Multiparameter assessment of exercise capacity in patients with arterial hypertension

Abstract

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.

Keywords

• hypertension
• exercise capacity
• cardiopulmonary exercise test
• six minute walk test
• impedance cardiography