </span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Aptos,sans-serif">All tests were evaluated and ventilatory thresholds determined by 3 independent, experienced operators. Our primary endpoint was a composite of CV death, urgent transplant or left ventricular assist device (LVAD) implantation and HF hospitalization. </span></span></p>

<p><span style="font-size:11pt"><span style="font-family:Aptos,sans-serif"><strong>Results: </strong></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Aptos,sans-serif">We included 247 patients (mean age 58 &plusmn; 12 years, 83% males). The HF aetiology was mostly ischemic in nature (67%), with LVEF of 34 &plusmn; 9% and median NTproBNP of 744 (244 &ndash; 2250) pg/mL. Most patients (64%) were in class NYHA I-II and with high prevalence of GDMT &nbsp;(94% ACEi/ARB; 97% beta-blockers and 64% on MRA). </span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Aptos,sans-serif">Peak VO2 was 18.4 &plusmn; 6.1 mL/Kg/min and 42% had exercise oscillatory ventilation. Mean RER in this group was 1.15 &plusmn; 0.08 and most patients (92%) attained VT2. </span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Aptos,sans-serif">The different methods of measuring resulted in a high variability between measurements. Median pre-VT2 Slope, post-VT2 Slope and Total Slope were 34.2 &plusmn; 8.6, 43.6 &plusmn; 8.6 and 41.3, respectively (p &lt; 0.001). Median (a) Slope value for the power equation was 41.4 &plusmn; 10, which was similar to Total Slope but different from other measurements. </span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Aptos,sans-serif">&nbsp;Multivariate analysis showed that all measurement methods where independent predictors of prognosis after adjusting for LVEF, NTproBNP and pVO2. ROC curve analysis for 1-year mortality showed AUC of 0.832 (0.759 &ndash; 0.905), 0.857 (0.790 &ndash; 0.924), 0.845 (0.781 &ndash; 0.909) and 0.785 (0.699 &ndash; 0.872) for Total Slope, (a) Slope value for power equation, pre and post-VT2 Slope, respectively. </span></span></p>

<p><span style="font-size:11pt"><span style="font-family:Aptos,sans-serif"><strong>Conclusions:</strong></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Aptos,sans-serif">Although all methods showed to be independent predictors of prognosis, the fitted power equation slope (a) showed a slight numerical advantage over the remaining methods in a contemporary population of HF patients.&nbsp; </span></span></p>