Exercise capacity is related to attenuated responses in oxygen extraction and left ventricular longitudinal strain in asymptomatic type 2 diabetes patients

Abstract

Aims Type 2 diabetes mellitus (T2DM) is associated with reduced exercise capacity and cardiovascular diseases, both increasing morbidity and risk for premature death. As exercise intolerance often relates to cardiac dysfunction, it remains to be elucidated to what extent such an interplay occurs in T2DM patients without overt cardiovascular diseases. Design: Cross-sectional study, NCT03299790. Methods and results Fifty-three T2DM patients underwent exercise echocardiography (semi-supine bicycle) with combined ergospirometry. Cardiac output (CO), left ventricular longitudinal strain (LS), oxygen uptake (<(V)over dot>O-2), and oxygen (O-2) extraction were assessed simultaneously at rest, low-intensity exercise, and high-intensity exercise. Glycaemic control and lipid profile were assessed in the fasted state. Participants were assigned according to their exercise capacity being adequate or impaired (EXadequate: <(V)over dot>O-2peak <80% and EXimpaired: <(V)over dot> O-2peak > >= 80% of predicted <(V)over dot> O-2peak) to compare O-2 extraction, CO, and LS at all stages. Thirty-eight participants (EXimpaired: n = 20 and EXadequate: n = 18) were included in the analyses. Groups were similar regarding HbA1c, age, and sex (P > 0.05). At rest, CO was similar in the EXimpaired group vs. EXadequate group (5.1 +/- 1 L/min vs. 4.6 +/- 1.4 L/min, P > 0.05) and increased equally during exercise. EXimpaired patients displayed a 30.7% smaller increase in O-2 extraction during exercise compared to the EXadequate group (P = 0.016) which resulted in a lower O-2 extraction at high-intensity exercise (12.5 +/- 2.8 mL/dL vs. 15.3 +/- 3.9 mL/dL, P = 0.012). Left ventricular longitudinal strain was similar at rest but increased significantly less in the EXimpaired vs. EXadequate patients (1.9 +/- 2.5% vs. 5.9 +/- 4.1%, P = 0.004). Conclusions In asymptomatic T2DM patients, an impaired exercise capacity is associated with an impaired response in oxygen extraction and myocardial deformation (LS).