Multiparameter assessment of exercise capacity in patients with arterial hypertension

Introduction: Arterial hypertension (AH) can lead to the development of heart failure. Aim: Evaluating the relationship between parameters of exercise capacity assessed via a six-minute walk test (6MWT) and cardiopulmonary exercise test (CPET), with a hemodynamic assessment via impedance cardiography (ICG), in patients with AH. Methods: Exercise capacity was assessed in 98 hypertensive patients (54.5 ± 8.2 years) by means of oxygen uptake (VO₂) get from CPET, 6MWT distance (6MWTd) and hemodynamic parameters measured by ICG: heart rate (HR), stroke volume (SV), cardiac output (CO). Correlations between these parameters at rest, at anaerobic threshold (AT) and at peak of exercise as well as their changes (Δpeak-rest, Δpeak-AT, ΔAT-rest) were evaulated. Results: A large proportion of patients exhibited reduced exercise capacity, with 45.9% not reaching 80% of predicted peak VO₂ and 43.9% not reaching predicted 6MWTd. Clinically relevant correlations were noted between the absolute peak values and AT values of VO₂ vs HR and VO₂ vs CO. Furthermore ΔVO₂(peak-AT) correlated with ΔHR(peak-AT), ΔCO(peak-AT) and ΔSV(peak-AT); ΔVO₂(peak-rest) with ΔHR(peak-rest) and ΔCO(peak-rest); ΔVO₂(AT-rest) with ΔHR(AT-rest) and ΔCO(AT-rest). Stronger correlations between changes in the evaluated parameters were demonstrated in the subgroup of subjects with peak VO₂ < 80% of the predicted value; particularly ΔVO₂(peak-AT) correlated with ΔSV(peak-AT) and ΔCO(peak-AT). Conclusions: The hemodynamic parameters show significant correlations with more measures of cardiovascular capacity of proven clinical utility. Impedance cardiography is a reliable method for assessing the cardiovascular response to exercise.