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.