SPC365

Heart rate corrected peak O2 pulse as a significant predictor of cardiovascular adverse events in Heart Failure patients

Session: Best Posters
Speaker: Catarina Lagoas Pohle

Congress: CPC 2024
Topic: J. Preventive Cardiology
Theme: 29. Rehabilitation and Sports Cardiology
Subtheme: 29.1 Exercise Testing
Session Type: Cartazes
FP Number: ---
Authors: Catarina Lagoas Pohle; Rita Almeida Carvalho; Joana Silva Ferreira; Rui Antunes Coelho; Jéni Quintal; Patrícia Bernardes; Anaí Durazzo; Miguel Mendes; Catarina Sá; Filipe Seixo; Gonçalo Lopes da Cunha
<p style="text-align:justify"><span style="font-size:medium"><span style="font-family:Calibri,sans-serif"><span style="color:#000000"><strong>Introduction </strong></span></span></span></p>

<p style="text-align:justify"><span style="font-size:medium"><span style="font-family:Calibri,sans-serif"><span style="color:#000000">Peak O2 pulse (O2P) is a Cardiopulmonary Exercise Testing (CPET) parameter that reflects stroke volume. It is known that patients with chronotropic incompetence have increased time for diastole and, thus, falsely increased stroke volume, which frequently leads to normal or supranormal O2P values in this patient population. Peak O2 pulse has previously demonstrated its role as a predictor of adverse cardiovascular (CV) events. However, the inability to reach the predicted maximum heart rate (HR) may underestimate the ability of this variable to predict events. </span></span></span></p>

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<p style="text-align:justify"><span style="font-size:medium"><span style="font-family:Calibri,sans-serif"><span style="color:#000000"><strong>Aim</strong></span></span></span></p>

<p style="text-align:justify"><span style="font-size:medium"><span style="font-family:Calibri,sans-serif"><span style="color:#000000">We aimed to observe in a population of patients with Heart Failure (HF) whether a correction for peak O2P to the predicted maximal heart rate (HR) percentage can be used as a predictor of major adverse CV events (MACE).</span></span></span></p>

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<p style="text-align:justify"><span style="font-size:medium"><span style="font-family:Calibri,sans-serif"><span style="color:#000000"><strong>Methods</strong></span></span></span></p>

<p style="text-align:justify"><span style="font-size:medium"><span style="font-family:Calibri,sans-serif"><span style="color:#000000">A retrospective observational study was conducted with a sample of HF patients with ejection fraction &lt;50% who underwent CPET on a treadmill. Peak O2 pulse and maximal HR were collected, predicted O2 pulse was calculated from Wasserman&rsquo;s equation for predicted maximal oxygen uptake and predicted HR was calculated from Astrand&rsquo;s formula. The corrected O2P was obtained by dividing the measured peak OP2 by the percentage of the predicted maximal HR for age attained (Figure 1-A). Cox regression analysis was performed to assess possible associations with the intended outcomes (CV death, urgent heart transplantation, left ventricular assist device and HF hospitalization).</span></span></span></p>

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<p style="text-align:justify"><span style="font-size:medium"><span style="font-family:Calibri,sans-serif"><span style="color:#000000"><strong>Results</strong></span></span></span></p>

<p style="text-align:justify"><span style="font-size:medium"><span style="font-family:Calibri,sans-serif"><span style="color:#000000">A total of 248 patients with HF were included (17.3% were women), with a mean age of 58.3 &plusmn; 11.4 years. The etiology of HF was ischemic in 66.5% of patients, with a mean ejection fraction of 34&plusmn; 10% and a median NT-proBNP value of 744 micrograms/dL (IQR 241 to 2255). The median peak O2P value measured was 11.5 mL/beat (IQR 9.0 to 14.2), which corresponds to 87.1% (IQR 69.4 to 105.6) of the predicted O2P. The mean corrected O2P was 8.7 &plusmn; 3.2 mL/beat, corresponding to 64.8 &plusmn; 21% of the predicted O2P.</span></span></span></p>

<p style="text-align:justify"><span style="font-size:medium"><span style="font-family:Calibri,sans-serif"><span style="color:#000000">In univariate analysis for the primary endpoint, the Wald Chi square value was greater for the percentual corrected O2P (Wald 90.414, p&nbsp;&lt; 0.001), followed by the corrected O2P (Wald 68.922, p&nbsp;&lt; 0.001), percentual measured O2P (Wald 44.176, p &lt; 0.001) and measured peak O2P (Wald 1.827, p = 0.176) (Figure 1-B). </span></span></span></p>

<p style="text-align:justify"><span style="font-size:medium"><span style="font-family:Calibri,sans-serif"><span style="color:#000000">Percentual corrected O2P remained significantly associated with the primary endpoint (HR 0.970 [95% CI&nbsp;0.955 to 0.985; p&nbsp;&lt; 0.001] even when adjusted for NT-proBNP, VE/VCO2 slope and Peak oxygen uptake (pVO2). Furthermore, percentual corrected O2P was the strongest parameter in multivariate analysis, outperforming even VE/VCO2 slope and pVO2 for the prediction of events (Figure 1-B).</span></span></span></p>

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<p style="text-align:justify"><span style="font-size:medium"><span style="font-family:Calibri,sans-serif"><span style="color:#000000"><strong>Conclusion</strong></span></span></span></p>

<p style="text-align:justify"><span style="font-size:medium"><span style="font-family:Calibri,sans-serif"><span style="color:#000000">This study suggests that corrected O2P and percentual corrected O2P could be used as strong MACEs predictors. Additionally, percentual corrected O2P showed an even greater ability to predict adverse outcomes in HF patients than NT-proBNP, VE/VCO2 slope and pVO2.</span></span></span></p>