P637Impact of type 2 diabetes mellitus on cardiopulmonary exercise capacity in patients with ischemic heart disease

Abstract

Introduction: Patients with type 2 diabetes mellitus (T2DM) are predisposed to long-term complications, including ischemic heart disease (IHD). However, chronic hyperglycaemia may also directly affect the myocardial tissue, leading to ventricular stiffness and myocardial dysfunction. Besides, the lung has also been suggested to be another target organ of diabetes. Purpose: To assess the impact of T2DM on cardiopulmonary capacity in patients with IHD. Methods:We analysed 91 consecutive patients (57±10 years, 90% men) who underwent a cardiopulmonary exercise test (CPET) at the beginning of an exercisebased standard phase-II cardiac rehabilitation program within 2-3 months of an acute coronary event. All tests were performed in accordance with ATS/ACCP Statement CPET recommendations. Results: There were 24 (29%) T2DM patients. Peak O2 uptake (VO2), anaerobic threshold (AT), oxygen uptake efficiency slope (OUES) and pulse O2 trajectory were significantly lower in T2DM patients (Table). T2DM also showed a reduced end-tidal CO2 pressure (PETCO2) at AT, a steeper VE/VCO2-slope and a higher dead space to tidal volumen (VD/VT) ratio (Table). After multivariate analysis where we included age, gender, waist circumference, left ventricular ejection fraction (LVEF), Tiffeneau Index (TI) and β-blocker therapy, T2DM was an independent predictor of peak VO2 (P=0.005), VO2 at AT (P=0.041) and pulse O2 trajectory (P=0.001). T2DM was also a significant independent predictor of V-slope (P=0.046), PETCO2 at AT (P=0.037) and VD/VT ratio (P=0.049), regardless of age, gender, TI and LVEF. (Table Presented) Conclusion: IHD patients with T2DM had a reduced aerobic capacity and an impaired ventilation-perfusion mismatch compared to those without DM. T2DM may directly damage lung and cardiac structure or function, independently of the underlying atherosclerotic burden. The ability of CPET to integrate cardiac, lung and skeletal muscle function may be clinically useful to detect a functional heart or lung impairment promoted by T2DM.