Risk Stratification: Exercise Testing, Imaging, and Cardiac Catheterization

Abstract Background Cardiopulmonary exercise testing (CPET) is recommended in the evaluation of selected patients with Heart Failure (HF). Notwithstanding, its prognostic significance has mainly been ascertained in those with left ventricular ejection fraction (LVEF) <40% (i.e., HFrEF). The main goal of our study was to assess the role of CPET in risk stratification of HF with mid-range (40–49%) LVEF (i.e., HFmrEF) compared to HFrEF. Methods We conducted a single-center retrospective study of consecutive patients with HF and LVEF <50% who underwent CPET from 2003–2018. The primary composite endpoint of death, heart transplant or HF hospitalization was assessed. Results Overall, 404 HF patients (mean age 57±11 years, 78.2% male, 55.4% ischemic HF) were included, of whom 321 (79.5%) had HFrEF and 83 (20.5%) HFmrEF. Compared to the former, those with HFmrEF had a significantly higher mean peak oxygen uptake (pVO2) (20.2±6.1 vs 16.1±5.0 mL/kg/min; p<0.001), lower median minute ventilation/carbon dioxide production (VE/VCO2) [35.0 (IQR: 29.1–41.2) vs 39.0 (IQR: 32.0–47.0); p=0.002) and fewer patients with exercise oscillatory ventilation (EOV) (22.0 vs 46.3%; p<0.001). Over a median follow-up of 28.7 (IQR: 13.0–92.3) months, 117 (28.9%) patients died, 53 (13.1%) underwent heart transplantation, and 134 (33.2%) had at least one HF hospitalization. In both HFmrEF and HFrEF, pVO2 <12 mL/kg/min, VE/VCO2 >35 and EOV identified patients at higher risk for events (all p<0.05). In Cox regression multivariate analysis, pVO2 was predictive of the primary endpoint in both HFmrEF and HFrEF (HR per +1 mL/kg/min: 0.81; CI: 0.72–0.92; p=0.001; and HR per +1 mL/kg/min: 0.92; CI: 0.87–0.97; p=0.004), as was EOV (HR: 4.79; CI: 1.41–16.39; p=0.012; and HR: 2.15; CI: 1.51–3.07; p<0.001). VE/VCO2, on the other hand, was predictive of events in HFrEF but not in HFmrEF (HR per unit: 1.03; CI: 1.02–1.05; p<0.001; and HR per unit: 0.99; CI: 0.95–1.03; p=0.512, respectively). ROC curve analysis demonstrated that a pVO2 >16.7 and >15.8 mL/kg/min more accurately identified patients at lower risk for the primary endpoint (NPV: 91.2 and 60.5% for HFmrEF and HFrEF, respectively; both p<0.001). Conclusions CPET is a useful tool in HFmrEF. Both pVO2 and EOV independently predicted the primary endpoint in HFmrEF and HFrEF, contrasting with VE/VCO2, which remained predictive only in latter group. Our findings strengthen the prognostic role of CPET in HF with either reduced or mid-range LVEF. Funding Acknowledgement Type of funding source: None

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The role of cardiopulmonary exercise testing in a contemporary heart failure population

European Journal of Preventive Cardiology ◽

10.1093/eurjpc/zwab061.015 ◽

2021 ◽

Vol 28 (Supplement_1) ◽

Author(s):

P Garcia Bras ◽

A Valentim Goncalves ◽

J Reis ◽

T Pereira Da Silva ◽

R Ilhao Moreira ◽

...

Keyword(s):

Heart Failure ◽

Risk Stratification ◽

Exercise Testing ◽

Predictive Power ◽

Cardiopulmonary Exercise Testing ◽

Composite Endpoint ◽

Left Ventricular ◽

Left Ventricular Ejection ◽

Discriminative Power ◽

Cardiopulmonary Exercise

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Cardiopulmonary exercise testing (CPET) is used for risk stratification in patients with chronic heart failure (CHF). However, there is a lack of information regarding CPET prognostic power in patients under new HF therapies such as sacubitril/valsartan, Mitraclip, IV iron or SGLT2 inhibitors. The aim of this study was to evaluate the prognostic value of CPET parameters in a contemporary subset of patients with optimal medical and device therapy for CHF. Methods Retrospective evaluation of patients with CHF submitted to CPET in a tertiary center. Patients were followed up for 24 months for the composite endpoint of cardiac death, urgent heart transplantation or left ventricular assist device. CPET parameters, including peak oxygen consumption (pVO2) and VE/VCO2 slope, were analysed and their predictive power was measured. HF events were stratified according to cut-off values defined by the International Society for Heart and Lung Transplantation (ISHLT) guidelines: pVO2 of ≤12 mL/Kg/min and VE/VCO2 slope of >35. Results CPET was performed in 204 patients, from 2014 to 2018. Mean age was 59 ± 13 years, 83% male, with a mean left ventricular ejection fraction of 33 ± 8%, and a mean Heart Failure Survival Score of 8.6 ± 1.3. The discriminative power of CPET parameters is displayed in the Table. In patients with pVO2 ≤12 mL/Kg/min, the composite endpoint occurred in 18% of patients. A pVO2 value of ≤12 mL/Kg/min had a positive predictive power of 18% while pVO2 >12 had a negative predictive power of 93%. Regarding VE/VCO2 slope >35, the composite endpoint occurred in 13% of patients. A VE/VCO2 slope value of >35 had a positive predictive power of 13% while VE/VCO2 slope <35 had a negative predictive power or 94%. Conclusion Using ISHLT guideline cut-off values for advanced HF therapies patient selection, there was a reduced number of HF events (<20%) at 24 months in patients under optimal CHF therapy. While pVO2 and VE/VCO2 slope are still valuable parameters in risk stratification, redefining cut-off values may be necessary in a modern HF population. Discriminative power of CPET parameters Parameters HR; 95% CI AUC p-value Peak VO2 0.824 (0.728-0.934) 0.781 0.001 Percent of predicted pVO2 0.942 (0.907-0.978) 0.774 0.002 VE/VCO2 slope 1.068 (1.031-1.106) 0.756 0.008 Cardiorespiratory optimal point 1.118 (1.053-1.188) 0.746 0.004 PETCO2 maximum exercise 0.854 (0.768-0.950) 0.775 0.003 Ventilatory Power 0.358 (0.176-0.728) 0.796 0.002 HR Hazard ratio, AUC: Area under the curve, PETCO2: end-tidal CO2 pressure

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