Abstract P177: Effects of 1-year Lifestyle Modification Program on Cardiometabolic Risk Profile and Glucose Tolerance Status in Post Coronary Bypass Graft Patients

Abstract

Introduction: Patients with coronary artery diseases (CAD) are often characterized by impaired fasting glucose (IFG), impaired glucose tolerance (IGT) or type 2 diabetes (T2D), conditions which have also been related to high levels of visceral adipose tissue (VAT) and ectopic fat. Secondary prevention intervention involving physical activity should therefore also target VAT/ectopic fat to improve the cardiometabolic risk (CMR) profile. Objectives: The objective of the present pilot study was to compare the response of CMR variables in recent post coronary bypass graft patients with either normal glucose tolerance (NGT), IFG/IGT, and T2D to a 1-year intervention targeting the improvement of lifestyle habits. Methods: Anthropometric measurements, assessment of lipid profile, magnetic resonance imaging of the heart and the abdomen, an oral glucose tolerance test and a maximal exercise treadmill test were performed before and after the intervention (n=44). Results: No significant difference was found in baseline characteristics of the three subgroups, except that patients with IFG/IGT and T2D had significant higher levels of VAT than NGT patients. In response to the lifestyle intervention, patients with IFG/IGT and T2D improved their CMR profile with decreases in waist circumference (Δ=-5.1cm, p<0.01), abdominal visceral (Δ=-41.1ml/5mm, p<0.01) and subcutaneous adipose tissue volumes (Δ=-32.7ml/5mm, p<0.01) as well as in their intrathoracic epicardial (Δ=-3.5ml/5mm, p<0.0001) and pericardial (Δ=-7.7ml/5mm p<0.0001) adipose tissue volumes. They also improved their lipid/lipoprotein profile with decreases in apolipoproteins B (Δ=-0.02mmol/l, p<0.05), triglycerides (Δ=-0.17mmol/l, p<0.01) and total cholesterol/HDL ratio (Δ=-0.49mmol/l, p<0.0001), while HDL (Δ=+0.20mmol/l, p<0.01) and apolipoproteins A1 (Δ=+0.12mmol/l, p<0.01) increased. Cardiorespiratory fitness (CRF) was also improved as reflected by an increase in VO2peak (Δ=+5.06 mlO2/kg/min, p<0.0001) and by a reduced heart rate assessed at a standardized workload (1.7 mph, 5% slope) (Δ=-10bpm, p<0.0001). Patients with IFG/IG also improved significantly their glucose and insulin homeostasis with decreases in fasting glucose (Δ=-0.12mmol/l, p<0.05) and insulin levels (Δ=-15.53mmol/l, p<0.05), 2h-glucose (Δ=-1.50mmol/l, p<0.01) and insulin levels (Δ=-40.41mmol/l, p<0.05) and glucose area under the curve (Δ=-0.17 ρmolx10-3, p<0.01). Nine of seventeen patients with IFG/IGT normalized their glucose tolerance and two of nine patients with T2D reversed to IGT/IFG. Improvements of CMR variables were significantly correlated with changes in CRF. Conclusion: Results of this pilot study suggest that increasing CRF is a relevant target to mobilize VAT/ectopic fat in order to improve the CMR profile including plasma glucose homeostasis in CAD patients, irrespective of their glucose tolerance status.